Skip incompatible image formats when building discard pattern

If the pattern's dimensions are not an integer multiple of the format's block size, then do not attempt to create the discard pattern, just exit early.

Fixes 3466

renderdoc/driver/vulkan/vk_debug.cpp

@@ -2381,9 +2381,16 @@ void VulkanDebugManager::FillWithDiscardPattern(VkCommandBuffer cmd, DiscardType
   if(buf == VK_NULL_HANDLE)
   {
     GPUBuffer &stage = m_DiscardStage[key];
-    bytebuf pattern = GetDiscardPattern(key.second, MakeResourceFormat(key.first));
 
     BlockShape shape = GetBlockShape(key.first, 0);
+    if((PatternBatchWidth % shape.width) != 0 || (PatternBatchHeight % shape.height) != 0)
+    {
+      RDCWARN("Skipping discard pattern for %s as block size is incompatible (%d * %d)",
+              ToStr(MakeResourceFormat(key.first).type).c_str(), shape.width, shape.height);
+      return;
+    }
+
+    bytebuf pattern = GetDiscardPattern(key.second, MakeResourceFormat(key.first));
 
     if(key.first == VK_FORMAT_D32_SFLOAT_S8_UINT)
       shape = {1, 1, 4};