Use textureSize() instead of sending in uniforms manually. Same result, less code...

[nageru] / densify.vert

diff --git a/densify.vert b/densify.vert
index 4fbab1803b9b22fcdb400092d3ac15ac01eabadc..1859dfc2a0a33e0638ffd393263f7fa426116944 100644 (file)
--- a/densify.vert
+++ b/densify.vert
@@ -5,15 +5,19 @@ out vec2 image_pos;
 flat out vec2 flow_du;
 flat out float mean_diff;
 
-uniform int width_patches;
 uniform vec2 patch_size;  // In 0..1 coordinates.
 uniform vec2 patch_spacing;  // In 0..1 coordinates.
 uniform sampler2D flow_tex;
 
 void main()
 {
-       int patch_x = gl_InstanceID % width_patches;
-       int patch_y = gl_InstanceID / width_patches;
+       int patch_x = gl_InstanceID % textureSize(flow_tex, 0).x;
+       int patch_y = gl_InstanceID / textureSize(flow_tex, 0).x;
+
+       // 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) / (textureSize(flow_tex, 0) - 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,
@@ -24,9 +28,9 @@ void main()
        //
        // This maps [0.0,1.0] to [-0.25,1.25], ie. extends the patch by 25% in
        // all directions.
-       vec2 grown_pos = (position * 1.5) - vec2(0.25, 0.25);
+       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;