78 lines
2.7 KiB
C++
78 lines
2.7 KiB
C++
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/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_HWUI_SHADOW_TESSELLATOR_H
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#define ANDROID_HWUI_SHADOW_TESSELLATOR_H
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#include "Debug.h"
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#include "Matrix.h"
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#include "VertexBuffer.h"
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namespace android {
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namespace uirenderer {
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// All SHADOW_* are used to define all the geometry property of shadows.
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// Use a simplified example to illustrate the geometry setup here.
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// Assuming we use 6 rays and only 1 layer, Then we will have 2 hexagons, which
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// are 0 to 5 and 6 to 11. The area between them will be the penumbra area, and
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// the area inside the 2nd hexagon is the umbra.
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// Also, we need to add the centroid "12" to draw the umbra area as triangle fans.
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//
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// Triange strip indices for penumbra area: (0, 6, 1, 7, 2, 8, 3, 9, 4, 10, 5, 11, 0, 6)
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// Triange strip indices for numbra area: (6, 12, 7, 12, 8, 12, 9, 12, 10, 12, 11, 12, 6)
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// 0
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//
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// 5 6 1
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// 11 7
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// 12
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// 10 8
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// 4 9 2
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//
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// 3
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// The total number of rays starting from the centroid of shadow area, in order
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// to generate the shadow geometry.
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#define SHADOW_RAY_COUNT 128
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// The total number of all the vertices representing the shadow.
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#define SHADOW_VERTEX_COUNT (2 * SHADOW_RAY_COUNT + 1)
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// The total number of indices used for drawing the shadow geometry as triangle strips.
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#define SHADOW_INDEX_COUNT (2 * SHADOW_RAY_COUNT + 1 + 2 * (SHADOW_RAY_COUNT + 1))
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#define SHADOW_MIN_CASTER_Z 0.001f
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class ShadowTessellator {
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public:
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static void tessellateAmbientShadow(const Vector3* casterPolygon,
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int casterVertexCount, const Vector3& centroid3d,
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VertexBuffer& shadowVertexBuffer);
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static void tessellateSpotShadow(const Vector3* casterPolygon, int casterVertexCount,
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const Vector3& lightPosScale, const mat4& receiverTransform,
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int screenWidth, int screenHeight, VertexBuffer& shadowVertexBuffer);
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static void generateShadowIndices(uint16_t* shadowIndices);
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static Vector2 centroid2d(const Vector2* poly, int polyLength);
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}; // ShadowTessellator
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}; // namespace uirenderer
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}; // namespace android
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#endif // ANDROID_HWUI_SHADOW_TESSELLATOR_H
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