maplibre-gl/src/util/primitives/frustum.test.ts

BSD licensed community fork of mapbox-gl, a WebGL interactive maps library

import {describe, test, expect} from 'vitest';
import {mat4, type vec4} from 'gl-matrix';
import {Frustum} from './frustum';

describe('frustum', () => {
    test('Create a frustum from inverse projection matrix', () => {
        const proj = new Float64Array(16) as any as mat4;
        const invProj = new Float64Array(16) as any as mat4;
        mat4.perspective(proj, Math.PI / 2, 1.0, 0.1, 100.0);
        mat4.invert(invProj, proj);

        const frustum = Frustum.fromInvProjectionMatrix(invProj, 1.0, 0.0);
        // mat4.perspective generates a projection matrix for right handed coordinate space.
        // This means that forward direction will be -z
        const expectedFrustumPoints = [
            [-0.1, 0.1, -0.1, 1.0],
            [0.1, 0.1, -0.1, 1.0],
            [0.1, -0.1, -0.1, 1.0],
            [-0.1, -0.1, -0.1, 1.0],
            [-100.0, 100.0, -100.0, 1.0],
            [100.0, 100.0, -100.0, 1.0],
            [100.0, -100.0, -100.0, 1.0],
            [-100.0, -100.0, -100.0, 1.0],
        ];

        frustum.points = frustum.points.map(array => array.map(n => Math.round(n * 10) / 10)) as vec4[];
        frustum.planes = frustum.planes.map(array => array.map(n => Math.round(n * 1000) / 1000)) as vec4[];

        const expectedFrustumPlanes = [
            [0, 0, 1.0, 0.1],
            [-0, -0, -1.0, -100.0],
            [-0.707, 0, 0.707, -0],
            [0.707, 0, 0.707, -0],
            [0, -0.707, 0.707, -0],
            [-0, 0.707, 0.707, -0]
        ];

        expect(frustum.points).toEqual(expectedFrustumPoints);
        expect(frustum.planes).toEqual(expectedFrustumPlanes);
    });
});