uniform usampler2D equation_tex;
uniform int phase;
+uniform bool zero_diff_flow;
+
// See pack_floats_shared() in equations.frag.
vec2 unpack_floats_shared(uint c)
{
float inv_A22 = uintBitsToFloat(equation.z);
vec2 b = unpack_floats_shared(equation.w);
- // Subtract the missing terms from the right-hand side
- // (it couldn't be done earlier, because we didn't know
- // the values of the neighboring pixels; they change for
- // each SOR iteration).
- float smooth_l = textureOffset(smoothness_x_tex, tc, ivec2(-1, 0)).x;
- float smooth_r = texture(smoothness_x_tex, tc).x;
- float smooth_d = textureOffset(smoothness_y_tex, tc, ivec2( 0, -1)).x;
- float smooth_u = texture(smoothness_y_tex, tc).x;
- b += smooth_l * textureOffset(diff_flow_tex, tc, ivec2(-1, 0)).xy;
- b += smooth_r * textureOffset(diff_flow_tex, tc, ivec2( 1, 0)).xy;
- b += smooth_d * textureOffset(diff_flow_tex, tc, ivec2( 0, -1)).xy;
- b += smooth_u * textureOffset(diff_flow_tex, tc, ivec2( 0, 1)).xy;
+ if (zero_diff_flow) {
+ diff_flow = vec2(0.0f);
+ } else {
+ // Subtract the missing terms from the right-hand side
+ // (it couldn't be done earlier, because we didn't know
+ // the values of the neighboring pixels; they change for
+ // each SOR iteration).
+ float smooth_l = textureOffset(smoothness_x_tex, tc, ivec2(-1, 0)).x;
+ float smooth_r = texture(smoothness_x_tex, tc).x;
+ float smooth_d = textureOffset(smoothness_y_tex, tc, ivec2( 0, -1)).x;
+ float smooth_u = texture(smoothness_y_tex, tc).x;
+ b += smooth_l * textureOffset(diff_flow_tex, tc, ivec2(-1, 0)).xy;
+ b += smooth_r * textureOffset(diff_flow_tex, tc, ivec2( 1, 0)).xy;
+ b += smooth_d * textureOffset(diff_flow_tex, tc, ivec2( 0, -1)).xy;
+ b += smooth_u * textureOffset(diff_flow_tex, tc, ivec2( 0, 1)).xy;
+ diff_flow = texture(diff_flow_tex, tc).xy;
+ }
const float omega = 1.8; // Marginally better than 1.6, it seems.
- diff_flow = texture(diff_flow_tex, tc).xy;
// From https://en.wikipedia.org/wiki/Successive_over-relaxation.
float sigma_u = A12 * diff_flow.y;