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      1 /*
      2  * Copyright (C) 2012 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef WebGraphicsContext3D_h
     32 #define WebGraphicsContext3D_h
     33 
     34 #include "WebCommon.h"
     35 #include "WebNonCopyable.h"
     36 #include "WebString.h"
     37 
     38 struct GrGLInterface;
     39 
     40 namespace blink {
     41 
     42 // WGC3D types match the corresponding GL types as defined in OpenGL ES 2.0
     43 // header file gl2.h from khronos.org.
     44 typedef char WGC3Dchar;
     45 typedef unsigned WGC3Denum;
     46 typedef unsigned char WGC3Dboolean;
     47 typedef unsigned WGC3Dbitfield;
     48 typedef signed char WGC3Dbyte;
     49 typedef unsigned char WGC3Dubyte;
     50 typedef short WGC3Dshort;
     51 typedef unsigned short WGC3Dushort;
     52 typedef int WGC3Dint;
     53 typedef int WGC3Dsizei;
     54 typedef unsigned WGC3Duint;
     55 typedef float WGC3Dfloat;
     56 typedef float WGC3Dclampf;
     57 typedef signed long int WGC3Dintptr;
     58 typedef signed long int WGC3Dsizeiptr;
     59 
     60 // Typedef for server-side objects like OpenGL textures and program objects.
     61 typedef WGC3Duint WebGLId;
     62 
     63 // This interface abstracts the operations performed by the
     64 // GraphicsContext3D in order to implement WebGL. Nearly all of the
     65 // methods exposed on this interface map directly to entry points in
     66 // the OpenGL ES 2.0 API.
     67 //
     68 // Creating a WebGraphicsContext does not make it current, or guarantee
     69 // that the context has been created successfully. Use
     70 // makeContextCurrent() to complete initialization of the context, treating
     71 // a false return value as indication that the context could not be created
     72 // successfully.
     73 class WebGraphicsContext3D : public WebNonCopyable {
     74 public:
     75     // Return value from getActiveUniform and getActiveAttrib.
     76     struct ActiveInfo {
     77         WebString name;
     78         WGC3Denum type;
     79         WGC3Dint size;
     80     };
     81 
     82     // Context creation attributes.
     83     struct Attributes {
     84         Attributes()
     85             : alpha(true)
     86             , depth(true)
     87             , stencil(true)
     88             , antialias(true)
     89             , premultipliedAlpha(true)
     90             , canRecoverFromContextLoss(true)
     91             , noExtensions(false)
     92             , shareResources(true)
     93             , preferDiscreteGPU(false)
     94             , noAutomaticFlushes(false)
     95             , failIfMajorPerformanceCaveat(false)
     96         {
     97         }
     98 
     99         bool alpha;
    100         bool depth;
    101         bool stencil;
    102         bool antialias;
    103         bool premultipliedAlpha;
    104         bool canRecoverFromContextLoss;
    105         bool noExtensions;
    106         bool shareResources;
    107         bool preferDiscreteGPU;
    108         bool noAutomaticFlushes;
    109         bool failIfMajorPerformanceCaveat;
    110         // FIXME: ideally this would be a WebURL, but it is currently not
    111         // possible to pass a WebURL by value across the WebKit API boundary.
    112         // See https://bugs.webkit.org/show_bug.cgi?id=103793#c13 .
    113         WebString topDocumentURL;
    114     };
    115 
    116     class WebGraphicsContextLostCallback {
    117     public:
    118         virtual void onContextLost() = 0;
    119 
    120     protected:
    121         virtual ~WebGraphicsContextLostCallback() { }
    122     };
    123 
    124     class WebGraphicsErrorMessageCallback {
    125     public:
    126         virtual void onErrorMessage(const WebString&, WGC3Dint) = 0;
    127 
    128     protected:
    129         virtual ~WebGraphicsErrorMessageCallback() { }
    130     };
    131 
    132     class WebGraphicsSwapBuffersCompleteCallbackCHROMIUM {
    133     public:
    134         virtual void onSwapBuffersComplete() = 0;
    135 
    136     protected:
    137         virtual ~WebGraphicsSwapBuffersCompleteCallbackCHROMIUM() { }
    138     };
    139 
    140     // This destructor needs to be public so that using classes can destroy instances if initialization fails.
    141     virtual ~WebGraphicsContext3D() { }
    142 
    143     // Makes the OpenGL context current on the current thread. Returns true on
    144     // success.
    145     virtual bool makeContextCurrent() = 0;
    146 
    147     // Each flush or finish is assigned an unique ID. The larger
    148     // the ID number, the more recently the context has been flushed.
    149     virtual uint32_t lastFlushID() { return 0; }
    150 
    151     // Resizes the region into which this WebGraphicsContext3D is drawing.
    152     virtual void reshapeWithScaleFactor(int width, int height, float scaleFactor) { }
    153 
    154     // GL_CHROMIUM_setVisibility - Changes the visibility of the backbuffer
    155     virtual void setVisibilityCHROMIUM(bool visible) = 0;
    156 
    157     // GL_EXT_discard_framebuffer - makes specified attachments of currently bound framebuffer undefined.
    158     virtual void discardFramebufferEXT(WGC3Denum target, WGC3Dsizei numAttachments, const WGC3Denum* attachments) { }
    159 
    160     // GL_CHROMIUM_discard_backbuffer - controls allocation/deallocation of the back buffer.
    161     virtual void discardBackbufferCHROMIUM() { }
    162     virtual void ensureBackbufferCHROMIUM() { }
    163 
    164     virtual unsigned insertSyncPoint() { return 0; }
    165     virtual void waitSyncPoint(unsigned) { }
    166 
    167     // Copies the contents of the off-screen render target used by the WebGL
    168     // context to the corresponding texture used by the compositor.
    169     virtual void prepareTexture() = 0;
    170 
    171     // GL_CHROMIUM_post_sub_buffer - Copies part of the back buffer to the front buffer.
    172     virtual void postSubBufferCHROMIUM(int x, int y, int width, int height) = 0;
    173 
    174     // Synthesizes an OpenGL error which will be returned from a
    175     // later call to getError. This is used to emulate OpenGL ES
    176     // 2.0 behavior on the desktop and to enforce additional error
    177     // checking mandated by WebGL.
    178     //
    179     // Per the behavior of glGetError, this stores at most one
    180     // instance of any given error, and returns them from calls to
    181     // getError in the order they were added.
    182     virtual void synthesizeGLError(WGC3Denum) = 0;
    183 
    184     virtual bool isContextLost() = 0;
    185 
    186     // GL_CHROMIUM_map_sub
    187     virtual void* mapBufferSubDataCHROMIUM(WGC3Denum target, WGC3Dintptr offset, WGC3Dsizeiptr size, WGC3Denum access) = 0;
    188     virtual void unmapBufferSubDataCHROMIUM(const void*) = 0;
    189     virtual void* mapTexSubImage2DCHROMIUM(WGC3Denum target, WGC3Dint level, WGC3Dint xoffset, WGC3Dint yoffset, WGC3Dsizei width, WGC3Dsizei height, WGC3Denum format, WGC3Denum type, WGC3Denum access) = 0;
    190     virtual void unmapTexSubImage2DCHROMIUM(const void*) = 0;
    191 
    192     // GL_CHROMIUM_request_extension
    193     virtual WebString getRequestableExtensionsCHROMIUM() = 0;
    194     virtual void requestExtensionCHROMIUM(const char*) = 0;
    195 
    196     // GL_CHROMIUM_framebuffer_multisample
    197     virtual void blitFramebufferCHROMIUM(WGC3Dint srcX0, WGC3Dint srcY0, WGC3Dint srcX1, WGC3Dint srcY1, WGC3Dint dstX0, WGC3Dint dstY0, WGC3Dint dstX1, WGC3Dint dstY1, WGC3Dbitfield mask, WGC3Denum filter) = 0;
    198     virtual void renderbufferStorageMultisampleCHROMIUM(WGC3Denum target, WGC3Dsizei samples, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height) = 0;
    199 
    200     // GL_CHROMIUM_swapbuffers_complete_callback
    201     virtual void setSwapBuffersCompleteCallbackCHROMIUM(WebGraphicsSwapBuffersCompleteCallbackCHROMIUM* callback) { }
    202 
    203     // GL_CHROMIUM_rate_limit_offscreen_context
    204     virtual void rateLimitOffscreenContextCHROMIUM() { }
    205 
    206     // GL_CHROMIUM_lose_context
    207     virtual void loseContextCHROMIUM(WGC3Denum current, WGC3Denum other) { }
    208 
    209     // The entry points below map directly to the OpenGL ES 2.0 API.
    210     // See: http://www.khronos.org/registry/gles/
    211     // and: http://www.khronos.org/opengles/sdk/docs/man/
    212     virtual void activeTexture(WGC3Denum texture) = 0;
    213     virtual void attachShader(WebGLId program, WebGLId shader) = 0;
    214     virtual void bindAttribLocation(WebGLId program, WGC3Duint index, const WGC3Dchar* name) = 0;
    215     virtual void bindBuffer(WGC3Denum target, WebGLId buffer) = 0;
    216     virtual void bindFramebuffer(WGC3Denum target, WebGLId framebuffer) = 0;
    217     virtual void bindRenderbuffer(WGC3Denum target, WebGLId renderbuffer) = 0;
    218     virtual void bindTexture(WGC3Denum target, WebGLId texture) = 0;
    219     virtual void blendColor(WGC3Dclampf red, WGC3Dclampf green, WGC3Dclampf blue, WGC3Dclampf alpha) = 0;
    220     virtual void blendEquation(WGC3Denum mode) = 0;
    221     virtual void blendEquationSeparate(WGC3Denum modeRGB, WGC3Denum modeAlpha) = 0;
    222     virtual void blendFunc(WGC3Denum sfactor, WGC3Denum dfactor) = 0;
    223     virtual void blendFuncSeparate(WGC3Denum srcRGB, WGC3Denum dstRGB, WGC3Denum srcAlpha, WGC3Denum dstAlpha) = 0;
    224 
    225     virtual void bufferData(WGC3Denum target, WGC3Dsizeiptr size, const void* data, WGC3Denum usage) = 0;
    226     virtual void bufferSubData(WGC3Denum target, WGC3Dintptr offset, WGC3Dsizeiptr size, const void* data) = 0;
    227 
    228     virtual WGC3Denum checkFramebufferStatus(WGC3Denum target) = 0;
    229     virtual void clear(WGC3Dbitfield mask) = 0;
    230     virtual void clearColor(WGC3Dclampf red, WGC3Dclampf green, WGC3Dclampf blue, WGC3Dclampf alpha) = 0;
    231     virtual void clearDepth(WGC3Dclampf depth) = 0;
    232     virtual void clearStencil(WGC3Dint s) = 0;
    233     virtual void colorMask(WGC3Dboolean red, WGC3Dboolean green, WGC3Dboolean blue, WGC3Dboolean alpha) = 0;
    234     virtual void compileShader(WebGLId shader) = 0;
    235 
    236     virtual void compressedTexImage2D(WGC3Denum target, WGC3Dint level, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height, WGC3Dint border, WGC3Dsizei imageSize, const void* data) = 0;
    237     virtual void compressedTexSubImage2D(WGC3Denum target, WGC3Dint level, WGC3Dint xoffset, WGC3Dint yoffset, WGC3Dsizei width, WGC3Dsizei height, WGC3Denum format, WGC3Dsizei imageSize, const void* data) = 0;
    238     virtual void copyTexImage2D(WGC3Denum target, WGC3Dint level, WGC3Denum internalformat, WGC3Dint x, WGC3Dint y, WGC3Dsizei width, WGC3Dsizei height, WGC3Dint border) = 0;
    239     virtual void copyTexSubImage2D(WGC3Denum target, WGC3Dint level, WGC3Dint xoffset, WGC3Dint yoffset, WGC3Dint x, WGC3Dint y, WGC3Dsizei width, WGC3Dsizei height) = 0;
    240     virtual void cullFace(WGC3Denum mode) = 0;
    241     virtual void depthFunc(WGC3Denum func) = 0;
    242     virtual void depthMask(WGC3Dboolean flag) = 0;
    243     virtual void depthRange(WGC3Dclampf zNear, WGC3Dclampf zFar) = 0;
    244     virtual void detachShader(WebGLId program, WebGLId shader) = 0;
    245     virtual void disable(WGC3Denum cap) = 0;
    246     virtual void disableVertexAttribArray(WGC3Duint index) = 0;
    247     virtual void drawArrays(WGC3Denum mode, WGC3Dint first, WGC3Dsizei count) = 0;
    248     virtual void drawElements(WGC3Denum mode, WGC3Dsizei count, WGC3Denum type, WGC3Dintptr offset) = 0;
    249 
    250     virtual void enable(WGC3Denum cap) = 0;
    251     virtual void enableVertexAttribArray(WGC3Duint index) = 0;
    252     virtual void finish() = 0;
    253     virtual void flush() = 0;
    254     virtual void framebufferRenderbuffer(WGC3Denum target, WGC3Denum attachment, WGC3Denum renderbuffertarget, WebGLId renderbuffer) = 0;
    255     virtual void framebufferTexture2D(WGC3Denum target, WGC3Denum attachment, WGC3Denum textarget, WebGLId texture, WGC3Dint level) = 0;
    256     virtual void frontFace(WGC3Denum mode) = 0;
    257     virtual void generateMipmap(WGC3Denum target) = 0;
    258 
    259     virtual bool getActiveAttrib(WebGLId program, WGC3Duint index, ActiveInfo&) = 0;
    260     virtual bool getActiveUniform(WebGLId program, WGC3Duint index, ActiveInfo&) = 0;
    261     virtual void getAttachedShaders(WebGLId program, WGC3Dsizei maxCount, WGC3Dsizei* count, WebGLId* shaders) = 0;
    262     virtual WGC3Dint getAttribLocation(WebGLId program, const WGC3Dchar* name) = 0;
    263     virtual void getBooleanv(WGC3Denum pname, WGC3Dboolean* value) = 0;
    264     virtual void getBufferParameteriv(WGC3Denum target, WGC3Denum pname, WGC3Dint* value) = 0;
    265     virtual WGC3Denum getError() = 0;
    266     virtual void getFloatv(WGC3Denum pname, WGC3Dfloat* value) = 0;
    267     virtual void getFramebufferAttachmentParameteriv(WGC3Denum target, WGC3Denum attachment, WGC3Denum pname, WGC3Dint* value) = 0;
    268     virtual void getIntegerv(WGC3Denum pname, WGC3Dint* value) = 0;
    269     virtual void getProgramiv(WebGLId program, WGC3Denum pname, WGC3Dint* value) = 0;
    270     virtual WebString getProgramInfoLog(WebGLId program) = 0;
    271     virtual void getRenderbufferParameteriv(WGC3Denum target, WGC3Denum pname, WGC3Dint* value) = 0;
    272     virtual void getShaderiv(WebGLId shader, WGC3Denum pname, WGC3Dint* value) = 0;
    273     virtual WebString getShaderInfoLog(WebGLId shader) = 0;
    274     virtual void getShaderPrecisionFormat(WGC3Denum shadertype, WGC3Denum precisiontype, WGC3Dint* range, WGC3Dint* precision) = 0;
    275     virtual WebString getShaderSource(WebGLId shader) = 0;
    276     virtual WebString getString(WGC3Denum name) = 0;
    277     virtual void getTexParameterfv(WGC3Denum target, WGC3Denum pname, WGC3Dfloat* value) = 0;
    278     virtual void getTexParameteriv(WGC3Denum target, WGC3Denum pname, WGC3Dint* value) = 0;
    279     virtual void getUniformfv(WebGLId program, WGC3Dint location, WGC3Dfloat* value) = 0;
    280     virtual void getUniformiv(WebGLId program, WGC3Dint location, WGC3Dint* value) = 0;
    281     virtual WGC3Dint getUniformLocation(WebGLId program, const WGC3Dchar* name) = 0;
    282     virtual void getVertexAttribfv(WGC3Duint index, WGC3Denum pname, WGC3Dfloat* value) = 0;
    283     virtual void getVertexAttribiv(WGC3Duint index, WGC3Denum pname, WGC3Dint* value) = 0;
    284     virtual WGC3Dsizeiptr getVertexAttribOffset(WGC3Duint index, WGC3Denum pname) = 0;
    285 
    286     virtual void hint(WGC3Denum target, WGC3Denum mode) = 0;
    287     virtual WGC3Dboolean isBuffer(WebGLId buffer) = 0;
    288     virtual WGC3Dboolean isEnabled(WGC3Denum cap) = 0;
    289     virtual WGC3Dboolean isFramebuffer(WebGLId framebuffer) = 0;
    290     virtual WGC3Dboolean isProgram(WebGLId program) = 0;
    291     virtual WGC3Dboolean isRenderbuffer(WebGLId renderbuffer) = 0;
    292     virtual WGC3Dboolean isShader(WebGLId shader) = 0;
    293     virtual WGC3Dboolean isTexture(WebGLId texture) = 0;
    294     virtual void lineWidth(WGC3Dfloat) = 0;
    295     virtual void linkProgram(WebGLId program) = 0;
    296     virtual void pixelStorei(WGC3Denum pname, WGC3Dint param) = 0;
    297     virtual void polygonOffset(WGC3Dfloat factor, WGC3Dfloat units) = 0;
    298 
    299     virtual void readPixels(WGC3Dint x, WGC3Dint y, WGC3Dsizei width, WGC3Dsizei height, WGC3Denum format, WGC3Denum type, void* pixels) = 0;
    300 
    301     virtual void releaseShaderCompiler() = 0;
    302 
    303     virtual void renderbufferStorage(WGC3Denum target, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height) = 0;
    304     virtual void sampleCoverage(WGC3Dclampf value, WGC3Dboolean invert) = 0;
    305     virtual void scissor(WGC3Dint x, WGC3Dint y, WGC3Dsizei width, WGC3Dsizei height) = 0;
    306     virtual void shaderSource(WebGLId shader, const WGC3Dchar* string) = 0;
    307     virtual void stencilFunc(WGC3Denum func, WGC3Dint ref, WGC3Duint mask) = 0;
    308     virtual void stencilFuncSeparate(WGC3Denum face, WGC3Denum func, WGC3Dint ref, WGC3Duint mask) = 0;
    309     virtual void stencilMask(WGC3Duint mask) = 0;
    310     virtual void stencilMaskSeparate(WGC3Denum face, WGC3Duint mask) = 0;
    311     virtual void stencilOp(WGC3Denum fail, WGC3Denum zfail, WGC3Denum zpass) = 0;
    312     virtual void stencilOpSeparate(WGC3Denum face, WGC3Denum fail, WGC3Denum zfail, WGC3Denum zpass) = 0;
    313 
    314     virtual void texImage2D(WGC3Denum target, WGC3Dint level, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height, WGC3Dint border, WGC3Denum format, WGC3Denum type, const void* pixels) = 0;
    315 
    316     virtual void texParameterf(WGC3Denum target, WGC3Denum pname, WGC3Dfloat param) = 0;
    317     virtual void texParameteri(WGC3Denum target, WGC3Denum pname, WGC3Dint param) = 0;
    318 
    319     virtual void texSubImage2D(WGC3Denum target, WGC3Dint level, WGC3Dint xoffset, WGC3Dint yoffset, WGC3Dsizei width, WGC3Dsizei height, WGC3Denum format, WGC3Denum type, const void* pixels) = 0;
    320 
    321     virtual void uniform1f(WGC3Dint location, WGC3Dfloat x) = 0;
    322     virtual void uniform1fv(WGC3Dint location, WGC3Dsizei count, const WGC3Dfloat* v) = 0;
    323     virtual void uniform1i(WGC3Dint location, WGC3Dint x) = 0;
    324     virtual void uniform1iv(WGC3Dint location, WGC3Dsizei count, const WGC3Dint* v) = 0;
    325     virtual void uniform2f(WGC3Dint location, WGC3Dfloat x, WGC3Dfloat y) = 0;
    326     virtual void uniform2fv(WGC3Dint location, WGC3Dsizei count, const WGC3Dfloat* v) = 0;
    327     virtual void uniform2i(WGC3Dint location, WGC3Dint x, WGC3Dint y) = 0;
    328     virtual void uniform2iv(WGC3Dint location, WGC3Dsizei count, const WGC3Dint* v) = 0;
    329     virtual void uniform3f(WGC3Dint location, WGC3Dfloat x, WGC3Dfloat y, WGC3Dfloat z) = 0;
    330     virtual void uniform3fv(WGC3Dint location, WGC3Dsizei count, const WGC3Dfloat* v) = 0;
    331     virtual void uniform3i(WGC3Dint location, WGC3Dint x, WGC3Dint y, WGC3Dint z) = 0;
    332     virtual void uniform3iv(WGC3Dint location, WGC3Dsizei count, const WGC3Dint* v) = 0;
    333     virtual void uniform4f(WGC3Dint location, WGC3Dfloat x, WGC3Dfloat y, WGC3Dfloat z, WGC3Dfloat w) = 0;
    334     virtual void uniform4fv(WGC3Dint location, WGC3Dsizei count, const WGC3Dfloat* v) = 0;
    335     virtual void uniform4i(WGC3Dint location, WGC3Dint x, WGC3Dint y, WGC3Dint z, WGC3Dint w) = 0;
    336     virtual void uniform4iv(WGC3Dint location, WGC3Dsizei count, const WGC3Dint* v) = 0;
    337     virtual void uniformMatrix2fv(WGC3Dint location, WGC3Dsizei count, WGC3Dboolean transpose, const WGC3Dfloat* value) = 0;
    338     virtual void uniformMatrix3fv(WGC3Dint location, WGC3Dsizei count, WGC3Dboolean transpose, const WGC3Dfloat* value) = 0;
    339     virtual void uniformMatrix4fv(WGC3Dint location, WGC3Dsizei count, WGC3Dboolean transpose, const WGC3Dfloat* value) = 0;
    340 
    341     virtual void useProgram(WebGLId program) = 0;
    342     virtual void validateProgram(WebGLId program) = 0;
    343 
    344     virtual void vertexAttrib1f(WGC3Duint index, WGC3Dfloat x) = 0;
    345     virtual void vertexAttrib1fv(WGC3Duint index, const WGC3Dfloat* values) = 0;
    346     virtual void vertexAttrib2f(WGC3Duint index, WGC3Dfloat x, WGC3Dfloat y) = 0;
    347     virtual void vertexAttrib2fv(WGC3Duint index, const WGC3Dfloat* values) = 0;
    348     virtual void vertexAttrib3f(WGC3Duint index, WGC3Dfloat x, WGC3Dfloat y, WGC3Dfloat z) = 0;
    349     virtual void vertexAttrib3fv(WGC3Duint index, const WGC3Dfloat* values) = 0;
    350     virtual void vertexAttrib4f(WGC3Duint index, WGC3Dfloat x, WGC3Dfloat y, WGC3Dfloat z, WGC3Dfloat w) = 0;
    351     virtual void vertexAttrib4fv(WGC3Duint index, const WGC3Dfloat* values) = 0;
    352     virtual void vertexAttribPointer(WGC3Duint index, WGC3Dint size, WGC3Denum type, WGC3Dboolean normalized,
    353                                      WGC3Dsizei stride, WGC3Dintptr offset) = 0;
    354 
    355     virtual void viewport(WGC3Dint x, WGC3Dint y, WGC3Dsizei width, WGC3Dsizei height) = 0;
    356 
    357     // Support for buffer creation and deletion.
    358     virtual void genBuffers(WGC3Dsizei count, WebGLId* ids) { }
    359     virtual void genFramebuffers(WGC3Dsizei count, WebGLId* ids) { }
    360     virtual void genRenderbuffers(WGC3Dsizei count, WebGLId* ids) { }
    361     virtual void genTextures(WGC3Dsizei count, WebGLId* ids) { }
    362 
    363     virtual void deleteBuffers(WGC3Dsizei count, WebGLId* ids) { }
    364     virtual void deleteFramebuffers(WGC3Dsizei count, WebGLId* ids) { }
    365     virtual void deleteRenderbuffers(WGC3Dsizei count, WebGLId* ids) { }
    366     virtual void deleteTextures(WGC3Dsizei count, WebGLId* ids) { }
    367 
    368     virtual WebGLId createBuffer() = 0;
    369     virtual WebGLId createFramebuffer() = 0;
    370     virtual WebGLId createRenderbuffer() = 0;
    371     virtual WebGLId createTexture() = 0;
    372 
    373     virtual void deleteBuffer(WebGLId) = 0;
    374     virtual void deleteFramebuffer(WebGLId) = 0;
    375     virtual void deleteRenderbuffer(WebGLId) = 0;
    376     virtual void deleteTexture(WebGLId) = 0;
    377 
    378     virtual WebGLId createProgram() = 0;
    379     virtual WebGLId createShader(WGC3Denum) = 0;
    380 
    381     virtual void deleteShader(WebGLId) = 0;
    382     virtual void deleteProgram(WebGLId) = 0;
    383 
    384     virtual void setContextLostCallback(WebGraphicsContextLostCallback* callback) { }
    385     virtual void setErrorMessageCallback(WebGraphicsErrorMessageCallback* callback) { }
    386     // GL_ARB_robustness
    387     //
    388     // This entry point must provide slightly different semantics than
    389     // the GL_ARB_robustness extension; specifically, the lost context
    390     // state is sticky, rather than reported only once.
    391     virtual WGC3Denum getGraphicsResetStatusARB() { return 0; /* GL_NO_ERROR */ }
    392 
    393     virtual WebString getTranslatedShaderSourceANGLE(WebGLId shader) = 0;
    394 
    395     // GL_CHROMIUM_iosurface
    396     virtual void texImageIOSurface2DCHROMIUM(WGC3Denum target, WGC3Dint width, WGC3Dint height, WGC3Duint ioSurfaceId, WGC3Duint plane) { }
    397 
    398     // GL_EXT_texture_storage
    399     virtual void texStorage2DEXT(WGC3Denum target, WGC3Dint levels, WGC3Duint internalformat,
    400                                  WGC3Dint width, WGC3Dint height) { }
    401 
    402     // GL_EXT_occlusion_query
    403     virtual WebGLId createQueryEXT() { return 0; }
    404     virtual void deleteQueryEXT(WebGLId query) { }
    405     virtual WGC3Dboolean isQueryEXT(WebGLId query) { return false; }
    406     virtual void beginQueryEXT(WGC3Denum target, WebGLId query) { }
    407     virtual void endQueryEXT(WGC3Denum target) { }
    408     virtual void getQueryivEXT(WGC3Denum target, WGC3Denum pname, WGC3Dint* params) { }
    409     virtual void getQueryObjectuivEXT(WebGLId query, WGC3Denum pname, WGC3Duint* params) { }
    410 
    411     // GL_CHROMIUM_bind_uniform_location
    412     virtual void bindUniformLocationCHROMIUM(WebGLId program, WGC3Dint location, const WGC3Dchar* uniform) { }
    413 
    414     // GL_CHROMIUM_copy_texture
    415     virtual void copyTextureCHROMIUM(WGC3Denum target, WGC3Duint sourceId,
    416         WGC3Duint destId, WGC3Dint level, WGC3Denum internalFormat, WGC3Denum destType) { }
    417 
    418     // GL_CHROMIUM_shallow_flush
    419     virtual void shallowFlushCHROMIUM() { }
    420     virtual void shallowFinishCHROMIUM() { }
    421 
    422     // GL_CHROMIUM_texture_mailbox
    423     virtual void genMailboxCHROMIUM(WGC3Dbyte* mailbox) { }
    424     virtual void produceTextureCHROMIUM(WGC3Denum target, const WGC3Dbyte* mailbox) { }
    425     virtual void produceTextureDirectCHROMIUM(WebGLId texture, WGC3Denum target, const WGC3Dbyte* mailbox) { }
    426 
    427     virtual void consumeTextureCHROMIUM(WGC3Denum target, const WGC3Dbyte* mailbox) { }
    428     virtual WebGLId createAndConsumeTextureCHROMIUM(WGC3Denum target, const WGC3Dbyte* mailbox) { return 0; }
    429 
    430     // GL_EXT_debug_marker
    431     virtual void insertEventMarkerEXT(const WGC3Dchar* marker) { }
    432     virtual void pushGroupMarkerEXT(const WGC3Dchar* marker) { }
    433     virtual void popGroupMarkerEXT(void) { }
    434 
    435     // GL_OES_vertex_array_object
    436     virtual WebGLId createVertexArrayOES() { return 0; }
    437     virtual void deleteVertexArrayOES(WebGLId array) { }
    438     virtual WGC3Dboolean isVertexArrayOES(WebGLId array) { return false; }
    439     virtual void bindVertexArrayOES(WebGLId array) { }
    440 
    441     // GL_CHROMIUM_texture_from_image
    442     virtual void bindTexImage2DCHROMIUM(WGC3Denum target, WGC3Dint imageId) { }
    443     virtual void releaseTexImage2DCHROMIUM(WGC3Denum target, WGC3Dint imageId) { }
    444 
    445     // GL_CHROMIUM_pixel_transfer_buffer_object
    446     virtual void* mapBufferCHROMIUM(WGC3Denum target, WGC3Denum access) { return 0; }
    447     virtual WGC3Dboolean unmapBufferCHROMIUM(WGC3Denum target) { return false; }
    448 
    449     // GL_CHROMIUM_async_pixel_transfers
    450     virtual void asyncTexImage2DCHROMIUM(WGC3Denum target, WGC3Dint level, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height, WGC3Dint border, WGC3Denum format, WGC3Denum type, const void* pixels) { }
    451     virtual void asyncTexSubImage2DCHROMIUM(WGC3Denum target, WGC3Dint level, WGC3Dint xoffset, WGC3Dint yoffset, WGC3Dsizei width, WGC3Dsizei height, WGC3Denum format, WGC3Denum type, const void* pixels) { }
    452     virtual void waitAsyncTexImage2DCHROMIUM(WGC3Denum) { }
    453 
    454     // GL_EXT_draw_buffers
    455     virtual void drawBuffersEXT(WGC3Dsizei n, const WGC3Denum* bufs) { }
    456 
    457     virtual GrGLInterface* createGrGLInterface() { return 0; }
    458 
    459     // GL_CHROMIUM_map_image
    460     virtual WGC3Duint createImageCHROMIUM(WGC3Dsizei width, WGC3Dsizei height, WGC3Denum internalformat, WGC3Denum usage) { return 0; }
    461     virtual void destroyImageCHROMIUM(WGC3Duint imageId) { }
    462     virtual void getImageParameterivCHROMIUM(WGC3Duint imageId, WGC3Denum pname, WGC3Dint* params) { }
    463     virtual void* mapImageCHROMIUM(WGC3Duint imageId) { return 0; }
    464     virtual void unmapImageCHROMIUM(WGC3Duint imageId) { }
    465 
    466     // GL_ANGLE_instanced_arrays
    467     virtual void drawArraysInstancedANGLE(WGC3Denum mode, WGC3Dint first, WGC3Dsizei count, WGC3Dsizei primcount) { }
    468     virtual void drawElementsInstancedANGLE(WGC3Denum mode, WGC3Dsizei count, WGC3Denum type, WGC3Dintptr offset, WGC3Dsizei primcount) { }
    469     virtual void vertexAttribDivisorANGLE(WGC3Duint index, WGC3Duint divisor) { }
    470 
    471     // GL_EXT_multisampled_render_to_texture
    472     virtual void framebufferTexture2DMultisampleEXT(WGC3Denum target, WGC3Denum attachment, WGC3Denum textarget, WebGLId texture, WGC3Dint level, WGC3Dsizei samples) { }
    473     virtual void renderbufferStorageMultisampleEXT(WGC3Denum target, WGC3Dsizei samples, WGC3Denum internalformat, WGC3Dsizei width, WGC3Dsizei height) { };
    474 };
    475 
    476 } // namespace blink
    477 
    478 #endif
    479