From ad6451e4e3ab6e1a8c51befbd183a47afa9e07ba Mon Sep 17 00:00:00 2001 From: "Steinar H. Gunderson" Date: Mon, 23 Jul 2018 18:31:41 +0200 Subject: [PATCH] Make motion search happen mostly in pixels; a bit less code that way. --- motion_search.frag | 24 +++++++++++------------- 1 file changed, 11 insertions(+), 13 deletions(-) diff --git a/motion_search.frag b/motion_search.frag index 163db2c..490db33 100644 --- a/motion_search.frag +++ b/motion_search.frag @@ -90,24 +90,21 @@ void main() mat2 H_inv = inverse(H); - // Fetch the initial guess for the flow. - vec2 initial_u = texture(flow_tex, flow_tc).xy * inv_prev_level_size; - - // Note: The flow is in OpenGL coordinates [0..1], but the calculations - // generally come out in pixels since the gradient is in pixels, - // so we need to convert at the end. + // Fetch the initial guess for the flow, and convert from the previous size to this one. + vec2 initial_u = texture(flow_tex, flow_tc).xy * (image_size * inv_prev_level_size); vec2 u = initial_u; float mean_diff, first_mean_diff; for (uint i = 0; i < num_iterations; ++i) { vec2 du = vec2(0.0, 0.0); float warped_sum = 0.0f; + vec2 u_norm = u * inv_image_size; // In [0..1] coordinates instead of pixels. 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; - float warped = texture(image1_tex, tc + u).x; + float warped = texture(image1_tex, tc + u_norm).x; du += grad * (warped - t); warped_sum += warped; } @@ -132,22 +129,23 @@ void main() } // Do the actual update. - u -= (H_inv * du) * inv_image_size; + u -= H_inv * du; } // Reject if we moved too far. Also reject if the patch goes out-of-bounds // (the paper does not mention this, but the code does, and it seems to be // critical to avoid really bad behavior at the edges). - if ((length((u - initial_u) * image_size) > patch_size) || - u.x * image_size.x < -(patch_size * 0.5f) || - (1.0 - u.x) * image_size.x < -(patch_size * 0.5f) || - u.y * image_size.y < -(patch_size * 0.5f) || - (1.0 - u.y) * image_size.y < -(patch_size * 0.5f)) { + if (length(u - initial_u) > patch_size || + u.x < -(patch_size * 0.5f) || + image_size.x - u.x < -(patch_size * 0.5f) || + u.y < -(patch_size * 0.5f) || + image_size.y - u.y < -(patch_size * 0.5f)) { u = initial_u; mean_diff = first_mean_diff; } // NOTE: The mean patch diff will be for the second-to-last patch, // not the true position of du. But hopefully, it will be very close. + u *= inv_image_size; out_flow = vec3(u.x, u.y, mean_diff); } -- 2.39.2