gecko-dev/gfx/thebes/GLContext.cpp

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 *   Mozilla Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Vladimir Vukicevic <vladimir@pobox.com>
 *   Mark Steele <mwsteele@gmail.com>
 *   Bas Schouten <bschouten@mozilla.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */


#include <string.h>
#include <stdio.h>

#include "prlink.h"

#include "gfxImageSurface.h"
#include "GLContext.h"
#include "GLContextProvider.h"

namespace mozilla {
namespace gl {

// define this here since it's global to GLContextProvider, not any
// specific implementation
typedef GLContextProvider::ContextFormat ContextFormat;
const ContextFormat ContextFormat::BasicRGBA32Format(ContextFormat::BasicRGBA32);

#define MAX_SYMBOL_LENGTH 128
#define MAX_SYMBOL_NAMES 5

PRBool
LibrarySymbolLoader::OpenLibrary(const char *library)
{
    PRLibSpec lspec;
    lspec.type = PR_LibSpec_Pathname;
    lspec.value.pathname = library;

    mLibrary = PR_LoadLibraryWithFlags(lspec, PR_LD_LAZY | PR_LD_LOCAL);
    if (!mLibrary)
        return PR_FALSE;

    return PR_TRUE;
}

PRBool
LibrarySymbolLoader::LoadSymbols(SymLoadStruct *firstStruct, PRBool tryplatform, const char *prefix)
{
    return LoadSymbols(mLibrary, firstStruct, tryplatform ? mLookupFunc : nsnull, prefix);
}

PRFuncPtr
LibrarySymbolLoader::LookupSymbol(PRLibrary *lib,
                                  const char *sym,
                                  PlatformLookupFunction lookupFunction)
{
    PRFuncPtr res = 0;

    // try finding it in the library directly, if we have one
    if (lib) {
        res = PR_FindFunctionSymbol(lib, sym);
    }

    // try finding it in the process
    if (!res) {
        PRLibrary *leakedLibRef;
        res = PR_FindFunctionSymbolAndLibrary(sym, &leakedLibRef);
    }

    // no? then try looking it up via the lookup symbol
    if (!res && lookupFunction) {
        res = lookupFunction(sym);
    }

    return res;
}

PRBool
LibrarySymbolLoader::LoadSymbols(PRLibrary *lib,
                                 SymLoadStruct *firstStruct,
                                 PlatformLookupFunction lookupFunction,
                                 const char *prefix)
{
    char sbuf[MAX_SYMBOL_LENGTH * 2];

    SymLoadStruct *ss = firstStruct;
    while (ss->symPointer) {
        *ss->symPointer = 0;

        for (int i = 0; i < MAX_SYMBOL_NAMES; i++) {
            if (ss->symNames[i] == nsnull)
                break;

            const char *s = ss->symNames[i];
            if (prefix && *prefix != 0) {
                strcpy(sbuf, prefix);
                strcat(sbuf, ss->symNames[i]);
                s = sbuf;
            }

            PRFuncPtr p = LookupSymbol(lib, s, lookupFunction);
            if (p) {
                *ss->symPointer = p;
                break;
            }
        }

        if (*ss->symPointer == 0) {
            fprintf (stderr, "Can't find symbol '%s'\n", ss->symNames[0]);
            return PR_FALSE;
        }

        ss++;
    }

    return PR_TRUE;
}

/*
 * XXX - we should really know the ARB/EXT variants of these
 * instead of only handling the symbol if it's exposed directly.
 */

PRBool
GLContext::InitWithPrefix(const char *prefix, PRBool trygl)
{
    if (mInitialized) {
        return PR_TRUE;
    }

    SymLoadStruct symbols[] = {
        { (PRFuncPtr*) &fActiveTexture, { "ActiveTexture", "ActiveTextureARB", NULL } },
        { (PRFuncPtr*) &fAttachShader, { "AttachShader", "AttachShaderARB", NULL } },
        { (PRFuncPtr*) &fBindAttribLocation, { "BindAttribLocation", "BindAttribLocationARB", NULL } },
        { (PRFuncPtr*) &fBindBuffer, { "BindBuffer", "BindBufferARB", NULL } },
        { (PRFuncPtr*) &fBindTexture, { "BindTexture", "BindTextureARB", NULL } },
        { (PRFuncPtr*) &fBlendColor, { "BlendColor", NULL } },
        { (PRFuncPtr*) &fBlendEquation, { "BlendEquation", NULL } },
        { (PRFuncPtr*) &fBlendEquationSeparate, { "BlendEquationSeparate", "BlendEquationSeparateEXT", NULL } },
        { (PRFuncPtr*) &fBlendFunc, { "BlendFunc", NULL } },
        { (PRFuncPtr*) &fBlendFuncSeparate, { "BlendFuncSeparate", "BlendFuncSeparateEXT", NULL } },
        { (PRFuncPtr*) &fBufferData, { "BufferData", NULL } },
        { (PRFuncPtr*) &fBufferSubData, { "BufferSubData", NULL } },
        { (PRFuncPtr*) &fClear, { "Clear", NULL } },
        { (PRFuncPtr*) &fClearColor, { "ClearColor", NULL } },
#ifdef USE_GLES2
        { (PRFuncPtr*) &fClearDepthf, { "ClearDepthf", NULL } },
#else
        { (PRFuncPtr*) &fClearDepth, { "ClearDepth", NULL } },
#endif
        { (PRFuncPtr*) &fClearStencil, { "ClearStencil", NULL } },
        { (PRFuncPtr*) &fColorMask, { "ColorMask", NULL } },
        { (PRFuncPtr*) &fCreateProgram, { "CreateProgram", "CreateProgramARB", NULL } },
        { (PRFuncPtr*) &fCreateShader, { "CreateShader", "CreateShaderARB", NULL } },
        { (PRFuncPtr*) &fCullFace, { "CullFace", NULL } },
        { (PRFuncPtr*) &fDeleteBuffers, { "DeleteBuffers", "DeleteBuffersARB", NULL } },
        { (PRFuncPtr*) &fDeleteTextures, { "DeleteTextures", "DeleteTexturesARB", NULL } },
        { (PRFuncPtr*) &fDeleteProgram, { "DeleteProgram", "DeleteProgramARB", NULL } },
        { (PRFuncPtr*) &fDeleteShader, { "DeleteShader", "DeleteShaderARB", NULL } },
        { (PRFuncPtr*) &fDetachShader, { "DetachShader", "DetachShaderARB", NULL } },
        { (PRFuncPtr*) &fDepthFunc, { "DepthFunc", NULL } },
        { (PRFuncPtr*) &fDepthMask, { "DepthMask", NULL } },
#ifdef USE_GLES2
        { (PRFuncPtr*) &fDepthRangef, { "DepthRangef", NULL } },
#else
        { (PRFuncPtr*) &fDepthRange, { "DepthRange", NULL } },
#endif
        { (PRFuncPtr*) &fDisable, { "Disable", NULL } },
#ifndef USE_GLES2
        { (PRFuncPtr*) &fDisableClientState, { "DisableClientState", NULL } },
#endif
        { (PRFuncPtr*) &fDisableVertexAttribArray, { "DisableVertexAttribArray", "DisableVertexAttribArrayARB", NULL } },
        { (PRFuncPtr*) &fDrawArrays, { "DrawArrays", NULL } },
        { (PRFuncPtr*) &fDrawElements, { "DrawElements", NULL } },
        { (PRFuncPtr*) &fEnable, { "Enable", NULL } },
#ifndef USE_GLES2
        { (PRFuncPtr*) &fEnableClientState, { "EnableClientState", NULL } },
#endif
        { (PRFuncPtr*) &fEnableVertexAttribArray, { "EnableVertexAttribArray", "EnableVertexAttribArrayARB", NULL } },
        { (PRFuncPtr*) &fFinish, { "Finish", NULL } },
        { (PRFuncPtr*) &fFlush, { "Flush", NULL } },
        { (PRFuncPtr*) &fFrontFace, { "FrontFace", NULL } },
        { (PRFuncPtr*) &fGetActiveAttrib, { "GetActiveAttrib", "GetActiveAttribARB", NULL } },
        { (PRFuncPtr*) &fGetActiveUniform, { "GetActiveUniform", "GetActiveUniformARB", NULL } },
        { (PRFuncPtr*) &fGetAttachedShaders, { "GetAttachedShaders", "GetAttachedShadersARB", NULL } },
        { (PRFuncPtr*) &fGetAttribLocation, { "GetAttribLocation", "GetAttribLocationARB", NULL } },
        { (PRFuncPtr*) &fGetIntegerv, { "GetIntegerv", NULL } },
        { (PRFuncPtr*) &fGetFloatv, { "GetFloatv", NULL } },
        { (PRFuncPtr*) &fGetBooleanv, { "GetBooleanv", NULL } },
        { (PRFuncPtr*) &fGetBufferParameteriv, { "GetBufferParameteriv", "GetBufferParameterivARB", NULL } },
        { (PRFuncPtr*) &fGenBuffers, { "GenBuffers", "GenBuffersARB", NULL } },
        { (PRFuncPtr*) &fGenTextures, { "GenTextures", NULL } },
        { (PRFuncPtr*) &fGetError, { "GetError", NULL } },
        { (PRFuncPtr*) &fGetProgramiv, { "GetProgramiv", "GetProgramivARB", NULL } },
        { (PRFuncPtr*) &fGetProgramInfoLog, { "GetProgramInfoLog", "GetProgramInfoLogARB", NULL } },
#ifndef USE_GLES2
        { (PRFuncPtr*) &fTexCoordPointer, { "TexCoordPointer", NULL } },
#endif
        { (PRFuncPtr*) &fTexParameteri, { "TexParameteri", NULL } },
        { (PRFuncPtr*) &fTexParameterf, { "TexParameterf", NULL } },
        { (PRFuncPtr*) &fGetString, { "GetString", NULL } },
        { (PRFuncPtr*) &fGetTexParameterfv, { "GetTexParameterfv", NULL } },
        { (PRFuncPtr*) &fGetTexParameteriv, { "GetTexParameteriv", NULL } },
        { (PRFuncPtr*) &fGetUniformfv, { "GetUniformfv", "GetUniformfvARB", NULL } },
        { (PRFuncPtr*) &fGetUniformiv, { "GetUniformiv", "GetUniformivARB", NULL } },
        { (PRFuncPtr*) &fGetUniformLocation, { "GetUniformLocation", "GetUniformLocationARB", NULL } },
        { (PRFuncPtr*) &fGetVertexAttribfv, { "GetVertexAttribfv", "GetVertexAttribfvARB", NULL } },
        { (PRFuncPtr*) &fGetVertexAttribiv, { "GetVertexAttribiv", "GetVertexAttribivARB", NULL } },
        { (PRFuncPtr*) &fHint, { "Hint", NULL } },
        { (PRFuncPtr*) &fIsBuffer, { "IsBuffer", "IsBufferARB", NULL } },
        { (PRFuncPtr*) &fIsEnabled, { "IsEnabled", NULL } },
        { (PRFuncPtr*) &fIsProgram, { "IsProgram", "IsProgramARB", NULL } },
        { (PRFuncPtr*) &fIsShader, { "IsShader", "IsShaderARB", NULL } },
        { (PRFuncPtr*) &fIsTexture, { "IsTexture", "IsTextureARB", NULL } },
        { (PRFuncPtr*) &fLineWidth, { "LineWidth", NULL } },
        { (PRFuncPtr*) &fLinkProgram, { "LinkProgram", "LinkProgramARB", NULL } },
        { (PRFuncPtr*) &fPixelStorei, { "PixelStorei", NULL } },
        { (PRFuncPtr*) &fPolygonOffset, { "PolygonOffset", NULL } },
#ifndef USE_GLES2
        { (PRFuncPtr*) &fReadBuffer,  { "ReadBuffer", NULL } },
#endif
        { (PRFuncPtr*) &fReadPixels, { "ReadPixels", NULL } },
        { (PRFuncPtr*) &fSampleCoverage, { "SampleCoverage", NULL } },
        { (PRFuncPtr*) &fScissor, { "Scissor", NULL } },
        { (PRFuncPtr*) &fStencilFunc, { "StencilFunc", NULL } },
        { (PRFuncPtr*) &fStencilFuncSeparate, { "StencilFuncSeparate", "StencilFuncSeparateEXT", NULL } },
        { (PRFuncPtr*) &fStencilMask, { "StencilMask", NULL } },
        { (PRFuncPtr*) &fStencilMaskSeparate, { "StencilMaskSeparate", "StencilMaskSeparateEXT", NULL } },
        { (PRFuncPtr*) &fStencilOp, { "StencilOp", NULL } },
        { (PRFuncPtr*) &fStencilOpSeparate, { "StencilOpSeparate", "StencilOpSeparateEXT", NULL } },
#ifndef USE_GLES2
        { (PRFuncPtr*) &fTexEnvf, { "TexEnvf",  NULL } },
#endif
        { (PRFuncPtr*) &fTexImage2D, { "TexImage2D", NULL } },
        { (PRFuncPtr*) &fTexSubImage2D, { "TexSubImage2D", NULL } },
        { (PRFuncPtr*) &fUniform1f, { "Uniform1f", NULL } },
        { (PRFuncPtr*) &fUniform1fv, { "Uniform1fv", NULL } },
        { (PRFuncPtr*) &fUniform1i, { "Uniform1i", NULL } },
        { (PRFuncPtr*) &fUniform1iv, { "Uniform1iv", NULL } },
        { (PRFuncPtr*) &fUniform2f, { "Uniform2f", NULL } },
        { (PRFuncPtr*) &fUniform2fv, { "Uniform2fv", NULL } },
        { (PRFuncPtr*) &fUniform2i, { "Uniform2i", NULL } },
        { (PRFuncPtr*) &fUniform2iv, { "Uniform2iv", NULL } },
        { (PRFuncPtr*) &fUniform3f, { "Uniform3f", NULL } },
        { (PRFuncPtr*) &fUniform3fv, { "Uniform3fv", NULL } },
        { (PRFuncPtr*) &fUniform3i, { "Uniform3i", NULL } },
        { (PRFuncPtr*) &fUniform3iv, { "Uniform3iv", NULL } },
        { (PRFuncPtr*) &fUniform4f, { "Uniform4f", NULL } },
        { (PRFuncPtr*) &fUniform4fv, { "Uniform4fv", NULL } },
        { (PRFuncPtr*) &fUniform4i, { "Uniform4i", NULL } },
        { (PRFuncPtr*) &fUniform4iv, { "Uniform4iv", NULL } },
        { (PRFuncPtr*) &fUniformMatrix2fv, { "UniformMatrix2fv", NULL } },
        { (PRFuncPtr*) &fUniformMatrix3fv, { "UniformMatrix3fv", NULL } },
        { (PRFuncPtr*) &fUniformMatrix4fv, { "UniformMatrix4fv", NULL } },
        { (PRFuncPtr*) &fUseProgram, { "UseProgram", NULL } },
        { (PRFuncPtr*) &fValidateProgram, { "ValidateProgram", NULL } },
        { (PRFuncPtr*) &fVertexAttribPointer, { "VertexAttribPointer", NULL } },
        { (PRFuncPtr*) &fVertexAttrib1f, { "VertexAttrib1f", NULL } },
        { (PRFuncPtr*) &fVertexAttrib2f, { "VertexAttrib2f", NULL } },
        { (PRFuncPtr*) &fVertexAttrib3f, { "VertexAttrib3f", NULL } },
        { (PRFuncPtr*) &fVertexAttrib4f, { "VertexAttrib4f", NULL } },
        { (PRFuncPtr*) &fVertexAttrib1fv, { "VertexAttrib1fv", NULL } },
        { (PRFuncPtr*) &fVertexAttrib2fv, { "VertexAttrib2fv", NULL } },
        { (PRFuncPtr*) &fVertexAttrib3fv, { "VertexAttrib3fv", NULL } },
        { (PRFuncPtr*) &fVertexAttrib4fv, { "VertexAttrib4fv", NULL } },
#ifndef USE_GLES2
        { (PRFuncPtr*) &fVertexPointer, { "VertexPointer", NULL } },
#endif
        { (PRFuncPtr*) &fViewport, { "Viewport", NULL } },
        { (PRFuncPtr*) &fCompileShader, { "CompileShader", NULL } },
        { (PRFuncPtr*) &fCopyTexImage2D, { "CopyTexImage2D", NULL } },
        { (PRFuncPtr*) &fCopyTexSubImage2D, { "CopyTexSubImage2D", NULL } },
        { (PRFuncPtr*) &fGetShaderiv, { "GetShaderiv", NULL } },
        { (PRFuncPtr*) &fGetShaderInfoLog, { "GetShaderInfoLog", NULL } },
        { (PRFuncPtr*) &fGetShaderSource, { "GetShaderSource", NULL } },
        { (PRFuncPtr*) &fShaderSource, { "ShaderSource", NULL } },
        { (PRFuncPtr*) &fVertexAttribPointer, { "VertexAttribPointer", NULL } },
        { (PRFuncPtr*) &fBindFramebuffer, { "BindFramebuffer", "BindFramebufferEXT", NULL } },
        { (PRFuncPtr*) &fBindRenderbuffer, { "BindRenderbuffer", "BindRenderbufferEXT", NULL } },
        { (PRFuncPtr*) &fCheckFramebufferStatus, { "CheckFramebufferStatus", "CheckFramebufferStatusEXT", NULL } },
        { (PRFuncPtr*) &fDeleteFramebuffers, { "DeleteFramebuffers", "DeleteFramebuffersEXT", NULL } },
        { (PRFuncPtr*) &fDeleteRenderbuffers, { "DeleteRenderbuffers", "DeleteRenderbuffersEXT", NULL } },
        { (PRFuncPtr*) &fFramebufferRenderbuffer, { "FramebufferRenderbuffer", "FramebufferRenderbufferEXT", NULL } },
        { (PRFuncPtr*) &fFramebufferTexture2D, { "FramebufferTexture2D", "FramebufferTexture2DEXT", NULL } },
        { (PRFuncPtr*) &fGenerateMipmap, { "GenerateMipmap", "GenerateMipmapEXT", NULL } },
        { (PRFuncPtr*) &fGenFramebuffers, { "GenFramebuffers", "GenFramebuffersEXT", NULL } },
        { (PRFuncPtr*) &fGenRenderbuffers, { "GenRenderbuffers", "GenRenderbuffersEXT", NULL } },
        { (PRFuncPtr*) &fGetFramebufferAttachmentParameteriv, { "GetFramebufferAttachmentParameteriv", "GetFramebufferAttachmentParameterivEXT", NULL } },
        { (PRFuncPtr*) &fGetRenderbufferParameteriv, { "GetRenderbufferParameteriv", "GetRenderbufferParameterivEXT", NULL } },
        { (PRFuncPtr*) &fIsFramebuffer, { "IsFramebuffer", "IsFramebufferEXT", NULL } },
        { (PRFuncPtr*) &fIsRenderbuffer, { "IsRenderbuffer", "IsRenderbufferEXT", NULL } },
        { (PRFuncPtr*) &fRenderbufferStorage, { "RenderbufferStorage", "RenderbufferStorageEXT", NULL } },
#if 0
        { (PRFuncPtr*) &fMapBuffer, { "MapBuffer", NULL } },
        { (PRFuncPtr*) &fUnmapBuffer, { "UnmapBuffer", NULL } },
#endif

        { NULL, { NULL } },

    };

    mInitialized = LoadSymbols(&symbols[0], trygl, prefix);
    return mInitialized;
}

PRBool
GLContext::IsExtensionSupported(const char *extension)
{
    const GLubyte *extensions = NULL;
    const GLubyte *start;
    GLubyte *where, *terminator;

    /* Extension names should not have spaces. */
    where = (GLubyte *) strchr(extension, ' ');
    if (where || *extension == '\0')
        return PR_FALSE;

    extensions = fGetString(LOCAL_GL_EXTENSIONS);
    /* 
     * It takes a bit of care to be fool-proof about parsing the
     * OpenGL extensions string. Don't be fooled by sub-strings,
     * etc. 
     */
    start = extensions;
    for (;;) {
        where = (GLubyte *) strstr((const char *) start, extension);
        if (!where) {
            break;
        }
        terminator = where + strlen(extension);
        if (where == start || *(where - 1) == ' ') {
            if (*terminator == ' ' || *terminator == '\0') {
                return PR_TRUE;
            }
        }
        start = terminator;
    }
    return PR_FALSE;
}

already_AddRefed<TextureImage>
GLContext::CreateTextureImage(const nsIntSize& aSize,
                              TextureImage::ContentType aContentType,
                              GLint aWrapMode,
                              PRBool aUseNearestFilter)
{
  MakeCurrent();

  GLuint texture;
  fGenTextures(1, &texture);

  fActiveTexture(LOCAL_GL_TEXTURE0);
  fBindTexture(LOCAL_GL_TEXTURE_2D, texture);

  GLint texfilter = aUseNearestFilter ? LOCAL_GL_NEAREST : LOCAL_GL_LINEAR;
  fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_MIN_FILTER, texfilter);
  fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_MAG_FILTER, texfilter);
  fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_WRAP_S, aWrapMode);
  fTexParameteri(LOCAL_GL_TEXTURE_2D, LOCAL_GL_TEXTURE_WRAP_T, aWrapMode);
  DEBUG_GL_ERROR_CHECK(this);

  return CreateBasicTextureImage(texture, aSize, aContentType, this);
}

BasicTextureImage::~BasicTextureImage()
{
    mGLContext->MakeCurrent();
    mGLContext->fDeleteTextures(1, &mTexture);
}

gfxContext*
BasicTextureImage::BeginUpdate(nsIntRegion& aRegion)
{
    NS_ASSERTION(!mUpdateContext, "BeginUpdate() without EndUpdate()?");

    // determine the region the client will need to repaint
    if (!mTextureInited)
        // if the texture hasn't been initialized yet, force the
        // client to paint everything
        mUpdateRect = nsIntRect(nsIntPoint(0, 0), mSize);
    else
        mUpdateRect = aRegion.GetBounds();
    // the basic impl can't upload updates to disparate regions,
    // only rects
    aRegion = nsIntRegion(mUpdateRect);
        
    nsIntSize rgnSize = mUpdateRect.Size();
    if (!nsIntRect(nsIntPoint(0, 0), mSize).Contains(mUpdateRect))
    {
        NS_ERROR("update outside of image");
        return NULL;
    }

    ImageFormat format =
        (GetContentType() == gfxASurface::CONTENT_COLOR) ?
        gfxASurface::ImageFormatRGB24 : gfxASurface::ImageFormatARGB32;
    nsRefPtr<gfxASurface> updateSurface =
        CreateUpdateSurface(gfxIntSize(rgnSize.width, rgnSize.height),
                            format);
    if (!updateSurface)
        return NULL;

    mUpdateContext = new gfxContext(updateSurface);
    return mUpdateContext;
}

PRBool
BasicTextureImage::EndUpdate()
{
    NS_ASSERTION(!!mUpdateContext, "EndUpdate() without BeginUpdate()?");

    // FIXME: this is the slow boat.  Make me fast (with GLXPixmap?).
    nsRefPtr<gfxImageSurface> uploadImage =
        GetImageForUpload(mUpdateContext->OriginalSurface());
    if (!uploadImage)
        return PR_FALSE;

    mGLContext->fBindTexture(LOCAL_GL_TEXTURE_2D, mTexture);
    if (!mTextureInited)
    {
        mGLContext->fTexImage2D(LOCAL_GL_TEXTURE_2D,
                                0,
                                LOCAL_GL_RGBA,
                                mUpdateRect.width,
                                mUpdateRect.height,
                                0,
                                LOCAL_GL_RGBA,
                                LOCAL_GL_UNSIGNED_BYTE,
                                uploadImage->Data());
        mTextureInited = PR_TRUE;
    } else {
        mGLContext->fTexSubImage2D(LOCAL_GL_TEXTURE_2D,
                                   0,
                                   mUpdateRect.x,
                                   mUpdateRect.y,
                                   mUpdateRect.width,
                                   mUpdateRect.height,
                                   LOCAL_GL_RGBA,
                                   LOCAL_GL_UNSIGNED_BYTE,
                                   uploadImage->Data());
    }
    mUpdateContext = NULL;
    return PR_TRUE;         // mTexture is bound
}

} /* namespace gl */
} /* namespace mozilla */