fix(🐛): fix mapPoint3d implementation (#521)

src/Matrix4.ts

@@ -78,27 +78,42 @@ export const identity4: Matrix4 = [
   1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1,
 ];
 
-const translate = (x: number, y: number, z: number): Matrix4 => {
+/**
+ * @worklet
+ */
+export const translate = (x: number, y: number, z: number): Matrix4 => {
   "worklet";
   return [1, 0, 0, x, 0, 1, 0, y, 0, 0, 1, z, 0, 0, 0, 1];
 };
 
+/**
+ * @worklet
+ */
 const scale = (sx: number, sy: number, sz: number): Matrix4 => {
   "worklet";
   return [sx, 0, 0, 0, 0, sy, 0, 0, 0, 0, sz, 0, 0, 0, 0, 1];
 };
 
-const skewX = (s: number): Matrix4 => {
+/**
+ * @worklet
+ */
+export const skewX = (s: number): Matrix4 => {
   "worklet";
   return [1, 0, 0, 0, Math.tan(s), 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1];
 };
 
-const skewY = (s: number): Matrix4 => {
+/**
+ * @worklet
+ */
+export const skewY = (s: number): Matrix4 => {
   "worklet";
   return [1, Math.tan(s), 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1];
 };
 
-const perspective = (p: number): Matrix4 => {
+/**
+ * @worklet
+ */
+export const perspective = (p: number): Matrix4 => {
   "worklet";
   return [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, -1 / p, 1];
 };
@@ -144,7 +159,10 @@ const rotatedUnitSinCos = (
   ];
 };
 
-const rotate = (axis: Vec3, value: number) => {
+/**
+ * @worklet
+ */
+export const rotate = (axis: Vec3, value: number) => {
   "worklet";
   return rotatedUnitSinCos(
     normalizeVec(axis),
@@ -156,14 +174,13 @@ const rotate = (axis: Vec3, value: number) => {
 /**
  * @worklet
  */
-export const matrixVecMul4 = (m: Matrix4, v: Vec4) => {
+export const matrixVecMul4 = (m: Matrix4, v: Vec4): Vec4 => {
   "worklet";
-  const [vx, vy, vz, vw] = v;
   return [
-    vx * m[0] + vy * m[4] + vz * m[8] + vw * m[12],
-    vx * m[1] + vy * m[5] + vz * m[9] + vw * m[13],
-    vx * m[2] + vy * m[6] + vz * m[10] + vw * m[14],
-    vx * m[3] + vy * m[7] + vz * m[11] + vw * m[15],
+    m[0] * v[0] + m[1] * v[1] + m[2] * v[2] + m[3] * v[3],
+    m[4] * v[0] + m[5] * v[1] + m[6] * v[2] + m[7] * v[3],
+    m[8] * v[0] + m[9] * v[1] + m[10] * v[2] + m[11] * v[3],
+    m[12] * v[0] + m[13] * v[1] + m[14] * v[2] + m[15] * v[3],
   ];
 };
 

src/__tests__/Matrix4.test.ts

@@ -1,6 +1,7 @@
 import {
   concat4,
   identity4,
+  translate,
   mapPoint3d,
   matrixVecMul4,
   multiply4,
@@ -139,4 +140,16 @@ describe("4x4 matrices", () => {
       ])
     );
   });
+  it("should correctly transform a point with an identity matrix", () => {
+    const point = [100, -100, 200] as const; // Define some test point
+    const result = mapPoint3d(identity4, point);
+    expect(result).toEqual(point);
+  });
+  it("should correctly transform a point with a translation matrix", () => {
+    const translationMatrix = translate(100, 100, 100);
+    const point = [100, -100, 200] as const; // Define some test point
+    const expectedResult = [200, 0, 300] as const;
+    const result = mapPoint3d(translationMatrix, point);
+    expect(result).toEqual(expectedResult);
+  });
 });

src/__tests__/matrix.ts

@@ -150,11 +150,11 @@ const rotatedUnitSinCos = (
   ];
 };
 
-export const transformPoint = (m4: number[], t: number[]): number[] => {
-  const x = m4[0] * t[0] + m4[4] * t[1] + m4[8] * t[2] + m4[12] * t[3];
-  const y = m4[1] * t[0] + m4[5] * t[1] + m4[9] * t[2] + m4[13] * t[3];
-  const z = m4[2] * t[0] + m4[6] * t[1] + m4[10] * t[2] + m4[14] * t[3];
-  const w = m4[3] * t[0] + m4[7] * t[1] + m4[11] * t[2] + m4[15] * t[3];
+export const transformPoint = (m: number[], t: number[]): number[] => {
+  const x = m[0] * t[0] + m[1] * t[1] + m[2] * t[2] + m[3] * t[3];
+  const y = m[4] * t[0] + m[5] * t[1] + m[6] * t[2] + m[7] * t[3];
+  const z = m[8] * t[0] + m[9] * t[1] + m[10] * t[2] + m[11] * t[3];
+  const w = m[12] * t[0] + m[13] * t[1] + m[14] * t[2] + m[15] * t[3];
   return [x, y, z, w];
 };