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Remove curve support from line shader

This commit is contained in:
Patrick Walton 2018-12-30 18:01:48 -08:00
parent 6c8e4de739
commit e09a3f2977
1 changed files with 3 additions and 4 deletions
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7
demo2/stencil.fs.glsl
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@ -27,16 +27,15 @@ void main() {
// Determine winding, and sort into a consistent order so we only need to find one root below.
bool winding = from.x < to.x;
vec2 left = winding ? from : to, right = winding ? to : from;
vec2 v0 = ctrl - left, v1 = right - ctrl;
// Shoot a vertical ray toward the curve.
vec2 window = clamp(vec2(from.x, to.x), -0.5, 0.5);
float offset = mix(window.x, window.y, 0.5) - left.x;
float t = offset / (v0.x + sqrt(v1.x * offset - v0.x * (offset - v0.x)));
float t = offset / (right.x - left.x);
// Compute position and derivative to form a line approximation.
float y = mix(mix(left.y, ctrl.y, t), mix(ctrl.y, right.y, t), t);
float d = mix(v0.y, v1.y, t) / mix(v0.x, v1.x, t);
float y = mix(left.y, right.y, t);
float d = (right.y - left.y) / (right.x - left.x);
// Look up area under that line, and scale horizontally to the window size.
float dX = window.x - window.y;