diff options
Diffstat (limited to 'apps/web/src/masks/utils.ts')
| -rw-r--r-- | apps/web/src/masks/utils.ts | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/apps/web/src/masks/utils.ts b/apps/web/src/masks/utils.ts new file mode 100644 index 00000000..b1ac2c39 --- /dev/null +++ b/apps/web/src/masks/utils.ts @@ -0,0 +1,64 @@ +const LINE_PARALLEL_EPSILON = 1e-10;
+
+export function lineEdgeIntersection({
+ lineX,
+ lineY,
+ normalX,
+ normalY,
+ x1,
+ y1,
+ x2,
+ y2,
+}: {
+ lineX: number;
+ lineY: number;
+ normalX: number;
+ normalY: number;
+ x1: number;
+ y1: number;
+ x2: number;
+ y2: number;
+}): { x: number; y: number } | null {
+ const distance1 = halfPlaneSign({
+ lineX,
+ lineY,
+ normalX,
+ normalY,
+ x: x1,
+ y: y1,
+ });
+ const distance2 = halfPlaneSign({
+ lineX,
+ lineY,
+ normalX,
+ normalY,
+ x: x2,
+ y: y2,
+ });
+ const denom = distance1 - distance2;
+ if (Math.abs(denom) < LINE_PARALLEL_EPSILON) return null;
+ const t = distance1 / denom;
+ if (t < 0 || t > 1) return null;
+ return {
+ x: x1 + (x2 - x1) * t,
+ y: y1 + (y2 - y1) * t,
+ };
+}
+
+export function halfPlaneSign({
+ lineX,
+ lineY,
+ normalX,
+ normalY,
+ x,
+ y,
+}: {
+ lineX: number;
+ lineY: number;
+ normalX: number;
+ normalY: number;
+ x: number;
+ y: number;
+}): number {
+ return (x - lineX) * normalX + (y - lineY) * normalY;
+}
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