3 * Copyright (C) 2013 The Android Open Source Project
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
18 #ifndef ANDROID_HWUI_SHADOW_TESSELLATOR_H
19 #define ANDROID_HWUI_SHADOW_TESSELLATOR_H
27 namespace uirenderer {
31 // All SHADOW_* are used to define all the geometry property of shadows.
32 // Use a simplified example to illustrate the geometry setup here.
33 // Assuming we use 6 rays and only 1 layer, Then we will have 2 hexagons, which
34 // are 0 to 5 and 6 to 11. The area between them will be the penumbra area, and
35 // the area inside the 2nd hexagon is the umbra.
36 // Ambient shadow is using only 1 layer for opaque caster, otherwise, spot
37 // shadow and ambient shadow are using 2 layers.
38 // Triange strip indices for penumbra area: (0, 6, 1, 7, 2, 8, 3, 9, 4, 10, 5, 11, 0, 6)
49 // The total number of rays starting from the centroid of shadow area, in order
50 // to generate the shadow geometry.
51 #define SHADOW_RAY_COUNT 128
53 // The total number of all the vertices representing the shadow.
54 // For the case we only have 1 layer, then we will just fill only 2/3 of it.
55 #define SHADOW_VERTEX_COUNT (3 * SHADOW_RAY_COUNT)
57 // The total number of indices used for drawing the shadow geometry as triangle strips.
58 // Depending on the mode we are drawing, we can have 1 layer or 2 layers.
59 // Therefore, we only build the longer index buffer.
60 #define TWO_POLY_RING_SHADOW_INDEX_COUNT (4 * (SHADOW_RAY_COUNT + 1))
61 #define ONE_POLY_RING_SHADOW_INDEX_COUNT (2 * (SHADOW_RAY_COUNT + 1))
63 #define MAX_SHADOW_INDEX_COUNT TWO_POLY_RING_SHADOW_INDEX_COUNT
65 #define SHADOW_MIN_CASTER_Z 0.001f
67 #define MINIMAL_DELTA_THETA (M_PI / 180 / 1000)
69 class ShadowTessellator {
71 static void tessellateAmbientShadow(bool isCasterOpaque,
72 const Vector3* casterPolygon, int casterVertexCount,
73 const Vector3& centroid3d, const Rect& casterBounds,
74 const Rect& localClip, float maxZ, VertexBuffer& shadowVertexBuffer);
76 static void tessellateSpotShadow(bool isCasterOpaque,
77 const Vector3* casterPolygon, int casterVertexCount, const Vector3& casterCentroid,
78 const mat4& receiverTransform, const Vector3& lightCenter, int lightRadius,
79 const Rect& casterBounds, const Rect& localClip, VertexBuffer& shadowVertexBuffer);
81 static Vector2 centroid2d(const Vector2* poly, int polyLength);
83 static Vector2 calculateNormal(const Vector2& p1, const Vector2& p2);
85 static int getExtraVertexNumber(const Vector2& vector1, const Vector2& vector2,
88 static void checkOverflow(int used, int total, const char* bufferName);
89 }; // ShadowTessellator
91 }; // namespace uirenderer
92 }; // namespace android
94 #endif // ANDROID_HWUI_SHADOW_TESSELLATOR_H