DebugTools,Text: SwiftShader is trash, should just ditch that thing.

I can use llvmpipe on the CI already, this rotten pile of crap is a
waste of energy.

src/Magnum/DebugTools/Test/TextureImageGLTest.cpp

@@ -324,8 +324,15 @@ void TextureImageGLTest::subImage2DArray() {
     CORRADE_COMPARE(image.format(), pixelFormatWrap(GL::PixelFormat::RGBA));
     CORRADE_COMPARE(GL::PixelType(image.formatExtra()), GL::PixelType::UnsignedByte);
     CORRADE_COMPARE(image.pixelSize(), 4);
-    CORRADE_COMPARE_AS(Containers::arrayCast<UnsignedByte>(image.data()),
-        Containers::arrayView(Data2D), TestSuite::Compare::Container);
+
+    {
+        #ifdef MAGNUM_TARGET_GLES
+        CORRADE_EXPECT_FAIL_IF(data.layer != 0 && GL::Context::current().detectedDriver() >= GL::Context::DetectedDriver::SwiftShader,
+            "SwiftShader is trash and doesn't implement reading from non-zero array layers.");
+        #endif
+        CORRADE_COMPARE_AS(Containers::arrayCast<UnsignedByte>(image.data()),
+            Containers::arrayView(Data2D), TestSuite::Compare::Container);
+    }
 }
 
 void TextureImageGLTest::subImage2DArrayNotReadable() {
@@ -558,9 +565,16 @@ void TextureImageGLTest::subImage2DFloat() {
     CORRADE_COMPARE(image.format(), pixelFormatWrap(GL::PixelFormat::Red));
     CORRADE_COMPARE(GL::PixelType(image.formatExtra()), GL::PixelType::Float);
     CORRADE_COMPARE(image.pixelSize(), 4);
-    CORRADE_COMPARE_AS(Containers::arrayCast<Float>(image.data()),
-        Containers::arrayView(Data2DFloat),
-        TestSuite::Compare::Container);
+
+    {
+        #ifdef MAGNUM_TARGET_GLES
+        CORRADE_EXPECT_FAIL_IF(data.level != 0 && GL::Context::current().detectedDriver() >= GL::Context::DetectedDriver::SwiftShader,
+            "SwiftShader is trash and doesn't implement texelFetch() from non-zero levels.");
+        #endif
+        CORRADE_COMPARE_AS(Containers::arrayCast<Float>(image.data()),
+            Containers::arrayView(Data2DFloat),
+            TestSuite::Compare::Container);
+    }
 }
 
 void TextureImageGLTest::subImage2DFloatGeneric() {
@@ -582,9 +596,16 @@ void TextureImageGLTest::subImage2DFloatGeneric() {
     CORRADE_COMPARE(image.format(), PixelFormat::R32F);
     CORRADE_COMPARE(image.formatExtra(), 0);
     CORRADE_COMPARE(image.pixelSize(), 4);
-    CORRADE_COMPARE_AS(Containers::arrayCast<Float>(image.data()),
-        Containers::arrayView(Data2DFloat),
-        TestSuite::Compare::Container);
+
+    {
+        #ifdef MAGNUM_TARGET_GLES
+        CORRADE_EXPECT_FAIL_IF(data.level != 0 && GL::Context::current().detectedDriver() >= GL::Context::DetectedDriver::SwiftShader,
+            "SwiftShader is trash and doesn't implement texelFetch() from non-zero levels.");
+        #endif
+        CORRADE_COMPARE_AS(Containers::arrayCast<Float>(image.data()),
+            Containers::arrayView(Data2DFloat),
+            TestSuite::Compare::Container);
+    }
 }
 
 const Half Data2DHalf[] = { 1.0_h,

src/Magnum/Text/Test/GlyphCacheGLTest.cpp

@@ -650,12 +650,21 @@ void GlyphCacheGLTest::setImageArray() {
     CORRADE_COMPARE_AS(image0,
         (ImageView2D{PixelFormat::RG8Unorm, {8, 8}, expectedTextureData03}),
         DebugTools::CompareImage);
-    CORRADE_COMPARE_AS(image1,
-        (ImageView2D{PixelFormat::RG8Unorm, {8, 8}, expectedTextureData1}),
-        DebugTools::CompareImage);
-    CORRADE_COMPARE_AS(image2,
-        (ImageView2D{PixelFormat::RG8Unorm, {8, 8}, expectedTextureData2}),
-        DebugTools::CompareImage);
+    {
+        #ifdef MAGNUM_TARGET_GLES
+        CORRADE_EXPECT_FAIL_IF(GL::Context::current().detectedDriver() >= GL::Context::DetectedDriver::SwiftShader,
+            "SwiftShader is trash and doesn't implement reading from non-zero array layers.");
+        #endif
+        CORRADE_COMPARE_AS(image1,
+            (ImageView2D{PixelFormat::RG8Unorm, {8, 8}, expectedTextureData1}),
+            DebugTools::CompareImage);
+        CORRADE_COMPARE_AS(image2,
+            (ImageView2D{PixelFormat::RG8Unorm, {8, 8}, expectedTextureData2}),
+            DebugTools::CompareImage);
+    }
+    /* This is broken on SwiftShader too, returning the first layer (or all
+       zeros) but since we expect the same as first layer (which is all zeros),
+       it passes */
     CORRADE_COMPARE_AS(image3,
         (ImageView2D{PixelFormat::RG8Unorm, {8, 8}, expectedTextureData03}),
         DebugTools::CompareImage);