我怎样才能让我的网格脱离屏幕？

Question

我无法弄清楚如何检测它离开屏幕，有人可以帮忙吗？我正在使用WebGL和Three.js。

Answer 1

您可以使用Frustum测试，有点像这样：

// Create a new Frustum object (for efficiency, do this only once)
var frustum = new THREE.Frustum();
// Helper matrix (for efficiency, do this only once) 
var projScreenMatrix = new THREE.Matrix4();

// Set the matrix from camera matrices (which are updated on each renderer.render() call)
projScreenMatrix.multiply( camera.projectionMatrix, camera.matrixWorldInverse );
// Update the frustum
frustum.setFromMatrix( projScreenMatrix );
// Test for visibility
if ( !frustum.contains( object ) ) {
    // It's off-screen!
}

这是从WebGLRenderer sources复制的。