Pack the gradients and image together into a single 32-bit texture; seems to help...

[nageru] / motion_search.frag

diff --git a/motion_search.frag b/motion_search.frag
index 136d316ef4cfe43ac4e4604e12379cec81be9385..9ef607c3fae79146b3b5ab97ab5298d8456b9faa 100644 (file)
--- a/motion_search.frag
+++ b/motion_search.frag
@@ -42,12 +42,37 @@ in vec2 flow_tc;
 in vec2 patch_center;
 out vec3 out_flow;
 
-uniform sampler2D flow_tex, grad0_tex, image0_tex, image1_tex;
+uniform sampler2D flow_tex, image1_tex;
+uniform usampler2D grad0_tex;  // Also contains image0.
 uniform vec2 inv_image_size, inv_prev_level_size;
 
+vec3 unpack_gradients(uint v)
+{
+       uint vi = v & 0xff;
+       uint xi = (v >> 8) & 0xfff;
+       uint yi = v >> 20;
+       vec3 r = vec3(xi * (1.0f / 4095.0f) - 0.5f, yi * (1.0f / 4095.0f) - 0.5f, vi * (1.0f / 255.0f));
+       return r;
+}
+
+// Note: The third variable is the actual pixel value.
+vec3 get_gradients(vec2 tc)
+{
+       vec3 grad = unpack_gradients(texture(grad0_tex, tc).x);
+
+       // Zero gradients outside the image. (We'd do this with a sampler,
+       // but we want the repeat behavior for the actual texels, in the
+       // z channel.)
+       if (any(lessThan(tc, vec2(0.0f))) || any(greaterThan(tc, vec2(1.0f)))) {
+               grad.xy = vec2(0.0f);
+       }
+
+       return grad;
+}
+
 void main()
 {
-       vec2 image_size = textureSize(image0_tex, 0);
+       vec2 image_size = textureSize(grad0_tex, 0);
 
        // Lock the patch center to an integer, so that we never get
        // any bilinear artifacts for the gradient. (NOTE: This assumes an
@@ -71,13 +96,13 @@ void main()
        for (uint y = 0; y < patch_size; ++y) {
                for (uint x = 0; x < patch_size; ++x) {
                        vec2 tc = base + uvec2(x, y) * inv_image_size;
-                       vec2 grad = texture(grad0_tex, tc).xy;
+                       vec3 grad = get_gradients(tc);
                        H[0][0] += grad.x * grad.x;
                        H[1][1] += grad.y * grad.y;
                        H[0][1] += grad.x * grad.y;
 
-                       template_sum += texture(image0_tex, tc).x;
-                       grad_sum += grad;
+                       template_sum += grad.z;  // The actual template pixel value.
+                       grad_sum += grad.xy;
                }
        }
        H[1][0] = H[0][1];
@@ -105,10 +130,10 @@ void main()
                for (uint y = 0; y < patch_size; ++y) {
                        for (uint x = 0; x < patch_size; ++x) {
                                vec2 tc = base + uvec2(x, y) * inv_image_size;
-                               vec2 grad = texture(grad0_tex, tc).xy;
-                               float t = texture(image0_tex, tc).x;
+                               vec3 grad = get_gradients(tc);
+                               float t = grad.z;
                                float warped = texture(image1_tex, tc + u_norm).x;
-                               du += grad * (warped - t);
+                               du += grad.xy * (warped - t);
                                warped_sum += warped;
                        }
                }