@openhps/core
Version:
Open Hybrid Positioning System - Core component
51 lines (50 loc) • 1.8 kB
JavaScript
import { modelWorldMatrix } from '../accessors/ModelNode.js';
import { cameraViewMatrix, cameraProjectionMatrix } from '../accessors/Camera.js';
import { positionLocal } from '../accessors/Position.js';
import { Fn, defined } from '../tsl/TSLBase.js';
/**
* This can be used to achieve a billboarding behavior for flat meshes. That means they are
* oriented always towards the camera.
*
* ```js
* material.vertexNode = billboarding();
* ```
*
* @tsl
* @function
* @param {Object} config - The configuration object.
* @param {?Node<vec3>} [config.position=null] - Can be used to define the vertex positions in world space.
* @param {boolean} [config.horizontal=true] - Whether to follow the camera rotation horizontally or not.
* @param {boolean} [config.vertical=false] - Whether to follow the camera rotation vertically or not.
* @return {Node<vec3>} The updated vertex position in clip space.
*/
export const billboarding = /*@__PURE__*/Fn(({
position = null,
horizontal = true,
vertical = false
}) => {
let worldMatrix;
if (position !== null) {
worldMatrix = modelWorldMatrix.toVar();
worldMatrix[3][0] = position.x;
worldMatrix[3][1] = position.y;
worldMatrix[3][2] = position.z;
} else {
worldMatrix = modelWorldMatrix;
}
const modelViewMatrix = cameraViewMatrix.mul(worldMatrix);
if (defined(horizontal)) {
modelViewMatrix[0][0] = modelWorldMatrix[0].length();
modelViewMatrix[0][1] = 0;
modelViewMatrix[0][2] = 0;
}
if (defined(vertical)) {
modelViewMatrix[1][0] = 0;
modelViewMatrix[1][1] = modelWorldMatrix[1].length();
modelViewMatrix[1][2] = 0;
}
modelViewMatrix[2][0] = 0;
modelViewMatrix[2][1] = 0;
modelViewMatrix[2][2] = 1;
return cameraProjectionMatrix.mul(modelViewMatrix).mul(positionLocal);
});