force BC3 instead of BC1a compression for alpha textures

libraries/image/src/image/Image.cpp

@@ -493,6 +493,10 @@ gpu::TexturePointer TextureUsage::process2DTextureColorFromImage(const QImage& s
 
     if (validAlpha) {
         processTextureAlpha(image, validAlpha, alphaAsMask);
+
+        // NOTE: This disables BC1a compression becuase it was producing odd artifacts on text textures
+        // for the tutorial. Instead we use BC3 (which is larger) but doesn't produce the same artifacts).
+        alphaAsMask = false;
     }
 
     gpu::TexturePointer theTexture = nullptr;