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 #ifndef LOG_TAG 21 #define LOG_TAG "OpenGLRenderer" 22 #endif 23 24 #include <GLES2/gl2.h> 25 26 #include <cutils/compiler.h> 27 28 namespace android { 29 namespace uirenderer { 30 31 /////////////////////////////////////////////////////////////////////////////// 32 // Stencil buffer management 33 /////////////////////////////////////////////////////////////////////////////// 34 35 class ANDROID_API Stencil { 36 public: 37 Stencil(); 38 39 /** 40 * Returns the desired size for the stencil buffer. If the returned value 41 * is 0, then no stencil buffer is required. 42 */ 43 ANDROID_API static uint32_t getStencilSize(); 44 45 /** 46 * Returns the smallest stencil format accepted by render buffers. 47 */ 48 static GLenum getSmallestStencilFormat(); 49 50 /** 51 * Clears the stencil buffer. 52 */ 53 void clear(); 54 55 /** 56 * Enables stencil test. When the stencil test is enabled the stencil 57 * buffer is not written into. 58 */ 59 void enableTest(); 60 61 /** 62 * Enables stencil write. When stencil write is enabled, the stencil 63 * test always succeeds and the value 0x1 is written in the stencil 64 * buffer for each fragment. 65 */ 66 void enableWrite(); 67 68 /** 69 * The test passes only when equal to the specified value. 70 */ 71 void enableDebugTest(GLint value, bool greater = false); 72 73 /** 74 * Used for debugging. The stencil test always passes and increments. 75 */ 76 void enableDebugWrite(); 77 78 /** 79 * Disables stencil test and write. 80 */ 81 void disable(); 82 83 /** 84 * Indicates whether either test or write is enabled. 85 */ 86 bool isEnabled() { 87 return mState != kDisabled; 88 } 89 90 /** 91 * Indicates whether testing only is enabled. 92 */ 93 bool isTestEnabled() { 94 return mState == kTest; 95 } 96 97 private: 98 void enable(); 99 100 enum StencilState { 101 kDisabled, 102 kTest, 103 kWrite 104 }; 105 106 StencilState mState; 107 108 }; // class Stencil 109 110 }; // namespace uirenderer 111 }; // namespace android 112 113 #endif // ANDROID_HWUI_STENCIL_H 114