feat(shader-ast-stdlib): add SDF domain ops

- add sdfMirror2()
- add sdfRepeatPolar()

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

@@ -56,8 +56,11 @@ export * from "./sdf/box";
 export * from "./sdf/cylinder";
 export * from "./sdf/isec";
 export * from "./sdf/line";
+export * from "./sdf/mirror";
 export * from "./sdf/plane";
+export * from "./sdf/polyhedra";
 export * from "./sdf/repeat";
+export * from "./sdf/repeat-polar";
 export * from "./sdf/round";
 export * from "./sdf/smooth-isec";
 export * from "./sdf/smooth-sub";

packages/shader-ast-stdlib/src/sdf/mirror.ts

@@ -0,0 +1,43 @@
+import {
+    add,
+    defn,
+    div,
+    FLOAT05,
+    floor,
+    mod,
+    mul,
+    ret,
+    sub,
+    sym,
+    Vec2Sym,
+    VEC2_1,
+    VEC2_2,
+} from "@thi.ng/shader-ast";
+
+/**
+ * @remarks
+ * Based on HG_SDF (Mercury Demogroup). Does not compute cell index.
+ *
+ * @param p - point
+ * @param size - mirror box size
+ */
+export const sdfMirror2 = defn(
+    "vec2",
+    "sdfMirror2",
+    ["vec2", "vec2"],
+    (p, size) => {
+        let halfSize: Vec2Sym;
+        return [
+            (halfSize = sym(mul(size, FLOAT05))),
+            ret(
+                mul(
+                    sub(mod(add(p, halfSize), size), halfSize),
+                    sub(
+                        mul(mod(floor(div(add(p, halfSize), size)), VEC2_2), 2),
+                        VEC2_1
+                    )
+                )
+            ),
+        ];
+    }
+);

packages/shader-ast-stdlib/src/sdf/repeat-polar.ts

@@ -0,0 +1,42 @@
+import {
+    $x,
+    $y,
+    add,
+    atan,
+    defn,
+    div,
+    FLOAT05,
+    FloatSym,
+    length,
+    mod,
+    mul,
+    ret,
+    sub,
+    sym,
+    TAU,
+} from "@thi.ng/shader-ast";
+import { cossin } from "../math/sincos";
+
+/**
+ * @remarks
+ * Based on HG_SDF (Mercury Demogroup). Does not compute cell index.
+ *
+ * @param p - point
+ * @param n - number of polar repetitions
+ */
+export const sdfRepeatPolar2 = defn(
+    "vec2",
+    "sdfRepeatPolar2",
+    ["vec2", "float"],
+    (p, n) => {
+        let angle: FloatSym;
+        let angle2: FloatSym;
+        let a: FloatSym;
+        return [
+            (angle = sym(div(TAU, n))),
+            (angle2 = sym(mul(angle, FLOAT05))),
+            (a = sym(sub(mod(add(angle2, atan($y(p), $x(p))), angle), angle2))),
+            ret(mul(cossin(a), length(p))),
+        ];
+    }
+);