Make image width/height consistently a vec2.

[nageru] / motion_search.frag

diff --git a/motion_search.frag b/motion_search.frag
index 616e2080dc1084342dd1723c283ba9deab755fc9..5f2b6f8c2e1c79ffaee0de5b9c04ace4153b0f1d 100644 (file)
--- a/motion_search.frag
+++ b/motion_search.frag
@@ -43,14 +43,14 @@ in vec2 patch_bottom_left_texel;  // Center of bottom-left texel of patch.
 out vec2 out_flow;
 
 uniform sampler2D flow_tex, grad0_tex, image0_tex, image1_tex;
-uniform float image_width, image_height, inv_image_width, inv_image_height;
+uniform vec2 image_size, inv_image_size;
 
 void main()
 {
        // Lock patch_bottom_left_texel to an integer, so that we never get
        // any bilinear artifacts for the gradient.
-       vec2 base = round(patch_bottom_left_texel * vec2(image_width, image_height))
-               * vec2(inv_image_width, inv_image_height);
+       vec2 base = round(patch_bottom_left_texel * image_size)
+               * inv_image_size;
 
        // First, precompute the pseudo-Hessian for the template patch.
        // This is the part where we really save by the inverse search
@@ -65,9 +65,7 @@ void main()
        mat2 H = mat2(0.0f);
        for (uint y = 0; y < patch_size; ++y) {
                for (uint x = 0; x < patch_size; ++x) {
-                       vec2 tc;
-                       tc.x = base.x + x * inv_image_width;
-                       tc.y = base.y + y * inv_image_height;
+                       vec2 tc = base + uvec2(x, y) * inv_image_size;
                        vec2 grad = texture(grad0_tex, tc).xy;
                        H[0][0] += grad.x * grad.x;
                        H[1][1] += grad.y * grad.y;
@@ -87,27 +85,36 @@ void main()
 
        mat2 H_inv = inverse(H);
 
-       // Fetch the initial guess for the flow.
-       vec2 initial_u = texture(flow_tex, flow_tc).xy;
+       // Fetch the initial guess for the flow. (We need the normalization step
+       // because densification works by accumulating; see the comments on the
+       // Densify class.)
+       vec3 prev_flow = texture(flow_tex, flow_tc).xyz;
+       vec2 initial_u;
+       if (prev_flow.z < 1e-3) {
+               initial_u = vec2(0.0, 0.0);
+       } else {
+               initial_u = prev_flow.xy / prev_flow.z;
+       }
        vec2 u = initial_u;
 
        for (uint i = 0; i < num_iterations; ++i) {
                vec2 du = vec2(0.0, 0.0);
                for (uint y = 0; y < patch_size; ++y) {
                        for (uint x = 0; x < patch_size; ++x) {
-                               vec2 tc;
-                               tc.x = base.x + x * inv_image_width;
-                               tc.y = base.y + y * inv_image_height;
+                               vec2 tc = base + uvec2(x, y) * inv_image_size;
                                vec2 grad = texture(grad0_tex, tc).xy;
                                float t = texture(image0_tex, tc).x;
                                float warped = texture(image1_tex, tc + u).x;
                                du += grad * (warped - t);
                        }
                }
-               u += H_inv * du * vec2(inv_image_width, inv_image_height);
+               u += (H_inv * du) * inv_image_size;
        }
 
-       // TODO: reject if moving too far
+       // Reject if we moved too far.
+       if (length((u - initial_u) * image_size) > patch_size) {
+               u = initial_u;
+       }
 
        out_flow = u;
 }