Fix flow output after we did normalization in the add step.

[nageru] / flow.cpp

diff --git a/flow.cpp b/flow.cpp
index 5e93cd8daa208da92fc0a698628370038cd9716e..06d29d847325fe9d7283c198132939d2297abe5f 100644 (file)
--- a/flow.cpp
+++ b/flow.cpp
@@ -386,6 +386,8 @@ void Densify::exec(GLuint tex0_view, GLuint tex1_view, GLuint flow_tex, GLuint d
 
        float patch_spacing_x = float(level_width - patch_size_pixels) / (width_patches - 1);
        float patch_spacing_y = float(level_height - patch_size_pixels) / (height_patches - 1);
+       if (width_patches == 1) patch_spacing_x = 0.0f;  // Avoid infinities.
+       if (height_patches == 1) patch_spacing_y = 0.0f;
        glProgramUniform2f(densify_program, uniform_patch_spacing,
                patch_spacing_x / level_width,
                patch_spacing_y / level_height);
@@ -995,8 +997,8 @@ int main(void)
 
        int level_width = WIDTH >> finest_level;
        int level_height = HEIGHT >> finest_level;
-       unique_ptr<float[]> dense_flow(new float[level_width * level_height * 3]);
-       glGetTextureImage(prev_level_flow_tex, 0, GL_RGB, GL_FLOAT, level_width * level_height * 3 * sizeof(float), dense_flow.get());
+       unique_ptr<float[]> dense_flow(new float[level_width * level_height * 2]);
+       glGetTextureImage(prev_level_flow_tex, 0, GL_RG, GL_FLOAT, level_width * level_height * 2 * sizeof(float), dense_flow.get());
 
        FILE *fp = fopen("flow.ppm", "wb");
        FILE *flowfp = fopen("flow.flo", "wb");
@@ -1007,12 +1009,11 @@ int main(void)
        for (unsigned y = 0; y < unsigned(level_height); ++y) {
                int yy = level_height - y - 1;
                for (unsigned x = 0; x < unsigned(level_width); ++x) {
-                       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];
+                       float du = dense_flow[(yy * level_width + x) * 2 + 0];
+                       float dv = dense_flow[(yy * level_width + x) * 2 + 1];
 
-                       du = (du / w) * level_width;
-                       dv = (-dv / w) * level_height;
+                       du = du * level_width;
+                       dv = -dv * level_height;
 
                        fwrite(&du, 4, 1, flowfp);
                        fwrite(&dv, 4, 1, flowfp);