Recombine the YUV420 shader source

We don't build shaders with hardcoded CSC constants anymore.

Author: cgutman

app/shaders/d3d11_video_pixel_end.hlsli

@@ -1,4 +1,17 @@
-#include "d3d11_video_pixel_start.hlsli"
+Texture2D<min16float> luminancePlane : register(t0);
+Texture2D<min16float2> chrominancePlane : register(t1);
+SamplerState theSampler : register(s0);
+
+struct ShaderInput
+{
+    float4 pos : SV_POSITION;
+    float2 tex : TEXCOORD0;
+};
+
+cbuffer ChromaLimitBuf : register(b0)
+{
+    min16float3 chromaTexMax;
+};
 
 cbuffer CSC_CONST_BUF : register(b1)
 {
@@ -7,4 +20,17 @@ cbuffer CSC_CONST_BUF : register(b1)
     min16float2 chromaOffset;
 };
 
-#include "d3d11_video_pixel_end.hlsli"
+min16float4 main(ShaderInput input) : SV_TARGET
+{
+    // Clamp the chrominance texcoords to avoid sampling the row of texels adjacent to the alignment padding
+    min16float3 yuv = min16float3(luminancePlane.Sample(theSampler, input.tex),
+                                  chrominancePlane.Sample(theSampler, min(input.tex + chromaOffset, chromaTexMax.rg)));
+
+    // Subtract the YUV offset for limited vs full range
+    yuv -= offsets;
+
+    // Multiply by the conversion matrix for this colorspace
+    yuv = mul(yuv, cscMatrix);
+
+    return min16float4(yuv, 1.0);
+}