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Small clean up

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This commit is contained in:
Grant Sanderson
2023-01-18 13:07:18 -08:00
parent e20efda3df
commit 13c41be17f
1 changed files with 9 additions and 7 deletions
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16
manimlib/shaders/quadratic_bezier_stroke/frag.glsl
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@ -12,18 +12,21 @@ out vec4 frag_color;
const float QUICK_DIST_WIDTH = 0.2;
// Distance from (x0, y0) to the curve y = x^2
float dist_to_curve(float x0, float y0){
float dist_to_curve(){
// Returns distance from uv_coords to the curve v = u^2
float x0 = uv_coords.x;
float y0 = uv_coords.y;
// In the linear case, the curve will have
// been set to equal the x axis
if(bool(is_linear)) return y0;
if(bool(is_linear)) return abs(y0);
if(uv_stroke_width < QUICK_DIST_WIDTH){
// This is a quick approximation for computing
// the distance to the curve.
// Evaluate F(x, y) = y - x^2
// divide by its gradient's magnitude
return (y0 - x0 * x0) / sqrt(1 + 4 * x0 * x0);
return abs((y0 - x0 * x0) / sqrt(1 + 4 * x0 * x0));
}
// Otherwise, solve for the minimal distance.
// The distance squared between (x0, y0) and a point (x, x^2) looks like
@ -50,9 +53,8 @@ float dist_to_curve(float x0, float y0){
void main() {
if (uv_stroke_width == 0) discard;
// Compute sdf for the region around the curve we wish to color.
float dist = dist_to_curve(uv_coords.x, uv_coords.y);
float signed_dist = abs(dist) - 0.5 * uv_stroke_width;
// sdf for the region around the curve we wish to color.
float signed_dist = dist_to_curve() - 0.5 * uv_stroke_width;
frag_color = color;
frag_color.a *= smoothstep(0.5, -0.5, signed_dist / uv_anti_alias_width);