first pass

math.js

@@ -0,0 +1,109 @@
+// math.js
+export function mat4Identity() {
+    return new Float32Array([
+        1, 0, 0, 0,
+        0, 1, 0, 0,
+        0, 0, 1, 0,
+        0, 0, 0, 1
+    ]);
+}
+
+export function mat4Multiply(out, a, b) {
+    let a00 = a[0], a01 = a[1], a02 = a[2], a03 = a[3];
+    let a10 = a[4], a11 = a[5], a12 = a[6], a13 = a[7];
+    let a20 = a[8], a21 = a[9], a22 = a[10], a23 = a[11];
+    let a30 = a[12], a31 = a[13], a32 = a[14], a33 = a[15];
+
+    let b0 = b[0], b1 = b[1], b2 = b[2], b3 = b[3];
+    out[0] = b0*a00 + b1*a10 + b2*a20 + b3*a30;
+    out[1] = b0*a01 + b1*a11 + b2*a21 + b3*a31;
+    out[2] = b0*a02 + b1*a12 + b2*a22 + b3*a32;
+    out[3] = b0*a03 + b1*a13 + b2*a23 + b3*a33;
+
+    b0 = b[4]; b1 = b[5]; b2 = b[6]; b3 = b[7];
+    out[4] = b0*a00 + b1*a10 + b2*a20 + b3*a30;
+    out[5] = b0*a01 + b1*a11 + b2*a21 + b3*a31;
+    out[6] = b0*a02 + b1*a12 + b2*a22 + b3*a32;
+    out[7] = b0*a03 + b1*a13 + b2*a23 + b3*a33;
+
+    b0 = b[8]; b1 = b[9]; b2 = b[10]; b3 = b[11];
+    out[8] = b0*a00 + b1*a10 + b2*a20 + b3*a30;
+    out[9] = b0*a01 + b1*a11 + b2*a21 + b3*a31;
+    out[10] = b0*a02 + b1*a12 + b2*a22 + b3*a32;
+    out[11] = b0*a03 + b1*a13 + b2*a23 + b3*a33;
+
+    b0 = b[12]; b1 = b[13]; b2 = b[14]; b3 = b[15];
+    out[12] = b0*a00 + b1*a10 + b2*a20 + b3*a30;
+    out[13] = b0*a01 + b1*a11 + b2*a21 + b3*a31;
+    out[14] = b0*a02 + b1*a12 + b2*a22 + b3*a32;
+    out[15] = b0*a03 + b1*a13 + b2*a23 + b3*a33;
+    return out;
+}
+
+export function mat4Ortho(out, left, right, bottom, top, near, far) {
+    let lr = 1 / (left - right);
+    let bt = 1 / (bottom - top);
+    let nf = 1 / (near - far);
+    out.fill(0);
+    out[0] = -2 * lr;
+    out[5] = -2 * bt;
+    out[10] = 2 * nf;
+    out[12] = (left + right) * lr;
+    out[13] = (top + bottom) * bt;
+    out[14] = (far + near) * nf;
+    out[15] = 1;
+    return out;
+}
+
+export function mat4LookAt(out, eyeX, eyeY, eyeZ, centerX, centerY, centerZ, upX, upY, upZ) {
+    let z0 = eyeX - centerX, z1 = eyeY - centerY, z2 = eyeZ - centerZ;
+    let len = 1 / Math.hypot(z0, z1, z2);
+    z0 *= len; z1 *= len; z2 *= len;
+
+    let x0 = upY * z2 - upZ * z1, x1 = upZ * z0 - upX * z2, x2 = upX * z1 - upY * z0;
+    len = 1 / Math.hypot(x0, x1, x2);
+    x0 *= len; x1 *= len; x2 *= len;
+
+    let y0 = z1 * x2 - z2 * x1, y1 = z2 * x0 - z0 * x2, y2 = z0 * x1 - z1 * x0;
+
+    out[0] = x0; out[1] = y0; out[2] = z0; out[3] = 0;
+    out[4] = x1; out[5] = y1; out[6] = z1; out[7] = 0;
+    out[8] = x2; out[9] = y2; out[10] = z2; out[11] = 0;
+    out[12] = -(x0 * eyeX + x1 * eyeY + x2 * eyeZ);
+    out[13] = -(y0 * eyeX + y1 * eyeY + y2 * eyeZ);
+    out[14] = -(z0 * eyeX + z1 * eyeY + z2 * eyeZ);
+    out[15] = 1;
+    return out;
+}export function mat4Translate(out, a, v) {
+    let x = v[0], y = v[1], z = v[2];
+    if (a === out) {
+        out[12] = a[0] * x + a[4] * y + a[8] * z + a[12];
+        out[13] = a[1] * x + a[5] * y + a[9] * z + a[13];
+        out[14] = a[2] * x + a[6] * y + a[10] * z + a[14];
+        out[15] = a[3] * x + a[7] * y + a[11] * z + a[15];
+    } else {
+        // We only use this in-place for this prototype
+    }
+    return out;
+}
+
+export function mat4RotateY(out, a, rad) {
+    let s = Math.sin(rad), c = Math.cos(rad);
+    let a00 = a[0], a01 = a[1], a02 = a[2], a03 = a[3];
+    let a20 = a[8], a21 = a[9], a22 = a[10], a23 = a[11];
+
+    if (a !== out) {
+        out[4] = a[4]; out[5] = a[5]; out[6] = a[6]; out[7] = a[7];
+        out[12] = a[12]; out[13] = a[13]; out[14] = a[14]; out[15] = a[15];
+    }
+
+    out[0] = a00 * c - a20 * s;
+    out[1] = a01 * c - a21 * s;
+    out[2] = a02 * c - a22 * s;
+    out[3] = a03 * c - a23 * s;
+    out[8] = a00 * s + a20 * c;
+    out[9] = a01 * s + a21 * c;
+    out[10] = a02 * s + a22 * c;
+    out[11] = a03 * s + a23 * c;
+    return out;
+}