Move everything into a separate futatabi/ subdir, for the upcoming merge with Nageru.

[nageru] / futatabi / prewarp.frag

diff --git a/futatabi/prewarp.frag b/futatabi/prewarp.frag
new file mode 100644 (file)
index 0000000..baf24d1
--- /dev/null
+++ b/futatabi/prewarp.frag
@@ -0,0 +1,22 @@
+#version 450 core
+
+// Warps I_1 according to the flow, then computes the mean and difference to I_0.
+
+in vec3 tc;
+out float I, I_t;
+out vec2 normalized_flow;
+
+uniform sampler2DArray image_tex, flow_tex;
+
+void main()
+{
+       vec3 flow = texture(flow_tex, tc).xyz;
+       flow.xy /= flow.z;  // Normalize the sum coming out of the densification.
+
+       float I_0 = texture(image_tex, tc).x;
+       float I_w = texture(image_tex, vec3(tc.xy + flow.xy, 1.0f - tc.z)).x;  // NOTE: This is effectively a reverse warp since texture() is a gather operation and flow is conceptually scatter.
+
+       I = 0.5f * (I_0 + I_w);
+       I_t = I_w - I_0;
+       normalized_flow = flow.xy * textureSize(image_tex, 0).xy;
+}