dom/canvas/WebGLContextExtensions.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "WebGLContext.h"
   7 #include "ClientWebGLExtensions.h"
   8 #include "GLContext.h"
   9 #include "mozilla/dom/BindingDeclarations.h"
  10 #include "mozilla/dom/ToJSValue.h"
  11 #include "mozilla/EnumeratedRange.h"
  12 #include "nsString.h"
  13 #include "WebGLContextUtils.h"
  14 #include "WebGLExtensions.h"
  15
  16 namespace mozilla {
  17
  18 const char* GetExtensionName(const WebGLExtensionID ext) {
  19   static EnumeratedArray<WebGLExtensionID, WebGLExtensionID::Max, const char*>
  20       sExtensionNamesEnumeratedArray;
  21   static bool initialized = false;
  22
  23   if (!initialized) {
  24     initialized = true;
  25
  26 #define WEBGL_EXTENSION_IDENTIFIER(x) \
  27   sExtensionNamesEnumeratedArray[WebGLExtensionID::x] = #x;
  28
  29     WEBGL_EXTENSION_IDENTIFIER(ANGLE_instanced_arrays)
  30     WEBGL_EXTENSION_IDENTIFIER(EXT_blend_minmax)
  31     WEBGL_EXTENSION_IDENTIFIER(EXT_color_buffer_float)
  32     WEBGL_EXTENSION_IDENTIFIER(EXT_color_buffer_half_float)
  33     WEBGL_EXTENSION_IDENTIFIER(EXT_disjoint_timer_query)
  34     WEBGL_EXTENSION_IDENTIFIER(EXT_float_blend)
  35     WEBGL_EXTENSION_IDENTIFIER(EXT_frag_depth)
  36     WEBGL_EXTENSION_IDENTIFIER(EXT_shader_texture_lod)
  37     WEBGL_EXTENSION_IDENTIFIER(EXT_sRGB)
  38     WEBGL_EXTENSION_IDENTIFIER(EXT_texture_compression_bptc)
  39     WEBGL_EXTENSION_IDENTIFIER(EXT_texture_compression_rgtc)
  40     WEBGL_EXTENSION_IDENTIFIER(EXT_texture_filter_anisotropic)
  41     WEBGL_EXTENSION_IDENTIFIER(EXT_texture_norm16)
  42     WEBGL_EXTENSION_IDENTIFIER(MOZ_debug)
  43     WEBGL_EXTENSION_IDENTIFIER(OES_element_index_uint)
  44     WEBGL_EXTENSION_IDENTIFIER(OES_fbo_render_mipmap)
  45     WEBGL_EXTENSION_IDENTIFIER(OES_standard_derivatives)
  46     WEBGL_EXTENSION_IDENTIFIER(OES_texture_float)
  47     WEBGL_EXTENSION_IDENTIFIER(OES_texture_float_linear)
  48     WEBGL_EXTENSION_IDENTIFIER(OES_texture_half_float)
  49     WEBGL_EXTENSION_IDENTIFIER(OES_texture_half_float_linear)
  50     WEBGL_EXTENSION_IDENTIFIER(OES_vertex_array_object)
  51     WEBGL_EXTENSION_IDENTIFIER(OVR_multiview2)
  52     WEBGL_EXTENSION_IDENTIFIER(WEBGL_color_buffer_float)
  53     WEBGL_EXTENSION_IDENTIFIER(WEBGL_compressed_texture_astc)
  54     WEBGL_EXTENSION_IDENTIFIER(WEBGL_compressed_texture_etc)
  55     WEBGL_EXTENSION_IDENTIFIER(WEBGL_compressed_texture_etc1)
  56     WEBGL_EXTENSION_IDENTIFIER(WEBGL_compressed_texture_pvrtc)
  57     WEBGL_EXTENSION_IDENTIFIER(WEBGL_compressed_texture_s3tc)
  58     WEBGL_EXTENSION_IDENTIFIER(WEBGL_compressed_texture_s3tc_srgb)
  59     WEBGL_EXTENSION_IDENTIFIER(WEBGL_debug_renderer_info)
  60     WEBGL_EXTENSION_IDENTIFIER(WEBGL_debug_shaders)
  61     WEBGL_EXTENSION_IDENTIFIER(WEBGL_depth_texture)
  62     WEBGL_EXTENSION_IDENTIFIER(WEBGL_draw_buffers)
  63     WEBGL_EXTENSION_IDENTIFIER(WEBGL_explicit_present)
  64     WEBGL_EXTENSION_IDENTIFIER(WEBGL_lose_context)
  65
  66 #undef WEBGL_EXTENSION_IDENTIFIER
  67   }
  68
  69   return sExtensionNamesEnumeratedArray[ext];
  70 }
  71
  72 // ----------------------------
  73 // ClientWebGLContext
  74
  75 void ClientWebGLContext::GetExtension(JSContext* cx, const nsAString& wideName,
  76                                       JS::MutableHandle<JSObject*> retval,
  77                                       dom::CallerType callerType,
  78                                       ErrorResult& rv) {
  79   retval.set(nullptr);
  80   const FuncScope funcScope(*this, "getExtension");
  81   if (IsContextLost()) return;
  82
  83   const auto name = NS_ConvertUTF16toUTF8(wideName);
  84
  85   auto ext = WebGLExtensionID::Max;
  86
  87   // step 1: figure what extension is wanted
  88   for (const auto extension : MakeEnumeratedRange(WebGLExtensionID::Max)) {
  89     const auto& curName = GetExtensionName(extension);
  90     if (name.Equals(curName, nsCaseInsensitiveCStringComparator)) {
  91       ext = extension;
  92       break;
  93     }
  94   }
  95
  96   if (ext == WebGLExtensionID::Max) return;
  97
  98   RefPtr<ClientWebGLExtensionBase> extObj;
  99   if (ext == WebGLExtensionID::WEBGL_lose_context) {
 100     extObj = mExtLoseContext;
 101   } else {
 102     extObj = GetExtension(ext, callerType);
 103   }
 104   if (!extObj) return;
 105
 106   // Ugh, this would be easier returning `any` than `object`.
 107   JS::Rooted<JS::Value> v(cx);
 108   MOZ_ALWAYS_TRUE(dom::ToJSValue(cx, extObj, &v));
 109   if (v.isObject()) {
 110     retval.set(&v.toObject());
 111   }
 112 }
 113
 114 RefPtr<ClientWebGLExtensionBase> ClientWebGLContext::GetExtension(
 115     const WebGLExtensionID ext, const dom::CallerType callerType) {
 116   if (ext == WebGLExtensionID::WEBGL_lose_context) {
 117     // Always the same.
 118     return mExtLoseContext;
 119   }
 120
 121   if (!mNotLost) return nullptr;
 122
 123   if (!IsSupported(ext, callerType)) return nullptr;
 124
 125   auto& extSlot = mNotLost->extensions[UnderlyingValue(ext)];
 126   if (MOZ_UNLIKELY(!extSlot)) {
 127     extSlot = [&]() -> RefPtr<ClientWebGLExtensionBase> {
 128       switch (ext) {
 129         // ANGLE_
 130         case WebGLExtensionID::ANGLE_instanced_arrays:
 131           return new ClientWebGLExtensionInstancedArrays(*this);
 132
 133         // EXT_
 134         case WebGLExtensionID::EXT_blend_minmax:
 135           return new ClientWebGLExtensionBlendMinMax(*this);
 136         case WebGLExtensionID::EXT_color_buffer_float:
 137           return new ClientWebGLExtensionEXTColorBufferFloat(*this);
 138         case WebGLExtensionID::EXT_color_buffer_half_float:
 139           return new ClientWebGLExtensionColorBufferHalfFloat(*this);
 140         case WebGLExtensionID::EXT_disjoint_timer_query:
 141           return new ClientWebGLExtensionDisjointTimerQuery(*this);
 142         case WebGLExtensionID::EXT_float_blend:
 143           return new ClientWebGLExtensionFloatBlend(*this);
 144         case WebGLExtensionID::EXT_frag_depth:
 145           return new ClientWebGLExtensionFragDepth(*this);
 146         case WebGLExtensionID::EXT_shader_texture_lod:
 147           return new ClientWebGLExtensionShaderTextureLod(*this);
 148         case WebGLExtensionID::EXT_sRGB:
 149           return new ClientWebGLExtensionSRGB(*this);
 150         case WebGLExtensionID::EXT_texture_compression_bptc:
 151           return new ClientWebGLExtensionCompressedTextureBPTC(*this);
 152         case WebGLExtensionID::EXT_texture_compression_rgtc:
 153           return new ClientWebGLExtensionCompressedTextureRGTC(*this);
 154         case WebGLExtensionID::EXT_texture_filter_anisotropic:
 155           return new ClientWebGLExtensionTextureFilterAnisotropic(*this);
 156         case WebGLExtensionID::EXT_texture_norm16:
 157           return new ClientWebGLExtensionTextureNorm16(*this);
 158
 159         // MOZ_
 160         case WebGLExtensionID::MOZ_debug:
 161           return new ClientWebGLExtensionMOZDebug(*this);
 162
 163         // OES_
 164         case WebGLExtensionID::OES_element_index_uint:
 165           return new ClientWebGLExtensionElementIndexUint(*this);
 166         case WebGLExtensionID::OES_fbo_render_mipmap:
 167           return new ClientWebGLExtensionFBORenderMipmap(*this);
 168         case WebGLExtensionID::OES_standard_derivatives:
 169           return new ClientWebGLExtensionStandardDerivatives(*this);
 170         case WebGLExtensionID::OES_texture_float:
 171           return new ClientWebGLExtensionTextureFloat(*this);
 172         case WebGLExtensionID::OES_texture_float_linear:
 173           return new ClientWebGLExtensionTextureFloatLinear(*this);
 174         case WebGLExtensionID::OES_texture_half_float:
 175           return new ClientWebGLExtensionTextureHalfFloat(*this);
 176         case WebGLExtensionID::OES_texture_half_float_linear:
 177           return new ClientWebGLExtensionTextureHalfFloatLinear(*this);
 178         case WebGLExtensionID::OES_vertex_array_object:
 179           return new ClientWebGLExtensionVertexArray(*this);
 180
 181         // OVR_
 182         case WebGLExtensionID::OVR_multiview2:
 183           return new ClientWebGLExtensionMultiview(*this);
 184
 185         // WEBGL_
 186         case WebGLExtensionID::WEBGL_color_buffer_float:
 187           return new ClientWebGLExtensionColorBufferFloat(*this);
 188         case WebGLExtensionID::WEBGL_compressed_texture_astc:
 189           return new ClientWebGLExtensionCompressedTextureASTC(*this);
 190         case WebGLExtensionID::WEBGL_compressed_texture_etc:
 191           return new ClientWebGLExtensionCompressedTextureES3(*this);
 192         case WebGLExtensionID::WEBGL_compressed_texture_etc1:
 193           return new ClientWebGLExtensionCompressedTextureETC1(*this);
 194         case WebGLExtensionID::WEBGL_compressed_texture_pvrtc:
 195           return new ClientWebGLExtensionCompressedTexturePVRTC(*this);
 196         case WebGLExtensionID::WEBGL_compressed_texture_s3tc:
 197           return new ClientWebGLExtensionCompressedTextureS3TC(*this);
 198         case WebGLExtensionID::WEBGL_compressed_texture_s3tc_srgb:
 199           return new ClientWebGLExtensionCompressedTextureS3TC_SRGB(*this);
 200         case WebGLExtensionID::WEBGL_debug_renderer_info:
 201           return new ClientWebGLExtensionDebugRendererInfo(*this);
 202         case WebGLExtensionID::WEBGL_debug_shaders:
 203           return new ClientWebGLExtensionDebugShaders(*this);
 204         case WebGLExtensionID::WEBGL_depth_texture:
 205           return new ClientWebGLExtensionDepthTexture(*this);
 206         case WebGLExtensionID::WEBGL_draw_buffers:
 207           return new ClientWebGLExtensionDrawBuffers(*this);
 208         case WebGLExtensionID::WEBGL_explicit_present:
 209           return new ClientWebGLExtensionExplicitPresent(*this);
 210
 211         case WebGLExtensionID::WEBGL_lose_context:
 212         case WebGLExtensionID::Max:
 213           break;
 214       }
 215       MOZ_CRASH("illegal extension enum");
 216     }();
 217     MOZ_ASSERT(extSlot);
 218     RequestExtension(ext);
 219   }
 220
 221   return extSlot;
 222 }
 223
 224 // ----------------------------
 225 // WebGLContext
 226
 227 bool WebGLContext::IsExtensionSupported(WebGLExtensionID ext) const {
 228   switch (ext) {
 229     case WebGLExtensionID::MOZ_debug:
 230     case WebGLExtensionID::WEBGL_debug_renderer_info:
 231     case WebGLExtensionID::WEBGL_debug_shaders:
 232     case WebGLExtensionID::WEBGL_lose_context:
 233       // Always supported.
 234       return true;
 235
 236     // In alphabetical order
 237     // ANGLE_
 238     case WebGLExtensionID::ANGLE_instanced_arrays:
 239       return WebGLExtensionInstancedArrays::IsSupported(this);
 240
 241     // EXT_
 242     case WebGLExtensionID::EXT_blend_minmax:
 243       return WebGLExtensionBlendMinMax::IsSupported(this);
 244
 245     case WebGLExtensionID::EXT_color_buffer_float:
 246       return WebGLExtensionEXTColorBufferFloat::IsSupported(this);
 247
 248     case WebGLExtensionID::EXT_color_buffer_half_float:
 249       return WebGLExtensionColorBufferHalfFloat::IsSupported(this);
 250
 251     case WebGLExtensionID::EXT_disjoint_timer_query:
 252       return WebGLExtensionDisjointTimerQuery::IsSupported(this);
 253
 254     case WebGLExtensionID::EXT_float_blend:
 255       return WebGLExtensionFloatBlend::IsSupported(this);
 256
 257     case WebGLExtensionID::EXT_frag_depth:
 258       return WebGLExtensionFragDepth::IsSupported(this);
 259
 260     case WebGLExtensionID::EXT_shader_texture_lod:
 261       return WebGLExtensionShaderTextureLod::IsSupported(this);
 262
 263     case WebGLExtensionID::EXT_sRGB:
 264       return WebGLExtensionSRGB::IsSupported(this);
 265
 266     case WebGLExtensionID::EXT_texture_compression_bptc:
 267       return WebGLExtensionCompressedTextureBPTC::IsSupported(this);
 268
 269     case WebGLExtensionID::EXT_texture_compression_rgtc:
 270       return WebGLExtensionCompressedTextureRGTC::IsSupported(this);
 271
 272     case WebGLExtensionID::EXT_texture_filter_anisotropic:
 273       return gl->IsExtensionSupported(
 274           gl::GLContext::EXT_texture_filter_anisotropic);
 275
 276     case WebGLExtensionID::EXT_texture_norm16:
 277       return WebGLExtensionTextureNorm16::IsSupported(this);
 278
 279     // OES_
 280     case WebGLExtensionID::OES_element_index_uint:
 281       if (IsWebGL2()) return false;
 282       return gl->IsSupported(gl::GLFeature::element_index_uint);
 283
 284     case WebGLExtensionID::OES_fbo_render_mipmap:
 285       return WebGLExtensionFBORenderMipmap::IsSupported(this);
 286
 287     case WebGLExtensionID::OES_standard_derivatives:
 288       if (IsWebGL2()) return false;
 289       return gl->IsSupported(gl::GLFeature::standard_derivatives);
 290
 291     case WebGLExtensionID::OES_texture_float:
 292       return WebGLExtensionTextureFloat::IsSupported(this);
 293
 294     case WebGLExtensionID::OES_texture_float_linear:
 295       return gl->IsSupported(gl::GLFeature::texture_float_linear);
 296
 297     case WebGLExtensionID::OES_texture_half_float:
 298       return WebGLExtensionTextureHalfFloat::IsSupported(this);
 299
 300     case WebGLExtensionID::OES_texture_half_float_linear:
 301       if (IsWebGL2()) return false;
 302       return gl->IsSupported(gl::GLFeature::texture_half_float_linear);
 303
 304     case WebGLExtensionID::OES_vertex_array_object:
 305       return !IsWebGL2();  // Always supported in webgl1.
 306
 307     // OVR_
 308     case WebGLExtensionID::OVR_multiview2:
 309       return WebGLExtensionMultiview::IsSupported(this);
 310
 311     // WEBGL_
 312     case WebGLExtensionID::WEBGL_color_buffer_float:
 313       return WebGLExtensionColorBufferFloat::IsSupported(this);
 314
 315     case WebGLExtensionID::WEBGL_compressed_texture_astc:
 316       return WebGLExtensionCompressedTextureASTC::IsSupported(this);
 317
 318     case WebGLExtensionID::WEBGL_compressed_texture_etc:
 319       return gl->IsSupported(gl::GLFeature::ES3_compatibility) &&
 320              !gl->IsANGLE();
 321
 322     case WebGLExtensionID::WEBGL_compressed_texture_etc1:
 323       return gl->IsExtensionSupported(
 324                  gl::GLContext::OES_compressed_ETC1_RGB8_texture) &&
 325              !gl->IsANGLE();
 326
 327     case WebGLExtensionID::WEBGL_compressed_texture_pvrtc:
 328       return gl->IsExtensionSupported(
 329           gl::GLContext::IMG_texture_compression_pvrtc);
 330
 331     case WebGLExtensionID::WEBGL_compressed_texture_s3tc:
 332       return WebGLExtensionCompressedTextureS3TC::IsSupported(this);
 333
 334     case WebGLExtensionID::WEBGL_compressed_texture_s3tc_srgb:
 335       return WebGLExtensionCompressedTextureS3TC_SRGB::IsSupported(this);
 336
 337     case WebGLExtensionID::WEBGL_depth_texture:
 338       return WebGLExtensionDepthTexture::IsSupported(this);
 339
 340     case WebGLExtensionID::WEBGL_draw_buffers:
 341       return WebGLExtensionDrawBuffers::IsSupported(this);
 342
 343     case WebGLExtensionID::WEBGL_explicit_present:
 344       return WebGLExtensionExplicitPresent::IsSupported(this);
 345
 346     case WebGLExtensionID::Max:
 347       break;
 348   }
 349
 350   MOZ_CRASH();
 351 }
 352
 353 bool WebGLContext::IsExtensionExplicit(const WebGLExtensionID ext) const {
 354   return mExtensions[ext] && mExtensions[ext]->IsExplicit();
 355 }
 356
 357 void WebGLContext::WarnIfImplicit(const WebGLExtensionID ext) const {
 358   const auto& extension = mExtensions[ext];
 359   if (!extension || extension->IsExplicit()) return;
 360
 361   GenerateWarning(
 362       "Using format enabled by implicitly enabled extension: %s. "
 363       "For maximal portability enable it explicitly.",
 364       GetExtensionName(ext));
 365 }
 366
 367 void WebGLContext::RequestExtension(const WebGLExtensionID ext,
 368                                     const bool explicitly) {
 369   const auto& limits = Limits();
 370   if (!limits.supportedExtensions[ext]) return;
 371
 372   auto& slot = mExtensions[ext];
 373   switch (ext) {
 374     // ANGLE_
 375     case WebGLExtensionID::ANGLE_instanced_arrays:
 376       slot.reset(new WebGLExtensionInstancedArrays(this));
 377       break;
 378
 379     // EXT_
 380     case WebGLExtensionID::EXT_blend_minmax:
 381       slot.reset(new WebGLExtensionBlendMinMax(this));
 382       break;
 383     case WebGLExtensionID::EXT_color_buffer_float:
 384       slot.reset(new WebGLExtensionEXTColorBufferFloat(this));
 385       break;
 386     case WebGLExtensionID::EXT_color_buffer_half_float:
 387       slot.reset(new WebGLExtensionColorBufferHalfFloat(this));
 388       break;
 389     case WebGLExtensionID::EXT_disjoint_timer_query:
 390       slot.reset(new WebGLExtensionDisjointTimerQuery(this));
 391       break;
 392     case WebGLExtensionID::EXT_float_blend:
 393       slot.reset(new WebGLExtensionFloatBlend(this));
 394       break;
 395     case WebGLExtensionID::EXT_frag_depth:
 396       slot.reset(new WebGLExtensionFragDepth(this));
 397       break;
 398     case WebGLExtensionID::EXT_shader_texture_lod:
 399       slot.reset(new WebGLExtensionShaderTextureLod(this));
 400       break;
 401     case WebGLExtensionID::EXT_sRGB:
 402       slot.reset(new WebGLExtensionSRGB(this));
 403       break;
 404     case WebGLExtensionID::EXT_texture_compression_bptc:
 405       slot.reset(new WebGLExtensionCompressedTextureBPTC(this));
 406       break;
 407     case WebGLExtensionID::EXT_texture_compression_rgtc:
 408       slot.reset(new WebGLExtensionCompressedTextureRGTC(this));
 409       break;
 410     case WebGLExtensionID::EXT_texture_filter_anisotropic:
 411       slot.reset(new WebGLExtensionTextureFilterAnisotropic(this));
 412       break;
 413     case WebGLExtensionID::EXT_texture_norm16:
 414       slot.reset(new WebGLExtensionTextureNorm16(this));
 415       break;
 416
 417     // MOZ_
 418     case WebGLExtensionID::MOZ_debug:
 419       slot.reset(new WebGLExtensionMOZDebug(this));
 420       break;
 421
 422     // OES_
 423     case WebGLExtensionID::OES_element_index_uint:
 424       slot.reset(new WebGLExtensionElementIndexUint(this));
 425       break;
 426     case WebGLExtensionID::OES_fbo_render_mipmap:
 427       slot.reset(new WebGLExtensionFBORenderMipmap(this));
 428       break;
 429     case WebGLExtensionID::OES_standard_derivatives:
 430       slot.reset(new WebGLExtensionStandardDerivatives(this));
 431       break;
 432     case WebGLExtensionID::OES_texture_float:
 433       slot.reset(new WebGLExtensionTextureFloat(this));
 434       break;
 435     case WebGLExtensionID::OES_texture_float_linear:
 436       slot.reset(new WebGLExtensionTextureFloatLinear(this));
 437       break;
 438     case WebGLExtensionID::OES_texture_half_float:
 439       slot.reset(new WebGLExtensionTextureHalfFloat(this));
 440       break;
 441     case WebGLExtensionID::OES_texture_half_float_linear:
 442       slot.reset(new WebGLExtensionTextureHalfFloatLinear(this));
 443       break;
 444     case WebGLExtensionID::OES_vertex_array_object:
 445       slot.reset(new WebGLExtensionVertexArray(this));
 446       break;
 447
 448     // WEBGL_
 449     case WebGLExtensionID::OVR_multiview2:
 450       slot.reset(new WebGLExtensionMultiview(this));
 451       break;
 452
 453     // WEBGL_
 454     case WebGLExtensionID::WEBGL_color_buffer_float:
 455       slot.reset(new WebGLExtensionColorBufferFloat(this));
 456       break;
 457     case WebGLExtensionID::WEBGL_compressed_texture_astc:
 458       slot.reset(new WebGLExtensionCompressedTextureASTC(this));
 459       break;
 460     case WebGLExtensionID::WEBGL_compressed_texture_etc:
 461       slot.reset(new WebGLExtensionCompressedTextureES3(this));
 462       break;
 463     case WebGLExtensionID::WEBGL_compressed_texture_etc1:
 464       slot.reset(new WebGLExtensionCompressedTextureETC1(this));
 465       break;
 466     case WebGLExtensionID::WEBGL_compressed_texture_pvrtc:
 467       slot.reset(new WebGLExtensionCompressedTexturePVRTC(this));
 468       break;
 469     case WebGLExtensionID::WEBGL_compressed_texture_s3tc:
 470       slot.reset(new WebGLExtensionCompressedTextureS3TC(this));
 471       break;
 472     case WebGLExtensionID::WEBGL_compressed_texture_s3tc_srgb:
 473       slot.reset(new WebGLExtensionCompressedTextureS3TC_SRGB(this));
 474       break;
 475     case WebGLExtensionID::WEBGL_debug_renderer_info:
 476       slot.reset(new WebGLExtensionDebugRendererInfo(this));
 477       break;
 478     case WebGLExtensionID::WEBGL_debug_shaders:
 479       slot.reset(new WebGLExtensionDebugShaders(this));
 480       break;
 481     case WebGLExtensionID::WEBGL_depth_texture:
 482       slot.reset(new WebGLExtensionDepthTexture(this));
 483       break;
 484     case WebGLExtensionID::WEBGL_draw_buffers:
 485       slot.reset(new WebGLExtensionDrawBuffers(this));
 486       break;
 487     case WebGLExtensionID::WEBGL_explicit_present:
 488       slot.reset(new WebGLExtensionExplicitPresent(this));
 489       break;
 490     case WebGLExtensionID::WEBGL_lose_context:
 491       slot.reset(new WebGLExtensionLoseContext(this));
 492       break;
 493
 494     case WebGLExtensionID::Max:
 495       MOZ_CRASH();
 496   }
 497   MOZ_ASSERT(slot);
 498   const auto& obj = slot;
 499
 500   if (explicitly && !obj->IsExplicit()) {
 501     obj->SetExplicit();
 502   }
 503
 504   // Also enable implied extensions.
 505   switch (ext) {
 506     case WebGLExtensionID::EXT_color_buffer_float:
 507       RequestExtension(WebGLExtensionID::EXT_float_blend, false);
 508       break;
 509
 510     case WebGLExtensionID::OES_texture_float:
 511       RequestExtension(WebGLExtensionID::EXT_float_blend, false);
 512       RequestExtension(WebGLExtensionID::WEBGL_color_buffer_float, false);
 513       break;
 514
 515     case WebGLExtensionID::OES_texture_half_float:
 516       RequestExtension(WebGLExtensionID::EXT_color_buffer_half_float, false);
 517       break;
 518
 519     case WebGLExtensionID::WEBGL_color_buffer_float:
 520       RequestExtension(WebGLExtensionID::EXT_float_blend, false);
 521       break;
 522
 523     default:
 524       break;
 525   }
 526 }
 527
 528 }  // namespace mozilla