Various fixes to flow visualization. Still broken.

diff --git a/flow.cpp b/flow.cpp
index 7eec660b30c26e1b3b7783cce7b92dd528c77c3a..2ddaf58dd6b78abb3c51db830b2e674433a16b56 100644 (file)
--- a/flow.cpp
+++ b/flow.cpp
@@ -452,21 +452,22 @@ int main(void)
        FILE *fp = fopen("flow.ppm", "wb");
        fprintf(fp, "P6\n%d %d\n255\n", level_width, level_height);
        for (unsigned y = 0; y < level_height; ++y) {
+               int yy = level_height - y - 1;
                for (unsigned x = 0; x < level_width; ++x) {
-                       float du = dense_flow[(y * level_width + x) * 3 + 0];
-                       float dv = dense_flow[(y * level_width + x) * 3 + 1];
-                       float w = dense_flow[(y * level_width + x) * 3 + 2];
+                       float du = dense_flow[(yy * level_width + x) * 3 + 0];
+                       float dv = dense_flow[(yy * level_width + x) * 3 + 1];
+                       float w = dense_flow[(yy * level_width + x) * 3 + 2];
 
                        du /= w;
                        dv /= w;
 
-                       float angle = atan2(dv, du);
+                       float angle = atan2(dv * level_width, du * level_height);
                        float magnitude = min(hypot(du * level_width, dv * level_height) / 20.0, 1.0);
                        
                        // HSV to RGB (from Wikipedia). Saturation is 1.
                        float c = magnitude;
-                       float h = angle * 6.0 / (2.0 * M_PI);
-                       float X = c * (1.0 - (fmod(h, 2.0) - 1.0));
+                       float h = (angle + M_PI) * 6.0 / (2.0 * M_PI);
+                       float X = c * (1.0 - fabs(fmod(h, 2.0) - 1.0));
                        float r = 0.0f, g = 0.0f, b = 0.0f;
                        if (h < 1.0f) {
                                r = c; g = X;
@@ -484,7 +485,7 @@ int main(void)
                                // h is NaN, so black is fine.
                        }
                        float m = magnitude - c;
-                       r += m, g += m, b += m;
+                       r += m; g += m; b += m;
                        r = max(min(r, 1.0f), 0.0f);
                        g = max(min(g, 1.0f), 0.0f);
                        b = max(min(b, 1.0f), 0.0f);

diff --git a/motion_search.frag b/motion_search.frag
index 98ebff81b814357cb471e864bbd4c70baa0a5991..ef860b815d9d33624d50d7ccfb23b0dfff054453 100644 (file)
--- a/motion_search.frag
+++ b/motion_search.frag
@@ -104,7 +104,7 @@ void main()
                                du += grad * (warped - t);
                        }
                }
-               u += H_inv * du * vec2(inv_image_width, inv_image_height);
+               u += (H_inv * du) * vec2(inv_image_width, inv_image_height);
        }
 
        // Reject if we moved too far.