GL: Add allow_etc_formats workaround

include/platform/FeaturesGL.h

@@ -37,6 +37,10 @@ struct FeaturesGL : FeatureSetBase
                                                     FeatureCategory::OpenGLWorkarounds,
                                                     "GL_RGBA4 is not color renderable", &members};
 
+    // Newer Intel GPUs natively support ETC2/EAC compressed texture formats.
+    Feature allowEtcFormats = {"allow_etc_formats", FeatureCategory::OpenGLWorkarounds,
+                               "Enable ETC2/EAC on desktop OpenGL", &members};
+
     // When clearing a framebuffer on Intel or AMD drivers, when GL_FRAMEBUFFER_SRGB is enabled, the
     // driver clears to the linearized clear color despite the framebuffer not supporting SRGB
     // blending.  It only seems to do this when the framebuffer has only linear attachments, mixed

src/libANGLE/renderer/driver_utils.cpp

@@ -31,6 +31,9 @@ namespace rx
 // Referenced from https://cgit.freedesktop.org/vaapi/intel-driver/tree/src/i965_pciids.h
 namespace
 {
+// gen6
+const uint32_t SandyBridge[] = {0x0102, 0x0106, 0x010A, 0x0112, 0x0122, 0x0116, 0x0126};
+
 // gen7
 const uint32_t IvyBridge[] = {0x0152, 0x0156, 0x015A, 0x0162, 0x0166, 0x016A};
 
@@ -101,6 +104,12 @@ bool IntelDriverVersion::operator>=(const IntelDriverVersion &version)
     return !(*this < version);
 }
 
+bool IsSandyBridge(uint32_t DeviceId)
+{
+    return std::find(std::begin(SandyBridge), std::end(SandyBridge), DeviceId) !=
+           std::end(SandyBridge);
+}
+
 bool IsIvyBridge(uint32_t DeviceId)
 {
     return std::find(std::begin(IvyBridge), std::end(IvyBridge), DeviceId) != std::end(IvyBridge);

src/libANGLE/renderer/driver_utils.h

@@ -137,6 +137,7 @@ class IntelDriverVersion
     uint16_t mVersionPart;
 };
 
+bool IsSandyBridge(uint32_t DeviceId);
 bool IsIvyBridge(uint32_t DeviceId);
 bool IsHaswell(uint32_t DeviceId);
 bool IsBroadwell(uint32_t DeviceId);

src/libANGLE/renderer/gl/renderergl_utils.cpp

@@ -1534,8 +1534,9 @@ void GenerateCaps(const FunctionsGL *functions,
     // ANGLE_compressed_texture_etc
     // Expose this extension only when we support the formats or we're running on top of a native
     // ES driver.
-    extensions->compressedTextureETC = functions->standard == STANDARD_GL_ES &&
-                                       gl::DetermineCompressedTextureETCSupport(*textureCapsMap);
+    extensions->compressedTextureETC =
+        (features.allowEtcFormats.enabled || functions->standard == STANDARD_GL_ES) &&
+        gl::DetermineCompressedTextureETCSupport(*textureCapsMap);
 
     // To work around broken unsized sRGB textures, sized sRGB textures are used. Disable EXT_sRGB
     // if those formats are not available.
@@ -1656,6 +1657,12 @@ void InitializeFeatures(const FunctionsGL *functions, angle::FeaturesGL *feature
     ANGLE_FEATURE_CONDITION(features, rgba4IsNotSupportedForColorRendering,
                             functions->standard == STANDARD_GL_DESKTOP && isIntel);
 
+    // Although "Sandy Bridge", "Ivy Bridge", and "Haswell" may support GL_ARB_ES3_compatibility
+    // extension, ETC2/EAC formats are emulated there. Newer Intel GPUs support them natively.
+    ANGLE_FEATURE_CONDITION(
+        features, allowEtcFormats,
+        isIntel && !IsSandyBridge(device) && !IsIvyBridge(device) && !IsHaswell(device));
+
     // Ported from gpu_driver_bug_list.json (#183)
     ANGLE_FEATURE_CONDITION(features, emulateAbsIntFunction, IsApple() && isIntel);