/*

 * 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 SkDrawShadowInfo_DEFINED

#define SkDrawShadowInfo_DEFINED

#include "include/core/SkColor.h"

#include "include/core/SkPoint.h"

#include "include/core/SkPoint3.h"

#include "include/private/SkTPin.h"

class SkMatrix;

class SkPath;

struct SkRect;

struct SkDrawShadowRec {

    SkPoint3    fZPlaneParams;

    SkPoint3    fLightPos;

    SkScalar    fLightRadius;

    SkColor     fAmbientColor;

    SkColor     fSpotColor;

    uint32_t    fFlags;

};

namespace SkDrawShadowMetrics {

static constexpr auto kAmbientHeightFactor = 1.0f / 128.0f;

static constexpr auto kAmbientGeomFactor = 64.0f;

// Assuming that we have a light height of 600 for the spot shadow,

// the spot values will reach their maximum at a height of approximately 292.3077.

// We'll round up to 300 to keep it simple.

static constexpr auto kMaxAmbientRadius = 300*kAmbientHeightFactor*kAmbientGeomFactor;

static inline float divide_and_pin(float numer, float denom, float min, float max) {

    float result = SkTPin(sk_ieee_float_divide(numer, denom), min, max);

    // ensure that SkTPin handled non-finites correctly

    SkASSERT(result >= min && result <= max);

    return result;

}

Unexecuted instantiation: SkPictureRecorder.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkRecordedDrawable.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkRecorder.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkShadowUtils.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkGlobalInitialization_default.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: Device.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SurfaceDrawContext.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkDrawShadowInfo.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkMiniRecorder.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkRecord.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkRecordDraw.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkRecordOpts.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkRecords.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkBigPicture.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkPicture.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkPicturePlayback.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkPictureRecord.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkShadowTessellator.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkShadowUtils.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SurfaceDrawContext.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: SkDrawShadowInfo.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: FuzzCanvas.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: DebugCanvas.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: DebugLayerManager.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: DrawCommand.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

Unexecuted instantiation: JsonWriteBuffer.cpp:SkDrawShadowMetrics::divide_and_pin(float, float, float, float)

inline SkScalar AmbientBlurRadius(SkScalar height) {

    return std::min(height*kAmbientHeightFactor*kAmbientGeomFactor, kMaxAmbientRadius);

}

inline SkScalar AmbientRecipAlpha(SkScalar height) {

    return 1.0f + std::max(height*kAmbientHeightFactor, 0.0f);

}

inline SkScalar SpotBlurRadius(SkScalar occluderZ, SkScalar lightZ, SkScalar lightRadius) {

    return lightRadius*divide_and_pin(occluderZ, lightZ - occluderZ, 0.0f, 0.95f);

}

inline void GetSpotParams(SkScalar occluderZ, SkScalar lightX, SkScalar lightY, SkScalar lightZ,

                          SkScalar lightRadius,

                          SkScalar* blurRadius, SkScalar* scale, SkVector* translate) {

    SkScalar zRatio = divide_and_pin(occluderZ, lightZ - occluderZ, 0.0f, 0.95f);

    *blurRadius = lightRadius*zRatio;

    *scale = divide_and_pin(lightZ, lightZ - occluderZ, 1.0f, 1.95f);

    *translate = SkVector::Make(-zRatio * lightX, -zRatio * lightY);

}

inline void GetDirectionalParams(SkScalar occluderZ, SkScalar lightX, SkScalar lightY,

                                 SkScalar lightZ, SkScalar lightRadius,

                                 SkScalar* blurRadius, SkScalar* scale, SkVector* translate) {

    *blurRadius = lightRadius*occluderZ;

    *scale = 1;

    // Max z-ratio is "max expected elevation"/"min allowable z"

    constexpr SkScalar kMaxZRatio = 64/SK_ScalarNearlyZero;

    SkScalar zRatio = divide_and_pin(occluderZ, lightZ, 0.0f, kMaxZRatio);

    *translate = SkVector::Make(-zRatio * lightX, -zRatio * lightY);

}

// Create the transformation to apply to a path to get its base shadow outline, given the light

// parameters and the path's 3D transformation (given by ctm and zPlaneParams).

// Also computes the blur radius to apply the transformed outline.

bool GetSpotShadowTransform(const SkPoint3& lightPos, SkScalar lightRadius,

                            const SkMatrix& ctm, const SkPoint3& zPlaneParams,

                            const SkRect& pathBounds, bool directional,

                            SkMatrix* shadowTransform, SkScalar* radius);

// get bounds prior to the ctm being applied

void GetLocalBounds(const SkPath&, const SkDrawShadowRec&, const SkMatrix& ctm, SkRect* bounds);

}  // namespace SkDrawShadowMetrics

#endif