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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.
*/
#include <math.h>
#include <utils/Log.h>
#include <utils/Trace.h>
#include <utils/MathUtils.h>
#include "AmbientShadow.h"
#include "Properties.h"
#include "ShadowTessellator.h"
#include "SpotShadow.h"
#include "Vector.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;
if (CC_UNLIKELY(Properties::overrideAmbientRatio > 0.0f)) {
heightFactor *= Properties::overrideAmbientRatio;
}
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();
Vector3 adjustedLightCenter(lightCenter);
if (CC_UNLIKELY(Properties::overrideLightPosY > 0)) {
adjustedLightCenter.y = - Properties::overrideLightPosY; // negated since this shifts up
}
if (CC_UNLIKELY(Properties::overrideLightPosZ > 0)) {
adjustedLightCenter.z = Properties::overrideLightPosZ;
}
#if DEBUG_SHADOW
ALOGD("light center %f %f %f %d",
adjustedLightCenter.x, adjustedLightCenter.y, adjustedLightCenter.z, lightRadius);
#endif
if (isnan(adjustedLightCenter.x)
|| isnan(adjustedLightCenter.y)
|| isnan(adjustedLightCenter.z)) {
return;
}
// 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(Properties::overrideLightRadius > 0)) {
lightRadius = Properties::overrideLightRadius;
}
// 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;
}
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);
// make sure that dotProduct value is in acsof input range [-1, 1]
dotProduct = MathUtils::clamp(dotProduct, -1.0f, 1.0f);
// 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
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