Point Sprite

Hi everyone,

Actually I'm doing some sort of particle simulation using DirectCompute. In order to use the same buffer for both rendering and processing, I'm using the command Graphics.DrawProcedural(...).

However, I'm facing a problem. I have a HLSL code that can render a sphere from a point. For this to work, the Texture Coordinate must be generated automatically (setting D3DRS_POINTSPRITEENABLE = true). I'm lost where I issue this command using Unity. I've tried to submit a texture coordinate for each vertex but they are not interpolated in the pixel shader. Here is my code:

Code (CSharp):

1. Shader "Custom/Point"
2. {
3.     Properties
4.     {
5.         _PointSize("Point Size", Float) = 5.0
6.         _Radius("Radius", Float) = 5.0
7.     }
8.     SubShader {
9.  
10.         Pass {
11.             Tags { "RenderType"="Opaque" }
12.             LOD 200
13.  
14.  
15.             CGPROGRAM
16.             #pragma vertex vert
17.             #pragma fragment frag
18.             #include "UnityCG.cginc"
19.  
20.  
21.             uniform float _PointSize = 5.0;
22.             uniform float _Radius = 5.0;
23.  
24.  
25.             StructuredBuffer<float4> positions;
26.             StructuredBuffer<float4> colors;
27.             StructuredBuffer<float2> texCoord;
28.            
29.  
30.             struct VertexOutput {
31.                 float4 pos : SV_POSITION;
32.                 float4 col : COLOR;
33.                 float size : PSIZE;
34.                 float2 texCoord : TEXCOORD0;
35.             };
36.  
37.  
38.  
39.             VertexOutput vert(uint id : SV_VertexID, uint inst : SV_InstanceID)
40.             {
41.                 VertexOutput o;
42.                 float3 p = positions[id];
43.                 float dist = length(posEye);
44.                 o.size =_Radius * (_PointSize / dist);
45.                 o.pos = UnityObjectToClipPos(p);
46.                
47.                 o.col = colors[id];
48.                 o.texCoord = texCoord[id];
49.                
50.  
51.                 return o;
52.             }
53.  
54.             float4 frag(VertexOutput o) : SV_Target
55.             {
56.                 return float4(o.texCoord.xy, 0, 1);
57.             }
58.             ENDCG
59.         }
60.     }
61.     FallBack "Diffuse"
62. }
63.  

I'm just output the texcoord as a color but they are all black.
Please, do you have any ideia how to perform it?

Thanks.