Implement helper functionalities for computing image size with ES3 settings.

gpu/command_buffer/common/gles2_cmd_utils.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file is here so other GLES2 related files can have a common set of
 // includes where appropriate.
 
 #ifndef GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 #define GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_
 
@@ skipping 34 matching lines @@
 
 // Does an add checking for overflow.  If there was no overflow returns true.
 inline bool SafeAddInt32(int32_t a, int32_t b, int32_t* dst) {
   DCHECK(dst);
   base::CheckedNumeric<int32_t> checked = a;
   checked += b;
   *dst = checked.ValueOrDefault(0);
   return checked.IsValid();
 }
 
+struct GLES2_UTILS_EXPORT PixelStoreParams {
+  PixelStoreParams()
+      : alignment(4),
+        row_length(0),
+        image_height(0),
+        skip_pixels(0),
+        skip_rows(0),
+        skip_images(0) {
+  }
+
+  int32_t alignment;
+  int32_t row_length;
+  int32_t image_height;
+  int32_t skip_pixels;
+  int32_t skip_rows;
+  int32_t skip_images;
+};
+
 // Utilties for GLES2 support.
 class GLES2_UTILS_EXPORT GLES2Util {
  public:
   static const int kNumFaces = 6;
 
   // Bits returned by GetChannelsForFormat
   enum ChannelBits {
     kRed = 0x1,
     kGreen = 0x2,
     kBlue = 0x4,
@@ skipping 37 matching lines @@
 
   // Computes the size of a single group of elements from a format and type pair
   static uint32_t ComputeImageGroupSize(int format, int type);
 
   // Computes the size of an image row including alignment padding
   static bool ComputeImagePaddedRowSize(
       int width, int format, int type, int unpack_alignment,
       uint32_t* padded_row_size);
 
   // Computes the size of image data for TexImage2D and TexSubImage2D.
-  // Optionally the unpadded and padded row sizes can be returned. If height < 2
-  // then the padded_row_size will be the same as the unpadded_row_size since
-  // padding is not necessary.
+  // Optionally the unpadded and padded row sizes can be returned.
   static bool ComputeImageDataSizes(
       int width, int height, int depth, int format, int type,
       int unpack_alignment, uint32_t* size, uint32_t* unpadded_row_size,
       uint32_t* padded_row_size);
 
+  // Similar to the above function, but taking into consideration all ES3
+  // pixel pack/unpack parameters.
+  // Optionally the skipped bytes in the beginning can be returned.
+  // Note the returned |size| includes |skip_size|.
+  static bool ComputeImageDataSizes(
+      int width, int height, int depth, int format, int type,
+      const PixelStoreParams& params,
+      uint32_t* size, uint32_t* unpadded_row_size,
+      uint32_t* padded_row_size, uint32_t* skip_size);
+
   static size_t RenderbufferBytesPerPixel(int format);
 
   // Return the element's number of bytes.
   // For example, GL_FLOAT_MAT3 returns sizeof(GLfloat).
   static uint32_t GetElementSizeForUniformType(int type);
   // Return the number of elements.
   // For example, GL_FLOAT_MAT3 returns 9.
   static uint32_t GetElementCountForUniformType(int type);
 
   static size_t GetGLTypeSizeForTexturesAndBuffers(uint32_t type);
@@ skipping 119 matching lines @@
   bool fail_if_major_perf_caveat;
   bool lose_context_when_out_of_memory;
   ContextType context_type;
 };
 
 }  // namespace gles2
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_GLES2_CMD_UTILS_H_