libs/hwui/ShadowTessellator.cpp - platform/frameworks/base - Gitiles

 /*
  * Copyright (C) 2013 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #define LOG_TAG "OpenGLRenderer"
 #define ATRACE_TAG ATRACE_TAG_VIEW

 #include <math.h>
 #include <utils/Log.h>
 #include <utils/Trace.h>

 #include "AmbientShadow.h"
 #include "Caches.h"
 #include "ShadowTessellator.h"
 #include "SpotShadow.h"

 namespace android {
 namespace uirenderer {

 template<typename T>
 static inline T max(T a, T b) {
     return a > b ? a : b;
 }

 VertexBufferMode ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque,
         const Vector3* casterPolygon, int casterVertexCount,
         const Vector3& centroid3d, const Rect& casterBounds,
         const Rect& localClip, float maxZ, VertexBuffer& shadowVertexBuffer) {
     ATRACE_CALL();

     // A bunch of parameters to tweak the shadow.
     // TODO: Allow some of these changable by debug settings or APIs.
     float heightFactor = 1.0f / 128;
     const float geomFactor = 64;

     Caches& caches = Caches::getInstance();
     if (CC_UNLIKELY(caches.propertyAmbientRatio > 0.0f)) {
         heightFactor *= caches.propertyAmbientRatio;
     }

     Rect ambientShadowBounds(casterBounds);
     ambientShadowBounds.outset(maxZ * geomFactor * heightFactor);

     if (!localClip.intersects(ambientShadowBounds)) {
 #if DEBUG_SHADOW
         ALOGD("Ambient shadow is out of clip rect!");
 #endif
         return kVertexBufferMode_OnePolyRingShadow;
     }

     return AmbientShadow::createAmbientShadow(isCasterOpaque, casterPolygon,
             casterVertexCount, centroid3d, heightFactor, geomFactor,
             shadowVertexBuffer);

 }

 VertexBufferMode ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque,
         const Vector3* casterPolygon, int casterVertexCount,
         const mat4& receiverTransform,
         int screenWidth, int screenHeight, const Rect& casterBounds,
         const Rect& localClip, VertexBuffer& shadowVertexBuffer) {
     ATRACE_CALL();

     Caches& caches = Caches::getInstance();

     // A bunch of parameters to tweak the shadow.
     // TODO: Allow some of these changable by debug settings or APIs.
     int maximal = max(screenWidth, screenHeight);
     Vector3 lightCenter(screenWidth * 0.5f, 0, maximal);

     if (CC_UNLIKELY(caches.propertyLightPosY > 0)) {
         lightCenter.y = - caches.propertyLightPosY; // negated since this shifts up
     }
     if (CC_UNLIKELY(caches.propertyLightPosZ > 0)) {
         lightCenter.z = caches.propertyLightPosZ;
     }


 #if DEBUG_SHADOW
     ALOGD("light center %f %f %f", lightCenter.x, lightCenter.y, lightCenter.z);
 #endif

     // light position (because it's in local space) needs to compensate for receiver transform
     // TODO: should apply to light orientation, not just position
     Matrix4 reverseReceiverTransform;
     reverseReceiverTransform.loadInverse(receiverTransform);
     reverseReceiverTransform.mapPoint3d(lightCenter);

     float lightSize = maximal / 4;
     const int lightVertexCount = 8;

     if (CC_UNLIKELY(caches.propertyLightDiameter > 0)) {
         lightSize = caches.propertyLightDiameter;
     }

     // Now light and caster are both in local space, we will check whether
     // the shadow is within the clip area.
     Rect lightRect = Rect(lightCenter.x - lightSize, lightCenter.y - lightSize,
             lightCenter.x + lightSize, lightCenter.y + lightSize);
     lightRect.unionWith(localClip);
     if (!lightRect.intersects(casterBounds)) {
 #if DEBUG_SHADOW
         ALOGD("Spot shadow is out of clip rect!");
 #endif
         return kVertexBufferMode_OnePolyRingShadow;
     }

     VertexBufferMode mode = SpotShadow::createSpotShadow(isCasterOpaque,
             casterPolygon, casterVertexCount, lightCenter, lightSize,
             lightVertexCount, shadowVertexBuffer);

 #if DEBUG_SHADOW
      if(shadowVertexBuffer.getVertexCount() <= 0) {
         ALOGD("Spot shadow generation failed %d", shadowVertexBuffer.getVertexCount());
      }
 #endif
      return mode;
 }

 void ShadowTessellator::generateShadowIndices(uint16_t* shadowIndices) {
     int currentIndex = 0;
     const int rays = SHADOW_RAY_COUNT;
     // For the penumbra area.
     for (int layer = 0; layer < 2; layer ++) {
         int baseIndex = layer * rays;
         for (int i = 0; i < rays; i++) {
             shadowIndices[currentIndex++] = i + baseIndex;
             shadowIndices[currentIndex++] = rays + i + baseIndex;
         }
         // To close the loop, back to the ray 0.
         shadowIndices[currentIndex++] = 0 + baseIndex;
          // Note this is the same as the first index of next layer loop.
         shadowIndices[currentIndex++] = rays + baseIndex;
     }

 #if DEBUG_SHADOW
     if (currentIndex != MAX_SHADOW_INDEX_COUNT) {
         ALOGW("vertex index count is wrong. current %d, expected %d",
                 currentIndex, MAX_SHADOW_INDEX_COUNT);
     }
     for (int i = 0; i < MAX_SHADOW_INDEX_COUNT; i++) {
         ALOGD("vertex index is (%d, %d)", i, shadowIndices[i]);
     }
 #endif
 }

 /**
  * Calculate the centroid of a 2d polygon.
  *
  * @param poly The polygon, which is represented in a Vector2 array.
  * @param polyLength The length of the polygon in terms of number of vertices.
  * @return the centroid of the polygon.
  */
 Vector2 ShadowTessellator::centroid2d(const Vector2* poly, int polyLength) {
     double sumx = 0;
     double sumy = 0;
     int p1 = polyLength - 1;
     double area = 0;
     for (int p2 = 0; p2 < polyLength; p2++) {
         double x1 = poly[p1].x;
         double y1 = poly[p1].y;
         double x2 = poly[p2].x;
         double y2 = poly[p2].y;
         double a = (x1 * y2 - x2 * y1);
         sumx += (x1 + x2) * a;
         sumy += (y1 + y2) * a;
         area += a;
         p1 = p2;
     }

     Vector2 centroid = poly[0];
     if (area != 0) {
         centroid = Vector2(sumx / (3 * area), sumy / (3 * area));
     } else {
         ALOGW("Area is 0 while computing centroid!");
     }
     return centroid;
 }

 /**
  * Test whether the polygon is order in clockwise.
  *
  * @param polygon the polygon as a Vector2 array
  * @param len the number of points of the polygon
  */
 bool ShadowTessellator::isClockwise(const Vector2* polygon, int len) {
     double sum = 0;
     double p1x = polygon[len - 1].x;
     double p1y = polygon[len - 1].y;
     for (int i = 0; i < len; i++) {

         double p2x = polygon[i].x;
         double p2y = polygon[i].y;
         sum += p1x * p2y - p2x * p1y;
         p1x = p2x;
         p1y = p2y;
     }
     return sum < 0;
 }

 bool ShadowTessellator::isClockwisePath(const SkPath& path) {
     SkPath::Iter iter(path, false);
     SkPoint pts[4];
     SkPath::Verb v;

     Vector<Vector2> arrayForDirection;
     while (SkPath::kDone_Verb != (v = iter.next(pts))) {
             switch (v) {
             case SkPath::kMove_Verb:
                 arrayForDirection.add(Vector2(pts[0].x(), pts[0].y()));
                 break;
             case SkPath::kLine_Verb:
                 arrayForDirection.add(Vector2(pts[1].x(), pts[1].y()));
                 break;
             case SkPath::kQuad_Verb:
                 arrayForDirection.add(Vector2(pts[1].x(), pts[1].y()));
                 arrayForDirection.add(Vector2(pts[2].x(), pts[2].y()));
                 break;
             case SkPath::kCubic_Verb:
                 arrayForDirection.add(Vector2(pts[1].x(), pts[1].y()));
                 arrayForDirection.add(Vector2(pts[2].x(), pts[2].y()));
                 arrayForDirection.add(Vector2(pts[3].x(), pts[3].y()));
                 break;
             default:
                 break;
             }
     }

     return isClockwise(arrayForDirection.array(), arrayForDirection.size());
 }

 void ShadowTessellator::reverseVertexArray(Vertex* polygon, int len) {
     int n = len / 2;
     for (int i = 0; i < n; i++) {
         Vertex tmp = polygon[i];
         int k = len - 1 - i;
         polygon[i] = polygon[k];
         polygon[k] = tmp;
     }
 }

 }; // namespace uirenderer
 }; // namespace android
	/*
	* Copyright (C) 2013 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#define LOG_TAG "OpenGLRenderer"
	#define ATRACE_TAG ATRACE_TAG_VIEW

	#include <math.h>
	#include <utils/Log.h>
	#include <utils/Trace.h>

	#include "AmbientShadow.h"
	#include "Caches.h"
	#include "ShadowTessellator.h"
	#include "SpotShadow.h"

	namespace android {
	namespace uirenderer {

	template<typename T>
	static inline T max(T a, T b) {
	return a > b ? a : b;
	}

	VertexBufferMode ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque,
	const Vector3* casterPolygon, int casterVertexCount,
	const Vector3& centroid3d, const Rect& casterBounds,
	const Rect& localClip, float maxZ, VertexBuffer& shadowVertexBuffer) {
	ATRACE_CALL();

	// A bunch of parameters to tweak the shadow.
	// TODO: Allow some of these changable by debug settings or APIs.
	float heightFactor = 1.0f / 128;
	const float geomFactor = 64;

	Caches& caches = Caches::getInstance();
	if (CC_UNLIKELY(caches.propertyAmbientRatio > 0.0f)) {
	heightFactor *= caches.propertyAmbientRatio;
	}

	Rect ambientShadowBounds(casterBounds);
	ambientShadowBounds.outset(maxZ * geomFactor * heightFactor);

	if (!localClip.intersects(ambientShadowBounds)) {
	#if DEBUG_SHADOW
	ALOGD("Ambient shadow is out of clip rect!");
	#endif
	return kVertexBufferMode_OnePolyRingShadow;
	}

	return AmbientShadow::createAmbientShadow(isCasterOpaque, casterPolygon,
	casterVertexCount, centroid3d, heightFactor, geomFactor,
	shadowVertexBuffer);

	}

	VertexBufferMode ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque,
	const Vector3* casterPolygon, int casterVertexCount,
	const mat4& receiverTransform,
	int screenWidth, int screenHeight, const Rect& casterBounds,
	const Rect& localClip, VertexBuffer& shadowVertexBuffer) {
	ATRACE_CALL();

	Caches& caches = Caches::getInstance();

	// A bunch of parameters to tweak the shadow.
	// TODO: Allow some of these changable by debug settings or APIs.
	int maximal = max(screenWidth, screenHeight);
	Vector3 lightCenter(screenWidth * 0.5f, 0, maximal);

	if (CC_UNLIKELY(caches.propertyLightPosY > 0)) {
	lightCenter.y = - caches.propertyLightPosY; // negated since this shifts up
	}
	if (CC_UNLIKELY(caches.propertyLightPosZ > 0)) {
	lightCenter.z = caches.propertyLightPosZ;
	}


	#if DEBUG_SHADOW
	ALOGD("light center %f %f %f", lightCenter.x, lightCenter.y, lightCenter.z);
	#endif

	// light position (because it's in local space) needs to compensate for receiver transform
	// TODO: should apply to light orientation, not just position
	Matrix4 reverseReceiverTransform;
	reverseReceiverTransform.loadInverse(receiverTransform);
	reverseReceiverTransform.mapPoint3d(lightCenter);

	float lightSize = maximal / 4;
	const int lightVertexCount = 8;

	if (CC_UNLIKELY(caches.propertyLightDiameter > 0)) {
	lightSize = caches.propertyLightDiameter;
	}

	// Now light and caster are both in local space, we will check whether
	// the shadow is within the clip area.
	Rect lightRect = Rect(lightCenter.x - lightSize, lightCenter.y - lightSize,
	lightCenter.x + lightSize, lightCenter.y + lightSize);
	lightRect.unionWith(localClip);
	if (!lightRect.intersects(casterBounds)) {
	#if DEBUG_SHADOW
	ALOGD("Spot shadow is out of clip rect!");
	#endif
	return kVertexBufferMode_OnePolyRingShadow;
	}

	VertexBufferMode mode = SpotShadow::createSpotShadow(isCasterOpaque,
	casterPolygon, casterVertexCount, lightCenter, lightSize,
	lightVertexCount, shadowVertexBuffer);

	#if DEBUG_SHADOW
	if(shadowVertexBuffer.getVertexCount() <= 0) {
	ALOGD("Spot shadow generation failed %d", shadowVertexBuffer.getVertexCount());
	}
	#endif
	return mode;
	}

	void ShadowTessellator::generateShadowIndices(uint16_t* shadowIndices) {
	int currentIndex = 0;
	const int rays = SHADOW_RAY_COUNT;
	// For the penumbra area.
	for (int layer = 0; layer < 2; layer ++) {
	int baseIndex = layer * rays;
	for (int i = 0; i < rays; i++) {
	shadowIndices[currentIndex++] = i + baseIndex;
	shadowIndices[currentIndex++] = rays + i + baseIndex;
	}
	// To close the loop, back to the ray 0.
	shadowIndices[currentIndex++] = 0 + baseIndex;
	// Note this is the same as the first index of next layer loop.
	shadowIndices[currentIndex++] = rays + baseIndex;
	}

	#if DEBUG_SHADOW
	if (currentIndex != MAX_SHADOW_INDEX_COUNT) {
	ALOGW("vertex index count is wrong. current %d, expected %d",
	currentIndex, MAX_SHADOW_INDEX_COUNT);
	}
	for (int i = 0; i < MAX_SHADOW_INDEX_COUNT; i++) {
	ALOGD("vertex index is (%d, %d)", i, shadowIndices[i]);
	}
	#endif
	}

	/**
	* Calculate the centroid of a 2d polygon.
	*
	* @param poly The polygon, which is represented in a Vector2 array.
	* @param polyLength The length of the polygon in terms of number of vertices.
	* @return the centroid of the polygon.
	*/
	Vector2 ShadowTessellator::centroid2d(const Vector2* poly, int polyLength) {
	double sumx = 0;
	double sumy = 0;
	int p1 = polyLength - 1;
	double area = 0;
	for (int p2 = 0; p2 < polyLength; p2++) {
	double x1 = poly[p1].x;
	double y1 = poly[p1].y;
	double x2 = poly[p2].x;
	double y2 = poly[p2].y;
	double a = (x1 * y2 - x2 * y1);
	sumx += (x1 + x2) * a;
	sumy += (y1 + y2) * a;
	area += a;
	p1 = p2;
	}

	Vector2 centroid = poly[0];
	if (area != 0) {
	centroid = Vector2(sumx / (3 * area), sumy / (3 * area));
	} else {
	ALOGW("Area is 0 while computing centroid!");
	}
	return centroid;
	}

	/**
	* Test whether the polygon is order in clockwise.
	*
	* @param polygon the polygon as a Vector2 array
	* @param len the number of points of the polygon
	*/
	bool ShadowTessellator::isClockwise(const Vector2* polygon, int len) {
	double sum = 0;
	double p1x = polygon[len - 1].x;
	double p1y = polygon[len - 1].y;
	for (int i = 0; i < len; i++) {

	double p2x = polygon[i].x;
	double p2y = polygon[i].y;
	sum += p1x * p2y - p2x * p1y;
	p1x = p2x;
	p1y = p2y;
	}
	return sum < 0;
	}

	bool ShadowTessellator::isClockwisePath(const SkPath& path) {
	SkPath::Iter iter(path, false);
	SkPoint pts[4];
	SkPath::Verb v;

	Vector<Vector2> arrayForDirection;
	while (SkPath::kDone_Verb != (v = iter.next(pts))) {
	switch (v) {
	case SkPath::kMove_Verb:
	arrayForDirection.add(Vector2(pts[0].x(), pts[0].y()));
	break;
	case SkPath::kLine_Verb:
	arrayForDirection.add(Vector2(pts[1].x(), pts[1].y()));
	break;
	case SkPath::kQuad_Verb:
	arrayForDirection.add(Vector2(pts[1].x(), pts[1].y()));
	arrayForDirection.add(Vector2(pts[2].x(), pts[2].y()));
	break;
	case SkPath::kCubic_Verb:
	arrayForDirection.add(Vector2(pts[1].x(), pts[1].y()));
	arrayForDirection.add(Vector2(pts[2].x(), pts[2].y()));
	arrayForDirection.add(Vector2(pts[3].x(), pts[3].y()));
	break;
	default:
	break;
	}
	}

	return isClockwise(arrayForDirection.array(), arrayForDirection.size());
	}

	void ShadowTessellator::reverseVertexArray(Vertex* polygon, int len) {
	int n = len / 2;
	for (int i = 0; i < n; i++) {
	Vertex tmp = polygon[i];
	int k = len - 1 - i;
	polygon[i] = polygon[k];
	polygon[k] = tmp;
	}
	}

	}; // namespace uirenderer
	}; // namespace android