gpu/command_buffer/service/feature_info.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "gpu/command_buffer/service/feature_info.h"
   6
   7 #include <set>
   8 #include <vector>
   9
  10 #include "base/command_line.h"
  11 #include "base/metrics/histogram_macros.h"
  12 #include "base/strings/string_number_conversions.h"
  13 #include "base/strings/string_split.h"
  14 #include "gpu/command_buffer/service/gpu_switches.h"
  15 #include "gpu/command_buffer/service/texture_definition.h"
  16 #include "gpu/config/gpu_switches.h"
  17 #include "ui/gl/gl_bindings.h"
  18 #include "ui/gl/gl_fence.h"
  19 #include "ui/gl/gl_implementation.h"
  20 #include "ui/gl/gl_switches.h"
  21 #include "ui/gl/gl_version_info.h"
  22
  23 #if !defined(OS_MACOSX)
  24 #include "ui/gl/gl_fence_egl.h"
  25 #endif
  26
  27 namespace gpu {
  28 namespace gles2 {
  29
  30 namespace {
  31
  32 struct FormatInfo {
  33   GLenum format;
  34   const GLenum* types;
  35   size_t count;
  36 };
  37
  38 class StringSet {
  39  public:
  40   StringSet() {}
  41
  42   StringSet(const char* s) {
  43     Init(s);
  44   }
  45
  46   StringSet(const std::string& str) {
  47     Init(str);
  48   }
  49
  50   StringSet(const std::vector<std::string>& strs) {
  51     string_set_.insert(strs.begin(), strs.end());
  52   }
  53
  54   void Init(const char* s) {
  55     std::string str(s ? s : "");
  56     Init(str);
  57   }
  58
  59   void Init(const std::string& str) {
  60     std::vector<std::string> tokens = base::SplitString(
  61         str, " ", base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
  62     string_set_.insert(tokens.begin(), tokens.end());
  63   }
  64
  65   bool Contains(const char* s) {
  66     return string_set_.find(s) != string_set_.end();
  67   }
  68
  69   bool Contains(const std::string& s) {
  70     return string_set_.find(s) != string_set_.end();
  71   }
  72
  73   const std::set<std::string>& GetImpl() {
  74     return string_set_;
  75   }
  76
  77  private:
  78   std::set<std::string> string_set_;
  79 };
  80
  81 // Process a string of wordaround type IDs (seperated by ',') and set up
  82 // the corresponding Workaround flags.
  83 void StringToWorkarounds(
  84     const std::string& types, FeatureInfo::Workarounds* workarounds) {
  85   DCHECK(workarounds);
  86   for (const base::StringPiece& piece :
  87        base::SplitStringPiece(
  88            types, ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL)) {
  89     int number = 0;
  90     bool succeed = base::StringToInt(piece, &number);
  91     DCHECK(succeed);
  92     switch (number) {
  93 #define GPU_OP(type, name)    \
  94   case gpu::type:             \
  95     workarounds->name = true; \
  96     break;
  97       GPU_DRIVER_BUG_WORKAROUNDS(GPU_OP)
  98 #undef GPU_OP
  99       default:
 100         NOTIMPLEMENTED();
 101     }
 102   }
 103   if (workarounds->max_texture_size_limit_4096)
 104     workarounds->max_texture_size = 4096;
 105   if (workarounds->max_cube_map_texture_size_limit_4096)
 106     workarounds->max_cube_map_texture_size = 4096;
 107   if (workarounds->max_cube_map_texture_size_limit_1024)
 108     workarounds->max_cube_map_texture_size = 1024;
 109   if (workarounds->max_cube_map_texture_size_limit_512)
 110     workarounds->max_cube_map_texture_size = 512;
 111
 112   if (workarounds->max_fragment_uniform_vectors_32)
 113     workarounds->max_fragment_uniform_vectors = 32;
 114   if (workarounds->max_varying_vectors_16)
 115     workarounds->max_varying_vectors = 16;
 116   if (workarounds->max_vertex_uniform_vectors_256)
 117     workarounds->max_vertex_uniform_vectors = 256;
 118
 119   if (workarounds->max_copy_texture_chromium_size_262144)
 120     workarounds->max_copy_texture_chromium_size = 262144;
 121 }
 122
 123 }  // anonymous namespace.
 124
 125 FeatureInfo::FeatureFlags::FeatureFlags()
 126     : chromium_color_buffer_float_rgba(false),
 127       chromium_color_buffer_float_rgb(false),
 128       chromium_framebuffer_multisample(false),
 129       chromium_sync_query(false),
 130       use_core_framebuffer_multisample(false),
 131       multisampled_render_to_texture(false),
 132       use_img_for_multisampled_render_to_texture(false),
 133       oes_standard_derivatives(false),
 134       oes_egl_image_external(false),
 135       oes_depth24(false),
 136       oes_compressed_etc1_rgb8_texture(false),
 137       packed_depth24_stencil8(false),
 138       npot_ok(false),
 139       enable_texture_float_linear(false),
 140       enable_texture_half_float_linear(false),
 141       angle_translated_shader_source(false),
 142       angle_pack_reverse_row_order(false),
 143       arb_texture_rectangle(false),
 144       angle_instanced_arrays(false),
 145       occlusion_query_boolean(false),
 146       use_arb_occlusion_query2_for_occlusion_query_boolean(false),
 147       use_arb_occlusion_query_for_occlusion_query_boolean(false),
 148       native_vertex_array_object(false),
 149       ext_texture_format_astc(false),
 150       ext_texture_format_atc(false),
 151       ext_texture_format_bgra8888(false),
 152       ext_texture_format_dxt1(false),
 153       ext_texture_format_dxt5(false),
 154       enable_shader_name_hashing(false),
 155       enable_samplers(false),
 156       ext_draw_buffers(false),
 157       nv_draw_buffers(false),
 158       ext_frag_depth(false),
 159       ext_shader_texture_lod(false),
 160       use_async_readpixels(false),
 161       map_buffer_range(false),
 162       ext_discard_framebuffer(false),
 163       angle_depth_texture(false),
 164       is_swiftshader(false),
 165       angle_texture_usage(false),
 166       ext_texture_storage(false),
 167       chromium_path_rendering(false),
 168       blend_equation_advanced(false),
 169       blend_equation_advanced_coherent(false),
 170       ext_texture_rg(false),
 171       chromium_image_ycbcr_422(false),
 172       enable_subscribe_uniform(false),
 173       emulate_primitive_restart_fixed_index(false),
 174       ext_render_buffer_format_bgra8888(false) {}
 175
 176 FeatureInfo::Workarounds::Workarounds() :
 177 #define GPU_OP(type, name) name(false),
 178     GPU_DRIVER_BUG_WORKAROUNDS(GPU_OP)
 179 #undef GPU_OP
 180     max_texture_size(0),
 181     max_cube_map_texture_size(0),
 182     max_fragment_uniform_vectors(0),
 183     max_varying_vectors(0),
 184     max_vertex_uniform_vectors(0),
 185     max_copy_texture_chromium_size(0) {
 186 }
 187
 188 FeatureInfo::FeatureInfo() {
 189   InitializeBasicState(base::CommandLine::InitializedForCurrentProcess()
 190                            ? base::CommandLine::ForCurrentProcess()
 191                            : nullptr);
 192 }
 193
 194 FeatureInfo::FeatureInfo(const base::CommandLine& command_line) {
 195   InitializeBasicState(&command_line);
 196 }
 197
 198 void FeatureInfo::InitializeBasicState(const base::CommandLine* command_line) {
 199   if (!command_line)
 200     return;
 201
 202   if (command_line->HasSwitch(switches::kGpuDriverBugWorkarounds)) {
 203     std::string types = command_line->GetSwitchValueASCII(
 204         switches::kGpuDriverBugWorkarounds);
 205     StringToWorkarounds(types, &workarounds_);
 206   }
 207   feature_flags_.enable_shader_name_hashing =
 208       !command_line->HasSwitch(switches::kDisableShaderNameHashing);
 209
 210   feature_flags_.is_swiftshader =
 211       (command_line->GetSwitchValueASCII(switches::kUseGL) == "swiftshader");
 212
 213   feature_flags_.enable_subscribe_uniform =
 214       command_line->HasSwitch(switches::kEnableSubscribeUniformExtension);
 215
 216   enable_unsafe_es3_apis_switch_ =
 217       command_line->HasSwitch(switches::kEnableUnsafeES3APIs);
 218
 219   enable_gl_path_rendering_switch_ =
 220       command_line->HasSwitch(switches::kEnableGLPathRendering);
 221
 222   // The shader translator is needed to translate from WebGL-conformant GLES SL
 223   // to normal GLES SL, enforce WebGL conformance, translate from GLES SL 1.0 to
 224   // target context GLSL, etc.
 225   // The flag here is for testing only.
 226   disable_shader_translator_ =
 227       command_line->HasSwitch(switches::kDisableGLSLTranslator);
 228
 229   unsafe_es3_apis_enabled_ = false;
 230 }
 231
 232 bool FeatureInfo::Initialize() {
 233   disallowed_features_ = DisallowedFeatures();
 234   InitializeFeatures();
 235   return true;
 236 }
 237
 238 bool FeatureInfo::Initialize(const DisallowedFeatures& disallowed_features) {
 239   disallowed_features_ = disallowed_features;
 240   InitializeFeatures();
 241   return true;
 242 }
 243
 244 bool IsGL_REDSupportedOnFBOs() {
 245   // Skia uses GL_RED with frame buffers, unfortunately, Mesa claims to support
 246   // GL_EXT_texture_rg, but it doesn't support it on frame buffers.  To fix
 247   // this, we try it, and if it fails, we don't expose GL_EXT_texture_rg.
 248   GLint fb_binding = 0;
 249   GLint tex_binding = 0;
 250   glGetIntegerv(GL_FRAMEBUFFER_BINDING, &fb_binding);
 251   glGetIntegerv(GL_TEXTURE_BINDING_2D, &tex_binding);
 252
 253   GLuint textureId = 0;
 254   glGenTextures(1, &textureId);
 255   glBindTexture(GL_TEXTURE_2D, textureId);
 256   GLubyte data[1] = {0};
 257   glTexImage2D(GL_TEXTURE_2D, 0, GL_RED_EXT, 1, 1, 0, GL_RED_EXT,
 258                GL_UNSIGNED_BYTE, data);
 259   GLuint textureFBOID = 0;
 260   glGenFramebuffersEXT(1, &textureFBOID);
 261   glBindFramebufferEXT(GL_FRAMEBUFFER, textureFBOID);
 262   glFramebufferTexture2DEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
 263                             textureId, 0);
 264   bool result =
 265       glCheckFramebufferStatusEXT(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_UNSUPPORTED;
 266   glDeleteFramebuffersEXT(1, &textureFBOID);
 267   glDeleteTextures(1, &textureId);
 268
 269   glBindFramebufferEXT(GL_FRAMEBUFFER, static_cast<GLuint>(fb_binding));
 270   glBindTexture(GL_TEXTURE_2D, static_cast<GLuint>(tex_binding));
 271
 272   DCHECK(glGetError() == GL_NO_ERROR);
 273
 274   return result;
 275 }
 276
 277 void FeatureInfo::InitializeFeatures() {
 278   // Figure out what extensions to turn on.
 279   StringSet extensions(gfx::GetGLExtensionsFromCurrentContext());
 280
 281   const char* version_str =
 282       reinterpret_cast<const char*>(glGetString(GL_VERSION));
 283   const char* renderer_str =
 284       reinterpret_cast<const char*>(glGetString(GL_RENDERER));
 285
 286   gl_version_info_.reset(new gfx::GLVersionInfo(
 287       version_str, renderer_str, extensions.GetImpl()));
 288
 289   AddExtensionString("GL_ANGLE_translated_shader_source");
 290   AddExtensionString("GL_CHROMIUM_async_pixel_transfers");
 291   AddExtensionString("GL_CHROMIUM_bind_uniform_location");
 292   AddExtensionString("GL_CHROMIUM_command_buffer_query");
 293   AddExtensionString("GL_CHROMIUM_command_buffer_latency_query");
 294   AddExtensionString("GL_CHROMIUM_copy_texture");
 295   AddExtensionString("GL_CHROMIUM_get_error_query");
 296   AddExtensionString("GL_CHROMIUM_lose_context");
 297   AddExtensionString("GL_CHROMIUM_pixel_transfer_buffer_object");
 298   AddExtensionString("GL_CHROMIUM_rate_limit_offscreen_context");
 299   AddExtensionString("GL_CHROMIUM_resize");
 300   AddExtensionString("GL_CHROMIUM_resource_safe");
 301   AddExtensionString("GL_CHROMIUM_strict_attribs");
 302   AddExtensionString("GL_CHROMIUM_texture_mailbox");
 303   AddExtensionString("GL_CHROMIUM_trace_marker");
 304   AddExtensionString("GL_EXT_debug_marker");
 305
 306   if (feature_flags_.enable_subscribe_uniform) {
 307     AddExtensionString("GL_CHROMIUM_subscribe_uniform");
 308   }
 309
 310   // OES_vertex_array_object is emulated if not present natively,
 311   // so the extension string is always exposed.
 312   AddExtensionString("GL_OES_vertex_array_object");
 313
 314   if (!disallowed_features_.gpu_memory_manager)
 315     AddExtensionString("GL_CHROMIUM_gpu_memory_manager");
 316
 317   if (extensions.Contains("GL_ANGLE_translated_shader_source")) {
 318     feature_flags_.angle_translated_shader_source = true;
 319   }
 320
 321   // Check if we should allow GL_EXT_texture_compression_dxt1 and
 322   // GL_EXT_texture_compression_s3tc.
 323   bool enable_dxt1 = false;
 324   bool enable_dxt3 = false;
 325   bool enable_dxt5 = false;
 326   bool have_s3tc = extensions.Contains("GL_EXT_texture_compression_s3tc");
 327   bool have_dxt3 =
 328       have_s3tc || extensions.Contains("GL_ANGLE_texture_compression_dxt3");
 329   bool have_dxt5 =
 330       have_s3tc || extensions.Contains("GL_ANGLE_texture_compression_dxt5");
 331
 332   if (extensions.Contains("GL_EXT_texture_compression_dxt1") || have_s3tc) {
 333     enable_dxt1 = true;
 334   }
 335   if (have_dxt3) {
 336     enable_dxt3 = true;
 337   }
 338   if (have_dxt5) {
 339     enable_dxt5 = true;
 340   }
 341
 342   if (enable_dxt1) {
 343     feature_flags_.ext_texture_format_dxt1 = true;
 344
 345     AddExtensionString("GL_EXT_texture_compression_dxt1");
 346     validators_.compressed_texture_format.AddValue(
 347         GL_COMPRESSED_RGB_S3TC_DXT1_EXT);
 348     validators_.compressed_texture_format.AddValue(
 349         GL_COMPRESSED_RGBA_S3TC_DXT1_EXT);
 350
 351     validators_.texture_internal_format_storage.AddValue(
 352         GL_COMPRESSED_RGB_S3TC_DXT1_EXT);
 353     validators_.texture_internal_format_storage.AddValue(
 354         GL_COMPRESSED_RGBA_S3TC_DXT1_EXT);
 355   }
 356
 357   if (enable_dxt3) {
 358     // The difference between GL_EXT_texture_compression_s3tc and
 359     // GL_CHROMIUM_texture_compression_dxt3 is that the former
 360     // requires on the fly compression. The latter does not.
 361     AddExtensionString("GL_CHROMIUM_texture_compression_dxt3");
 362     validators_.compressed_texture_format.AddValue(
 363         GL_COMPRESSED_RGBA_S3TC_DXT3_EXT);
 364     validators_.texture_internal_format_storage.AddValue(
 365         GL_COMPRESSED_RGBA_S3TC_DXT3_EXT);
 366   }
 367
 368   if (enable_dxt5) {
 369     feature_flags_.ext_texture_format_dxt5 = true;
 370
 371     // The difference between GL_EXT_texture_compression_s3tc and
 372     // GL_CHROMIUM_texture_compression_dxt5 is that the former
 373     // requires on the fly compression. The latter does not.
 374     AddExtensionString("GL_CHROMIUM_texture_compression_dxt5");
 375     validators_.compressed_texture_format.AddValue(
 376         GL_COMPRESSED_RGBA_S3TC_DXT5_EXT);
 377     validators_.texture_internal_format_storage.AddValue(
 378         GL_COMPRESSED_RGBA_S3TC_DXT5_EXT);
 379   }
 380
 381   bool have_astc = extensions.Contains("GL_KHR_texture_compression_astc_ldr");
 382   if (have_astc) {
 383     feature_flags_.ext_texture_format_astc = true;
 384     AddExtensionString("GL_KHR_texture_compression_astc_ldr");
 385
 386     // GL_COMPRESSED_RGBA_ASTC(0x93B0 ~ 0x93BD)
 387     GLint astc_format_it = GL_COMPRESSED_RGBA_ASTC_4x4_KHR;
 388     GLint astc_format_max = GL_COMPRESSED_RGBA_ASTC_12x12_KHR;
 389     for (; astc_format_it <= astc_format_max; astc_format_it++)
 390         validators_.compressed_texture_format.AddValue(astc_format_it);
 391
 392     // GL_COMPRESSED_SRGB8_ALPHA8_ASTC(0x93D0 ~ 0x93DD)
 393     astc_format_it = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR;
 394     astc_format_max = GL_COMPRESSED_SRGB8_ALPHA8_ASTC_12x12_KHR;
 395     for (; astc_format_it <= astc_format_max; astc_format_it++)
 396         validators_.compressed_texture_format.AddValue(astc_format_it);
 397   }
 398
 399   bool have_atc = extensions.Contains("GL_AMD_compressed_ATC_texture") ||
 400                   extensions.Contains("GL_ATI_texture_compression_atitc");
 401   if (have_atc) {
 402     feature_flags_.ext_texture_format_atc = true;
 403
 404     AddExtensionString("GL_AMD_compressed_ATC_texture");
 405     validators_.compressed_texture_format.AddValue(GL_ATC_RGB_AMD);
 406     validators_.compressed_texture_format.AddValue(
 407         GL_ATC_RGBA_INTERPOLATED_ALPHA_AMD);
 408
 409     validators_.texture_internal_format_storage.AddValue(GL_ATC_RGB_AMD);
 410     validators_.texture_internal_format_storage.AddValue(
 411         GL_ATC_RGBA_INTERPOLATED_ALPHA_AMD);
 412   }
 413
 414   // Check if we should enable GL_EXT_texture_filter_anisotropic.
 415   if (extensions.Contains("GL_EXT_texture_filter_anisotropic")) {
 416     AddExtensionString("GL_EXT_texture_filter_anisotropic");
 417     validators_.texture_parameter.AddValue(
 418         GL_TEXTURE_MAX_ANISOTROPY_EXT);
 419     validators_.g_l_state.AddValue(
 420         GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT);
 421   }
 422
 423   // Check if we should support GL_OES_packed_depth_stencil and/or
 424   // GL_GOOGLE_depth_texture / GL_CHROMIUM_depth_texture.
 425   //
 426   // NOTE: GL_OES_depth_texture requires support for depth cubemaps.
 427   // GL_ARB_depth_texture requires other features that
 428   // GL_OES_packed_depth_stencil does not provide.
 429   //
 430   // Therefore we made up GL_GOOGLE_depth_texture / GL_CHROMIUM_depth_texture.
 431   //
 432   // GL_GOOGLE_depth_texture is legacy. As we exposed it into NaCl we can't
 433   // get rid of it.
 434   //
 435   bool enable_depth_texture = false;
 436   if (!workarounds_.disable_depth_texture &&
 437       (extensions.Contains("GL_ARB_depth_texture") ||
 438        extensions.Contains("GL_OES_depth_texture") ||
 439        extensions.Contains("GL_ANGLE_depth_texture") ||
 440        gl_version_info_->is_es3 ||
 441        gl_version_info_->is_desktop_core_profile)) {
 442     enable_depth_texture = true;
 443     feature_flags_.angle_depth_texture =
 444         extensions.Contains("GL_ANGLE_depth_texture");
 445   }
 446
 447   if (enable_depth_texture) {
 448     AddExtensionString("GL_CHROMIUM_depth_texture");
 449     AddExtensionString("GL_GOOGLE_depth_texture");
 450     validators_.texture_internal_format.AddValue(GL_DEPTH_COMPONENT);
 451     validators_.texture_format.AddValue(GL_DEPTH_COMPONENT);
 452     validators_.pixel_type.AddValue(GL_UNSIGNED_SHORT);
 453     validators_.pixel_type.AddValue(GL_UNSIGNED_INT);
 454   }
 455
 456   if (extensions.Contains("GL_EXT_packed_depth_stencil") ||
 457       extensions.Contains("GL_OES_packed_depth_stencil") ||
 458       gl_version_info_->is_es3 ||
 459       gl_version_info_->is_desktop_core_profile) {
 460     AddExtensionString("GL_OES_packed_depth_stencil");
 461     feature_flags_.packed_depth24_stencil8 = true;
 462     if (enable_depth_texture) {
 463       validators_.texture_internal_format.AddValue(GL_DEPTH_STENCIL);
 464       validators_.texture_format.AddValue(GL_DEPTH_STENCIL);
 465       validators_.pixel_type.AddValue(GL_UNSIGNED_INT_24_8);
 466     }
 467     validators_.render_buffer_format.AddValue(GL_DEPTH24_STENCIL8);
 468   }
 469
 470   if (gl_version_info_->is_es3 ||
 471       gl_version_info_->is_desktop_core_profile ||
 472       extensions.Contains("GL_OES_vertex_array_object") ||
 473       extensions.Contains("GL_ARB_vertex_array_object") ||
 474       extensions.Contains("GL_APPLE_vertex_array_object")) {
 475     feature_flags_.native_vertex_array_object = true;
 476   }
 477
 478   // If we're using client_side_arrays we have to emulate
 479   // vertex array objects since vertex array objects do not work
 480   // with client side arrays.
 481   if (workarounds_.use_client_side_arrays_for_stream_buffers) {
 482     feature_flags_.native_vertex_array_object = false;
 483   }
 484
 485   if (gl_version_info_->is_es3 ||
 486       extensions.Contains("GL_OES_element_index_uint") ||
 487       gfx::HasDesktopGLFeatures()) {
 488     AddExtensionString("GL_OES_element_index_uint");
 489     validators_.index_type.AddValue(GL_UNSIGNED_INT);
 490   }
 491
 492   // With EXT_sRGB, unsized SRGB_EXT and SRGB_ALPHA_EXT are accepted by the
 493   // <format> and <internalformat> parameter of TexImage2D. GLES3 adds support
 494   // for SRGB Textures but the accepted internal formats for TexImage2D are only
 495   // sized formats GL_SRGB8 and GL_SRGB8_ALPHA8. Also, SRGB_EXT isn't a valid
 496   // <format> in this case. So, even with GLES3 explicitly check for
 497   // GL_EXT_sRGB.
 498   if (((gl_version_info_->is_es3 ||
 499         extensions.Contains("GL_OES_rgb8_rgba8")) &&
 500       extensions.Contains("GL_EXT_sRGB")) || gfx::HasDesktopGLFeatures()) {
 501     AddExtensionString("GL_EXT_sRGB");
 502     validators_.texture_internal_format.AddValue(GL_SRGB_EXT);
 503     validators_.texture_internal_format.AddValue(GL_SRGB_ALPHA_EXT);
 504     validators_.texture_format.AddValue(GL_SRGB_EXT);
 505     validators_.texture_format.AddValue(GL_SRGB_ALPHA_EXT);
 506     validators_.render_buffer_format.AddValue(GL_SRGB8_ALPHA8_EXT);
 507     validators_.frame_buffer_parameter.AddValue(
 508         GL_FRAMEBUFFER_ATTACHMENT_COLOR_ENCODING_EXT);
 509   }
 510
 511   bool enable_texture_format_bgra8888 = false;
 512   bool enable_read_format_bgra = false;
 513   bool enable_render_buffer_bgra = false;
 514   bool enable_immutable_texture_format_bgra_on_es3 =
 515       extensions.Contains("GL_APPLE_texture_format_BGRA8888");
 516
 517   // Check if we should allow GL_EXT_texture_format_BGRA8888
 518   if (extensions.Contains("GL_EXT_texture_format_BGRA8888") ||
 519       enable_immutable_texture_format_bgra_on_es3 ||
 520       !gl_version_info_->is_es) {
 521     enable_texture_format_bgra8888 = true;
 522   }
 523
 524   // Only desktop GL extension GL_EXT_bgra or ANGLE guarantee that we can
 525   // allocate a renderbuffer with this format.
 526   if (extensions.Contains("GL_EXT_bgra") || gl_version_info_->is_angle) {
 527     enable_render_buffer_bgra = true;
 528   }
 529
 530   if (extensions.Contains("GL_EXT_read_format_bgra") ||
 531       extensions.Contains("GL_EXT_bgra")) {
 532     enable_read_format_bgra = true;
 533   }
 534
 535   if (enable_texture_format_bgra8888) {
 536     feature_flags_.ext_texture_format_bgra8888 = true;
 537     AddExtensionString("GL_EXT_texture_format_BGRA8888");
 538     validators_.texture_internal_format.AddValue(GL_BGRA_EXT);
 539     validators_.texture_format.AddValue(GL_BGRA_EXT);
 540   }
 541
 542   if (enable_read_format_bgra) {
 543     AddExtensionString("GL_EXT_read_format_bgra");
 544     validators_.read_pixel_format.AddValue(GL_BGRA_EXT);
 545   }
 546
 547   // We only support timer queries if we also support glGetInteger64v.
 548   // For GL_EXT_disjoint_timer_query, glGetInteger64v is only support under ES3.
 549   if ((gl_version_info_->is_es3 &&
 550        extensions.Contains("GL_EXT_disjoint_timer_query")) ||
 551       extensions.Contains("GL_ARB_timer_query") ||
 552       extensions.Contains("GL_EXT_timer_query")) {
 553     AddExtensionString("GL_EXT_disjoint_timer_query");
 554   }
 555
 556   if (enable_render_buffer_bgra) {
 557     feature_flags_.ext_render_buffer_format_bgra8888 = true;
 558     AddExtensionString("GL_CHROMIUM_renderbuffer_format_BGRA8888");
 559     validators_.render_buffer_format.AddValue(GL_BGRA8_EXT);
 560   }
 561
 562   if (extensions.Contains("GL_OES_rgb8_rgba8") || gfx::HasDesktopGLFeatures()) {
 563     AddExtensionString("GL_OES_rgb8_rgba8");
 564     validators_.render_buffer_format.AddValue(GL_RGB8_OES);
 565     validators_.render_buffer_format.AddValue(GL_RGBA8_OES);
 566   }
 567
 568   // Check if we should allow GL_OES_texture_npot
 569   if (!disallowed_features_.npot_support &&
 570       (gl_version_info_->is_es3 ||
 571        gl_version_info_->is_desktop_core_profile ||
 572        extensions.Contains("GL_ARB_texture_non_power_of_two") ||
 573        extensions.Contains("GL_OES_texture_npot"))) {
 574     AddExtensionString("GL_OES_texture_npot");
 575     feature_flags_.npot_ok = true;
 576   }
 577
 578   // Check if we should allow GL_OES_texture_float, GL_OES_texture_half_float,
 579   // GL_OES_texture_float_linear, GL_OES_texture_half_float_linear
 580   bool enable_texture_float = false;
 581   bool enable_texture_float_linear = false;
 582   bool enable_texture_half_float = false;
 583   bool enable_texture_half_float_linear = false;
 584
 585   bool may_enable_chromium_color_buffer_float = false;
 586
 587   if (extensions.Contains("GL_ARB_texture_float") ||
 588       gl_version_info_->is_desktop_core_profile) {
 589     enable_texture_float = true;
 590     enable_texture_float_linear = true;
 591     enable_texture_half_float = true;
 592     enable_texture_half_float_linear = true;
 593     may_enable_chromium_color_buffer_float = true;
 594   } else {
 595     // GLES3 adds support for Float type by default but it doesn't support all
 596     // formats as GL_OES_texture_float(i.e.LUMINANCE_ALPHA,LUMINANCE and Alpha)
 597     if (extensions.Contains("GL_OES_texture_float")) {
 598       enable_texture_float = true;
 599       if (extensions.Contains("GL_OES_texture_float_linear")) {
 600         enable_texture_float_linear = true;
 601       }
 602       // This extension allows a variety of floating point formats to be
 603       // rendered to via framebuffer objects. Enable it's usage only if
 604       // support for Floating textures is enabled.
 605       if ((gl_version_info_->is_es3 &&
 606            extensions.Contains("GL_EXT_color_buffer_float")) ||
 607           gl_version_info_->is_angle) {
 608         may_enable_chromium_color_buffer_float = true;
 609       }
 610     }
 611
 612     // TODO(dshwang): GLES3 supports half float by default but GL_HALF_FLOAT_OES
 613     // isn't equal to GL_HALF_FLOAT.
 614     if (extensions.Contains("GL_OES_texture_half_float")) {
 615       enable_texture_half_float = true;
 616       if (extensions.Contains("GL_OES_texture_half_float_linear")) {
 617         enable_texture_half_float_linear = true;
 618       }
 619     }
 620   }
 621
 622   if (enable_texture_float) {
 623     validators_.pixel_type.AddValue(GL_FLOAT);
 624     validators_.read_pixel_type.AddValue(GL_FLOAT);
 625     AddExtensionString("GL_OES_texture_float");
 626     if (enable_texture_float_linear) {
 627       AddExtensionString("GL_OES_texture_float_linear");
 628     }
 629   }
 630
 631   if (enable_texture_half_float) {
 632     validators_.pixel_type.AddValue(GL_HALF_FLOAT_OES);
 633     validators_.read_pixel_type.AddValue(GL_HALF_FLOAT_OES);
 634     AddExtensionString("GL_OES_texture_half_float");
 635     if (enable_texture_half_float_linear) {
 636       AddExtensionString("GL_OES_texture_half_float_linear");
 637     }
 638   }
 639
 640   if (may_enable_chromium_color_buffer_float) {
 641     static_assert(GL_RGBA32F_ARB == GL_RGBA32F &&
 642                   GL_RGBA32F_EXT == GL_RGBA32F &&
 643                   GL_RGB32F_ARB == GL_RGB32F &&
 644                   GL_RGB32F_EXT == GL_RGB32F,
 645                   "sized float internal format variations must match");
 646     // We don't check extension support beyond ARB_texture_float on desktop GL,
 647     // and format support varies between GL configurations. For example, spec
 648     // prior to OpenGL 3.0 mandates framebuffer support only for one
 649     // implementation-chosen format, and ES3.0 EXT_color_buffer_float does not
 650     // support rendering to RGB32F. Check for framebuffer completeness with
 651     // formats that the extensions expose, and only enable an extension when a
 652     // framebuffer created with its texture format is reported as complete.
 653     GLint fb_binding = 0;
 654     GLint tex_binding = 0;
 655     glGetIntegerv(GL_FRAMEBUFFER_BINDING, &fb_binding);
 656     glGetIntegerv(GL_TEXTURE_BINDING_2D, &tex_binding);
 657
 658     GLuint tex_id = 0;
 659     GLuint fb_id = 0;
 660     GLsizei width = 16;
 661
 662     glGenTextures(1, &tex_id);
 663     glGenFramebuffersEXT(1, &fb_id);
 664     glBindTexture(GL_TEXTURE_2D, tex_id);
 665     // Nearest filter needed for framebuffer completeness on some drivers.
 666     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 667     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, width, width, 0, GL_RGBA,
 668                  GL_FLOAT, NULL);
 669     glBindFramebufferEXT(GL_FRAMEBUFFER, fb_id);
 670     glFramebufferTexture2DEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
 671                               GL_TEXTURE_2D, tex_id, 0);
 672     GLenum statusRGBA = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER);
 673     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F, width, width, 0, GL_RGB,
 674                  GL_FLOAT, NULL);
 675     GLenum statusRGB = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER);
 676     glDeleteFramebuffersEXT(1, &fb_id);
 677     glDeleteTextures(1, &tex_id);
 678
 679     glBindFramebufferEXT(GL_FRAMEBUFFER, static_cast<GLuint>(fb_binding));
 680     glBindTexture(GL_TEXTURE_2D, static_cast<GLuint>(tex_binding));
 681
 682     DCHECK(glGetError() == GL_NO_ERROR);
 683
 684     if (statusRGBA == GL_FRAMEBUFFER_COMPLETE) {
 685       validators_.texture_internal_format.AddValue(GL_RGBA32F);
 686       feature_flags_.chromium_color_buffer_float_rgba = true;
 687       AddExtensionString("GL_CHROMIUM_color_buffer_float_rgba");
 688     }
 689     if (statusRGB == GL_FRAMEBUFFER_COMPLETE) {
 690       validators_.texture_internal_format.AddValue(GL_RGB32F);
 691       feature_flags_.chromium_color_buffer_float_rgb = true;
 692       AddExtensionString("GL_CHROMIUM_color_buffer_float_rgb");
 693     }
 694   }
 695
 696   // Check for multisample support
 697   if (!workarounds_.disable_chromium_framebuffer_multisample) {
 698     bool ext_has_multisample =
 699         extensions.Contains("GL_EXT_framebuffer_multisample") ||
 700         gl_version_info_->is_es3 ||
 701         gl_version_info_->is_desktop_core_profile;
 702     if (gl_version_info_->is_angle) {
 703       ext_has_multisample |=
 704           extensions.Contains("GL_ANGLE_framebuffer_multisample");
 705     }
 706     feature_flags_.use_core_framebuffer_multisample =
 707         gl_version_info_->is_es3 || gl_version_info_->is_desktop_core_profile;
 708     if (ext_has_multisample) {
 709       feature_flags_.chromium_framebuffer_multisample = true;
 710       validators_.frame_buffer_target.AddValue(GL_READ_FRAMEBUFFER_EXT);
 711       validators_.frame_buffer_target.AddValue(GL_DRAW_FRAMEBUFFER_EXT);
 712       validators_.g_l_state.AddValue(GL_READ_FRAMEBUFFER_BINDING_EXT);
 713       validators_.g_l_state.AddValue(GL_MAX_SAMPLES_EXT);
 714       validators_.render_buffer_parameter.AddValue(GL_RENDERBUFFER_SAMPLES_EXT);
 715       AddExtensionString("GL_CHROMIUM_framebuffer_multisample");
 716     }
 717   }
 718
 719   if (!workarounds_.disable_multisampled_render_to_texture) {
 720     if (extensions.Contains("GL_EXT_multisampled_render_to_texture")) {
 721       feature_flags_.multisampled_render_to_texture = true;
 722     } else if (extensions.Contains("GL_IMG_multisampled_render_to_texture")) {
 723       feature_flags_.multisampled_render_to_texture = true;
 724       feature_flags_.use_img_for_multisampled_render_to_texture = true;
 725     }
 726     if (feature_flags_.multisampled_render_to_texture) {
 727       validators_.render_buffer_parameter.AddValue(
 728           GL_RENDERBUFFER_SAMPLES_EXT);
 729       validators_.g_l_state.AddValue(GL_MAX_SAMPLES_EXT);
 730       validators_.frame_buffer_parameter.AddValue(
 731           GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_SAMPLES_EXT);
 732       AddExtensionString("GL_EXT_multisampled_render_to_texture");
 733     }
 734   }
 735
 736   if (extensions.Contains("GL_OES_depth24") || gfx::HasDesktopGLFeatures() ||
 737       gl_version_info_->is_es3) {
 738     AddExtensionString("GL_OES_depth24");
 739     feature_flags_.oes_depth24 = true;
 740     validators_.render_buffer_format.AddValue(GL_DEPTH_COMPONENT24);
 741   }
 742
 743   if (gl_version_info_->is_es3 ||
 744       extensions.Contains("GL_OES_standard_derivatives") ||
 745       gfx::HasDesktopGLFeatures()) {
 746     AddExtensionString("GL_OES_standard_derivatives");
 747     feature_flags_.oes_standard_derivatives = true;
 748     validators_.hint_target.AddValue(GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES);
 749     validators_.g_l_state.AddValue(GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES);
 750   }
 751
 752   if (extensions.Contains("GL_OES_EGL_image_external")) {
 753     AddExtensionString("GL_OES_EGL_image_external");
 754     feature_flags_.oes_egl_image_external = true;
 755     validators_.texture_bind_target.AddValue(GL_TEXTURE_EXTERNAL_OES);
 756     validators_.get_tex_param_target.AddValue(GL_TEXTURE_EXTERNAL_OES);
 757     validators_.texture_parameter.AddValue(GL_REQUIRED_TEXTURE_IMAGE_UNITS_OES);
 758     validators_.g_l_state.AddValue(GL_TEXTURE_BINDING_EXTERNAL_OES);
 759   }
 760
 761   if (extensions.Contains("GL_OES_compressed_ETC1_RGB8_texture")) {
 762     AddExtensionString("GL_OES_compressed_ETC1_RGB8_texture");
 763     feature_flags_.oes_compressed_etc1_rgb8_texture = true;
 764     validators_.compressed_texture_format.AddValue(GL_ETC1_RGB8_OES);
 765     validators_.texture_internal_format_storage.AddValue(GL_ETC1_RGB8_OES);
 766   }
 767
 768   if (extensions.Contains("GL_AMD_compressed_ATC_texture")) {
 769     AddExtensionString("GL_AMD_compressed_ATC_texture");
 770     validators_.compressed_texture_format.AddValue(
 771         GL_ATC_RGB_AMD);
 772     validators_.compressed_texture_format.AddValue(
 773         GL_ATC_RGBA_EXPLICIT_ALPHA_AMD);
 774     validators_.compressed_texture_format.AddValue(
 775         GL_ATC_RGBA_INTERPOLATED_ALPHA_AMD);
 776
 777     validators_.texture_internal_format_storage.AddValue(
 778         GL_ATC_RGB_AMD);
 779     validators_.texture_internal_format_storage.AddValue(
 780         GL_ATC_RGBA_EXPLICIT_ALPHA_AMD);
 781     validators_.texture_internal_format_storage.AddValue(
 782         GL_ATC_RGBA_INTERPOLATED_ALPHA_AMD);
 783   }
 784
 785   if (extensions.Contains("GL_IMG_texture_compression_pvrtc")) {
 786     AddExtensionString("GL_IMG_texture_compression_pvrtc");
 787     validators_.compressed_texture_format.AddValue(
 788         GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG);
 789     validators_.compressed_texture_format.AddValue(
 790         GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG);
 791     validators_.compressed_texture_format.AddValue(
 792         GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG);
 793     validators_.compressed_texture_format.AddValue(
 794         GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG);
 795
 796     validators_.texture_internal_format_storage.AddValue(
 797         GL_COMPRESSED_RGB_PVRTC_4BPPV1_IMG);
 798     validators_.texture_internal_format_storage.AddValue(
 799         GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG);
 800     validators_.texture_internal_format_storage.AddValue(
 801         GL_COMPRESSED_RGBA_PVRTC_4BPPV1_IMG);
 802     validators_.texture_internal_format_storage.AddValue(
 803         GL_COMPRESSED_RGBA_PVRTC_2BPPV1_IMG);
 804   }
 805
 806   // Ideally we would only expose this extension on Mac OS X, to
 807   // support GL_CHROMIUM_iosurface and the compositor. We don't want
 808   // applications to start using it; they should use ordinary non-
 809   // power-of-two textures. However, for unit testing purposes we
 810   // expose it on all supported platforms.
 811   if (extensions.Contains("GL_ARB_texture_rectangle") ||
 812       gl_version_info_->is_desktop_core_profile) {
 813     AddExtensionString("GL_ARB_texture_rectangle");
 814     feature_flags_.arb_texture_rectangle = true;
 815     // Rectangle textures are used as samplers via glBindTexture, framebuffer
 816     // textures via glFramebufferTexture2D, and copy destinations via
 817     // glCopyPixels.
 818     validators_.texture_bind_target.AddValue(GL_TEXTURE_RECTANGLE_ARB);
 819     validators_.texture_target.AddValue(GL_TEXTURE_RECTANGLE_ARB);
 820     validators_.get_tex_param_target.AddValue(GL_TEXTURE_RECTANGLE_ARB);
 821     validators_.g_l_state.AddValue(GL_TEXTURE_BINDING_RECTANGLE_ARB);
 822   }
 823
 824 #if defined(OS_MACOSX)
 825   AddExtensionString("GL_CHROMIUM_iosurface");
 826 #endif
 827
 828   if (extensions.Contains("GL_APPLE_ycbcr_422")) {
 829     AddExtensionString("GL_CHROMIUM_ycbcr_422_image");
 830     feature_flags_.chromium_image_ycbcr_422 = true;
 831   }
 832
 833   // TODO(gman): Add support for these extensions.
 834   //     GL_OES_depth32
 835
 836   feature_flags_.enable_texture_float_linear |= enable_texture_float_linear;
 837   feature_flags_.enable_texture_half_float_linear |=
 838       enable_texture_half_float_linear;
 839
 840   if (extensions.Contains("GL_ANGLE_pack_reverse_row_order")) {
 841     AddExtensionString("GL_ANGLE_pack_reverse_row_order");
 842     feature_flags_.angle_pack_reverse_row_order = true;
 843     validators_.pixel_store.AddValue(GL_PACK_REVERSE_ROW_ORDER_ANGLE);
 844     validators_.g_l_state.AddValue(GL_PACK_REVERSE_ROW_ORDER_ANGLE);
 845   }
 846
 847   if (extensions.Contains("GL_ANGLE_texture_usage")) {
 848     feature_flags_.angle_texture_usage = true;
 849     AddExtensionString("GL_ANGLE_texture_usage");
 850     validators_.texture_parameter.AddValue(GL_TEXTURE_USAGE_ANGLE);
 851   }
 852
 853   // Note: Only APPLE_texture_format_BGRA8888 extension allows BGRA8_EXT in
 854   // ES3's glTexStorage2D. We prefer support BGRA to texture storage.
 855   // So we don't expose GL_EXT_texture_storage when ES3 +
 856   // GL_EXT_texture_format_BGRA8888 because we fail the GL_BGRA8 requirement.
 857   // However we expose GL_EXT_texture_storage when just ES3 because we don't
 858   // claim to handle GL_BGRA8.
 859   bool support_texture_storage_on_es3 =
 860       (gl_version_info_->is_es3 &&
 861        enable_immutable_texture_format_bgra_on_es3) ||
 862       (gl_version_info_->is_es3 &&
 863        !enable_texture_format_bgra8888);
 864   if (!workarounds_.disable_texture_storage &&
 865       (extensions.Contains("GL_EXT_texture_storage") ||
 866        extensions.Contains("GL_ARB_texture_storage") ||
 867        support_texture_storage_on_es3 ||
 868        gl_version_info_->is_desktop_core_profile)) {
 869     feature_flags_.ext_texture_storage = true;
 870     AddExtensionString("GL_EXT_texture_storage");
 871     validators_.texture_parameter.AddValue(GL_TEXTURE_IMMUTABLE_FORMAT_EXT);
 872     if (enable_texture_format_bgra8888)
 873         validators_.texture_internal_format_storage.AddValue(GL_BGRA8_EXT);
 874     if (enable_texture_float) {
 875         validators_.texture_internal_format_storage.AddValue(GL_RGBA32F_EXT);
 876         validators_.texture_internal_format_storage.AddValue(GL_RGB32F_EXT);
 877         validators_.texture_internal_format_storage.AddValue(GL_ALPHA32F_EXT);
 878         validators_.texture_internal_format_storage.AddValue(
 879             GL_LUMINANCE32F_EXT);
 880         validators_.texture_internal_format_storage.AddValue(
 881             GL_LUMINANCE_ALPHA32F_EXT);
 882     }
 883     if (enable_texture_half_float) {
 884         validators_.texture_internal_format_storage.AddValue(GL_RGBA16F_EXT);
 885         validators_.texture_internal_format_storage.AddValue(GL_RGB16F_EXT);
 886         validators_.texture_internal_format_storage.AddValue(GL_ALPHA16F_EXT);
 887         validators_.texture_internal_format_storage.AddValue(
 888             GL_LUMINANCE16F_EXT);
 889         validators_.texture_internal_format_storage.AddValue(
 890             GL_LUMINANCE_ALPHA16F_EXT);
 891     }
 892   }
 893
 894   bool have_ext_occlusion_query_boolean =
 895       extensions.Contains("GL_EXT_occlusion_query_boolean");
 896   bool have_arb_occlusion_query2 =
 897       extensions.Contains("GL_ARB_occlusion_query2");
 898   bool have_arb_occlusion_query =
 899       extensions.Contains("GL_ARB_occlusion_query");
 900
 901   if (have_ext_occlusion_query_boolean ||
 902       have_arb_occlusion_query2 ||
 903       have_arb_occlusion_query) {
 904     AddExtensionString("GL_EXT_occlusion_query_boolean");
 905     feature_flags_.occlusion_query_boolean = true;
 906     feature_flags_.use_arb_occlusion_query2_for_occlusion_query_boolean =
 907         !have_ext_occlusion_query_boolean && have_arb_occlusion_query2;
 908     feature_flags_.use_arb_occlusion_query_for_occlusion_query_boolean =
 909         !have_ext_occlusion_query_boolean && have_arb_occlusion_query &&
 910         !have_arb_occlusion_query2;
 911   }
 912
 913   if (!workarounds_.disable_angle_instanced_arrays &&
 914       (extensions.Contains("GL_ANGLE_instanced_arrays") ||
 915        (extensions.Contains("GL_ARB_instanced_arrays") &&
 916         extensions.Contains("GL_ARB_draw_instanced")) ||
 917        gl_version_info_->is_es3)) {
 918     AddExtensionString("GL_ANGLE_instanced_arrays");
 919     feature_flags_.angle_instanced_arrays = true;
 920     validators_.vertex_attribute.AddValue(GL_VERTEX_ATTRIB_ARRAY_DIVISOR_ANGLE);
 921   }
 922
 923   bool vendor_agnostic_draw_buffers =
 924       extensions.Contains("GL_ARB_draw_buffers") ||
 925       extensions.Contains("GL_EXT_draw_buffers");
 926   if (!workarounds_.disable_ext_draw_buffers &&
 927       (vendor_agnostic_draw_buffers ||
 928        (extensions.Contains("GL_NV_draw_buffers") &&
 929         gl_version_info_->is_es3) ||
 930        gl_version_info_->is_desktop_core_profile)) {
 931     AddExtensionString("GL_EXT_draw_buffers");
 932     feature_flags_.ext_draw_buffers = true;
 933
 934     // This flag is set to enable emulation of EXT_draw_buffers when we're
 935     // running on GLES 3.0+, NV_draw_buffers extension is supported and
 936     // glDrawBuffers from GLES 3.0 core has been bound. It toggles using the
 937     // NV_draw_buffers extension directive instead of EXT_draw_buffers extension
 938     // directive in ESSL 100 shaders translated by ANGLE, enabling them to write
 939     // into multiple gl_FragData values, which is not by default possible in
 940     // ESSL 100 with core GLES 3.0. For more information, see the
 941     // NV_draw_buffers specification.
 942     feature_flags_.nv_draw_buffers = !vendor_agnostic_draw_buffers;
 943
 944     GLint max_color_attachments = 0;
 945     glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &max_color_attachments);
 946     for (GLenum i = GL_COLOR_ATTACHMENT1_EXT;
 947          i < static_cast<GLenum>(GL_COLOR_ATTACHMENT0 + max_color_attachments);
 948          ++i) {
 949       validators_.attachment.AddValue(i);
 950     }
 951     static_assert(GL_COLOR_ATTACHMENT0_EXT == GL_COLOR_ATTACHMENT0,
 952                   "GL_COLOR_ATTACHMENT0_EXT should equal GL_COLOR_ATTACHMENT0");
 953
 954     validators_.g_l_state.AddValue(GL_MAX_COLOR_ATTACHMENTS_EXT);
 955     validators_.g_l_state.AddValue(GL_MAX_DRAW_BUFFERS_ARB);
 956     GLint max_draw_buffers = 0;
 957     glGetIntegerv(GL_MAX_DRAW_BUFFERS_ARB, &max_draw_buffers);
 958     for (GLenum i = GL_DRAW_BUFFER0_ARB;
 959          i < static_cast<GLenum>(GL_DRAW_BUFFER0_ARB + max_draw_buffers);
 960          ++i) {
 961       validators_.g_l_state.AddValue(i);
 962     }
 963   }
 964
 965   if (gl_version_info_->is_es3 ||
 966       extensions.Contains("GL_EXT_blend_minmax") ||
 967       gfx::HasDesktopGLFeatures()) {
 968     AddExtensionString("GL_EXT_blend_minmax");
 969     validators_.equation.AddValue(GL_MIN_EXT);
 970     validators_.equation.AddValue(GL_MAX_EXT);
 971     static_assert(GL_MIN_EXT == GL_MIN && GL_MAX_EXT == GL_MAX,
 972                   "min & max variations must match");
 973   }
 974
 975   // TODO(dshwang): GLES3 supports gl_FragDepth, not gl_FragDepthEXT.
 976   if (extensions.Contains("GL_EXT_frag_depth") || gfx::HasDesktopGLFeatures()) {
 977     AddExtensionString("GL_EXT_frag_depth");
 978     feature_flags_.ext_frag_depth = true;
 979   }
 980
 981   if (extensions.Contains("GL_EXT_shader_texture_lod") ||
 982       gfx::HasDesktopGLFeatures()) {
 983     AddExtensionString("GL_EXT_shader_texture_lod");
 984     feature_flags_.ext_shader_texture_lod = true;
 985   }
 986
 987   bool ui_gl_fence_works = gfx::GLFence::IsSupported();
 988   UMA_HISTOGRAM_BOOLEAN("GPU.FenceSupport", ui_gl_fence_works);
 989
 990   feature_flags_.map_buffer_range =
 991       gl_version_info_->is_es3 ||
 992       gl_version_info_->is_desktop_core_profile ||
 993       extensions.Contains("GL_ARB_map_buffer_range") ||
 994       extensions.Contains("GL_EXT_map_buffer_range");
 995
 996   // Really it's part of core OpenGL 2.1 and up, but let's assume the
 997   // extension is still advertised.
 998   bool has_pixel_buffers =
 999       gl_version_info_->is_es3 ||
1000       gl_version_info_->is_desktop_core_profile ||
1001       extensions.Contains("GL_ARB_pixel_buffer_object") ||
1002       extensions.Contains("GL_NV_pixel_buffer_object");
1003
1004   // We will use either glMapBuffer() or glMapBufferRange() for async readbacks.
1005   if (has_pixel_buffers && ui_gl_fence_works &&
1006       !workarounds_.disable_async_readpixels) {
1007     feature_flags_.use_async_readpixels = true;
1008   }
1009
1010   if (gl_version_info_->is_es3 ||
1011       extensions.Contains("GL_ARB_sampler_objects")) {
1012     feature_flags_.enable_samplers = true;
1013     // TODO(dsinclair): Add AddExtensionString("GL_CHROMIUM_sampler_objects")
1014     // when available.
1015   }
1016
1017   if ((gl_version_info_->is_es3 ||
1018        extensions.Contains("GL_EXT_discard_framebuffer")) &&
1019       !workarounds_.disable_discard_framebuffer) {
1020     // DiscardFramebufferEXT is automatically bound to InvalidateFramebuffer.
1021     AddExtensionString("GL_EXT_discard_framebuffer");
1022     feature_flags_.ext_discard_framebuffer = true;
1023   }
1024
1025   if (ui_gl_fence_works) {
1026     AddExtensionString("GL_CHROMIUM_sync_query");
1027     feature_flags_.chromium_sync_query = true;
1028   }
1029
1030   if (!workarounds_.disable_blend_equation_advanced) {
1031     bool blend_equation_advanced_coherent =
1032         extensions.Contains("GL_NV_blend_equation_advanced_coherent") ||
1033         extensions.Contains("GL_KHR_blend_equation_advanced_coherent");
1034
1035     if (blend_equation_advanced_coherent ||
1036         extensions.Contains("GL_NV_blend_equation_advanced") ||
1037         extensions.Contains("GL_KHR_blend_equation_advanced")) {
1038       const GLenum equations[] = {GL_MULTIPLY_KHR,
1039                                   GL_SCREEN_KHR,
1040                                   GL_OVERLAY_KHR,
1041                                   GL_DARKEN_KHR,
1042                                   GL_LIGHTEN_KHR,
1043                                   GL_COLORDODGE_KHR,
1044                                   GL_COLORBURN_KHR,
1045                                   GL_HARDLIGHT_KHR,
1046                                   GL_SOFTLIGHT_KHR,
1047                                   GL_DIFFERENCE_KHR,
1048                                   GL_EXCLUSION_KHR,
1049                                   GL_HSL_HUE_KHR,
1050                                   GL_HSL_SATURATION_KHR,
1051                                   GL_HSL_COLOR_KHR,
1052                                   GL_HSL_LUMINOSITY_KHR};
1053
1054       for (GLenum equation : equations)
1055         validators_.equation.AddValue(equation);
1056       if (blend_equation_advanced_coherent)
1057         AddExtensionString("GL_KHR_blend_equation_advanced_coherent");
1058
1059       AddExtensionString("GL_KHR_blend_equation_advanced");
1060       feature_flags_.blend_equation_advanced = true;
1061       feature_flags_.blend_equation_advanced_coherent =
1062           blend_equation_advanced_coherent;
1063     }
1064   }
1065
1066   if (enable_gl_path_rendering_switch_ &&
1067       !workarounds_.disable_gl_path_rendering &&
1068       extensions.Contains("GL_NV_path_rendering") &&
1069       (extensions.Contains("GL_EXT_direct_state_access") ||
1070        gl_version_info_->is_es3)) {
1071     AddExtensionString("GL_CHROMIUM_path_rendering");
1072     feature_flags_.chromium_path_rendering = true;
1073     validators_.g_l_state.AddValue(GL_PATH_MODELVIEW_MATRIX_CHROMIUM);
1074     validators_.g_l_state.AddValue(GL_PATH_PROJECTION_MATRIX_CHROMIUM);
1075     validators_.g_l_state.AddValue(GL_PATH_STENCIL_FUNC_CHROMIUM);
1076     validators_.g_l_state.AddValue(GL_PATH_STENCIL_REF_CHROMIUM);
1077     validators_.g_l_state.AddValue(GL_PATH_STENCIL_VALUE_MASK_CHROMIUM);
1078   }
1079
1080   if ((gl_version_info_->is_es3 || gl_version_info_->is_desktop_core_profile ||
1081        extensions.Contains("GL_EXT_texture_rg") ||
1082        extensions.Contains("GL_ARB_texture_rg")) &&
1083       IsGL_REDSupportedOnFBOs()) {
1084     feature_flags_.ext_texture_rg = true;
1085     AddExtensionString("GL_EXT_texture_rg");
1086
1087     validators_.texture_format.AddValue(GL_RED_EXT);
1088     validators_.texture_format.AddValue(GL_RG_EXT);
1089     validators_.texture_internal_format.AddValue(GL_RED_EXT);
1090     validators_.texture_internal_format.AddValue(GL_R8_EXT);
1091     validators_.texture_internal_format.AddValue(GL_RG_EXT);
1092     validators_.texture_internal_format.AddValue(GL_RG8_EXT);
1093     validators_.read_pixel_format.AddValue(GL_RED_EXT);
1094     validators_.read_pixel_format.AddValue(GL_RG_EXT);
1095     validators_.render_buffer_format.AddValue(GL_R8_EXT);
1096     validators_.render_buffer_format.AddValue(GL_RG8_EXT);
1097   }
1098   UMA_HISTOGRAM_BOOLEAN("GPU.TextureRG", feature_flags_.ext_texture_rg);
1099
1100 #if !defined(OS_MACOSX)
1101   if (workarounds_.ignore_egl_sync_failures) {
1102     gfx::GLFenceEGL::SetIgnoreFailures();
1103   }
1104 #endif
1105
1106   if (workarounds_.avoid_egl_image_target_texture_reuse) {
1107     TextureDefinition::AvoidEGLTargetTextureReuse();
1108   }
1109
1110   if (gl_version_info_->IsLowerThanGL(4, 3)) {
1111     // crbug.com/481184.
1112     // GL_PRIMITIVE_RESTART_FIXED_INDEX is only available on Desktop GL 4.3+,
1113     // but we emulate ES 3.0 on top of Desktop GL 4.2+.
1114     feature_flags_.emulate_primitive_restart_fixed_index = true;
1115   }
1116 }
1117
1118 bool FeatureInfo::IsES3Capable() const {
1119   if (!enable_unsafe_es3_apis_switch_)
1120     return false;
1121   if (gl_version_info_)
1122     return gl_version_info_->IsES3Capable();
1123   return false;
1124 }
1125
1126 void FeatureInfo::EnableES3Validators() {
1127   DCHECK(IsES3Capable());
1128   validators_.UpdateValuesES3();
1129
1130   GLint max_color_attachments = 0;
1131   glGetIntegerv(GL_MAX_COLOR_ATTACHMENTS, &max_color_attachments);
1132   const int kTotalColorAttachmentEnums = 16;
1133   const GLenum kColorAttachments[] = {
1134     GL_COLOR_ATTACHMENT0,
1135     GL_COLOR_ATTACHMENT1,
1136     GL_COLOR_ATTACHMENT2,
1137     GL_COLOR_ATTACHMENT3,
1138     GL_COLOR_ATTACHMENT4,
1139     GL_COLOR_ATTACHMENT5,
1140     GL_COLOR_ATTACHMENT6,
1141     GL_COLOR_ATTACHMENT7,
1142     GL_COLOR_ATTACHMENT8,
1143     GL_COLOR_ATTACHMENT9,
1144     GL_COLOR_ATTACHMENT10,
1145     GL_COLOR_ATTACHMENT11,
1146     GL_COLOR_ATTACHMENT12,
1147     GL_COLOR_ATTACHMENT13,
1148     GL_COLOR_ATTACHMENT14,
1149     GL_COLOR_ATTACHMENT15,
1150   };
1151   if (max_color_attachments < kTotalColorAttachmentEnums) {
1152     validators_.attachment.RemoveValues(
1153         kColorAttachments + max_color_attachments,
1154         kTotalColorAttachmentEnums - max_color_attachments);
1155   }
1156
1157   GLint max_draw_buffers = 0;
1158   glGetIntegerv(GL_MAX_DRAW_BUFFERS, &max_draw_buffers);
1159   const int kTotalDrawBufferEnums = 16;
1160   const GLenum kDrawBuffers[] = {
1161     GL_DRAW_BUFFER0,
1162     GL_DRAW_BUFFER1,
1163     GL_DRAW_BUFFER2,
1164     GL_DRAW_BUFFER3,
1165     GL_DRAW_BUFFER4,
1166     GL_DRAW_BUFFER5,
1167     GL_DRAW_BUFFER6,
1168     GL_DRAW_BUFFER7,
1169     GL_DRAW_BUFFER8,
1170     GL_DRAW_BUFFER9,
1171     GL_DRAW_BUFFER10,
1172     GL_DRAW_BUFFER11,
1173     GL_DRAW_BUFFER12,
1174     GL_DRAW_BUFFER13,
1175     GL_DRAW_BUFFER14,
1176     GL_DRAW_BUFFER15,
1177   };
1178   if (max_draw_buffers < kTotalDrawBufferEnums) {
1179     validators_.g_l_state.RemoveValues(
1180         kDrawBuffers + max_draw_buffers,
1181         kTotalDrawBufferEnums - max_draw_buffers);
1182   }
1183
1184   unsafe_es3_apis_enabled_ = true;
1185 }
1186
1187 void FeatureInfo::AddExtensionString(const char* s) {
1188   std::string str(s);
1189   size_t pos = extensions_.find(str);
1190   while (pos != std::string::npos &&
1191          pos + str.length() < extensions_.length() &&
1192          extensions_.substr(pos + str.length(), 1) != " ") {
1193     // This extension name is a substring of another.
1194     pos = extensions_.find(str, pos + str.length());
1195   }
1196   if (pos == std::string::npos) {
1197     extensions_ += (extensions_.empty() ? "" : " ") + str;
1198   }
1199 }
1200
1201 FeatureInfo::~FeatureInfo() {
1202 }
1203
1204 }  // namespace gles2
1205 }  // namespace gpu