/**

 * meshoptimizer - version 0.25

 *

 * Copyright (C) 2016-2025, by Arseny Kapoulkine (arseny.kapoulkine@gmail.com)

 * Report bugs and download new versions at https://github.com/zeux/meshoptimizer

 *

 * This library is distributed under the MIT License. See notice at the end of this file.

 */

#pragma once

#include <assert.h>

#include <stddef.h>

/* Version macro; major * 1000 + minor * 10 + patch */

#define MESHOPTIMIZER_VERSION 250 /* 0.25 */

/* If no API is defined, assume default */

#ifndef MESHOPTIMIZER_API

#define MESHOPTIMIZER_API

#endif

/* Set the calling-convention for alloc/dealloc function pointers */

#ifndef MESHOPTIMIZER_ALLOC_CALLCONV

#ifdef _MSC_VER

#define MESHOPTIMIZER_ALLOC_CALLCONV __cdecl

#else

#define MESHOPTIMIZER_ALLOC_CALLCONV

#endif

#endif

/* Experimental APIs have unstable interface and might have implementation that's not fully tested or optimized */

#ifndef MESHOPTIMIZER_EXPERIMENTAL

#define MESHOPTIMIZER_EXPERIMENTAL MESHOPTIMIZER_API

#endif

/* C interface */

#ifdef __cplusplus

extern "C"

{

#endif

/**

 * Vertex attribute stream

 * Each element takes size bytes, beginning at data, with stride controlling the spacing between successive elements (stride >= size).

 */

struct meshopt_Stream

{

  const void* data;

  size_t size;

  size_t stride;

};

/**

 * Generates a vertex remap table from the vertex buffer and an optional index buffer and returns number of unique vertices

 * As a result, all vertices that are binary equivalent map to the same (new) location, with no gaps in the resulting sequence.

 * Resulting remap table maps old vertices to new vertices and can be used in meshopt_remapVertexBuffer/meshopt_remapIndexBuffer.

 * Note that binary equivalence considers all vertex_size bytes, including padding which should be zero-initialized.

 *

 * destination must contain enough space for the resulting remap table (vertex_count elements)

 * indices can be NULL if the input is unindexed

 */

MESHOPTIMIZER_API size_t meshopt_generateVertexRemap(unsigned int* destination, const unsigned int* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size);

/**

 * Generates a vertex remap table from multiple vertex streams and an optional index buffer and returns number of unique vertices

 * As a result, all vertices that are binary equivalent map to the same (new) location, with no gaps in the resulting sequence.

 * Resulting remap table maps old vertices to new vertices and can be used in meshopt_remapVertexBuffer/meshopt_remapIndexBuffer.

 * To remap vertex buffers, you will need to call meshopt_remapVertexBuffer for each vertex stream.

 * Note that binary equivalence considers all size bytes in each stream, including padding which should be zero-initialized.

 *

 * destination must contain enough space for the resulting remap table (vertex_count elements)

 * indices can be NULL if the input is unindexed

 * stream_count must be <= 16

 */

MESHOPTIMIZER_API size_t meshopt_generateVertexRemapMulti(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count, const struct meshopt_Stream* streams, size_t stream_count);

/**

 * Generates a vertex remap table from the vertex buffer and an optional index buffer and returns number of unique vertices

 * As a result, all vertices that are equivalent map to the same (new) location, with no gaps in the resulting sequence.

 * Equivalence is checked in two steps: vertex positions are compared for equality, and then the user-specified equality function is called (if provided).

 * Resulting remap table maps old vertices to new vertices and can be used in meshopt_remapVertexBuffer/meshopt_remapIndexBuffer.

 *

 * destination must contain enough space for the resulting remap table (vertex_count elements)

 * indices can be NULL if the input is unindexed

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * callback can be NULL if no additional equality check is needed; otherwise, it should return 1 if vertices with specified indices are equivalent and 0 if they are not

 */

MESHOPTIMIZER_API size_t meshopt_generateVertexRemapCustom(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, int (*callback)(void*, unsigned int, unsigned int), void* context);

/**

 * Generates vertex buffer from the source vertex buffer and remap table generated by meshopt_generateVertexRemap

 *

 * destination must contain enough space for the resulting vertex buffer (unique_vertex_count elements, returned by meshopt_generateVertexRemap)

 * vertex_count should be the initial vertex count and not the value returned by meshopt_generateVertexRemap

 */

MESHOPTIMIZER_API void meshopt_remapVertexBuffer(void* destination, const void* vertices, size_t vertex_count, size_t vertex_size, const unsigned int* remap);

/**

 * Generate index buffer from the source index buffer and remap table generated by meshopt_generateVertexRemap

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 * indices can be NULL if the input is unindexed

 */

MESHOPTIMIZER_API void meshopt_remapIndexBuffer(unsigned int* destination, const unsigned int* indices, size_t index_count, const unsigned int* remap);

/**

 * Generate index buffer that can be used for more efficient rendering when only a subset of the vertex attributes is necessary

 * All vertices that are binary equivalent (wrt first vertex_size bytes) map to the first vertex in the original vertex buffer.

 * This makes it possible to use the index buffer for Z pre-pass or shadowmap rendering, while using the original index buffer for regular rendering.

 * Note that binary equivalence considers all vertex_size bytes, including padding which should be zero-initialized.

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 */

MESHOPTIMIZER_API void meshopt_generateShadowIndexBuffer(unsigned int* destination, const unsigned int* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size, size_t vertex_stride);

/**

 * Generate index buffer that can be used for more efficient rendering when only a subset of the vertex attributes is necessary

 * All vertices that are binary equivalent (wrt specified streams) map to the first vertex in the original vertex buffer.

 * This makes it possible to use the index buffer for Z pre-pass or shadowmap rendering, while using the original index buffer for regular rendering.

 * Note that binary equivalence considers all size bytes in each stream, including padding which should be zero-initialized.

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 * stream_count must be <= 16

 */

MESHOPTIMIZER_API void meshopt_generateShadowIndexBufferMulti(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count, const struct meshopt_Stream* streams, size_t stream_count);

/**

 * Experimental: Generates a remap table that maps all vertices with the same position to the same (existing) index.

 * Similarly to meshopt_generateShadowIndexBuffer, this can be helpful to pre-process meshes for position-only rendering.

 * This can also be used to implement algorithms that require positional-only connectivity, such as hierarchical simplification.

 *

 * destination must contain enough space for the resulting remap table (vertex_count elements)

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 */

MESHOPTIMIZER_EXPERIMENTAL void meshopt_generatePositionRemap(unsigned int* destination, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

/**

 * Generate index buffer that can be used as a geometry shader input with triangle adjacency topology

 * Each triangle is converted into a 6-vertex patch with the following layout:

 * - 0, 2, 4: original triangle vertices

 * - 1, 3, 5: vertices adjacent to edges 02, 24 and 40

 * The resulting patch can be rendered with geometry shaders using e.g. VK_PRIMITIVE_TOPOLOGY_TRIANGLE_LIST_WITH_ADJACENCY.

 * This can be used to implement algorithms like silhouette detection/expansion and other forms of GS-driven rendering.

 *

 * destination must contain enough space for the resulting index buffer (index_count*2 elements)

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 */

MESHOPTIMIZER_API void meshopt_generateAdjacencyIndexBuffer(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

/**

 * Generate index buffer that can be used for PN-AEN tessellation with crack-free displacement

 * Each triangle is converted into a 12-vertex patch with the following layout:

 * - 0, 1, 2: original triangle vertices

 * - 3, 4: opposing edge for edge 0, 1

 * - 5, 6: opposing edge for edge 1, 2

 * - 7, 8: opposing edge for edge 2, 0

 * - 9, 10, 11: dominant vertices for corners 0, 1, 2

 * The resulting patch can be rendered with hardware tessellation using PN-AEN and displacement mapping.

 * See "Tessellation on Any Budget" (John McDonald, GDC 2011) for implementation details.

 *

 * destination must contain enough space for the resulting index buffer (index_count*4 elements)

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 */

MESHOPTIMIZER_API void meshopt_generateTessellationIndexBuffer(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

/**

 * Generate index buffer that can be used for visibility buffer rendering and returns the size of the reorder table

 * Each triangle's provoking vertex index is equal to primitive id; this allows passing it to the fragment shader using flat/nointerpolation attribute.

 * This is important for performance on hardware where primitive id can't be accessed efficiently in fragment shader.

 * The reorder table stores the original vertex id for each vertex in the new index buffer, and should be used in the vertex shader to load vertex data.

 * The provoking vertex is assumed to be the first vertex in the triangle; if this is not the case (OpenGL), rotate each triangle (abc -> bca) before rendering.

 * For maximum efficiency the input index buffer should be optimized for vertex cache first.

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 * reorder must contain enough space for the worst case reorder table (vertex_count + index_count/3 elements)

 */

MESHOPTIMIZER_API size_t meshopt_generateProvokingIndexBuffer(unsigned int* destination, unsigned int* reorder, const unsigned int* indices, size_t index_count, size_t vertex_count);

/**

 * Vertex transform cache optimizer

 * Reorders indices to reduce the number of GPU vertex shader invocations

 * If index buffer contains multiple ranges for multiple draw calls, this functions needs to be called on each range individually.

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 */

MESHOPTIMIZER_API void meshopt_optimizeVertexCache(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count);

/**

 * Vertex transform cache optimizer for strip-like caches

 * Produces inferior results to meshopt_optimizeVertexCache from the GPU vertex cache perspective

 * However, the resulting index order is more optimal if the goal is to reduce the triangle strip length or improve compression efficiency

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 */

MESHOPTIMIZER_API void meshopt_optimizeVertexCacheStrip(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count);

/**

 * Vertex transform cache optimizer for FIFO caches

 * Reorders indices to reduce the number of GPU vertex shader invocations

 * Generally takes ~3x less time to optimize meshes but produces inferior results compared to meshopt_optimizeVertexCache

 * If index buffer contains multiple ranges for multiple draw calls, this functions needs to be called on each range individually.

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 * cache_size should be less than the actual GPU cache size to avoid cache thrashing

 */

MESHOPTIMIZER_API void meshopt_optimizeVertexCacheFifo(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count, unsigned int cache_size);

/**

 * Overdraw optimizer

 * Reorders indices to reduce the number of GPU vertex shader invocations and the pixel overdraw

 * If index buffer contains multiple ranges for multiple draw calls, this functions needs to be called on each range individually.

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 * indices must contain index data that is the result of meshopt_optimizeVertexCache (*not* the original mesh indices!)

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * threshold indicates how much the overdraw optimizer can degrade vertex cache efficiency (1.05 = up to 5%) to reduce overdraw more efficiently

 */

MESHOPTIMIZER_API void meshopt_optimizeOverdraw(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, float threshold);

/**

 * Vertex fetch cache optimizer

 * Reorders vertices and changes indices to reduce the amount of GPU memory fetches during vertex processing

 * Returns the number of unique vertices, which is the same as input vertex count unless some vertices are unused

 * This functions works for a single vertex stream; for multiple vertex streams, use meshopt_optimizeVertexFetchRemap + meshopt_remapVertexBuffer for each stream.

 *

 * destination must contain enough space for the resulting vertex buffer (vertex_count elements)

 * indices is used both as an input and as an output index buffer

 */

MESHOPTIMIZER_API size_t meshopt_optimizeVertexFetch(void* destination, unsigned int* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size);

/**

 * Vertex fetch cache optimizer

 * Generates vertex remap to reduce the amount of GPU memory fetches during vertex processing

 * Returns the number of unique vertices, which is the same as input vertex count unless some vertices are unused

 * The resulting remap table should be used to reorder vertex/index buffers using meshopt_remapVertexBuffer/meshopt_remapIndexBuffer

 *

 * destination must contain enough space for the resulting remap table (vertex_count elements)

 */

MESHOPTIMIZER_API size_t meshopt_optimizeVertexFetchRemap(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count);

/**

 * Index buffer encoder

 * Encodes index data into an array of bytes that is generally much smaller (<1.5 bytes/triangle) and compresses better (<1 bytes/triangle) compared to original.

 * Input index buffer must represent a triangle list.

 * Returns encoded data size on success, 0 on error; the only error condition is if buffer doesn't have enough space

 * For maximum efficiency the index buffer being encoded has to be optimized for vertex cache and vertex fetch first.

 *

 * buffer must contain enough space for the encoded index buffer (use meshopt_encodeIndexBufferBound to compute worst case size)

 */

MESHOPTIMIZER_API size_t meshopt_encodeIndexBuffer(unsigned char* buffer, size_t buffer_size, const unsigned int* indices, size_t index_count);

MESHOPTIMIZER_API size_t meshopt_encodeIndexBufferBound(size_t index_count, size_t vertex_count);

/**

 * Set index encoder format version

 * version must specify the data format version to encode; valid values are 0 (decodable by all library versions) and 1 (decodable by 0.14+)

 */

MESHOPTIMIZER_API void meshopt_encodeIndexVersion(int version);

/**

 * Index buffer decoder

 * Decodes index data from an array of bytes generated by meshopt_encodeIndexBuffer

 * Returns 0 if decoding was successful, and an error code otherwise

 * The decoder is safe to use for untrusted input, but it may produce garbage data (e.g. out of range indices).

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 */

MESHOPTIMIZER_API int meshopt_decodeIndexBuffer(void* destination, size_t index_count, size_t index_size, const unsigned char* buffer, size_t buffer_size);

/**

 * Get encoded index format version

 * Returns format version of the encoded index buffer/sequence, or -1 if the buffer header is invalid

 * Note that a non-negative value doesn't guarantee that the buffer will be decoded correctly if the input is malformed.

 */

MESHOPTIMIZER_API int meshopt_decodeIndexVersion(const unsigned char* buffer, size_t buffer_size);

/**

 * Index sequence encoder

 * Encodes index sequence into an array of bytes that is generally smaller and compresses better compared to original.

 * Input index sequence can represent arbitrary topology; for triangle lists meshopt_encodeIndexBuffer is likely to be better.

 * Returns encoded data size on success, 0 on error; the only error condition is if buffer doesn't have enough space

 *

 * buffer must contain enough space for the encoded index sequence (use meshopt_encodeIndexSequenceBound to compute worst case size)

 */

MESHOPTIMIZER_API size_t meshopt_encodeIndexSequence(unsigned char* buffer, size_t buffer_size, const unsigned int* indices, size_t index_count);

MESHOPTIMIZER_API size_t meshopt_encodeIndexSequenceBound(size_t index_count, size_t vertex_count);

/**

 * Index sequence decoder

 * Decodes index data from an array of bytes generated by meshopt_encodeIndexSequence

 * Returns 0 if decoding was successful, and an error code otherwise

 * The decoder is safe to use for untrusted input, but it may produce garbage data (e.g. out of range indices).

 *

 * destination must contain enough space for the resulting index sequence (index_count elements)

 */

MESHOPTIMIZER_API int meshopt_decodeIndexSequence(void* destination, size_t index_count, size_t index_size, const unsigned char* buffer, size_t buffer_size);

/**

 * Vertex buffer encoder

 * Encodes vertex data into an array of bytes that is generally smaller and compresses better compared to original.

 * Returns encoded data size on success, 0 on error; the only error condition is if buffer doesn't have enough space

 * This function works for a single vertex stream; for multiple vertex streams, call meshopt_encodeVertexBuffer for each stream.

 * Note that all vertex_size bytes of each vertex are encoded verbatim, including padding which should be zero-initialized.

 * For maximum efficiency the vertex buffer being encoded has to be quantized and optimized for locality of reference (cache/fetch) first.

 *

 * buffer must contain enough space for the encoded vertex buffer (use meshopt_encodeVertexBufferBound to compute worst case size)

 */

MESHOPTIMIZER_API size_t meshopt_encodeVertexBuffer(unsigned char* buffer, size_t buffer_size, const void* vertices, size_t vertex_count, size_t vertex_size);

MESHOPTIMIZER_API size_t meshopt_encodeVertexBufferBound(size_t vertex_count, size_t vertex_size);

/**

 * Vertex buffer encoder

 * Encodes vertex data just like meshopt_encodeVertexBuffer, but allows to override compression level.

 * For compression level to take effect, the vertex encoding version must be set to 1.

 * The default compression level implied by meshopt_encodeVertexBuffer is 2.

 *

 * level should be in the range [0, 3] with 0 being the fastest and 3 being the slowest and producing the best compression ratio.

 * version should be -1 to use the default version (specified via meshopt_encodeVertexVersion), or 0/1 to override the version; per above, level won't take effect if version is 0.

 */

MESHOPTIMIZER_API size_t meshopt_encodeVertexBufferLevel(unsigned char* buffer, size_t buffer_size, const void* vertices, size_t vertex_count, size_t vertex_size, int level, int version);

/**

 * Set vertex encoder format version

 * version must specify the data format version to encode; valid values are 0 (decodable by all library versions) and 1 (decodable by 0.23+)

 */

MESHOPTIMIZER_API void meshopt_encodeVertexVersion(int version);

/**

 * Vertex buffer decoder

 * Decodes vertex data from an array of bytes generated by meshopt_encodeVertexBuffer

 * Returns 0 if decoding was successful, and an error code otherwise

 * The decoder is safe to use for untrusted input, but it may produce garbage data.

 *

 * destination must contain enough space for the resulting vertex buffer (vertex_count * vertex_size bytes)

 */

MESHOPTIMIZER_API int meshopt_decodeVertexBuffer(void* destination, size_t vertex_count, size_t vertex_size, const unsigned char* buffer, size_t buffer_size);

/**

 * Get encoded vertex format version

 * Returns format version of the encoded vertex buffer, or -1 if the buffer header is invalid

 * Note that a non-negative value doesn't guarantee that the buffer will be decoded correctly if the input is malformed.

 */

MESHOPTIMIZER_API int meshopt_decodeVertexVersion(const unsigned char* buffer, size_t buffer_size);

/**

 * Vertex buffer filters

 * These functions can be used to filter output of meshopt_decodeVertexBuffer in-place.

 *

 * meshopt_decodeFilterOct decodes octahedral encoding of a unit vector with K-bit (K <= 16) signed X/Y as an input; Z must store 1.0f.

 * Each component is stored as an 8-bit or 16-bit normalized integer; stride must be equal to 4 or 8. W is preserved as is.

 *

 * meshopt_decodeFilterQuat decodes 3-component quaternion encoding with K-bit (4 <= K <= 16) component encoding and a 2-bit component index indicating which component to reconstruct.

 * Each component is stored as an 16-bit integer; stride must be equal to 8.

 *

 * meshopt_decodeFilterExp decodes exponential encoding of floating-point data with 8-bit exponent and 24-bit integer mantissa as 2^E*M.

 * Each 32-bit component is decoded in isolation; stride must be divisible by 4.

 *

 * Experimental: meshopt_decodeFilterColor decodes YCoCg (+A) color encoding where RGB is converted to YCoCg space with variable bit quantization.

 * Each component is stored as an 8-bit or 16-bit normalized integer; stride must be equal to 4 or 8.

 */

MESHOPTIMIZER_API void meshopt_decodeFilterOct(void* buffer, size_t count, size_t stride);

MESHOPTIMIZER_API void meshopt_decodeFilterQuat(void* buffer, size_t count, size_t stride);

MESHOPTIMIZER_API void meshopt_decodeFilterExp(void* buffer, size_t count, size_t stride);

MESHOPTIMIZER_EXPERIMENTAL void meshopt_decodeFilterColor(void* buffer, size_t count, size_t stride);

/**

 * Vertex buffer filter encoders

 * These functions can be used to encode data in a format that meshopt_decodeFilter can decode

 *

 * meshopt_encodeFilterOct encodes unit vectors with K-bit (K <= 16) signed X/Y as an output.

 * Each component is stored as an 8-bit or 16-bit normalized integer; stride must be equal to 4 or 8. W is preserved as is.

 * Input data must contain 4 floats for every vector (count*4 total).

 *

 * meshopt_encodeFilterQuat encodes unit quaternions with K-bit (4 <= K <= 16) component encoding.

 * Each component is stored as an 16-bit integer; stride must be equal to 8.

 * Input data must contain 4 floats for every quaternion (count*4 total).

 *

 * meshopt_encodeFilterExp encodes arbitrary (finite) floating-point data with 8-bit exponent and K-bit integer mantissa (1 <= K <= 24).

 * Exponent can be shared between all components of a given vector as defined by stride or all values of a given component; stride must be divisible by 4.

 * Input data must contain stride/4 floats for every vector (count*stride/4 total).

 *

 * Experimental: meshopt_encodeFilterColor encodes RGBA color data by converting RGB to YCoCg color space with variable bit quantization.

 * Each component is stored as an 8-bit or 16-bit integer; stride must be equal to 4 or 8.

 * Input data must contain 4 floats for every color (count*4 total).

 */

enum meshopt_EncodeExpMode

{

  /* When encoding exponents, use separate values for each component (maximum quality) */

  meshopt_EncodeExpSeparate,

  /* When encoding exponents, use shared value for all components of each vector (better compression) */

  meshopt_EncodeExpSharedVector,

  /* When encoding exponents, use shared value for each component of all vectors (best compression) */

  meshopt_EncodeExpSharedComponent,

  /* When encoding exponents, use separate values for each component, but clamp to 0 (good quality if very small values are not important) */

  meshopt_EncodeExpClamped,

};

MESHOPTIMIZER_API void meshopt_encodeFilterOct(void* destination, size_t count, size_t stride, int bits, const float* data);

MESHOPTIMIZER_API void meshopt_encodeFilterQuat(void* destination, size_t count, size_t stride, int bits, const float* data);

MESHOPTIMIZER_API void meshopt_encodeFilterExp(void* destination, size_t count, size_t stride, int bits, const float* data, enum meshopt_EncodeExpMode mode);

MESHOPTIMIZER_EXPERIMENTAL void meshopt_encodeFilterColor(void* destination, size_t count, size_t stride, int bits, const float* data);

/**

 * Simplification options

 */

enum

{

  /* Do not move vertices that are located on the topological border (vertices on triangle edges that don't have a paired triangle). Useful for simplifying portions of the larger mesh. */

  meshopt_SimplifyLockBorder = 1 << 0,

  /* Improve simplification performance assuming input indices are a sparse subset of the mesh. Note that error becomes relative to subset extents. */

  meshopt_SimplifySparse = 1 << 1,

  /* Treat error limit and resulting error as absolute instead of relative to mesh extents. */

  meshopt_SimplifyErrorAbsolute = 1 << 2,

  /* Remove disconnected parts of the mesh during simplification incrementally, regardless of the topological restrictions inside components. */

  meshopt_SimplifyPrune = 1 << 3,

  /* Experimental: Produce more regular triangle sizes and shapes during simplification, at some cost to geometric quality. */

  meshopt_SimplifyRegularize = 1 << 4,

  /* Experimental: Allow collapses across attribute discontinuities, except for vertices that are tagged with meshopt_SimplifyVertex_Protect in vertex_lock. */

  meshopt_SimplifyPermissive = 1 << 5,

};

/**

 * Experimental: Simplification vertex flags/locks, for use in `vertex_lock` arrays in simplification APIs

 */

enum

{

  /* Do not move this vertex. */

  meshopt_SimplifyVertex_Lock = 1 << 0,

  /* Protect attribute discontinuity at this vertex; must be used together with meshopt_SimplifyPermissive option. */

  meshopt_SimplifyVertex_Protect = 1 << 1,

};

/**

 * Mesh simplifier

 * Reduces the number of triangles in the mesh, attempting to preserve mesh appearance as much as possible

 * The algorithm tries to preserve mesh topology and can stop short of the target goal based on topology constraints or target error.

 * If not all attributes from the input mesh are needed, it's recommended to reindex the mesh without them prior to simplification.

 * Returns the number of indices after simplification, with destination containing new index data

 *

 * The resulting index buffer references vertices from the original vertex buffer.

 * If the original vertex data isn't needed, creating a compact vertex buffer using meshopt_optimizeVertexFetch is recommended.

 *

 * destination must contain enough space for the target index buffer, worst case is index_count elements (*not* target_index_count)!

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * target_error represents the error relative to mesh extents that can be tolerated, e.g. 0.01 = 1% deformation; value range [0..1]

 * options must be a bitmask composed of meshopt_SimplifyX options; 0 is a safe default

 * result_error can be NULL; when it's not NULL, it will contain the resulting (relative) error after simplification

 */

MESHOPTIMIZER_API size_t meshopt_simplify(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t target_index_count, float target_error, unsigned int options, float* result_error);

/**

 * Mesh simplifier with attribute metric

 * Reduces the number of triangles in the mesh, attempting to preserve mesh appearance as much as possible.

 * Similar to meshopt_simplify, but incorporates attribute values into the error metric used to prioritize simplification order.

 * The algorithm tries to preserve mesh topology and can stop short of the target goal based on topology constraints or target error.

 * If not all attributes from the input mesh are needed, it's recommended to reindex the mesh without them prior to simplification.

 * Returns the number of indices after simplification, with destination containing new index data

 *

 * The resulting index buffer references vertices from the original vertex buffer.

 * If the original vertex data isn't needed, creating a compact vertex buffer using meshopt_optimizeVertexFetch is recommended.

 * Note that the number of attributes with non-zero weights affects memory requirements and running time.

 *

 * destination must contain enough space for the target index buffer, worst case is index_count elements (*not* target_index_count)!

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * vertex_attributes should have attribute_count floats for each vertex

 * attribute_weights should have attribute_count floats in total; the weights determine relative priority of attributes between each other and wrt position

 * attribute_count must be <= 32

 * vertex_lock can be NULL; when it's not NULL, it should have a value for each vertex; 1 denotes vertices that can't be moved

 * target_error represents the error relative to mesh extents that can be tolerated, e.g. 0.01 = 1% deformation; value range [0..1]

 * options must be a bitmask composed of meshopt_SimplifyX options; 0 is a safe default

 * result_error can be NULL; when it's not NULL, it will contain the resulting (relative) error after simplification

 */

MESHOPTIMIZER_API size_t meshopt_simplifyWithAttributes(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, const float* vertex_attributes, size_t vertex_attributes_stride, const float* attribute_weights, size_t attribute_count, const unsigned char* vertex_lock, size_t target_index_count, float target_error, unsigned int options, float* result_error);

/**

 * Experimental: Mesh simplifier with position/attribute update

 * Reduces the number of triangles in the mesh, attempting to preserve mesh appearance as much as possible.

 * Similar to meshopt_simplifyWithAttributes, but destructively updates positions and attribute values for optimal appearance.

 * The algorithm tries to preserve mesh topology and can stop short of the target goal based on topology constraints or target error.

 * If not all attributes from the input mesh are needed, it's recommended to reindex the mesh without them prior to simplification.

 * Returns the number of indices after simplification, indices are destructively updated with new index data

 *

 * The updated index buffer references vertices from the original vertex buffer, however the vertex positions and attributes are updated in-place.

 * Creating a compact vertex buffer using meshopt_optimizeVertexFetch is recommended; if the original vertex data is needed, it should be copied before simplification.

 * Note that the number of attributes with non-zero weights affects memory requirements and running time. Attributes with zero weights are not updated.

 *

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * vertex_attributes should have attribute_count floats for each vertex

 * attribute_weights should have attribute_count floats in total; the weights determine relative priority of attributes between each other and wrt position

 * attribute_count must be <= 32

 * vertex_lock can be NULL; when it's not NULL, it should have a value for each vertex; 1 denotes vertices that can't be moved

 * target_error represents the error relative to mesh extents that can be tolerated, e.g. 0.01 = 1% deformation; value range [0..1]

 * options must be a bitmask composed of meshopt_SimplifyX options; 0 is a safe default

 * result_error can be NULL; when it's not NULL, it will contain the resulting (relative) error after simplification

 */

MESHOPTIMIZER_EXPERIMENTAL size_t meshopt_simplifyWithUpdate(unsigned int* indices, size_t index_count, float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, float* vertex_attributes, size_t vertex_attributes_stride, const float* attribute_weights, size_t attribute_count, const unsigned char* vertex_lock, size_t target_index_count, float target_error, unsigned int options, float* result_error);

/**

 * Experimental: Mesh simplifier (sloppy)

 * Reduces the number of triangles in the mesh, sacrificing mesh appearance for simplification performance

 * The algorithm doesn't preserve mesh topology but can stop short of the target goal based on target error.

 * Returns the number of indices after simplification, with destination containing new index data

 * The resulting index buffer references vertices from the original vertex buffer.

 * If the original vertex data isn't needed, creating a compact vertex buffer using meshopt_optimizeVertexFetch is recommended.

 *

 * destination must contain enough space for the target index buffer, worst case is index_count elements (*not* target_index_count)!

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * vertex_lock can be NULL; when it's not NULL, it should have a value for each vertex; vertices that can't be moved should set 1 consistently for all indices with the same position

 * target_error represents the error relative to mesh extents that can be tolerated, e.g. 0.01 = 1% deformation; value range [0..1]

 * result_error can be NULL; when it's not NULL, it will contain the resulting (relative) error after simplification

 */

MESHOPTIMIZER_EXPERIMENTAL size_t meshopt_simplifySloppy(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, const unsigned char* vertex_lock, size_t target_index_count, float target_error, float* result_error);

/**

 * Mesh simplifier (pruner)

 * Reduces the number of triangles in the mesh by removing small isolated parts of the mesh

 * Returns the number of indices after simplification, with destination containing new index data

 * The resulting index buffer references vertices from the original vertex buffer.

 * If the original vertex data isn't needed, creating a compact vertex buffer using meshopt_optimizeVertexFetch is recommended.

 *

 * destination must contain enough space for the target index buffer, worst case is index_count elements

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * target_error represents the error relative to mesh extents that can be tolerated, e.g. 0.01 = 1% deformation; value range [0..1]

 */

MESHOPTIMIZER_API size_t meshopt_simplifyPrune(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, float target_error);

/**

 * Point cloud simplifier

 * Reduces the number of points in the cloud to reach the given target

 * Returns the number of points after simplification, with destination containing new index data

 * The resulting index buffer references vertices from the original vertex buffer.

 * If the original vertex data isn't needed, creating a compact vertex buffer using meshopt_optimizeVertexFetch is recommended.

 *

 * destination must contain enough space for the target index buffer (target_vertex_count elements)

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * vertex_colors can be NULL; when it's not NULL, it should have float3 color in the first 12 bytes of each vertex

 * color_weight determines relative priority of color wrt position; 1.0 is a safe default

 */

MESHOPTIMIZER_API size_t meshopt_simplifyPoints(unsigned int* destination, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, const float* vertex_colors, size_t vertex_colors_stride, float color_weight, size_t target_vertex_count);

/**

 * Returns the error scaling factor used by the simplifier to convert between absolute and relative extents

 *

 * Absolute error must be *divided* by the scaling factor before passing it to meshopt_simplify as target_error

 * Relative error returned by meshopt_simplify via result_error must be *multiplied* by the scaling factor to get absolute error.

 */

MESHOPTIMIZER_API float meshopt_simplifyScale(const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

/**

 * Mesh stripifier

 * Converts a previously vertex cache optimized triangle list to triangle strip, stitching strips using restart index or degenerate triangles

 * Returns the number of indices in the resulting strip, with destination containing new index data

 * For maximum efficiency the index buffer being converted has to be optimized for vertex cache first.

 * Using restart indices can result in ~10% smaller index buffers, but on some GPUs restart indices may result in decreased performance.

 *

 * destination must contain enough space for the target index buffer, worst case can be computed with meshopt_stripifyBound

 * restart_index should be 0xffff or 0xffffffff depending on index size, or 0 to use degenerate triangles

 */

MESHOPTIMIZER_API size_t meshopt_stripify(unsigned int* destination, const unsigned int* indices, size_t index_count, size_t vertex_count, unsigned int restart_index);

MESHOPTIMIZER_API size_t meshopt_stripifyBound(size_t index_count);

/**

 * Mesh unstripifier

 * Converts a triangle strip to a triangle list

 * Returns the number of indices in the resulting list, with destination containing new index data

 *

 * destination must contain enough space for the target index buffer, worst case can be computed with meshopt_unstripifyBound

 */

MESHOPTIMIZER_API size_t meshopt_unstripify(unsigned int* destination, const unsigned int* indices, size_t index_count, unsigned int restart_index);

MESHOPTIMIZER_API size_t meshopt_unstripifyBound(size_t index_count);

struct meshopt_VertexCacheStatistics

{

  unsigned int vertices_transformed;

  unsigned int warps_executed;

  float acmr; /* transformed vertices / triangle count; best case 0.5, worst case 3.0, optimum depends on topology */

  float atvr; /* transformed vertices / vertex count; best case 1.0, worst case 6.0, optimum is 1.0 (each vertex is transformed once) */

};

/**

 * Vertex transform cache analyzer

 * Returns cache hit statistics using a simplified FIFO model

 * Results may not match actual GPU performance

 */

MESHOPTIMIZER_API struct meshopt_VertexCacheStatistics meshopt_analyzeVertexCache(const unsigned int* indices, size_t index_count, size_t vertex_count, unsigned int cache_size, unsigned int warp_size, unsigned int primgroup_size);

struct meshopt_VertexFetchStatistics

{

  unsigned int bytes_fetched;

  float overfetch; /* fetched bytes / vertex buffer size; best case 1.0 (each byte is fetched once) */

};

/**

 * Vertex fetch cache analyzer

 * Returns cache hit statistics using a simplified direct mapped model

 * Results may not match actual GPU performance

 */

MESHOPTIMIZER_API struct meshopt_VertexFetchStatistics meshopt_analyzeVertexFetch(const unsigned int* indices, size_t index_count, size_t vertex_count, size_t vertex_size);

struct meshopt_OverdrawStatistics

{

  unsigned int pixels_covered;

  unsigned int pixels_shaded;

  float overdraw; /* shaded pixels / covered pixels; best case 1.0 */

};

/**

 * Overdraw analyzer

 * Returns overdraw statistics using a software rasterizer

 * Results may not match actual GPU performance

 *

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 */

MESHOPTIMIZER_API struct meshopt_OverdrawStatistics meshopt_analyzeOverdraw(const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

struct meshopt_CoverageStatistics

{

  float coverage[3];

  float extent; /* viewport size in mesh coordinates */

};

/**

 * Coverage analyzer

 * Returns coverage statistics (ratio of viewport pixels covered from each axis) using a software rasterizer

 *

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 */

MESHOPTIMIZER_API struct meshopt_CoverageStatistics meshopt_analyzeCoverage(const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

/**

 * Meshlet is a small mesh cluster (subset) that consists of:

 * - triangles, an 8-bit micro triangle (index) buffer, that for each triangle specifies three local vertices to use;

 * - vertices, a 32-bit vertex indirection buffer, that for each local vertex specifies which mesh vertex to fetch vertex attributes from.

 *

 * For efficiency, meshlet triangles and vertices are packed into two large arrays; this structure contains offsets and counts to access the data.

 */

struct meshopt_Meshlet

{

  /* offsets within meshlet_vertices and meshlet_triangles arrays with meshlet data */

  unsigned int vertex_offset;

  unsigned int triangle_offset;

  /* number of vertices and triangles used in the meshlet; data is stored in consecutive range defined by offset and count */

  unsigned int vertex_count;

  unsigned int triangle_count;

};

/**

 * Meshlet builder

 * Splits the mesh into a set of meshlets where each meshlet has a micro index buffer indexing into meshlet vertices that refer to the original vertex buffer

 * The resulting data can be used to render meshes using NVidia programmable mesh shading pipeline, or in other cluster-based renderers.

 * When targeting mesh shading hardware, for maximum efficiency meshlets should be further optimized using meshopt_optimizeMeshlet.

 * When using buildMeshlets, vertex positions need to be provided to minimize the size of the resulting clusters.

 * When using buildMeshletsScan, for maximum efficiency the index buffer being converted has to be optimized for vertex cache first.

 *

 * meshlets must contain enough space for all meshlets, worst case size can be computed with meshopt_buildMeshletsBound

 * meshlet_vertices must contain enough space for all meshlets, worst case size is equal to max_meshlets * max_vertices

 * meshlet_triangles must contain enough space for all meshlets, worst case size is equal to max_meshlets * max_triangles * 3

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * max_vertices and max_triangles must not exceed implementation limits (max_vertices <= 256, max_triangles <= 512; max_triangles must be divisible by 4)

 * cone_weight should be set to 0 when cone culling is not used, and a value between 0 and 1 otherwise to balance between cluster size and cone culling efficiency

 */

MESHOPTIMIZER_API size_t meshopt_buildMeshlets(struct meshopt_Meshlet* meshlets, unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t max_vertices, size_t max_triangles, float cone_weight);

MESHOPTIMIZER_API size_t meshopt_buildMeshletsScan(struct meshopt_Meshlet* meshlets, unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, const unsigned int* indices, size_t index_count, size_t vertex_count, size_t max_vertices, size_t max_triangles);

MESHOPTIMIZER_API size_t meshopt_buildMeshletsBound(size_t index_count, size_t max_vertices, size_t max_triangles);

/**

 * Experimental: Meshlet builder with flexible cluster sizes

 * Splits the mesh into a set of meshlets, similarly to meshopt_buildMeshlets, but allows to specify minimum and maximum number of triangles per meshlet.

 * Clusters between min and max triangle counts are split when the cluster size would have exceeded the expected cluster size by more than split_factor.

 *

 * meshlets must contain enough space for all meshlets, worst case size can be computed with meshopt_buildMeshletsBound using min_triangles (not max!)

 * meshlet_vertices must contain enough space for all meshlets, worst case size is equal to max_meshlets * max_vertices

 * meshlet_triangles must contain enough space for all meshlets, worst case size is equal to max_meshlets * max_triangles * 3

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * max_vertices, min_triangles and max_triangles must not exceed implementation limits (max_vertices <= 256, max_triangles <= 512; min_triangles <= max_triangles; both min_triangles and max_triangles must be divisible by 4)

 * cone_weight should be set to 0 when cone culling is not used, and a value between 0 and 1 otherwise to balance between cluster size and cone culling efficiency

 * split_factor should be set to a non-negative value; when greater than 0, clusters that have large bounds may be split unless they are under the min_triangles threshold

 */

MESHOPTIMIZER_EXPERIMENTAL size_t meshopt_buildMeshletsFlex(struct meshopt_Meshlet* meshlets, unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t max_vertices, size_t min_triangles, size_t max_triangles, float cone_weight, float split_factor);

/**

 * Experimental: Meshlet builder that produces clusters optimized for raytracing

 * Splits the mesh into a set of meshlets, similarly to meshopt_buildMeshlets, but optimizes cluster subdivision for raytracing and allows to specify minimum and maximum number of triangles per meshlet.

 *

 * meshlets must contain enough space for all meshlets, worst case size can be computed with meshopt_buildMeshletsBound using min_triangles (not max!)

 * meshlet_vertices must contain enough space for all meshlets, worst case size is equal to max_meshlets * max_vertices

 * meshlet_triangles must contain enough space for all meshlets, worst case size is equal to max_meshlets * max_triangles * 3

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * max_vertices, min_triangles and max_triangles must not exceed implementation limits (max_vertices <= 256, max_triangles <= 512; min_triangles <= max_triangles; both min_triangles and max_triangles must be divisible by 4)

 * fill_weight allows to prioritize clusters that are closer to maximum size at some cost to SAH quality; 0.5 is a safe default

 */

MESHOPTIMIZER_EXPERIMENTAL size_t meshopt_buildMeshletsSpatial(struct meshopt_Meshlet* meshlets, unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t max_vertices, size_t min_triangles, size_t max_triangles, float fill_weight);

/**

 * Meshlet optimizer

 * Reorders meshlet vertices and triangles to maximize locality to improve rasterizer throughput

 *

 * meshlet_triangles and meshlet_vertices must refer to meshlet triangle and vertex index data; when buildMeshlets* is used, these

 * need to be computed from meshlet's vertex_offset and triangle_offset

 * triangle_count and vertex_count must not exceed implementation limits (vertex_count <= 256, triangle_count <= 512)

 */

MESHOPTIMIZER_API void meshopt_optimizeMeshlet(unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, size_t triangle_count, size_t vertex_count);

struct meshopt_Bounds

{

  /* bounding sphere, useful for frustum and occlusion culling */

  float center[3];

  float radius;

  /* normal cone, useful for backface culling */

  float cone_apex[3];

  float cone_axis[3];

  float cone_cutoff; /* = cos(angle/2) */

  /* normal cone axis and cutoff, stored in 8-bit SNORM format; decode using x/127.0 */

  signed char cone_axis_s8[3];

  signed char cone_cutoff_s8;

};

/**

 * Cluster bounds generator

 * Creates bounding volumes that can be used for frustum, backface and occlusion culling.

 *

 * For backface culling with orthographic projection, use the following formula to reject backfacing clusters:

 *   dot(view, cone_axis) >= cone_cutoff

 *

 * For perspective projection, you can use the formula that needs cone apex in addition to axis & cutoff:

 *   dot(normalize(cone_apex - camera_position), cone_axis) >= cone_cutoff

 *

 * Alternatively, you can use the formula that doesn't need cone apex and uses bounding sphere instead:

 *   dot(normalize(center - camera_position), cone_axis) >= cone_cutoff + radius / length(center - camera_position)

 * or an equivalent formula that doesn't have a singularity at center = camera_position:

 *   dot(center - camera_position, cone_axis) >= cone_cutoff * length(center - camera_position) + radius

 *

 * The formula that uses the apex is slightly more accurate but needs the apex; if you are already using bounding sphere

 * to do frustum/occlusion culling, the formula that doesn't use the apex may be preferable (for derivation see

 * Real-Time Rendering 4th Edition, section 19.3).

 *

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 * vertex_count should specify the number of vertices in the entire mesh, not cluster or meshlet

 * index_count/3 and triangle_count must not exceed implementation limits (<= 512)

 */

MESHOPTIMIZER_API struct meshopt_Bounds meshopt_computeClusterBounds(const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

MESHOPTIMIZER_API struct meshopt_Bounds meshopt_computeMeshletBounds(const unsigned int* meshlet_vertices, const unsigned char* meshlet_triangles, size_t triangle_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

/**

 * Sphere bounds generator

 * Creates bounding sphere around a set of points or a set of spheres; returns the center and radius of the sphere, with other fields of the result set to 0.

 *

 * positions should have float3 position in the first 12 bytes of each element

 * radii can be NULL; when it's not NULL, it should have a non-negative float radius in the first 4 bytes of each element

 */

MESHOPTIMIZER_API struct meshopt_Bounds meshopt_computeSphereBounds(const float* positions, size_t count, size_t positions_stride, const float* radii, size_t radii_stride);

/**

 * Cluster partitioner

 * Partitions clusters into groups of similar size, prioritizing grouping clusters that share vertices or are close to each other.

 *

 * destination must contain enough space for the resulting partition data (cluster_count elements)

 * destination[i] will contain the partition id for cluster i, with the total number of partitions returned by the function

 * cluster_indices should have the vertex indices referenced by each cluster, stored sequentially

 * cluster_index_counts should have the number of indices in each cluster; sum of all cluster_index_counts must be equal to total_index_count

 * vertex_positions should have float3 position in the first 12 bytes of each vertex (or can be NULL if not used)

 * target_partition_size is a target size for each partition, in clusters; the resulting partitions may be smaller or larger

 */

MESHOPTIMIZER_API size_t meshopt_partitionClusters(unsigned int* destination, const unsigned int* cluster_indices, size_t total_index_count, const unsigned int* cluster_index_counts, size_t cluster_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t target_partition_size);

/**

 * Spatial sorter

 * Generates a remap table that can be used to reorder points for spatial locality.

 * Resulting remap table maps old vertices to new vertices and can be used in meshopt_remapVertexBuffer.

 *

 * destination must contain enough space for the resulting remap table (vertex_count elements)

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 */

MESHOPTIMIZER_API void meshopt_spatialSortRemap(unsigned int* destination, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

/**

 * Spatial sorter

 * Reorders triangles for spatial locality, and generates a new index buffer. The resulting index buffer can be used with other functions like optimizeVertexCache.

 *

 * destination must contain enough space for the resulting index buffer (index_count elements)

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 */

MESHOPTIMIZER_API void meshopt_spatialSortTriangles(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

/**

 * Spatial clusterizer

 * Reorders points into clusters optimized for spatial locality, and generates a new index buffer.

 * Ensures the output can be split into cluster_size chunks where each chunk has good positional locality. Only the last chunk will be smaller than cluster_size.

 *

 * destination must contain enough space for the resulting index buffer (vertex_count elements)

 * vertex_positions should have float3 position in the first 12 bytes of each vertex

 */

MESHOPTIMIZER_API void meshopt_spatialClusterPoints(unsigned int* destination, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t cluster_size);

/**

 * Quantize a float into half-precision (as defined by IEEE-754 fp16) floating point value

 * Generates +-inf for overflow, preserves NaN, flushes denormals to zero, rounds to nearest

 * Representable magnitude range: [6e-5; 65504]

 * Maximum relative reconstruction error: 5e-4

 */

MESHOPTIMIZER_API unsigned short meshopt_quantizeHalf(float v);

/**

 * Quantize a float into a floating point value with a limited number of significant mantissa bits, preserving the IEEE-754 fp32 binary representation

 * Generates +-inf for overflow, preserves NaN, flushes denormals to zero, rounds to nearest

 * Assumes N is in a valid mantissa precision range, which is 1..23

 */

MESHOPTIMIZER_API float meshopt_quantizeFloat(float v, int N);

/**

 * Reverse quantization of a half-precision (as defined by IEEE-754 fp16) floating point value

 * Preserves Inf/NaN, flushes denormals to zero

 */

MESHOPTIMIZER_API float meshopt_dequantizeHalf(unsigned short h);

/**

 * Set allocation callbacks

 * These callbacks will be used instead of the default operator new/operator delete for all temporary allocations in the library.

 * Note that all algorithms only allocate memory for temporary use.

 * allocate/deallocate are always called in a stack-like order - last pointer to be allocated is deallocated first.

 */

MESHOPTIMIZER_API void meshopt_setAllocator(void* (MESHOPTIMIZER_ALLOC_CALLCONV* allocate)(size_t), void (MESHOPTIMIZER_ALLOC_CALLCONV* deallocate)(void*));

#ifdef __cplusplus

} /* extern "C" */

#endif

/* Quantization into fixed point normalized formats; these are only available as inline C++ functions */

#ifdef __cplusplus

/**

 * Quantize a float in [0..1] range into an N-bit fixed point unorm value

 * Assumes reconstruction function (q / (2^N-1)), which is the case for fixed-function normalized fixed point conversion

 * Maximum reconstruction error: 1/2^(N+1)

 */

inline int meshopt_quantizeUnorm(float v, int N);

/**

 * Quantize a float in [-1..1] range into an N-bit fixed point snorm value

 * Assumes reconstruction function (q / (2^(N-1)-1)), which is the case for fixed-function normalized fixed point conversion (except early OpenGL versions)

 * Maximum reconstruction error: 1/2^N

 */

inline int meshopt_quantizeSnorm(float v, int N);

#endif

/**

 * C++ template interface

 *

 * These functions mirror the C interface the library provides, providing template-based overloads so that

 * the caller can use an arbitrary type for the index data, both for input and output.

 * When the supplied type is the same size as that of unsigned int, the wrappers are zero-cost; when it's not,

 * the wrappers end up allocating memory and copying index data to convert from one type to another.

 */

#if defined(__cplusplus) && !defined(MESHOPTIMIZER_NO_WRAPPERS)

template <typename T>

inline size_t meshopt_generateVertexRemap(unsigned int* destination, const T* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size);

template <typename T>

inline size_t meshopt_generateVertexRemapMulti(unsigned int* destination, const T* indices, size_t index_count, size_t vertex_count, const meshopt_Stream* streams, size_t stream_count);

template <typename F>

inline size_t meshopt_generateVertexRemapCustom(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, F callback);

template <typename T, typename F>

inline size_t meshopt_generateVertexRemapCustom(unsigned int* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, F callback);

template <typename T>

inline void meshopt_remapIndexBuffer(T* destination, const T* indices, size_t index_count, const unsigned int* remap);

template <typename T>

inline void meshopt_generateShadowIndexBuffer(T* destination, const T* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size, size_t vertex_stride);

template <typename T>

inline void meshopt_generateShadowIndexBufferMulti(T* destination, const T* indices, size_t index_count, size_t vertex_count, const meshopt_Stream* streams, size_t stream_count);

template <typename T>

inline void meshopt_generateAdjacencyIndexBuffer(T* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

template <typename T>

inline void meshopt_generateTessellationIndexBuffer(T* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

template <typename T>

inline size_t meshopt_generateProvokingIndexBuffer(T* destination, unsigned int* reorder, const T* indices, size_t index_count, size_t vertex_count);

template <typename T>

inline void meshopt_optimizeVertexCache(T* destination, const T* indices, size_t index_count, size_t vertex_count);

template <typename T>

inline void meshopt_optimizeVertexCacheStrip(T* destination, const T* indices, size_t index_count, size_t vertex_count);

template <typename T>

inline void meshopt_optimizeVertexCacheFifo(T* destination, const T* indices, size_t index_count, size_t vertex_count, unsigned int cache_size);

template <typename T>

inline void meshopt_optimizeOverdraw(T* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, float threshold);

template <typename T>

inline size_t meshopt_optimizeVertexFetchRemap(unsigned int* destination, const T* indices, size_t index_count, size_t vertex_count);

template <typename T>

inline size_t meshopt_optimizeVertexFetch(void* destination, T* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size);

template <typename T>

inline size_t meshopt_encodeIndexBuffer(unsigned char* buffer, size_t buffer_size, const T* indices, size_t index_count);

template <typename T>

inline int meshopt_decodeIndexBuffer(T* destination, size_t index_count, const unsigned char* buffer, size_t buffer_size);

template <typename T>

inline size_t meshopt_encodeIndexSequence(unsigned char* buffer, size_t buffer_size, const T* indices, size_t index_count);

template <typename T>

inline int meshopt_decodeIndexSequence(T* destination, size_t index_count, const unsigned char* buffer, size_t buffer_size);

inline size_t meshopt_encodeVertexBufferLevel(unsigned char* buffer, size_t buffer_size, const void* vertices, size_t vertex_count, size_t vertex_size, int level);

template <typename T>

inline size_t meshopt_simplify(T* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t target_index_count, float target_error, unsigned int options = 0, float* result_error = NULL);

template <typename T>

inline size_t meshopt_simplifyWithAttributes(T* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, const float* vertex_attributes, size_t vertex_attributes_stride, const float* attribute_weights, size_t attribute_count, const unsigned char* vertex_lock, size_t target_index_count, float target_error, unsigned int options = 0, float* result_error = NULL);

template <typename T>

inline size_t meshopt_simplifyWithUpdate(T* indices, size_t index_count, float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, float* vertex_attributes, size_t vertex_attributes_stride, const float* attribute_weights, size_t attribute_count, const unsigned char* vertex_lock, size_t target_index_count, float target_error, unsigned int options = 0, float* result_error = NULL);

template <typename T>

inline size_t meshopt_simplifySloppy(T* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t target_index_count, float target_error, float* result_error = NULL);

template <typename T>

inline size_t meshopt_simplifyPrune(T* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, float target_error);

template <typename T>

inline size_t meshopt_stripify(T* destination, const T* indices, size_t index_count, size_t vertex_count, T restart_index);

template <typename T>

inline size_t meshopt_unstripify(T* destination, const T* indices, size_t index_count, T restart_index);

template <typename T>

inline meshopt_VertexCacheStatistics meshopt_analyzeVertexCache(const T* indices, size_t index_count, size_t vertex_count, unsigned int cache_size, unsigned int warp_size, unsigned int buffer_size);

template <typename T>

inline meshopt_VertexFetchStatistics meshopt_analyzeVertexFetch(const T* indices, size_t index_count, size_t vertex_count, size_t vertex_size);

template <typename T>

inline meshopt_OverdrawStatistics meshopt_analyzeOverdraw(const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

template <typename T>

inline meshopt_CoverageStatistics meshopt_analyzeCoverage(const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

template <typename T>

inline size_t meshopt_buildMeshlets(meshopt_Meshlet* meshlets, unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t max_vertices, size_t max_triangles, float cone_weight);

template <typename T>

inline size_t meshopt_buildMeshletsScan(meshopt_Meshlet* meshlets, unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, const T* indices, size_t index_count, size_t vertex_count, size_t max_vertices, size_t max_triangles);

template <typename T>

inline size_t meshopt_buildMeshletsFlex(meshopt_Meshlet* meshlets, unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t max_vertices, size_t min_triangles, size_t max_triangles, float cone_weight, float split_factor);

template <typename T>

inline size_t meshopt_buildMeshletsSpatial(meshopt_Meshlet* meshlets, unsigned int* meshlet_vertices, unsigned char* meshlet_triangles, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t max_vertices, size_t min_triangles, size_t max_triangles, float fill_weight);

template <typename T>

inline meshopt_Bounds meshopt_computeClusterBounds(const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

template <typename T>

inline size_t meshopt_partitionClusters(unsigned int* destination, const T* cluster_indices, size_t total_index_count, const unsigned int* cluster_index_counts, size_t cluster_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, size_t target_partition_size);

template <typename T>

inline void meshopt_spatialSortTriangles(T* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride);

#endif

/* Inline implementation */

#ifdef __cplusplus

inline int meshopt_quantizeUnorm(float v, int N)

{

  const float scale = float((1 << N) - 1);

  v = (v >= 0) ? v : 0;

  v = (v <= 1) ? v : 1;

  return int(v * scale + 0.5f);

}

inline int meshopt_quantizeSnorm(float v, int N)

{

  const float scale = float((1 << (N - 1)) - 1);

  float round = (v >= 0 ? 0.5f : -0.5f);

  v = (v >= -1) ? v : -1;

  v = (v <= +1) ? v : +1;

  return int(v * scale + round);

}

#endif

/* Internal implementation helpers */

#ifdef __cplusplus

class meshopt_Allocator

{

public:

  struct Storage

  {

    void* (MESHOPTIMIZER_ALLOC_CALLCONV* allocate)(size_t);

    void (MESHOPTIMIZER_ALLOC_CALLCONV* deallocate)(void*);

  };

#ifdef MESHOPTIMIZER_ALLOC_EXPORT

  MESHOPTIMIZER_API static Storage& storage();

#else

  static Storage& storage()

  {

    static Storage s = {::operator new, ::operator delete };

    return s;

  }

#endif

  meshopt_Allocator()

      : blocks()

      , count(0)

  {

  }

  ~meshopt_Allocator()

  {

    for (size_t i = count; i > 0; --i)

      storage().deallocate(blocks[i - 1]);

  }

  template <typename T>

  T* allocate(size_t size)

  {

    assert(count < sizeof(blocks) / sizeof(blocks[0]));

    T* result = static_cast<T*>(storage().allocate(size > size_t(-1) / sizeof(T) ? size_t(-1) : size * sizeof(T)));

    blocks[count++] = result;

    return result;

  }

  void deallocate(void* ptr)

  {

    assert(count > 0 && blocks[count - 1] == ptr);

    storage().deallocate(ptr);

    count--;

  }

private:

  void* blocks[24];

  size_t count;

};

#endif

/* Inline implementation for C++ templated wrappers */

#if defined(__cplusplus) && !defined(MESHOPTIMIZER_NO_WRAPPERS)

template <typename T, bool ZeroCopy = sizeof(T) == sizeof(unsigned int)>

struct meshopt_IndexAdapter;

template <typename T>

struct meshopt_IndexAdapter<T, false>

{

  T* result;

  unsigned int* data;

  size_t count;

  meshopt_IndexAdapter(T* result_, const T* input, size_t count_)

      : result(result_)

      , data(NULL)

      , count(count_)

  {

    size_t size = count > size_t(-1) / sizeof(unsigned int) ? size_t(-1) : count * sizeof(unsigned int);

    data = static_cast<unsigned int*>(meshopt_Allocator::storage().allocate(size));

    if (input)

    {

      for (size_t i = 0; i < count; ++i)

        data[i] = input[i];

    }

  }

  ~meshopt_IndexAdapter()

  {

    if (result)

    {

      for (size_t i = 0; i < count; ++i)

        result[i] = T(data[i]);

    }

    meshopt_Allocator::storage().deallocate(data);

  }

};

template <typename T>

struct meshopt_IndexAdapter<T, true>

{

  unsigned int* data;

  meshopt_IndexAdapter(T* result, const T* input, size_t)

      : data(reinterpret_cast<unsigned int*>(result ? result : const_cast<T*>(input)))

  {

  }

};

template <typename T>

inline size_t meshopt_generateVertexRemap(unsigned int* destination, const T* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size)

{

  meshopt_IndexAdapter<T> in(NULL, indices, indices ? index_count : 0);

  return meshopt_generateVertexRemap(destination, indices ? in.data : NULL, index_count, vertices, vertex_count, vertex_size);

}

template <typename T>

inline size_t meshopt_generateVertexRemapMulti(unsigned int* destination, const T* indices, size_t index_count, size_t vertex_count, const meshopt_Stream* streams, size_t stream_count)

{

  meshopt_IndexAdapter<T> in(NULL, indices, indices ? index_count : 0);

  return meshopt_generateVertexRemapMulti(destination, indices ? in.data : NULL, index_count, vertex_count, streams, stream_count);

}

template <typename F>

inline size_t meshopt_generateVertexRemapCustom(unsigned int* destination, const unsigned int* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, F callback)

{

  struct Call

  {

    static int compare(void* context, unsigned int lhs, unsigned int rhs) { return (*static_cast<F*>(context))(lhs, rhs) ? 1 : 0; }

  };

  return meshopt_generateVertexRemapCustom(destination, indices, index_count, vertex_positions, vertex_count, vertex_positions_stride, &Call::compare, &callback);

}

template <typename T, typename F>

inline size_t meshopt_generateVertexRemapCustom(unsigned int* destination, const T* indices, size_t index_count, const float* vertex_positions, size_t vertex_count, size_t vertex_positions_stride, F callback)

{

  struct Call

  {

    static int compare(void* context, unsigned int lhs, unsigned int rhs) { return (*static_cast<F*>(context))(lhs, rhs) ? 1 : 0; }

  };

  meshopt_IndexAdapter<T> in(NULL, indices, indices ? index_count : 0);

  return meshopt_generateVertexRemapCustom(destination, indices ? in.data : NULL, index_count, vertex_positions, vertex_count, vertex_positions_stride, &Call::compare, &callback);

}

template <typename T>

inline void meshopt_remapIndexBuffer(T* destination, const T* indices, size_t index_count, const unsigned int* remap)

{

  meshopt_IndexAdapter<T> in(NULL, indices, indices ? index_count : 0);

  meshopt_IndexAdapter<T> out(destination, 0, index_count);

  meshopt_remapIndexBuffer(out.data, indices ? in.data : NULL, index_count, remap);

}

template <typename T>

inline void meshopt_generateShadowIndexBuffer(T* destination, const T* indices, size_t index_count, const void* vertices, size_t vertex_count, size_t vertex_size, size_t vertex_stride)

{

  meshopt_IndexAdapter<T> in(NULL, indices, index_count);

  meshopt_IndexAdapter<T> out(destination, NULL, index_count);

  meshopt_generateShadowIndexBuffer(out.data, in.data, index_count, vertices, vertex_count, vertex_size, vertex_stride);

}

template <typename T>

inline void meshopt_generateShadowIndexBufferMulti(T* destination, const T* indices, size_t index_count, size_t vertex_count, const meshopt_Stream* streams, size_t stream_count)

{

  meshopt_IndexAdapter<T> in(NULL, indices, index_count);

  meshopt_IndexAdapter<T> out(destination, NULL, index_count);

  meshopt_generateShadowIndexBufferMulti(out.data, in.data, index_count, vertex_count, streams, stream_count);

}