OpenGL ES: implement compressed texture support.

SwANGLE does not support GL_EXT_texture_compression_s3tc.
However, it does support GL_EXT_texture_compression_dxt1,
GL_ANGLE_texture_compression_dxt3 and GL_ANGLE_texture_compression_dxt5,
which should be sufficient for Dawn's purposes.

Note that sRGB formats may be problematic for OpenGL ES in general,
but ANGLE does support them, so we can satisfy the requirements for
Dawn's texture_compression_bc and exercise the codepaths on ES.

glPixelStorei is not only unsupported for CompressedTexSubImage*D()
but causes asserts in ANGLE and validation errors elsewhere. The fix
is to scope the glPixelStorei() calls to the non-compressed codepath.

Bug: dawn:580
Change-Id: I68fa019eda2aee37a097e697cfc87bcdc28c1f12
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/42120
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Stephen White <senorblanco@chromium.org>

src/dawn_native/opengl/BackendGL.cpp

@@ -208,7 +208,10 @@ namespace dawn_native { namespace opengl {
             {
                 // BC1, BC2 and BC3 are not supported in OpenGL or OpenGL ES core features.
                 bool supportsS3TC =
-                    mFunctions.IsGLExtensionSupported("GL_EXT_texture_compression_s3tc");
+                    mFunctions.IsGLExtensionSupported("GL_EXT_texture_compression_s3tc") ||
+                    (mFunctions.IsGLExtensionSupported("GL_EXT_texture_compression_dxt1") &&
+                     mFunctions.IsGLExtensionSupported("GL_ANGLE_texture_compression_dxt3") &&
+                     mFunctions.IsGLExtensionSupported("GL_ANGLE_texture_compression_dxt5"));
 
                 // COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT, COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT and
                 // COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT requires both GL_EXT_texture_sRGB and
@@ -217,8 +220,14 @@ namespace dawn_native { namespace opengl {
                 bool supportsTextureSRGB = mFunctions.IsGLExtensionSupported("GL_EXT_texture_sRGB");
 
                 // GL_EXT_texture_compression_s3tc_srgb is an extension in OpenGL ES.
+                // NVidia GLES drivers don't support this extension, but they do support
+                // GL_NV_sRGB_formats. (Note that GL_EXT_texture_sRGB does not exist on ES.
+                // GL_EXT_sRGB does (core in ES 3.0), but it does not automatically provide S3TC
+                // SRGB support even if S3TC is supported; see
+                // https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_sRGB.txt.)
                 bool supportsS3TCSRGB =
-                    mFunctions.IsGLExtensionSupported("GL_EXT_texture_compression_s3tc_srgb");
+                    mFunctions.IsGLExtensionSupported("GL_EXT_texture_compression_s3tc_srgb") ||
+                    mFunctions.IsGLExtensionSupported("GL_NV_sRGB_formats");
 
                 // BC4 and BC5
                 bool supportsRGTC =

src/dawn_native/opengl/CommandBufferGL.cpp

@@ -630,9 +630,6 @@ namespace dawn_native { namespace opengl {
 
                     const Format& formatInfo = texture->GetFormat();
                     const TexelBlockInfo& blockInfo = formatInfo.GetAspectInfo(dst.aspect).block;
-                    gl.PixelStorei(GL_UNPACK_ROW_LENGTH,
-                                   src.bytesPerRow / blockInfo.byteSize * blockInfo.width);
-                    gl.PixelStorei(GL_UNPACK_IMAGE_HEIGHT, src.rowsPerImage * blockInfo.height);
 
                     if (formatInfo.isCompressed) {
                         ASSERT(texture->GetDimension() == wgpu::TextureDimension::e2D);
@@ -691,6 +688,10 @@ namespace dawn_native { namespace opengl {
                             }
 
                         } else {
+                            gl.PixelStorei(GL_UNPACK_ROW_LENGTH,
+                                           src.bytesPerRow / blockInfo.byteSize * blockInfo.width);
+                            gl.PixelStorei(GL_UNPACK_IMAGE_HEIGHT,
+                                           src.rowsPerImage * blockInfo.height);
                             gl.PixelStorei(GL_UNPACK_COMPRESSED_BLOCK_SIZE, blockInfo.byteSize);
                             gl.PixelStorei(GL_UNPACK_COMPRESSED_BLOCK_WIDTH, blockInfo.width);
                             gl.PixelStorei(GL_UNPACK_COMPRESSED_BLOCK_HEIGHT, blockInfo.height);
@@ -714,12 +715,17 @@ namespace dawn_native { namespace opengl {
                                     reinterpret_cast<void*>(static_cast<uintptr_t>(src.offset)));
                             }
 
+                            gl.PixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+                            gl.PixelStorei(GL_UNPACK_IMAGE_HEIGHT, 0);
                             gl.PixelStorei(GL_UNPACK_COMPRESSED_BLOCK_SIZE, 0);
                             gl.PixelStorei(GL_UNPACK_COMPRESSED_BLOCK_WIDTH, 0);
                             gl.PixelStorei(GL_UNPACK_COMPRESSED_BLOCK_HEIGHT, 0);
                             gl.PixelStorei(GL_UNPACK_COMPRESSED_BLOCK_DEPTH, 0);
                         }
                     } else {
+                        gl.PixelStorei(GL_UNPACK_ROW_LENGTH,
+                                       src.bytesPerRow / blockInfo.byteSize * blockInfo.width);
+                        gl.PixelStorei(GL_UNPACK_IMAGE_HEIGHT, src.rowsPerImage * blockInfo.height);
                         switch (texture->GetDimension()) {
                             case wgpu::TextureDimension::e2D:
                                 if (texture->GetArrayLayers() > 1) {
@@ -742,10 +748,10 @@ namespace dawn_native { namespace opengl {
                             case wgpu::TextureDimension::e3D:
                                 UNREACHABLE();
                         }
-                    }
 
-                    gl.PixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+                        gl.PixelStorei(GL_UNPACK_ROW_LENGTH, 0);
-                    gl.PixelStorei(GL_UNPACK_IMAGE_HEIGHT, 0);
+                        gl.PixelStorei(GL_UNPACK_IMAGE_HEIGHT, 0);
+                    }
 
                     gl.BindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
                     break;

src/tests/end2end/CompressedTextureFormatTests.cpp

@@ -1187,6 +1187,9 @@ TEST_P(CompressedTextureWriteTextureTest, Basic) {
 
 // Test writing to multiple 2D texture array layers with BC formats.
 TEST_P(CompressedTextureWriteTextureTest, WriteMultiple2DArrayLayers) {
+    // TODO(crbug.com/dawn/593): This test uses glTextureView() which is not supported on OpenGL ES.
+    DAWN_SKIP_TEST_IF(IsOpenGLES());
+
     CopyConfig config;
     config.textureDescriptor.usage = kDefaultBCFormatTextureUsage;
     config.textureDescriptor.size = {20, 24, 9};
@@ -1206,6 +1209,9 @@ TEST_P(CompressedTextureWriteTextureTest, WriteMultiple2DArrayLayers) {
 // subresource is different from its virtual size.
 TEST_P(CompressedTextureWriteTextureTest,
        WriteIntoSubresourceWithPhysicalSizeNotEqualToVirtualSize) {
+    // TODO(crbug.com/dawn/593): This test uses glTextureView() which is not supported on OpenGL ES.
+    DAWN_SKIP_TEST_IF(IsOpenGLES());
+
     // Texture virtual size at mipLevel 2 will be {15, 15, 1} while the physical
     // size will be {16, 16, 1}.
     // Setting copyExtent.width or copyExtent.height to 16 fits in

src/tests/end2end/TextureZeroInitTests.cpp

@@ -1846,7 +1846,7 @@ TEST_P(CompressedTextureZeroInitTest, FullMipCopy) {
 // Test that 1 lazy clear count happens when we copy to half the texture
 TEST_P(CompressedTextureZeroInitTest, HalfCopyBufferToTexture) {
     // TODO(crbug.com/dawn/643): diagnose and fix this failure on OpenGL.
-    DAWN_SKIP_TEST_IF(IsOpenGL());
+    DAWN_SKIP_TEST_IF(IsOpenGL() || IsOpenGLES());
 
     wgpu::TextureDescriptor textureDescriptor;
     textureDescriptor.usage =
@@ -1865,6 +1865,9 @@ TEST_P(CompressedTextureZeroInitTest, HalfCopyBufferToTexture) {
 // Test that 0 lazy clear count happens when we copy buffer to texture to a nonzero mip level
 // (with physical size different from the virtual mip size)
 TEST_P(CompressedTextureZeroInitTest, FullCopyToNonZeroMipLevel) {
+    // TODO(crbug.com/dawn/593): This test uses glTextureView() which is not supported on OpenGL ES.
+    DAWN_SKIP_TEST_IF(IsOpenGLES());
+
     wgpu::TextureDescriptor textureDescriptor;
     textureDescriptor.usage =
         wgpu::TextureUsage::CopySrc | wgpu::TextureUsage::CopyDst | wgpu::TextureUsage::Sampled;
@@ -1888,7 +1891,7 @@ TEST_P(CompressedTextureZeroInitTest, FullCopyToNonZeroMipLevel) {
 // (with physical size different from the virtual mip size)
 TEST_P(CompressedTextureZeroInitTest, HalfCopyToNonZeroMipLevel) {
     // TODO(crbug.com/dawn/643): diagnose and fix this failure on OpenGL.
-    DAWN_SKIP_TEST_IF(IsOpenGL());
+    DAWN_SKIP_TEST_IF(IsOpenGL() || IsOpenGLES());
 
     wgpu::TextureDescriptor textureDescriptor;
     textureDescriptor.usage =
@@ -1911,6 +1914,9 @@ TEST_P(CompressedTextureZeroInitTest, HalfCopyToNonZeroMipLevel) {
 
 // Test that 0 lazy clear count happens when we copy buffer to nonzero array layer
 TEST_P(CompressedTextureZeroInitTest, FullCopyToNonZeroArrayLayer) {
+    // TODO(crbug.com/dawn/593): This test uses glTextureView() which is not supported on OpenGL ES.
+    DAWN_SKIP_TEST_IF(IsOpenGLES());
+
     wgpu::TextureDescriptor textureDescriptor;
     textureDescriptor.usage =
         wgpu::TextureUsage::CopySrc | wgpu::TextureUsage::CopyDst | wgpu::TextureUsage::Sampled;
@@ -1929,7 +1935,7 @@ TEST_P(CompressedTextureZeroInitTest, FullCopyToNonZeroArrayLayer) {
 // Test that 1 lazy clear count happens when we copy buffer to half texture to a nonzero array layer
 TEST_P(CompressedTextureZeroInitTest, HalfCopyToNonZeroArrayLayer) {
     // TODO(crbug.com/dawn/643): diagnose and fix this failure on OpenGL.
-    DAWN_SKIP_TEST_IF(IsOpenGL());
+    DAWN_SKIP_TEST_IF(IsOpenGL() || IsOpenGLES());
 
     wgpu::TextureDescriptor textureDescriptor;
     textureDescriptor.usage =
@@ -1948,6 +1954,9 @@ TEST_P(CompressedTextureZeroInitTest, HalfCopyToNonZeroArrayLayer) {
 
 // full copy texture to texture, 0 lazy clears are needed
 TEST_P(CompressedTextureZeroInitTest, FullCopyTextureToTextureMipLevel) {
+    // TODO(crbug.com/dawn/593): This test uses glTextureView() which is not supported on OpenGL ES.
+    DAWN_SKIP_TEST_IF(IsOpenGLES());
+
     // create srcTexture and fill it with data
     wgpu::TextureDescriptor srcDescriptor = CreateTextureDescriptor(
         3, 1,
@@ -1993,7 +2002,7 @@ TEST_P(CompressedTextureZeroInitTest, FullCopyTextureToTextureMipLevel) {
 // half copy texture to texture, lazy clears are needed for noncopied half
 TEST_P(CompressedTextureZeroInitTest, HalfCopyTextureToTextureMipLevel) {
     // TODO(crbug.com/dawn/643): diagnose and fix this failure on OpenGL.
-    DAWN_SKIP_TEST_IF(IsOpenGL());
+    DAWN_SKIP_TEST_IF(IsOpenGL() || IsOpenGLES());
 
     // create srcTexture with data
     wgpu::TextureDescriptor srcDescriptor = CreateTextureDescriptor(