Bug 1048668 - WebGL2 - Implement CopyBufferSubData.; r=jgilbert

--HG--
extra : source : b4c58b9519fc35c634d2a912f3900605ccc081a3

dom/canvas/WebGL2ContextBuffers.cpp

@@ -16,7 +16,8 @@ void
 WebGL2Context::CopyBufferSubData(GLenum readTarget, GLenum writeTarget, GLintptr readOffset,
                                  GLintptr writeOffset, GLsizeiptr size)
 {
-    MOZ_CRASH("Not Implemented.");
+    MakeContextCurrent();
+    gl->fCopyBufferSubData(readTarget, writeTarget, readOffset, writeOffset, size);
 }
 
 void

gfx/gl/GLContext.cpp

@@ -77,6 +77,7 @@ static const char *sExtensionNames[] = {
     "GL_ARB_ES2_compatibility",
     "GL_ARB_ES3_compatibility",
     "GL_ARB_color_buffer_float",
+    "GL_ARB_copy_buffer",
     "GL_ARB_depth_texture",
     "GL_ARB_draw_buffers",
     "GL_ARB_draw_instanced",
@@ -1029,6 +1030,20 @@ GLContext::InitWithPrefix(const char *prefix, bool trygl)
             }
         }
 
+        if (IsSupported(GLFeature::copy_buffer)) {
+            SymLoadStruct copyBufferSymbols[] = {
+                { (PRFuncPtr*) &mSymbols.fCopyBufferSubData, { "CopyBufferSubData", nullptr } },
+                END_SYMBOLS
+            };
+
+            if (!LoadSymbols(copyBufferSymbols, trygl, prefix)) {
+                NS_ERROR("GL supports copy_buffer without supplying its function.");
+
+                MarkUnsupported(GLFeature::copy_buffer);
+                ClearSymbols(copyBufferSymbols);
+            }
+        }
+
         if (IsSupported(GLFeature::draw_buffers)) {
             SymLoadStruct coreSymbols[] = {
                 { (PRFuncPtr*) &mSymbols.fDrawBuffers, { "DrawBuffers", nullptr } },

gfx/gl/GLContext.h

@@ -81,6 +81,7 @@ MOZ_BEGIN_ENUM_CLASS(GLFeature)
     bind_buffer_offset,
     blend_minmax,
     clear_buffers,
+    copy_buffer,
     depth_texture,
     draw_buffers,
     draw_instanced,
@@ -347,6 +348,7 @@ public:
         ARB_ES2_compatibility,
         ARB_ES3_compatibility,
         ARB_color_buffer_float,
+        ARB_copy_buffer,
         ARB_depth_texture,
         ARB_draw_buffers,
         ARB_draw_instanced,
@@ -2664,6 +2666,18 @@ public:
         AFTER_GL_CALL;
     }
 
+// Core GL & Extension ARB_copy_buffer
+public:
+    void fCopyBufferSubData(GLenum readtarget, GLenum writetarget,
+                            GLintptr readoffset, GLintptr writeoffset,
+                            GLsizeiptr size)
+    {
+        BEFORE_GL_CALL;
+        ASSERT_SYMBOL_PRESENT(fCopyBufferSubData);
+        mSymbols.fCopyBufferSubData(readtarget, writetarget, readoffset, writeoffset, size);
+        AFTER_GL_CALL;
+    }
+
 
 // -----------------------------------------------------------------------------
 // Constructor

gfx/gl/GLContextFeatures.cpp

@@ -80,6 +80,15 @@ static const FeatureInfo sFeatureInfoArr[] = {
             GLContext::Extensions_End
         }
     },
+    {
+        "copy_buffer",
+        310, // OpenGL version
+        300, // OpenGL ES version
+        GLContext::ARB_copy_buffer,
+        {
+            GLContext::Extensions_End
+        }
+    },
     {
         "depth_texture",
         200, // OpenGL version

gfx/gl/GLContextSymbols.h

@@ -420,6 +420,12 @@ struct GLContextSymbols
     typedef realGLboolean (GLAPIENTRY * PFNGLUNMAPBUFFER) (GLenum target);
     PFNGLUNMAPBUFFER fUnmapBuffer;
 
+    // ARB_copy_buffer / OpenGL 3.1 / OpenGL ES 3.0
+    typedef void (GLAPIENTRY * PFNGLCOPYBUFFERSUBDATAPROC) (GLenum readTarget, GLenum writeTarget,
+                                                            GLintptr readOffset, GLintptr writeOffset,
+                                                            GLsizeiptr size);
+    PFNGLCOPYBUFFERSUBDATAPROC fCopyBufferSubData;
+
     typedef GLenum (GLAPIENTRY * PFNGLGETGRAPHICSRESETSTATUS) (void);
     PFNGLGETGRAPHICSRESETSTATUS fGetGraphicsResetStatus;