Home | History | Annotate | Download | only in hwui 
      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