gfx/gl/GLReadTexImageHelper.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef GLREADTEXIMAGEHELPER_H_
   8 #define GLREADTEXIMAGEHELPER_H_
   9
  10 #include "GLContextTypes.h"
  11 #include "mozilla/Attributes.h"
  12 #include "nsSize.h"
  13 #include "mozilla/RefPtr.h"
  14 #include "mozilla/gfx/Types.h"
  15
  16 namespace mozilla {
  17
  18 namespace gfx {
  19 class DataSourceSurface;
  20 }  // namespace gfx
  21
  22 namespace gl {
  23
  24 // Returns true if the `dest{Format,Type}` are the same as the
  25 // `read{Format,Type}`.
  26 bool GetActualReadFormats(GLContext* gl, GLenum destFormat, GLenum destType,
  27                           GLenum* out_readFormat, GLenum* out_readType);
  28
  29 void ReadPixelsIntoDataSurface(GLContext* aGL,
  30                                gfx::DataSourceSurface* aSurface);
  31
  32 already_AddRefed<gfx::DataSourceSurface> ReadBackSurface(
  33     GLContext* gl, GLuint aTexture, bool aYInvert, gfx::SurfaceFormat aFormat);
  34
  35 already_AddRefed<gfx::DataSourceSurface> YInvertImageSurface(
  36     gfx::DataSourceSurface* aSurf, uint32_t aStride);
  37
  38 void SwapRAndBComponents(gfx::DataSourceSurface* surf);
  39
  40 class GLReadTexImageHelper final {
  41   // The GLContext is the sole owner of the GLBlitHelper.
  42   GLContext* mGL;
  43
  44   GLuint mPrograms[4];
  45
  46   GLuint TextureImageProgramFor(GLenum aTextureTarget, int aShader);
  47
  48   bool DidGLErrorOccur(const char* str);
  49
  50  public:
  51   explicit GLReadTexImageHelper(GLContext* gl);
  52   ~GLReadTexImageHelper();
  53
  54   /**
  55    * Read the image data contained in aTexture, and return it as an
  56    * ImageSurface. If GL_RGBA is given as the format, a
  57    * SurfaceFormat::A8R8G8B8_UINT32 surface is returned. Not implemented yet: If
  58    * GL_RGB is given as the format, a SurfaceFormat::X8R8G8B8_UINT32 surface is
  59    * returned. If GL_LUMINANCE is given as the format, a SurfaceFormat::A8
  60    * surface is returned.
  61    *
  62    * THIS IS EXPENSIVE.  It is ridiculously expensive.  Only do this
  63    * if you absolutely positively must, and never in any performance
  64    * critical path.
  65    *
  66    * NOTE: aShaderProgram is really mozilla::layers::ShaderProgramType. It is
  67    * passed as int to eliminate including LayerManagerOGLProgram.h here.
  68    */
  69   already_AddRefed<gfx::DataSourceSurface> ReadTexImage(
  70       GLuint aTextureId, GLenum aTextureTarget, const gfx::IntSize& aSize,
  71       /* ShaderProgramType */ int aShaderProgram, bool aYInvert = false);
  72
  73   bool ReadTexImage(gfx::DataSourceSurface* aDest, GLuint aTextureId,
  74                     GLenum aTextureTarget, const gfx::IntSize& aSize,
  75                     int aShaderProgram, bool aYInvert = false);
  76 };
  77
  78 }  // namespace gl
  79 }  // namespace mozilla
  80
  81 #endif