Add mat4.orthoZO, which is appropriate for WebGPU's normalized device coordinates

Author: toji

src/mat4.js

@@ -1621,7 +1621,9 @@ export function perspectiveFromFieldOfView(out, fov, near, far) {
 }
 
 /**
- * Generates a orthogonal projection matrix with the given bounds
+ * Generates a orthogonal projection matrix with the given bounds.
+ * The near/far clip planes correspond to a normalized device coordinate Z range of [-1, 1],
+ * which matches WebGL/OpenGL's clip volume.
  *
  * @param {mat4} out mat4 frustum matrix will be written into
  * @param {number} left Left bound of the frustum
@@ -1632,7 +1634,7 @@ export function perspectiveFromFieldOfView(out, fov, near, far) {
  * @param {number} far Far bound of the frustum
  * @returns {mat4} out
  */
-export function ortho(out, left, right, bottom, top, near, far) {
+export function orthoNO(out, left, right, bottom, top, near, far) {
   let lr = 1 / (left - right);
   let bt = 1 / (bottom - top);
   let nf = 1 / (near - far);
@@ -1655,6 +1657,49 @@ export function ortho(out, left, right, bottom, top, near, far) {
   return out;
 }
 
+/**
+ * Alias for {@link mat4.orthoNO}
+ * @function
+ */
+export const ortho = orthoNO;
+
+/**
+ * Generates a orthogonal projection matrix with the given bounds.
+ * The near/far clip planes correspond to a normalized device coordinate Z range of [0, 1],
+ * which matches WebGPU/Vulkan/DirectX/Metal's clip volume.
+ *
+ * @param {mat4} out mat4 frustum matrix will be written into
+ * @param {number} left Left bound of the frustum
+ * @param {number} right Right bound of the frustum
+ * @param {number} bottom Bottom bound of the frustum
+ * @param {number} top Top bound of the frustum
+ * @param {number} near Near bound of the frustum
+ * @param {number} far Far bound of the frustum
+ * @returns {mat4} out
+ */
+export function orthoZO(out, left, right, bottom, top, near, far) {
+  let lr = 1 / (left - right);
+  let bt = 1 / (bottom - top);
+  let nf = 1 / (near - far);
+  out[0] = -2 * lr;
+  out[1] = 0;
+  out[2] = 0;
+  out[3] = 0;
+  out[4] = 0;
+  out[5] = -2 * bt;
+  out[6] = 0;
+  out[7] = 0;
+  out[8] = 0;
+  out[9] = 0;
+  out[10] = nf;
+  out[11] = 0;
+  out[12] = (left + right) * lr;
+  out[13] = (top + bottom) * bt;
+  out[14] = near * nf;
+  out[15] = 1;
+  return out;
+}
+
 /**
  * Generates a look-at matrix with the given eye position, focal point, and up axis.
  * If you want a matrix that actually makes an object look at another object, you should use targetTo instead.