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 {

 void 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;
     }

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

 void ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque,
         const Vector3* casterPolygon, int casterVertexCount, const Vector3& casterCentroid,
         const mat4& receiverTransform, const Vector3& lightCenter, int lightRadius,
         const Rect& casterBounds, const Rect& localClip, VertexBuffer& shadowVertexBuffer) {
     ATRACE_CALL();

     Caches& caches = Caches::getInstance();

     Vector3 adjustedLightCenter(lightCenter);
     if (CC_UNLIKELY(caches.propertyLightPosY > 0)) {
         adjustedLightCenter.y = - caches.propertyLightPosY; // negated since this shifts up
     }
     if (CC_UNLIKELY(caches.propertyLightPosZ > 0)) {
         adjustedLightCenter.z = caches.propertyLightPosZ;
     }

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

     if (CC_UNLIKELY(caches.propertyLightRadius > 0)) {
         lightRadius = caches.propertyLightRadius;
     }

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

     SpotShadow::createSpotShadow(isCasterOpaque, adjustedLightCenter, lightRadius,
             casterPolygon, casterVertexCount, casterCentroid, shadowVertexBuffer);

 #if DEBUG_SHADOW
      if(shadowVertexBuffer.getVertexCount() <= 0) {
         ALOGD("Spot shadow generation failed %d", shadowVertexBuffer.getVertexCount());
      }
 #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){static_cast<float>(sumx / (3 * area)),
             static_cast<float>(sumy / (3 * area))};
     } else {
         ALOGW("Area is 0 while computing centroid!");
     }
     return centroid;
 }

 // Make sure p1 -> p2 is going CW around the poly.
 Vector2 ShadowTessellator::calculateNormal(const Vector2& p1, const Vector2& p2) {
     Vector2 result = p2 - p1;
     if (result.x != 0 || result.y != 0) {
         result.normalize();
         // Calculate the normal , which is CCW 90 rotate to the delta.
         float tempy = result.y;
         result.y = result.x;
         result.x = -tempy;
     }
     return result;
 }
 /**
  * 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) {
     if (len < 2 || polygon == nullptr) {
         return true;
     }
     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;
     }
 }

 int ShadowTessellator::getExtraVertexNumber(const Vector2& vector1,
         const Vector2& vector2, float divisor) {
     // When there is no distance difference, there is no need for extra vertices.
     if (vector1.lengthSquared() == 0 || vector2.lengthSquared() == 0) {
         return 0;
     }
     // The formula is :
     // extraNumber = floor(acos(dot(n1, n2)) / (M_PI / EXTRA_VERTEX_PER_PI))
     // The value ranges for each step are:
     // dot( ) --- [-1, 1]
     // acos( )     --- [0, M_PI]
     // floor(...)  --- [0, EXTRA_VERTEX_PER_PI]
     float dotProduct = vector1.dot(vector2);
     // TODO: Use look up table for the dotProduct to extraVerticesNumber
     // computation, if needed.
     float angle = acosf(dotProduct);
     return (int) floor(angle / divisor);
 }

 void ShadowTessellator::checkOverflow(int used, int total, const char* bufferName) {
     LOG_ALWAYS_FATAL_IF(used > total, "Error: %s overflow!!! used %d, total %d",
             bufferName, used, total);
 }

 }; // 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 {

	void 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;
	}

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

	void ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque,
	const Vector3* casterPolygon, int casterVertexCount, const Vector3& casterCentroid,
	const mat4& receiverTransform, const Vector3& lightCenter, int lightRadius,
	const Rect& casterBounds, const Rect& localClip, VertexBuffer& shadowVertexBuffer) {
	ATRACE_CALL();

	Caches& caches = Caches::getInstance();

	Vector3 adjustedLightCenter(lightCenter);
	if (CC_UNLIKELY(caches.propertyLightPosY > 0)) {
	adjustedLightCenter.y = - caches.propertyLightPosY; // negated since this shifts up
	}
	if (CC_UNLIKELY(caches.propertyLightPosZ > 0)) {
	adjustedLightCenter.z = caches.propertyLightPosZ;
	}

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

	if (CC_UNLIKELY(caches.propertyLightRadius > 0)) {
	lightRadius = caches.propertyLightRadius;
	}

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

	SpotShadow::createSpotShadow(isCasterOpaque, adjustedLightCenter, lightRadius,
	casterPolygon, casterVertexCount, casterCentroid, shadowVertexBuffer);

	#if DEBUG_SHADOW
	if(shadowVertexBuffer.getVertexCount() <= 0) {
	ALOGD("Spot shadow generation failed %d", shadowVertexBuffer.getVertexCount());
	}
	#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){static_cast<float>(sumx / (3 * area)),
	static_cast<float>(sumy / (3 * area))};
	} else {
	ALOGW("Area is 0 while computing centroid!");
	}
	return centroid;
	}

	// Make sure p1 -> p2 is going CW around the poly.
	Vector2 ShadowTessellator::calculateNormal(const Vector2& p1, const Vector2& p2) {
	Vector2 result = p2 - p1;
	if (result.x != 0 \|\| result.y != 0) {
	result.normalize();
	// Calculate the normal , which is CCW 90 rotate to the delta.
	float tempy = result.y;
	result.y = result.x;
	result.x = -tempy;
	}
	return result;
	}
	/**
	* 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) {
	if (len < 2 \|\| polygon == nullptr) {
	return true;
	}
	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;
	}
	}

	int ShadowTessellator::getExtraVertexNumber(const Vector2& vector1,
	const Vector2& vector2, float divisor) {
	// When there is no distance difference, there is no need for extra vertices.
	if (vector1.lengthSquared() == 0 \|\| vector2.lengthSquared() == 0) {
	return 0;
	}
	// The formula is :
	// extraNumber = floor(acos(dot(n1, n2)) / (M_PI / EXTRA_VERTEX_PER_PI))
	// The value ranges for each step are:
	// dot( ) --- [-1, 1]
	// acos( ) --- [0, M_PI]
	// floor(...) --- [0, EXTRA_VERTEX_PER_PI]
	float dotProduct = vector1.dot(vector2);
	// TODO: Use look up table for the dotProduct to extraVerticesNumber
	// computation, if needed.
	float angle = acosf(dotProduct);
	return (int) floor(angle / divisor);
	}

	void ShadowTessellator::checkOverflow(int used, int total, const char* bufferName) {
	LOG_ALWAYS_FATAL_IF(used > total, "Error: %s overflow!!! used %d, total %d",
	bufferName, used, total);
	}

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