Rework patch placement. Finally inches our EPE just below the reference code, it...

[nageru] / densify.vert

diff --git a/densify.vert b/densify.vert
index 0572afbdd54e015e82afd5ef2140330925fbdc2d..b7f78d74edad1d6ca30e7304f221e9018c5cfeba 100644 (file)
--- a/densify.vert
+++ b/densify.vert
@@ -9,12 +9,18 @@ uniform int width_patches;
 uniform vec2 patch_size;  // In 0..1 coordinates.
 uniform vec2 patch_spacing;  // In 0..1 coordinates.
 uniform sampler2D flow_tex;
+uniform vec2 flow_size;
 
 void main()
 {
        int patch_x = gl_InstanceID % width_patches;
        int patch_y = gl_InstanceID / width_patches;
 
+       // Convert the patch index to being the full 0..1 range, to match where
+       // the motion search puts the patches. We don't bother with the locking
+       // to texel centers, though.
+       vec2 patch_center = ivec2(patch_x, patch_y) / (flow_size - 1.0);
+
        // Increase the patch size a bit; since patch spacing is not necessarily
        // an integer number of pixels, and we don't use conservative rasterization,
        // we could be missing the outer edges of the patch. And it seemingly helps
@@ -26,7 +32,7 @@ void main()
        // all directions.
        vec2 grown_pos = (position * 1.5) - 0.25;
 
-       image_pos = patch_spacing * ivec2(patch_x, patch_y) + patch_size * grown_pos;
+       image_pos = patch_center + patch_size * (grown_pos - 0.5f);
 
        // Find the flow value for this patch, and send it on to the fragment shader.
        vec3 flow_du_and_mean_diff = texelFetch(flow_tex, ivec2(patch_x, patch_y), 0).xyz;