GL.Lines over Game Objects

[paulaceccon]

Hi, I made a grid (like we can see in Unity) with GL.Lines, using this shader:

static void CreateLineMaterial() 
{
    if( lineMaterial == null )
    { 
        lineMaterial = new Material( "Shader \"Lines/Colored Blended\" {" +
                       "SubShader {Tags { \"RenderType\"=\"Overdraw\" } Pass { " +
				       "ZWrite Off ZTest Always Cull Off Fog { Mode Off } " +
                       "BindChannels {" +
                       "Bind \"vertex\", vertex Bind \"color\", color }" +
                       "} } }");
        lineMaterial.hideFlags = HideFlags.HideAndDontSave;
	    lineMaterial.shader.hideFlags = HideFlags.HideAndDontSave;	
   }
}

The problem is that the grid is always over the others game objects, i.e, the lines that I draw overwrite the others item in the scene. I believe this is cause of the shader, but I don’t understand much about it…

What do I have to do to stop this behavior?

Thanks in advance.

[Bunny83]

That’s simply because your shader doesn’t perform a depth test and doesn’t write to the z-buffer. Try this:

lineMaterial = new Material( "Shader \"Lines/Colored Blended\" {" +
"SubShader {Tags { \"RenderType\"=\"Opaque\" } Pass { " +
"ZWrite On ZTest LEqual Cull Off Fog { Mode Off } " +
"BindChannels {" +
"Bind \"vertex\", vertex Bind \"color\", color }" +
"} } }");

I simply set the ZTest to the default LEqual (less or equal) turned on writing to the z buffer “ZWrite On” and changed the RenderType to “Opaque”

btw here’s the same shader with the @-string-syntax which allows multiline strings so it’s more readable:

lineMaterial = new Material(
@"Shader ""Lines/Colored Blended"" {
    SubShader {
        Tags { ""RenderType""=""Opaque"" }
        Pass {
            ZWrite On
            ZTest LEqual
            Cull Off
            Fog { Mode Off }
            BindChannels {
                Bind ""vertex"", vertex Bind ""color"", color
            }
        }
    }
}");