+#version 450 core
+
+in vec3 tc;
+
+#ifdef SPLIT_YCBCR_OUTPUT
+out float Y;
+out vec2 CbCr;
+#else
+out vec4 rgba;
+#endif
+
+uniform sampler2DArray image_tex;
+uniform sampler2D flow_tex;
+uniform float alpha;
+
+void main()
+{
+ vec2 flow = texture(flow_tex, tc.xy).xy;
+ vec4 I_0 = texture(image_tex, vec3(tc.xy - alpha * flow, 0));
+ vec4 I_1 = texture(image_tex, vec3(tc.xy + (1.0f - alpha) * flow, 1));
+
+ // Occlusion reasoning:
+
+ vec2 size = textureSize(image_tex, 0).xy;
+
+ // Follow the flow back to the initial point (where we sample I_0 from), then forward again.
+ // See how well we match the point we started at, which is out flow consistency.
+ float d0 = alpha * length(size * (texture(flow_tex, vec2(tc.xy - alpha * flow)).xy - flow));
+
+ // Same for d1.
+ float d1 = (1.0f - alpha) * length(size * (texture(flow_tex, vec2(tc.xy + (1.0f - alpha) * flow)).xy - flow));
+
+ vec4 result;
+ if (max(d0, d1) < 3.0f) { // Arbitrary constant, not all that tuned. The UW paper says 1.0 is fine for ground truth.
+ // Both are visible, so blend.
+ result = I_0 + alpha * (I_1 - I_0);
+ } else if (d0 < d1) {
+ result = I_0;
+ } else {
+ result = I_1;
+ }
+
+#ifdef SPLIT_YCBCR_OUTPUT
+ Y = result.r;
+ CbCr = result.gb;
+#else
+ rgba = result;
+#endif
+}