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      1 /*
      2  Copyright 2011 Google Inc.
      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 GrGeometryBuffer_DEFINED
     18 #define GrGeometryBuffer_DEFINED
     19 
     20 #include "GrResource.h"
     21 
     22 class GrGpu;
     23 
     24 /**
     25  * Parent class for vertex and index buffers
     26  */
     27 class GrGeometryBuffer : public GrResource {
     28 public:
     29     /**
     30      * Retrieves the size of the buffer
     31      *
     32      * @return the size of the buffer in bytes
     33      */
     34     size_t size() const { return fSizeInBytes; }
     35 
     36     /**
     37      *Retrieves whether the buffer was created with the dynamic flag
     38      *
     39      * @return true if the buffer was created with the dynamic flag
     40      */
     41     bool dynamic() const { return fDynamic; }
     42 
     43     /**
     44      * Locks the buffer to be written by the CPU.
     45      *
     46      * The previous content of the buffer is invalidated. It is an error
     47      * to draw from the buffer while it is locked. It is an error to call lock
     48      * on an already locked buffer.
     49      *
     50      * @return a pointer to the data or NULL if the lock fails.
     51      */
     52     virtual void* lock() = 0;
     53 
     54     /**
     55      * Returns the same ptr that lock() returned at time of lock or NULL if the
     56      * is not locked.
     57      *
     58      * @return ptr to locked buffer data or undefined if buffer is not locked.
     59      */
     60     virtual void* lockPtr() const = 0;
     61 
     62     /**
     63      * Unlocks the buffer.
     64      *
     65      * The pointer returned by the previous lock call will no longer be valid.
     66      */
     67     virtual void unlock() = 0;
     68 
     69     /**
     70      Queries whether the buffer has been locked.
     71 
     72      @return true if the buffer is locked, false otherwise.
     73      */
     74     virtual bool isLocked() const = 0;
     75 
     76     /**
     77      * Updates the buffer data.
     78      *
     79      * The size of the buffer will be preserved. The src data will be
     80      * placed at the begining of the buffer and any remaining contents will
     81      * be undefined.
     82      *
     83      * @return returns true if the update succeeds, false otherwise.
     84      */
     85     virtual bool updateData(const void* src, size_t srcSizeInBytes) = 0;
     86 
     87     /**
     88      * Updates a portion of the buffer data.
     89      *
     90      * The contents of the buffer outside the update region are preserved.
     91      *
     92      * @return returns true if the update succeeds, false otherwise.
     93      */
     94     virtual bool updateSubData(const void* src,
     95                                size_t srcSizeInBytes,
     96                                size_t offset) = 0;
     97 protected:
     98     GrGeometryBuffer(GrGpu* gpu, size_t sizeInBytes, bool dynamic)
     99         : INHERITED(gpu)
    100         , fSizeInBytes(sizeInBytes)
    101         , fDynamic(dynamic) {}
    102 
    103 private:
    104     size_t   fSizeInBytes;
    105     bool     fDynamic;
    106 
    107     typedef GrResource INHERITED;
    108 };
    109 
    110 #endif
    111