1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ANDROID_HWUI_STENCIL_H 18 #define ANDROID_HWUI_STENCIL_H 19 20 #include <GLES2/gl2.h> 21 22 #include <cutils/compiler.h> 23 24 namespace android { 25 namespace uirenderer { 26 27 /////////////////////////////////////////////////////////////////////////////// 28 // Stencil buffer management 29 /////////////////////////////////////////////////////////////////////////////// 30 31 class ANDROID_API Stencil { 32 public: 33 /** 34 * Returns the desired size for the stencil buffer. If the returned value 35 * is 0, then no stencil buffer is required. 36 */ 37 ANDROID_API static uint8_t getStencilSize(); 38 39 static GLenum getLayerStencilFormat(); 40 41 /** 42 * Clears the stencil buffer. 43 */ 44 void clear(); 45 46 /** 47 * Enables stencil test. When the stencil test is enabled the stencil buffer is not written 48 * into. An increment threshold of zero causes the stencil to use a constant reference value 49 * and GL_EQUAL for the test. A non-zero increment threshold causes the stencil to use that 50 * value as the reference value and GL_EQUAL for the test. 51 */ 52 void enableTest(int incrementThreshold); 53 54 /** 55 * Enables stencil write. When stencil write is enabled, the stencil 56 * test always succeeds and the value 0x1 is written in the stencil 57 * buffer for each fragment. An increment threshold of zero causes the stencil to use a constant 58 * reference value and GL_EQUAL for the test. A non-zero increment threshold causes the stencil 59 * to use that value as the reference value and GL_EQUAL for the test. 60 */ 61 void enableWrite(int incrementThreshold); 62 63 /** 64 * The test passes only when equal to the specified value. 65 */ 66 void enableDebugTest(GLint value, bool greater = false); 67 68 /** 69 * Used for debugging. The stencil test always passes and increments. 70 */ 71 void enableDebugWrite(); 72 73 /** 74 * Disables stencil test and write. 75 */ 76 void disable(); 77 78 /** 79 * Indicates whether either test or write is enabled. 80 */ isEnabled()81 bool isEnabled() { 82 return mState != StencilState::Disabled; 83 } 84 85 /** 86 * Indicates whether testing only is enabled. 87 */ isTestEnabled()88 bool isTestEnabled() { 89 return mState == StencilState::Test; 90 } 91 isWriteEnabled()92 bool isWriteEnabled() { 93 return mState == StencilState::Write; 94 } 95 96 void dump(); 97 98 private: 99 enum class StencilState { 100 Disabled, 101 Test, 102 Write 103 }; 104 105 void enable(); 106 StencilState mState = StencilState::Disabled; 107 108 }; // class Stencil 109 110 }; // namespace uirenderer 111 }; // namespace android 112 113 #endif // ANDROID_HWUI_STENCIL_H 114