1 files changed, 36 insertions, 0 deletions
diff --git a/LibOVR/Src/CAPI/Shaders/DistortionTimewarp_vs.vsh b/LibOVR/Src/CAPI/Shaders/DistortionTimewarp_vs.vsh
new file mode 100644
index 0000000..cf41ec0
--- /dev/null
+++ b/LibOVR/Src/CAPI/Shaders/DistortionTimewarp_vs.vsh
@@ -0,0 +1,36 @@
+float2   EyeToSourceUVScale;
+float2   EyeToSourceUVOffset;
+float4x4 EyeRotationStart;
+float4x4 EyeRotationEnd;
+
+float2 TimewarpTexCoordToWarpedPos(float2 inTexCoord, float4x4 rotMat)
+{
+    // Vertex inputs are in TanEyeAngle space for the R,G,B channels (i.e. after chromatic aberration and distortion).
+    // These are now "real world" vectors in direction (x,y,1) relative to the eye of the HMD.    
+    // Apply the 3x3 timewarp rotation to these vectors.
+	float3 transformed = float3( mul ( rotMat, float4(inTexCoord,1,1) ).xyz);
+    // Project them back onto the Z=1 plane of the rendered images.
+	float2 flattened = transformed.xy / transformed.z;
+    // Scale them into ([0,0.5],[0,1]) or ([0.5,0],[0,1]) UV lookup space (depending on eye)
+	return flattened * EyeToSourceUVScale + EyeToSourceUVOffset;
+	
+}
+
+void main(in float2 Position    : POSITION,    in float4 Color   : COLOR0,  in float2 TexCoord0   : TEXCOORD0,    
+          out float4 oPosition  : SV_Position, out float4 oColor : COLOR,   out float3 oTexCoord0 : TEXCOORD0)    
+{
+
+   oPosition.x = Position.x;
+   oPosition.y = Position.y;
+   oPosition.z = 0.5;
+   oPosition.w = 1.0;
+
+   float timewarpLerpFactor = Color.a;
+   float4x4 lerpedEyeRot = lerp(EyeRotationStart, EyeRotationEnd, timewarpLerpFactor);	
+
+    // Warped positions are a bit more involved, hence a separate function
+	oTexCoord0 = float3(TimewarpTexCoordToWarpedPos(TexCoord0, lerpedEyeRot), 1);
+   oColor = Color.r;              // Used for vignette fade.
+}
+
+