diff --git a/OSBindings/Mac/Clock Signal/ScanTarget/CSScanTarget.mm b/OSBindings/Mac/Clock Signal/ScanTarget/CSScanTarget.mm
index ccef3330d..8dd3c08e4 100644
--- a/OSBindings/Mac/Clock Signal/ScanTarget/CSScanTarget.mm	
+++ b/OSBindings/Mac/Clock Signal/ScanTarget/CSScanTarget.mm	
@@ -426,7 +426,7 @@ using BufferingScanTarget = Outputs::Display::BufferingScanTarget;
 	RangePerform(start, end, (_isUsingCompositionPipeline ? NumBufferedLines : NumBufferedScans), OutputStrips);
 #undef OutputStrips
 
-	// Complete encoding and return.
+	// Complete encoding.
 	[encoder endEncoding];
 }
 
@@ -489,10 +489,12 @@ using BufferingScanTarget = Outputs::Display::BufferingScanTarget;
 			id<MTLRenderCommandEncoder> encoder = [commandBuffer renderCommandEncoderWithDescriptor:_compositionRenderPass];
 			[encoder setRenderPipelineState:_composePipeline];
 
-			[encoder setFragmentTexture:_writeAreaTexture atIndex:0];
 			[encoder setVertexBuffer:_scansBuffer offset:0 atIndex:0];
 			[encoder setVertexBuffer:_uniformsBuffer offset:0 atIndex:1];
+			[encoder setVertexTexture:_compositionTexture atIndex:0];
+
 			[encoder setFragmentBuffer:_uniformsBuffer offset:0 atIndex:0];
+			[encoder setFragmentTexture:_writeAreaTexture atIndex:0];
 
 #define OutputScans(start, size)	[encoder drawPrimitives:MTLPrimitiveTypeLine vertexStart:0 vertexCount:2 instanceCount:size baseInstance:start]
 			RangePerform(outputArea.start.scan, outputArea.end.scan, NumBufferedScans, OutputScans);
diff --git a/OSBindings/Mac/Clock Signal/ScanTarget/ScanTarget.metal b/OSBindings/Mac/Clock Signal/ScanTarget/ScanTarget.metal
index 0dee02f91..6b550f7a9 100644
--- a/OSBindings/Mac/Clock Signal/ScanTarget/ScanTarget.metal	
+++ b/OSBindings/Mac/Clock Signal/ScanTarget/ScanTarget.metal	
@@ -171,13 +171,15 @@ vertex SourceInterpolator scanToComposition(	constant Uniforms &uniforms [[buffe
 	// Populate result as if direct texture access were available.
 	result.position.x = mix(scans[instanceID].endPoints[0].cyclesSinceRetrace, scans[instanceID].endPoints[1].cyclesSinceRetrace, float(vertexID));
 	result.position.y = scans[instanceID].line;
-	result.position.wz = float2(0.0, 1.0);
+	result.position.zw = float2(0.0, 1.0);
 	result.textureCoordinates.x = mix(scans[instanceID].endPoints[0].dataOffset, scans[instanceID].endPoints[1].dataOffset, float(vertexID));
 	result.textureCoordinates.y = scans[instanceID].dataY;
+	result.colourPhase = mix(scans[instanceID].endPoints[0].compositeAngle, scans[instanceID].endPoints[1].compositeAngle, float(vertexID))  / 32.0;
+	result.colourAmplitude = scans[instanceID].compositeAmplitude;
 
 	// Map position into eye space, allowing for target texture dimensions.
 	// TODO: is this really necessary? Is there nothing like coord::pixel that applies here?
-	result.position.xy = ((result.position.xy + float2(0.5)) / float2(texture.get_width(), texture.get_height())) * float2(2.0) - float2(1.0);
+	result.position.xy = ((result.position.xy + float2(0.5)) / float2(texture.get_width(), texture.get_height())) * float2(2.0, -2.0) + float2(-1.0, 1.0);
 
 	return result;
 }
@@ -302,6 +304,6 @@ fragment float4 copyFragment(CopyInterpolator vert [[stage_in]], texture2d<float
 	return texture.sample(standardSampler, vert.textureCoordinates);
 }
 
-fragment float4 clearFragment(CopyInterpolator vert [[stage_in]], texture2d<float> texture [[texture(0)]]) {
+fragment float4 clearFragment() {
 	return float4(0.0, 0.0, 0.0, 0.64);
 }