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/*
* 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