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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.
*/
#ifndef ANDROID_HWUI_AMBIENT_SHADOW_H
#define ANDROID_HWUI_AMBIENT_SHADOW_H
#include "Debug.h"
#include "OpenGLRenderer.h"
#include "Vector.h"
#include "VertexBuffer.h"
namespace android {
namespace uirenderer {
/**
* AmbientShadow is used to calculate the ambient shadow value around a polygon.
*
* TODO: calculateIntersection() now is O(N*M), where N is the number of
* polygon's vertics and M is the number of rays. In fact, by staring tracing
* the vertex from the previous intersection, the algorithm can be O(N + M);
*/
class AmbientShadow {
public:
static VertexBufferMode createAmbientShadow(bool isCasterOpaque, const Vector3* poly,
int polyLength, const Vector3& centroid3d, float heightFactor,
float geomFactor, VertexBuffer& shadowVertexBuffer);
private:
static void calculateRayDirections(int rays, Vector2* dir);
static void calculateIntersection(const Vector3* poly, int nbVertices,
const Vector3& start, const Vector2& dir, int& outEdgeIndex,
float& outEdgeFraction, float& outRayDist);
static void calculateNormal(int rays, int currentRayIndex, const Vector2* dir,
const float* rayDist, Vector2& normal);
}; // AmbientShadow
}; // namespace uirenderer
}; // namespace android
#endif // ANDROID_HWUI_AMBIENT_SHADOW_H