feat(shader-ast-stdlib): add isPointInCircle(), isPointInRect()

packages/shader-ast-stdlib/src/index.ts

@@ -11,6 +11,8 @@ export * from "./fog/exp.js";
 export * from "./fog/exp2.js";
 export * from "./fog/linear.js";
 
+export * from "./isec/point.js";
+
 export * from "./light/lambert.js";
 export * from "./light/trilight.js";
 

packages/shader-ast-stdlib/src/isec/point.ts

@@ -0,0 +1,36 @@
+import type { Vec2Sym } from "@thi.ng/shader-ast";
+import { F, V2 } from "@thi.ng/shader-ast/api/types";
+import { defn, ret } from "@thi.ng/shader-ast/ast/function";
+import { bool } from "@thi.ng/shader-ast/ast/lit";
+import { add } from "@thi.ng/shader-ast/ast/ops";
+import { $x, $y } from "@thi.ng/shader-ast/ast/swizzle";
+import { sym } from "@thi.ng/shader-ast/ast/sym";
+import { distance, min, step } from "@thi.ng/shader-ast/builtin/math";
+
+/**
+ * Predicate function to check if given point `p` is inside the circle defined
+ * by `pos` and `radius`.
+ */
+export const isPointInCircle = defn(
+	"bool",
+	null,
+	[V2, V2, F],
+	(p, pos, radius) => [ret(bool(step(distance(p, pos), radius)))]
+);
+
+/**
+ * Predicate function to check if given point `p` is inside the axis-aligned
+ * rect defined by `pos` and `size`. Branchless.
+ */
+export const isPointInRect = defn(
+	"bool",
+	null,
+	[V2, V2, V2],
+	(p, pos, size) => {
+		let q: Vec2Sym;
+		return [
+			(q = sym(min(step(pos, p), step(p, add(pos, size))))),
+			ret(bool(min($x(q), $y(q)))),
+		];
+	}
+);