Rendering textured quad with alpha using GL methods

Hi,

I'm trying to render a textured quad in OnRenderImage using GL methods. I've got a Material with this shader:

Code (csharp):

1. Shader "Custom/MarkerShader" {
2.     Properties {
3.         _Color ("Main Color", Color) = (1,1,1,1)
4.         _SpecColor ("Spec Color", Color) = (1,1,1,0)
5.         _Emission ("Emissive Color", Color) = (0,0,0,0)
6.         _Shininess ("Shininess", Range (0.1, 1)) = 0.7
7.         _MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
8.     }
9.  
10.     SubShader {
11.         Tags {"RenderType"="Transparent" "Queue"="Transparent"}
12.         // Render normally
13.         Pass {
14.             ZWrite Off
15.             Blend SrcAlpha OneMinusSrcAlpha
16.             ColorMask RGB
17.             Material {
18.                 Diffuse [_Color]
19.                 Ambient [_Color]
20.                 Shininess [_Shininess]
21.                 Specular [_SpecColor]
22.                 Emission [_Emission]
23.             }
24.             Lighting On
25.             SetTexture [_MainTex] {
26.                 Combine texture * primary DOUBLE, texture * primary
27.             }
28.         }
29.     }
30. }

In the inspector I set Main Color and Spec Color to (0,0,0,1), Emission to (0,1,0,1) and Shininess to 0. The texture is set to a png with alpha channel. I import the texture with "Alpha is Transparency" checked. In OnRenderImage, I first blit src to dst, then I try to draw the textured quad like this:

Code (csharp):

1.     Material mat = this.MarkerMaterial;
2.  
3.         GL.Color( Color.white );
4.  
5.         mat.SetPass( 0 );
6.  
7.         GL.PushMatrix();
8.         {
9.             GL.LoadOrtho();
10.             GL.LoadIdentity();
11.  
12.             pos.x *= ar;
13.             pos.y = 1.0f - pos.y;
14.             GL.MultMatrix( Matrix4x4.Scale( new Vector3( 1.0f / ar, 1.0f, 1.0f ) ) * Matrix4x4.TRS( pos, q, Vector3.one ) );
15.  
16.             GL.Begin( GL.QUADS );
17.             {
18.                 GL.Vertex3( -markerWidth, -markerHeight, 0.0f );
19.                 GL.Vertex3( -markerWidth, markerHeight, 0.0f );
20.                 GL.Vertex3( markerWidth, markerHeight, 0.0f );
21.                 GL.Vertex3( markerWidth, -markerHeight, 0.0f );
22.             }
23.             GL.End();
24.         }
25.         GL.PopMatrix();

When I try to render using the texture including alpha channel, I see nothing. When I replace it by another texture without alpha, it works.

Any ideas about what I'm doing wrong?

Thanks a lot.


<edit>
Now, that's embarrassing. When I switched from lines to quad I forgot that I now have to also set the uv coordinates. I was so distracted by all the ShaderLab syntax I'm not quite familiar with that I thought I must have made a mistake there somewhere.
</edit>

 

You need to assign texture coordinates before you submit a vertex. Use GL.TexCoord2(x, y); before each vertex.