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