unity3d實時Cubemap RenderToCubemap

转载自：http://oulehui.blog.163.com/blog/static/79614698201011921716215/

Description

Render into a cubemap from this camera.

This is used for real-time reflections into cubemap render textures. It can be quite expensive though, especially if all six cubemap faces are rendered each frame.

Camera's position, clear flags and clipping plane distances will be used to render into cubemap faces. faceMask is a bitfield indicating which cubemap faces should be rendered into. Each bit that is set corresponds to a face. Bit numbers are integer values of CubemapFace enum. By default all six cubemap faces will be rendered (default value 63 has six lowest bits on).

This function will return false if rendering to cubemap fails. Some graphics hardware does not support the functionality.

Note: This is a Unity PRO feature.

@script ExecuteInEditMode
var cubemapSize = 128;
var oneFacePerFrame = false;
private var cam : Camera;
private var rtex : RenderTexture;
function Start () {
// render all six faces at startup
UpdateCubemap( 63 );
}
function LateUpdate () {
if (oneFacePerFrame) {
var faceToRender = Time.frameCount % 6;
var faceMask = 1 << faceToRender;
UpdateCubemap (faceMask);
} else {
UpdateCubemap (63); // all six faces
}
}
function UpdateCubemap (faceMask : int) {
if (!cam) {
var go = new GameObject ("CubemapCamera", Camera);
go.hideFlags = HideFlags.HideAndDontSave;
go.transform.position = transform.position;
go.transform.rotation = Quaternion.identity;
cam = go.camera;
cam.farClipPlane = 100; // don't render very far into cubemap
cam.enabled = false;
}
if (!rtex) { 
rtex = new RenderTexture (cubemapSize, cubemapSize, 16);
rtex.isPowerOfTwo = true;
rtex.isCubemap = true;
rtex.hideFlags = HideFlags.HideAndDontSave;
renderer.sharedMaterial.SetTexture ("_Cube", rtex);
}
cam.transform.position = transform.position;
cam.RenderToCubemap (rtex, faceMask);
}
function OnDisable () {
DestroyImmediate (cam);
DestroyImmediate (rtex);
}