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      1 /*
      2  * Copyright 2012 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 
      8 
      9 #include "GrGLCaps.h"
     10 #include "GrGLContext.h"
     11 #include "SkTSearch.h"
     12 #include "SkTSort.h"
     13 
     14 GrGLCaps::GrGLCaps() {
     15     this->reset();
     16 }
     17 
     18 void GrGLCaps::reset() {
     19     INHERITED::reset();
     20 
     21     fVerifiedColorConfigs.reset();
     22     fStencilFormats.reset();
     23     fStencilVerifiedColorConfigs.reset();
     24     fMSFBOType = kNone_MSFBOType;
     25     fFBFetchType = kNone_FBFetchType;
     26     fMaxFragmentUniformVectors = 0;
     27     fMaxVertexAttributes = 0;
     28     fMaxFragmentTextureUnits = 0;
     29     fMaxFixedFunctionTextureCoords = 0;
     30     fRGBA8RenderbufferSupport = false;
     31     fBGRAFormatSupport = false;
     32     fBGRAIsInternalFormat = false;
     33     fTextureSwizzleSupport = false;
     34     fUnpackRowLengthSupport = false;
     35     fUnpackFlipYSupport = false;
     36     fPackRowLengthSupport = false;
     37     fPackFlipYSupport = false;
     38     fTextureUsageSupport = false;
     39     fTexStorageSupport = false;
     40     fTextureRedSupport = false;
     41     fImagingSupport = false;
     42     fTwoFormatLimit = false;
     43     fFragCoordsConventionSupport = false;
     44     fVertexArrayObjectSupport = false;
     45     fUseNonVBOVertexAndIndexDynamicData = false;
     46     fIsCoreProfile = false;
     47     fFixedFunctionSupport = false;
     48     fDiscardFBSupport = false;
     49     fFullClearIsFree = false;
     50 }
     51 
     52 GrGLCaps::GrGLCaps(const GrGLCaps& caps) : GrDrawTargetCaps() {
     53     *this = caps;
     54 }
     55 
     56 GrGLCaps& GrGLCaps::operator = (const GrGLCaps& caps) {
     57     INHERITED::operator=(caps);
     58     fVerifiedColorConfigs = caps.fVerifiedColorConfigs;
     59     fStencilFormats = caps.fStencilFormats;
     60     fStencilVerifiedColorConfigs = caps.fStencilVerifiedColorConfigs;
     61     fMaxFragmentUniformVectors = caps.fMaxFragmentUniformVectors;
     62     fMaxVertexAttributes = caps.fMaxVertexAttributes;
     63     fMaxFragmentTextureUnits = caps.fMaxFragmentTextureUnits;
     64     fMaxFixedFunctionTextureCoords = caps.fMaxFixedFunctionTextureCoords;
     65     fMSFBOType = caps.fMSFBOType;
     66     fFBFetchType = caps.fFBFetchType;
     67     fRGBA8RenderbufferSupport = caps.fRGBA8RenderbufferSupport;
     68     fBGRAFormatSupport = caps.fBGRAFormatSupport;
     69     fBGRAIsInternalFormat = caps.fBGRAIsInternalFormat;
     70     fTextureSwizzleSupport = caps.fTextureSwizzleSupport;
     71     fUnpackRowLengthSupport = caps.fUnpackRowLengthSupport;
     72     fUnpackFlipYSupport = caps.fUnpackFlipYSupport;
     73     fPackRowLengthSupport = caps.fPackRowLengthSupport;
     74     fPackFlipYSupport = caps.fPackFlipYSupport;
     75     fTextureUsageSupport = caps.fTextureUsageSupport;
     76     fTexStorageSupport = caps.fTexStorageSupport;
     77     fTextureRedSupport = caps.fTextureRedSupport;
     78     fImagingSupport = caps.fImagingSupport;
     79     fTwoFormatLimit = caps.fTwoFormatLimit;
     80     fFragCoordsConventionSupport = caps.fFragCoordsConventionSupport;
     81     fVertexArrayObjectSupport = caps.fVertexArrayObjectSupport;
     82     fUseNonVBOVertexAndIndexDynamicData = caps.fUseNonVBOVertexAndIndexDynamicData;
     83     fIsCoreProfile = caps.fIsCoreProfile;
     84     fFixedFunctionSupport = caps.fFixedFunctionSupport;
     85     fDiscardFBSupport = caps.fDiscardFBSupport;
     86     fFullClearIsFree = caps.fFullClearIsFree;
     87 
     88     return *this;
     89 }
     90 
     91 void GrGLCaps::init(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
     92 
     93     this->reset();
     94     if (!ctxInfo.isInitialized()) {
     95         return;
     96     }
     97 
     98     GrGLBinding binding = ctxInfo.binding();
     99     GrGLVersion version = ctxInfo.version();
    100 
    101     /**************************************************************************
    102      * Caps specific to GrGLCaps
    103      **************************************************************************/
    104 
    105     if (kES_GrGLBinding == binding) {
    106         GR_GL_GetIntegerv(gli, GR_GL_MAX_FRAGMENT_UNIFORM_VECTORS,
    107                           &fMaxFragmentUniformVectors);
    108     } else {
    109         SkASSERT(kDesktop_GrGLBinding == binding);
    110         GrGLint max;
    111         GR_GL_GetIntegerv(gli, GR_GL_MAX_FRAGMENT_UNIFORM_COMPONENTS, &max);
    112         fMaxFragmentUniformVectors = max / 4;
    113         if (version >= GR_GL_VER(3, 2)) {
    114             GrGLint profileMask;
    115             GR_GL_GetIntegerv(gli, GR_GL_CONTEXT_PROFILE_MASK, &profileMask);
    116             fIsCoreProfile = SkToBool(profileMask & GR_GL_CONTEXT_CORE_PROFILE_BIT);
    117         }
    118         if (!fIsCoreProfile) {
    119             fFixedFunctionSupport = true;
    120             GR_GL_GetIntegerv(gli, GR_GL_MAX_TEXTURE_COORDS, &fMaxFixedFunctionTextureCoords);
    121             // Sanity check
    122             SkASSERT(fMaxFixedFunctionTextureCoords > 0 && fMaxFixedFunctionTextureCoords < 128);
    123         }
    124     }
    125     GR_GL_GetIntegerv(gli, GR_GL_MAX_VERTEX_ATTRIBS, &fMaxVertexAttributes);
    126     GR_GL_GetIntegerv(gli, GR_GL_MAX_TEXTURE_IMAGE_UNITS, &fMaxFragmentTextureUnits);
    127 
    128     if (kDesktop_GrGLBinding == binding) {
    129         fRGBA8RenderbufferSupport = true;
    130     } else {
    131         fRGBA8RenderbufferSupport = version >= GR_GL_VER(3,0) ||
    132                                     ctxInfo.hasExtension("GL_OES_rgb8_rgba8") ||
    133                                     ctxInfo.hasExtension("GL_ARM_rgba8");
    134     }
    135 
    136     if (kDesktop_GrGLBinding == binding) {
    137         fBGRAFormatSupport = version >= GR_GL_VER(1,2) ||
    138                              ctxInfo.hasExtension("GL_EXT_bgra");
    139     } else {
    140         if (ctxInfo.hasExtension("GL_APPLE_texture_format_BGRA8888")) {
    141             fBGRAFormatSupport = true;
    142         } else if (ctxInfo.hasExtension("GL_EXT_texture_format_BGRA8888")) {
    143             fBGRAFormatSupport = true;
    144             fBGRAIsInternalFormat = true;
    145         }
    146         SkASSERT(fBGRAFormatSupport ||
    147                  kSkia8888_GrPixelConfig != kBGRA_8888_GrPixelConfig);
    148     }
    149 
    150     if (kDesktop_GrGLBinding == binding) {
    151         fTextureSwizzleSupport = version >= GR_GL_VER(3,3) ||
    152                                  ctxInfo.hasExtension("GL_ARB_texture_swizzle");
    153     } else {
    154         fTextureSwizzleSupport = version >= GR_GL_VER(3,0);
    155     }
    156 
    157     if (kDesktop_GrGLBinding == binding) {
    158         fUnpackRowLengthSupport = true;
    159         fUnpackFlipYSupport = false;
    160         fPackRowLengthSupport = true;
    161         fPackFlipYSupport = false;
    162     } else {
    163         fUnpackRowLengthSupport = version >= GR_GL_VER(3,0) ||
    164                                   ctxInfo.hasExtension("GL_EXT_unpack_subimage");
    165         fUnpackFlipYSupport = ctxInfo.hasExtension("GL_CHROMIUM_flipy");
    166         fPackRowLengthSupport = version >= GR_GL_VER(3,0) ||
    167                                 ctxInfo.hasExtension("GL_NV_pack_subimage");
    168         fPackFlipYSupport =
    169             ctxInfo.hasExtension("GL_ANGLE_pack_reverse_row_order");
    170     }
    171 
    172     fTextureUsageSupport = (kES_GrGLBinding == binding) &&
    173                             ctxInfo.hasExtension("GL_ANGLE_texture_usage");
    174 
    175     if (kDesktop_GrGLBinding == binding) {
    176         // The EXT version can apply to either GL or GLES.
    177         fTexStorageSupport = version >= GR_GL_VER(4,2) ||
    178                              ctxInfo.hasExtension("GL_ARB_texture_storage") ||
    179                              ctxInfo.hasExtension("GL_EXT_texture_storage");
    180     } else {
    181         // Qualcomm Adreno drivers appear to have issues with texture storage.
    182         fTexStorageSupport = (version >= GR_GL_VER(3,0) &&
    183                               kQualcomm_GrGLVendor != ctxInfo.vendor()) ||
    184                              ctxInfo.hasExtension("GL_EXT_texture_storage");
    185     }
    186 
    187     // ARB_texture_rg is part of OpenGL 3.0, but mesa doesn't support it if
    188     // it doesn't have ARB_texture_rg extension.
    189     if (kDesktop_GrGLBinding == binding) {
    190         if (ctxInfo.isMesa()) {
    191             fTextureRedSupport = ctxInfo.hasExtension("GL_ARB_texture_rg");
    192         } else {
    193             fTextureRedSupport = version >= GR_GL_VER(3,0) ||
    194                                  ctxInfo.hasExtension("GL_ARB_texture_rg");
    195         }
    196     } else {
    197         fTextureRedSupport =  version >= GR_GL_VER(3,0) ||
    198                               ctxInfo.hasExtension("GL_EXT_texture_rg");
    199     }
    200 
    201     fImagingSupport = kDesktop_GrGLBinding == binding &&
    202                       ctxInfo.hasExtension("GL_ARB_imaging");
    203 
    204     // ES 2 only guarantees RGBA/uchar + one other format/type combo for
    205     // ReadPixels. The other format has to checked at run-time since it
    206     // can change based on which render target is bound
    207     fTwoFormatLimit = kES_GrGLBinding == binding;
    208 
    209     // Known issue on at least some Intel platforms:
    210     // http://code.google.com/p/skia/issues/detail?id=946
    211     if (kIntel_GrGLVendor != ctxInfo.vendor()) {
    212         fFragCoordsConventionSupport = ctxInfo.glslGeneration() >= k150_GrGLSLGeneration ||
    213                                        ctxInfo.hasExtension("GL_ARB_fragment_coord_conventions");
    214     }
    215 
    216     // SGX and Mali GPUs that are based on a tiled-deferred architecture that have trouble with
    217     // frequently changing VBOs. We've measured a performance increase using non-VBO vertex
    218     // data for dynamic content on these GPUs. Perhaps we should read the renderer string and
    219     // limit this decision to specific GPU families rather than basing it on the vendor alone.
    220     if (!GR_GL_MUST_USE_VBO &&
    221         (kARM_GrGLVendor == ctxInfo.vendor() || kImagination_GrGLVendor == ctxInfo.vendor())) {
    222         fUseNonVBOVertexAndIndexDynamicData = true;
    223     }
    224 
    225     fDiscardFBSupport = ctxInfo.hasExtension("GL_EXT_discard_framebuffer");
    226 
    227     if (kARM_GrGLVendor == ctxInfo.vendor() || kImagination_GrGLVendor == ctxInfo.vendor()) {
    228         fFullClearIsFree = true;
    229     }
    230 
    231     if (kDesktop_GrGLBinding == binding) {
    232         fVertexArrayObjectSupport = version >= GR_GL_VER(3, 0) ||
    233                                     ctxInfo.hasExtension("GL_ARB_vertex_array_object");
    234     } else {
    235         fVertexArrayObjectSupport = version >= GR_GL_VER(3, 0) ||
    236                                     ctxInfo.hasExtension("GL_OES_vertex_array_object");
    237     }
    238 
    239     if (kES_GrGLBinding == binding) {
    240         if (ctxInfo.hasExtension("GL_EXT_shader_framebuffer_fetch")) {
    241             fFBFetchType = kEXT_FBFetchType;
    242         } else if (ctxInfo.hasExtension("GL_NV_shader_framebuffer_fetch")) {
    243             fFBFetchType = kNV_FBFetchType;
    244         }
    245     }
    246 
    247     this->initFSAASupport(ctxInfo, gli);
    248     this->initStencilFormats(ctxInfo);
    249 
    250     /**************************************************************************
    251      * GrDrawTargetCaps fields
    252      **************************************************************************/
    253     GrGLint numFormats;
    254     GR_GL_GetIntegerv(gli, GR_GL_NUM_COMPRESSED_TEXTURE_FORMATS, &numFormats);
    255     if (numFormats) {
    256         SkAutoSTMalloc<10, GrGLint> formats(numFormats);
    257         GR_GL_GetIntegerv(gli, GR_GL_COMPRESSED_TEXTURE_FORMATS, formats);
    258         for (int i = 0; i < numFormats; ++i) {
    259             if (formats[i] == GR_GL_PALETTE8_RGBA8) {
    260                 f8BitPaletteSupport = true;
    261                 break;
    262             }
    263         }
    264     }
    265 
    266     if (kDesktop_GrGLBinding == binding) {
    267         // we could also look for GL_ATI_separate_stencil extension or
    268         // GL_EXT_stencil_two_side but they use different function signatures
    269         // than GL2.0+ (and than each other).
    270         fTwoSidedStencilSupport = (ctxInfo.version() >= GR_GL_VER(2,0));
    271         // supported on GL 1.4 and higher or by extension
    272         fStencilWrapOpsSupport = (ctxInfo.version() >= GR_GL_VER(1,4)) ||
    273                                   ctxInfo.hasExtension("GL_EXT_stencil_wrap");
    274     } else {
    275         // ES 2 has two sided stencil and stencil wrap
    276         fTwoSidedStencilSupport = true;
    277         fStencilWrapOpsSupport = true;
    278     }
    279 
    280     if (kDesktop_GrGLBinding == binding) {
    281         fBufferLockSupport = true; // we require VBO support and the desktop VBO extension includes
    282                                    // glMapBuffer.
    283     } else {
    284         fBufferLockSupport = ctxInfo.hasExtension("GL_OES_mapbuffer");
    285     }
    286 
    287     if (kDesktop_GrGLBinding == binding) {
    288         if (ctxInfo.version() >= GR_GL_VER(2,0) ||
    289             ctxInfo.hasExtension("GL_ARB_texture_non_power_of_two")) {
    290             fNPOTTextureTileSupport = true;
    291         } else {
    292             fNPOTTextureTileSupport = false;
    293         }
    294     } else {
    295         // Unextended ES2 supports NPOT textures with clamp_to_edge and non-mip filters only
    296         // ES3 has no limitations.
    297         fNPOTTextureTileSupport = ctxInfo.version() >= GR_GL_VER(3,0) ||
    298                                   ctxInfo.hasExtension("GL_OES_texture_npot");
    299     }
    300 
    301     fHWAALineSupport = (kDesktop_GrGLBinding == binding);
    302 
    303     GR_GL_GetIntegerv(gli, GR_GL_MAX_TEXTURE_SIZE, &fMaxTextureSize);
    304     GR_GL_GetIntegerv(gli, GR_GL_MAX_RENDERBUFFER_SIZE, &fMaxRenderTargetSize);
    305     // Our render targets are always created with textures as the color
    306     // attachment, hence this min:
    307     fMaxRenderTargetSize = GrMin(fMaxTextureSize, fMaxRenderTargetSize);
    308 
    309     fPathRenderingSupport = GR_GL_USE_NV_PATH_RENDERING &&
    310                             ctxInfo.hasExtension("GL_NV_path_rendering");
    311 
    312     fDstReadInShaderSupport = kNone_FBFetchType != fFBFetchType;
    313 
    314     // Disable scratch texture reuse on Mali and Adreno devices
    315     fReuseScratchTextures = kARM_GrGLVendor != ctxInfo.vendor() &&
    316                             kQualcomm_GrGLVendor != ctxInfo.vendor();
    317 
    318     // Enable supported shader-related caps
    319     if (kDesktop_GrGLBinding == binding) {
    320         fDualSourceBlendingSupport = ctxInfo.version() >= GR_GL_VER(3,3) ||
    321                                      ctxInfo.hasExtension("GL_ARB_blend_func_extended");
    322         fShaderDerivativeSupport = true;
    323         // we don't support GL_ARB_geometry_shader4, just GL 3.2+ GS
    324         fGeometryShaderSupport = ctxInfo.version() >= GR_GL_VER(3,2) &&
    325                                  ctxInfo.glslGeneration() >= k150_GrGLSLGeneration;
    326     } else {
    327         fShaderDerivativeSupport = ctxInfo.hasExtension("GL_OES_standard_derivatives");
    328     }
    329 
    330     if (GrGLCaps::kES_IMG_MsToTexture_MSFBOType == fMSFBOType) {
    331         GR_GL_GetIntegerv(gli, GR_GL_MAX_SAMPLES_IMG, &fMaxSampleCount);
    332     } else if (GrGLCaps::kNone_MSFBOType != fMSFBOType) {
    333         GR_GL_GetIntegerv(gli, GR_GL_MAX_SAMPLES, &fMaxSampleCount);
    334     }
    335 
    336     this->initConfigRenderableTable(ctxInfo);
    337 }
    338 
    339 void GrGLCaps::initConfigRenderableTable(const GrGLContextInfo& ctxInfo) {
    340 
    341     // OpenGL < 3.0
    342     //  no support for render targets unless the GL_ARB_framebuffer_object
    343     //  extension is supported (in which case we get ALPHA, RED, RG, RGB,
    344     //  RGBA (ALPHA8, RGBA4, RGBA8) for OpenGL > 1.1). Note that we
    345     //  probably don't get R8 in this case.
    346 
    347     // OpenGL 3.0
    348     //  base color renderable: ALPHA, RED, RG, RGB, and RGBA
    349     //  sized derivatives: ALPHA8, R8, RGBA4, RGBA8
    350 
    351     // >= OpenGL 3.1
    352     //  base color renderable: RED, RG, RGB, and RGBA
    353     //  sized derivatives: R8, RGBA4, RGBA8
    354     //  if the GL_ARB_compatibility extension is supported then we get back
    355     //  support for GL_ALPHA and ALPHA8
    356 
    357     // GL_EXT_bgra adds BGRA render targets to any version
    358 
    359     // ES 2.0
    360     //  color renderable: RGBA4, RGB5_A1, RGB565
    361     //  GL_EXT_texture_rg adds support for R8 as a color render target
    362     //  GL_OES_rgb8_rgba8 and/or GL_ARM_rgba8 adds support for RGBA8
    363     //  GL_EXT_texture_format_BGRA8888 and/or GL_APPLE_texture_format_BGRA8888 added BGRA support
    364 
    365     // ES 3.0
    366     // Same as ES 2.0 except R8 and RGBA8 are supported without extensions (the functions called
    367     // below already account for this).
    368 
    369     enum {
    370         kNo_MSAA = 0,
    371         kYes_MSAA = 1,
    372     };
    373 
    374     if (kDesktop_GrGLBinding == ctxInfo.binding()) {
    375         // Post 3.0 we will get R8
    376         // Prior to 3.0 we will get ALPHA8 (with GL_ARB_framebuffer_object)
    377         if (ctxInfo.version() >= GR_GL_VER(3,0) ||
    378             ctxInfo.hasExtension("GL_ARB_framebuffer_object")) {
    379             fConfigRenderSupport[kAlpha_8_GrPixelConfig][kNo_MSAA] = true;
    380             fConfigRenderSupport[kAlpha_8_GrPixelConfig][kYes_MSAA] = true;
    381         }
    382     } else {
    383         // On ES we can only hope for R8
    384         fConfigRenderSupport[kAlpha_8_GrPixelConfig][kNo_MSAA] = fTextureRedSupport;
    385         fConfigRenderSupport[kAlpha_8_GrPixelConfig][kYes_MSAA] = fTextureRedSupport;
    386     }
    387 
    388     if (kDesktop_GrGLBinding != ctxInfo.binding()) {
    389         // only available in ES
    390         fConfigRenderSupport[kRGB_565_GrPixelConfig][kNo_MSAA] = true;
    391         fConfigRenderSupport[kRGB_565_GrPixelConfig][kYes_MSAA] = true;
    392     }
    393 
    394     // we no longer support 444 as a render target
    395     fConfigRenderSupport[kRGBA_4444_GrPixelConfig][kNo_MSAA]  = false;
    396     fConfigRenderSupport[kRGBA_4444_GrPixelConfig][kYes_MSAA]  = false;
    397 
    398     if (this->fRGBA8RenderbufferSupport) {
    399         fConfigRenderSupport[kRGBA_8888_GrPixelConfig][kNo_MSAA]  = true;
    400         fConfigRenderSupport[kRGBA_8888_GrPixelConfig][kYes_MSAA]  = true;
    401     }
    402 
    403     if (this->fBGRAFormatSupport) {
    404         fConfigRenderSupport[kBGRA_8888_GrPixelConfig][kNo_MSAA]  = true;
    405         // The GL_EXT_texture_format_BGRA8888 extension does not add BGRA to the list of
    406         // configs that are color-renderable and can be passed to glRenderBufferStorageMultisample.
    407         // Chromium may have an extension to allow BGRA renderbuffers to work on desktop platforms.
    408         if (ctxInfo.extensions().has("GL_CHROMIUM_renderbuffer_format_BGRA8888")) {
    409             fConfigRenderSupport[kBGRA_8888_GrPixelConfig][kYes_MSAA] = true;
    410         } else {
    411             fConfigRenderSupport[kBGRA_8888_GrPixelConfig][kYes_MSAA] =
    412                 !fBGRAIsInternalFormat || !this->usesMSAARenderBuffers();
    413         }
    414     }
    415 
    416     // If we don't support MSAA then undo any places above where we set a config as renderable with
    417     // msaa.
    418     if (kNone_MSFBOType == fMSFBOType) {
    419         for (int i = 0; i < kGrPixelConfigCnt; ++i) {
    420             fConfigRenderSupport[i][kYes_MSAA] = false;
    421         }
    422     }
    423 }
    424 
    425 bool GrGLCaps::readPixelsSupported(const GrGLInterface* intf,
    426                                    GrGLenum format,
    427                                    GrGLenum type) const {
    428     if (GR_GL_RGBA == format && GR_GL_UNSIGNED_BYTE == type) {
    429         // ES 2 guarantees this format is supported
    430         return true;
    431     }
    432 
    433     if (!fTwoFormatLimit) {
    434         // not limited by ES 2's constraints
    435         return true;
    436     }
    437 
    438     GrGLint otherFormat = GR_GL_RGBA;
    439     GrGLint otherType = GR_GL_UNSIGNED_BYTE;
    440 
    441     // The other supported format/type combo supported for ReadPixels
    442     // can change based on which render target is bound
    443     GR_GL_GetIntegerv(intf,
    444                       GR_GL_IMPLEMENTATION_COLOR_READ_FORMAT,
    445                       &otherFormat);
    446 
    447     GR_GL_GetIntegerv(intf,
    448                       GR_GL_IMPLEMENTATION_COLOR_READ_TYPE,
    449                       &otherType);
    450 
    451     return (GrGLenum)otherFormat == format && (GrGLenum)otherType == type;
    452 }
    453 
    454 void GrGLCaps::initFSAASupport(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
    455 
    456     fMSFBOType = kNone_MSFBOType;
    457     if (kDesktop_GrGLBinding != ctxInfo.binding()) {
    458         // We prefer the EXT/IMG extension over ES3 MSAA because we've observed
    459         // ES3 driver bugs on at least one device with a tiled GPU (N10).
    460         if (ctxInfo.hasExtension("GL_EXT_multisampled_render_to_texture")) {
    461             fMSFBOType = kES_EXT_MsToTexture_MSFBOType;
    462         } else if (ctxInfo.hasExtension("GL_IMG_multisampled_render_to_texture")) {
    463             fMSFBOType = kES_IMG_MsToTexture_MSFBOType;
    464         } else if (!GR_GL_IGNORE_ES3_MSAA && ctxInfo.version() >= GR_GL_VER(3,0)) {
    465             fMSFBOType = GrGLCaps::kES_3_0_MSFBOType;
    466         } else if (ctxInfo.hasExtension("GL_CHROMIUM_framebuffer_multisample")) {
    467             // chrome's extension is equivalent to the EXT msaa
    468             // and fbo_blit extensions.
    469             fMSFBOType = kDesktop_EXT_MSFBOType;
    470         } else if (ctxInfo.hasExtension("GL_APPLE_framebuffer_multisample")) {
    471             fMSFBOType = kES_Apple_MSFBOType;
    472         }
    473     } else {
    474         if ((ctxInfo.version() >= GR_GL_VER(3,0)) ||
    475             ctxInfo.hasExtension("GL_ARB_framebuffer_object")) {
    476             fMSFBOType = GrGLCaps::kDesktop_ARB_MSFBOType;
    477         } else if (ctxInfo.hasExtension("GL_EXT_framebuffer_multisample") &&
    478                    ctxInfo.hasExtension("GL_EXT_framebuffer_blit")) {
    479             fMSFBOType = GrGLCaps::kDesktop_EXT_MSFBOType;
    480         }
    481     }
    482 }
    483 
    484 namespace {
    485 const GrGLuint kUnknownBitCount = GrGLStencilBuffer::kUnknownBitCount;
    486 }
    487 
    488 void GrGLCaps::initStencilFormats(const GrGLContextInfo& ctxInfo) {
    489 
    490     // Build up list of legal stencil formats (though perhaps not supported on
    491     // the particular gpu/driver) from most preferred to least.
    492 
    493     // these consts are in order of most preferred to least preferred
    494     // we don't bother with GL_STENCIL_INDEX1 or GL_DEPTH32F_STENCIL8
    495 
    496     static const StencilFormat
    497                   // internal Format      stencil bits      total bits        packed?
    498         gS8    = {GR_GL_STENCIL_INDEX8,   8,                8,                false},
    499         gS16   = {GR_GL_STENCIL_INDEX16,  16,               16,               false},
    500         gD24S8 = {GR_GL_DEPTH24_STENCIL8, 8,                32,               true },
    501         gS4    = {GR_GL_STENCIL_INDEX4,   4,                4,                false},
    502     //  gS     = {GR_GL_STENCIL_INDEX,    kUnknownBitCount, kUnknownBitCount, false},
    503         gDS    = {GR_GL_DEPTH_STENCIL,    kUnknownBitCount, kUnknownBitCount, true };
    504 
    505     if (kDesktop_GrGLBinding == ctxInfo.binding()) {
    506         bool supportsPackedDS =
    507             ctxInfo.version() >= GR_GL_VER(3,0) ||
    508             ctxInfo.hasExtension("GL_EXT_packed_depth_stencil") ||
    509             ctxInfo.hasExtension("GL_ARB_framebuffer_object");
    510 
    511         // S1 thru S16 formats are in GL 3.0+, EXT_FBO, and ARB_FBO since we
    512         // require FBO support we can expect these are legal formats and don't
    513         // check. These also all support the unsized GL_STENCIL_INDEX.
    514         fStencilFormats.push_back() = gS8;
    515         fStencilFormats.push_back() = gS16;
    516         if (supportsPackedDS) {
    517             fStencilFormats.push_back() = gD24S8;
    518         }
    519         fStencilFormats.push_back() = gS4;
    520         if (supportsPackedDS) {
    521             fStencilFormats.push_back() = gDS;
    522         }
    523     } else {
    524         // ES2 has STENCIL_INDEX8 without extensions but requires extensions
    525         // for other formats.
    526         // ES doesn't support using the unsized format.
    527 
    528         fStencilFormats.push_back() = gS8;
    529         //fStencilFormats.push_back() = gS16;
    530         if (ctxInfo.version() >= GR_GL_VER(3,0) ||
    531             ctxInfo.hasExtension("GL_OES_packed_depth_stencil")) {
    532             fStencilFormats.push_back() = gD24S8;
    533         }
    534         if (ctxInfo.hasExtension("GL_OES_stencil4")) {
    535             fStencilFormats.push_back() = gS4;
    536         }
    537     }
    538     SkASSERT(0 == fStencilVerifiedColorConfigs.count());
    539     fStencilVerifiedColorConfigs.push_back_n(fStencilFormats.count());
    540 }
    541 
    542 void GrGLCaps::markColorConfigAndStencilFormatAsVerified(
    543                                     GrPixelConfig config,
    544                                     const GrGLStencilBuffer::Format& format) {
    545 #if !GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT
    546     return;
    547 #endif
    548     SkASSERT((unsigned)config < (unsigned)kGrPixelConfigCnt);
    549     SkASSERT(fStencilFormats.count() == fStencilVerifiedColorConfigs.count());
    550     int count = fStencilFormats.count();
    551     // we expect a really small number of possible formats so linear search
    552     // should be OK
    553     SkASSERT(count < 16);
    554     for (int i = 0; i < count; ++i) {
    555         if (format.fInternalFormat ==
    556             fStencilFormats[i].fInternalFormat) {
    557             fStencilVerifiedColorConfigs[i].markVerified(config);
    558             return;
    559         }
    560     }
    561     GrCrash("Why are we seeing a stencil format that "
    562             "GrGLCaps doesn't know about.");
    563 }
    564 
    565 bool GrGLCaps::isColorConfigAndStencilFormatVerified(
    566                                 GrPixelConfig config,
    567                                 const GrGLStencilBuffer::Format& format) const {
    568 #if !GR_GL_CHECK_FBO_STATUS_ONCE_PER_FORMAT
    569     return false;
    570 #endif
    571     SkASSERT((unsigned)config < (unsigned)kGrPixelConfigCnt);
    572     int count = fStencilFormats.count();
    573     // we expect a really small number of possible formats so linear search
    574     // should be OK
    575     SkASSERT(count < 16);
    576     for (int i = 0; i < count; ++i) {
    577         if (format.fInternalFormat ==
    578             fStencilFormats[i].fInternalFormat) {
    579             return fStencilVerifiedColorConfigs[i].isVerified(config);
    580         }
    581     }
    582     GrCrash("Why are we seeing a stencil format that "
    583             "GLCaps doesn't know about.");
    584     return false;
    585 }
    586 
    587 SkString GrGLCaps::dump() const {
    588 
    589     SkString r = INHERITED::dump();
    590 
    591     r.appendf("--- GL-Specific ---\n");
    592     for (int i = 0; i < fStencilFormats.count(); ++i) {
    593         r.appendf("Stencil Format %d, stencil bits: %02d, total bits: %02d\n",
    594                  i,
    595                  fStencilFormats[i].fStencilBits,
    596                  fStencilFormats[i].fTotalBits);
    597     }
    598 
    599     static const char* kMSFBOExtStr[] = {
    600         "None",
    601         "ARB",
    602         "EXT",
    603         "ES 3.0",
    604         "Apple",
    605         "IMG MS To Texture",
    606         "EXT MS To Texture",
    607     };
    608     GR_STATIC_ASSERT(0 == kNone_MSFBOType);
    609     GR_STATIC_ASSERT(1 == kDesktop_ARB_MSFBOType);
    610     GR_STATIC_ASSERT(2 == kDesktop_EXT_MSFBOType);
    611     GR_STATIC_ASSERT(3 == kES_3_0_MSFBOType);
    612     GR_STATIC_ASSERT(4 == kES_Apple_MSFBOType);
    613     GR_STATIC_ASSERT(5 == kES_IMG_MsToTexture_MSFBOType);
    614     GR_STATIC_ASSERT(6 == kES_EXT_MsToTexture_MSFBOType);
    615     GR_STATIC_ASSERT(GR_ARRAY_COUNT(kMSFBOExtStr) == kLast_MSFBOType + 1);
    616 
    617     static const char* kFBFetchTypeStr[] = {
    618         "None",
    619         "EXT",
    620         "NV",
    621     };
    622     GR_STATIC_ASSERT(0 == kNone_FBFetchType);
    623     GR_STATIC_ASSERT(1 == kEXT_FBFetchType);
    624     GR_STATIC_ASSERT(2 == kNV_FBFetchType);
    625     GR_STATIC_ASSERT(GR_ARRAY_COUNT(kFBFetchTypeStr) == kLast_FBFetchType + 1);
    626 
    627 
    628     r.appendf("Core Profile: %s\n", (fIsCoreProfile ? "YES" : "NO"));
    629     r.appendf("Fixed Function Support: %s\n", (fFixedFunctionSupport ? "YES" : "NO"));
    630     r.appendf("MSAA Type: %s\n", kMSFBOExtStr[fMSFBOType]);
    631     r.appendf("FB Fetch Type: %s\n", kFBFetchTypeStr[fFBFetchType]);
    632     r.appendf("Max FS Uniform Vectors: %d\n", fMaxFragmentUniformVectors);
    633     r.appendf("Max FS Texture Units: %d\n", fMaxFragmentTextureUnits);
    634     if (fFixedFunctionSupport) {
    635         r.appendf("Max Fixed Function Texture Coords: %d\n", fMaxFixedFunctionTextureCoords);
    636     }
    637     r.appendf("Max Vertex Attributes: %d\n", fMaxVertexAttributes);
    638     r.appendf("Support RGBA8 Render Buffer: %s\n", (fRGBA8RenderbufferSupport ? "YES": "NO"));
    639     r.appendf("BGRA support: %s\n", (fBGRAFormatSupport ? "YES": "NO"));
    640     r.appendf("BGRA is an internal format: %s\n", (fBGRAIsInternalFormat ? "YES": "NO"));
    641     r.appendf("Support texture swizzle: %s\n", (fTextureSwizzleSupport ? "YES": "NO"));
    642     r.appendf("Unpack Row length support: %s\n", (fUnpackRowLengthSupport ? "YES": "NO"));
    643     r.appendf("Unpack Flip Y support: %s\n", (fUnpackFlipYSupport ? "YES": "NO"));
    644     r.appendf("Pack Row length support: %s\n", (fPackRowLengthSupport ? "YES": "NO"));
    645     r.appendf("Pack Flip Y support: %s\n", (fPackFlipYSupport ? "YES": "NO"));
    646 
    647     r.appendf("Texture Usage support: %s\n", (fTextureUsageSupport ? "YES": "NO"));
    648     r.appendf("Texture Storage support: %s\n", (fTexStorageSupport ? "YES": "NO"));
    649     r.appendf("GL_R support: %s\n", (fTextureRedSupport ? "YES": "NO"));
    650     r.appendf("GL_ARB_imaging support: %s\n", (fImagingSupport ? "YES": "NO"));
    651     r.appendf("Two Format Limit: %s\n", (fTwoFormatLimit ? "YES": "NO"));
    652     r.appendf("Fragment coord conventions support: %s\n",
    653              (fFragCoordsConventionSupport ? "YES": "NO"));
    654     r.appendf("Vertex array object support: %s\n", (fVertexArrayObjectSupport ? "YES": "NO"));
    655     r.appendf("Use non-VBO for dynamic data: %s\n",
    656              (fUseNonVBOVertexAndIndexDynamicData ? "YES" : "NO"));
    657     r.appendf("Discard FrameBuffer support: %s\n", (fDiscardFBSupport ? "YES" : "NO"));
    658     r.appendf("Full screen clear is free: %s\n", (fFullClearIsFree ? "YES" : "NO"));
    659     return r;
    660 }
    661