In densification, grow the patch a bit. Seemingly helps a lot on the EPE.

diff --git a/densify.vert b/densify.vert
index e4db8fba94789e57145d7da20f1ccae455342290..0506b9caf7ee000eb4616611b982fac474003451 100644 (file)
--- a/densify.vert
+++ b/densify.vert
@@ -14,9 +14,18 @@ void main()
        int patch_x = gl_InstanceID % width_patches;
        int patch_y = gl_InstanceID / width_patches;
 
-       // TODO: Lock the bottom left of the patch to an integer number of pixels?
+       // 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
+       // a little bit in general to have some more candidates as well -- although
+       // this is measured without variational refinement, so it might be moot
+       // with it.
+       //
+       // Tihs maps [0.0,1.0] to [-0.25 to 1.25), ie. extends the patch by 25% in
+       // all directions.
+       vec2 grown_pos = (position * 1.5) - vec2(0.25, 0.25);
 
-       image_pos = patch_spacing * ivec2(patch_x, patch_y) + patch_size * position;
+       image_pos = patch_spacing * ivec2(patch_x, patch_y) + patch_size * grown_pos;
 
        // Find the flow value for this patch, and send it on to the fragment shader.
        flow_du = texelFetch(flow_tex, ivec2(patch_x, patch_y), 0).xy;