/*

 * Copyright 2017 Google Inc.

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef SkVertices_DEFINED

#define SkVertices_DEFINED

#include "include/core/SkColor.h"

#include "include/core/SkPoint.h"

#include "include/core/SkRect.h"

#include "include/core/SkRefCnt.h"

#include "include/private/base/SkAPI.h"

#include <cstddef>

#include <cstdint>

#include <memory>

class SkVerticesPriv;

/**

 * An immutable set of vertex data that can be used with SkCanvas::drawVertices.

 */

class SK_API SkVertices : public SkNVRefCnt<SkVertices> {

    struct Desc;

    struct Sizes;

public:

    enum VertexMode {

        kTriangles_VertexMode,

        kTriangleStrip_VertexMode,

        kTriangleFan_VertexMode,

        kLast_VertexMode = kTriangleFan_VertexMode,

    };

    /**

     *  Create a vertices by copying the specified arrays. texs, colors may be nullptr,

     *  and indices is ignored if indexCount == 0.

     */

    static sk_sp<SkVertices> MakeCopy(VertexMode mode, int vertexCount,

                                      const SkPoint positions[],

                                      const SkPoint texs[],

                                      const SkColor colors[],

                                      int indexCount,

                                      const uint16_t indices[]);

    static sk_sp<SkVertices> MakeCopy(VertexMode mode, int vertexCount,

                                      const SkPoint positions[],

                                      const SkPoint texs[],

                                      const SkColor colors[]) {

        return MakeCopy(mode,

                        vertexCount,

                        positions,

                        texs,

                        colors,

                        0,

                        nullptr);

    }

    enum BuilderFlags {

        kHasTexCoords_BuilderFlag   = 1 << 0,

        kHasColors_BuilderFlag      = 1 << 1,

    };

    class SK_API Builder {

    public:

        Builder(VertexMode mode, int vertexCount, int indexCount, uint32_t flags);

        bool isValid() const { return fVertices != nullptr; }

        SkPoint* positions();

        uint16_t* indices();        // returns null if there are no indices

        // If we have custom attributes, these will always be null

        SkPoint* texCoords();       // returns null if there are no texCoords

        SkColor* colors();          // returns null if there are no colors

        // Detach the built vertices object. After the first call, this will always return null.

        sk_sp<SkVertices> detach();

    private:

        Builder(const Desc&);

        void init(const Desc&);

        // holds a partially complete object. only completed in detach()

        sk_sp<SkVertices> fVertices;

        // Extra storage for intermediate vertices in the case where the client specifies indexed

        // triangle fans. These get converted to indexed triangles when the Builder is finalized.

        std::unique_ptr<uint8_t[]> fIntermediateFanIndices;

        friend class SkVertices;

        friend class SkVerticesPriv;

    };

    uint32_t uniqueID() const { return fUniqueID; }

    const SkRect& bounds() const { return fBounds; }

    // returns approximate byte size of the vertices object

    size_t approximateSize() const;

    // Provides access to functions that aren't part of the public API.

    SkVerticesPriv priv();

    const SkVerticesPriv priv() const;  // NOLINT(readability-const-return-type)

private:

    SkVertices() {}

    friend class SkVerticesPriv;

    // these are needed since we've manually sized our allocation (see Builder::init)

    friend class SkNVRefCnt<SkVertices>;

    void operator delete(void* p);

    Sizes getSizes() const;

    // we store this first, to pair with the refcnt in our base-class, so we don't have an

    // unnecessary pad between it and the (possibly 8-byte aligned) ptrs.

    uint32_t fUniqueID;

    // these point inside our allocation, so none of these can be "freed"

    SkPoint*     fPositions;        // [vertexCount]

    uint16_t*    fIndices;          // [indexCount] or null

    SkPoint*     fTexs;             // [vertexCount] or null

    SkColor*     fColors;           // [vertexCount] or null

    SkRect  fBounds;    // computed to be the union of the fPositions[]

    int     fVertexCount;

    int     fIndexCount;

    VertexMode fMode;

    // below here is where the actual array data is stored.

};

#endif