通道遮罩 ColorMask可以讓我們制定渲染結(jié)果的輸出通道，而不是通常情況下的RGBA這4個通道全部寫入?？蛇x參數(shù)是 RGBA 的任意組合以及 0， 這將意味著不會寫入到任何通道，可以用來單獨做一次Z測試，而不將結(jié)果寫入顏色通道

Shader "DepthMask" {

    SubShader {
        // Render the mask after regular geometry, but before masked geometry and
        // transparent things.

        Tags {"Queue" = "Geometry-10" }

        // Turn off lighting, because it's expensive and the thing is supposed to be
        // invisible anyway.

        Lighting Off

        // Draw into the depth buffer in the usual way.  This is probably the default,
        // but it doesn't hurt to be explicit.

        ZTest LEqual
        ZWrite On

        // Don't draw anything into the RGBA channels. This is an undocumented
        // argument to ColorMask which lets us avoid writing to anything except
        // the depth buffer.

        ColorMask 0

        // Do nothing specific in the pass:

        Pass {}
    }
}

實現(xiàn)如圖效果，前面的cube改為DepthMask的shader，實現(xiàn)在前面的cube透明，但是仍然擋住了后面cube的效果

fdd904b67e934e24b10e5c9c84392fc2[1].jpg