Metal: use render target height to adjust viewport when blitting (#2610)

RELEASE_NOTES.md

@@ -11,6 +11,7 @@ A new header is inserted each time a *tag* is created.
 - SSAO now has an optional high(er) quality upsampler.
 - Tone mappping now uses the real ACES tone mapper, applied in the proper color space.
 - Tone mapping is now applied via a LUT, which will later enable color grading capabilities.
+- Fixed bug in the Metal backend when SSR and MSAA were turned on
 - Fixed Metal issue with `BufferDescriptor` and `PixelBufferDescriptor`s not being called on application thread.
 
 ## v1.7.0

filament/backend/src/metal/MetalDriver.mm

@@ -931,12 +931,12 @@ void MetalDriver::blit(TargetBufferFlags buffers,
     // coordinates have (0, 0) at bottom-left.
     MTLRegion srcRegion = MTLRegionMake2D(
             (NSUInteger) srcRect.left,
-            srcTexture.height - (NSUInteger) srcRect.bottom - srcRect.height,
+            srcTarget->height - (NSUInteger) srcRect.bottom - srcRect.height,
             srcRect.width, srcRect.height);
 
     MTLRegion dstRegion = MTLRegionMake2D(
             (NSUInteger) dstRect.left,
-            dstTexture.height - (NSUInteger) dstRect.bottom - dstRect.height,
+            dstTarget->height - (NSUInteger) dstRect.bottom - dstRect.height,
             dstRect.width, dstRect.height);
 
     const uint8_t srcLevel = srcColorAttachment.level;

shaders/src/post_process.vs

@@ -8,7 +8,7 @@ void main() {
 
 // In Vulkan and Metal, texture coords are Y-down. In OpenGL, texture coords are Y-up.
 #if defined(TARGET_METAL_ENVIRONMENT) || defined(TARGET_VULKAN_ENVIRONMENT)
-    inputs.texelCoords.y = frameUniforms.resolution.y - 1.0 - inputs.texelCoords.y;
+    inputs.texelCoords.y = frameUniforms.resolution.y - inputs.texelCoords.y;
     inputs.normalizedUV.y = 1.0 - inputs.normalizedUV.y;
 #endif