var passCount : int

Description

How many passes are in this material (Read Only).

This is mostly used in direct drawing code using GL class (Unity Pro only). For example, Image Effects use materials for implementing screen post-processing. For each pass in the material they activate the pass (see SetPass) and draw a fullscreen quad.

Here is an example of a full image effect that inverts the colors. Add this script to the camera and see it in play mode.

private var mat : Material;

function Start () {
    mat = new Material (
        "Shader \"Hidden/Invert\" {" +
        "SubShader {" +
        "    Pass {" +
        "        ZTest Always Cull Off ZWrite Off" +
        "        SetTexture [_RenderTex] { combine one-texture }" +
        "    }" +
        "}" +
        "}"
    );
}

function OnRenderImage (source : RenderTexture, dest : RenderTexture) {
    RenderTexture.active = dest;
    source.SetGlobalShaderProperty ("_RenderTex");

    GL.PushMatrix ();
    GL.LoadOrtho ();

    // for each pass in the material (one in this case)
    for (var i = 0; i < mat.passCount; ++i) {
        // activate pass
        mat.SetPass (i);
        // draw a quad
        GL.Begin( GL.QUADS );
        GL.TexCoord2( 0, 0 ); GL.Vertex3( 0, 0, 0.1 );
        GL.TexCoord2( 1, 0 ); GL.Vertex3( 1, 0, 0.1 );
        GL.TexCoord2( 1, 1 ); GL.Vertex3( 1, 1, 0.1 );
        GL.TexCoord2( 0, 1 ); GL.Vertex3( 0, 1, 0.1 );
        GL.End();
    }
    GL.PopMatrix ();
}

See Also: SetPass function, GL class, ShaderLab documentation.