Unity4 point sprite texture coordinates

Unity Engine
1

In unity 4 now possible to draw a mesh as multiple dots.
If I create a mesh like this:

using UnityEngine;
    
    public class NewBehaviourScript : MonoBehaviour
    {
        public int number = 100;
    
    	[ContextMenu("crate mesh")]
    	void CrateMesh()
    	{
    	    if (number<=0)
    	    {
    	        return;
    	    }
    
    	    MeshFilter filter = GetComponent<MeshFilter>();
    
            Vector3[] vertexes = new Vector3[number];
            //Vector2[] texCoods = new Vector2[number];
            int[] indexes;
            Mesh mesh = new Mesh();
    
            //for (int i = 0; i < texCoods.Length; i++)//it's do nothing
            //    texCoods[i] = Vector2.one*0.5f;
    
    	    int vInd = 0;
    
            for (int x = 0; x < (int)Mathf.Sqrt(vertexes.Length); x++)
    	    {
                for (int y = 0; y < (int)Mathf.Sqrt(vertexes.Length); y++)
    	        {
                    vertexes[vInd] = new Vector3(x,0,y);
    	            ++vInd;
    	        }
    	    }
    
    
    	    indexes = new int[vertexes.Length];
    
    	    for (int i = 0; i < vertexes.Length; i++)
    	        indexes[i] = i;
    
    
    	    filter.mesh.Clear();
    
    	    mesh.vertices = vertexes;
    	    //mesh.uv = texCoods;
            mesh.SetIndices(indexes, MeshTopology.Points, 0);
    
    	    filter.mesh = mesh;
    	}
    }

And then render it with shader, which is used semantics PSIZE to size:

Shader "Point sprite"
    {
    
    Properties
    {
    	_MainTex ("Texture Image", 2D) = "white" {}
    	_PointSize("PointSize", Float) = 10
    }
    
    SubShader
    	{
    		Pass
    		{
    			CGPROGRAM
    			#pragma vertex vert
    			#pragma fragment frag
    			#include "UnityCG.cginc"
    
    			struct v2f
    			{
    				float4 pos : SV_POSITION;
    				half size:PSIZE;
    				half2 texcoord : TEXCOORD0;
    			};
    
    			half _PointSize;
    			sampler2D _MainTex;
    
    			v2f vert (appdata_base v)
    			{
    				v2f o;
    				o.pos = mul (UNITY_MATRIX_MVP, v.vertex);
    				o.size = _PointSize;
    				o.texcoord = v.texcoord;
    				return o;
    			}
    
    
    			half4 frag (v2f i) : COLOR
    			{
    				half4 c = tex2D(_MainTex,i.texcoord);
    				return c;
    			}
    
    			ENDCG
    
    		}
    	}
    }

I get the point sprites, but they do not have the texture coordinates.

What am I doing wrong, how to assign texture coordinates for the mesh, or calculate them in the shader?

English is not my native language, sorry for the mistakes.
Thank you!

2

Just guessing, is it required that you call mesh.Triangles= in order to set the indices? I’m not familiar with the SetIndices thing or how it’s different, but a mesh creation usually ends with setting triangles.

3

Each point in the indices is the square on the screen. The scripting reference said the following:<<SetTriangles and ::triangles always make the mesh be composed of triangles faces. Using SetIndices you can create a mesh that’s made out of lines or points, see MeshTopology enum. >>

4

Not in Unity 4; you can do quads/points/lines.

–Eric

5

up

6

Ok, I have the same problem. I’m rendering points and would like to use texture coordinates automatically generated by the hardware after the vertex shader. In OpenGL/GLSL one would simply use the build-in fragment shader input gl_PointCoord. What is the Unity/Cg equivalent of that?

Edit: I have created a new thread in the shader forum. I think it’s more likely to get an answer there.

7

I can’t get PSIZE to work on my mac, am I missing something?
Shader compiles, no warning, all points size 1.

8

Did you ever specify UV coordinates for the vertices? I don’t see it in your code…

There should be another array of Vector2[ ] assigned to mesh.uv, and filled with appropriate texture coordinates.

I’d definitely like to see if this works.

9

@rsodre: did you figure out the problem? i’m also on a mac and no matter what i set for PSIZE, the sprites are the same size!

10

I already reported this bug, unity know about it. This is usually some form of driver issue: with point sprites you cannot guarantee they are able to be bigger than a single pixel on a given driver and gpu.

You should use your own quad based system in situations like that. There’s no guarantee it will be fixed in a way that will work as expected on all platforms.

11

Hi hippocoder,
thanks for the answer. What do you mean with quad based system? Are you suggesting to make a mesh built out of quads?
I’m quite new to shaders, so if you could get into a bit more detail, I would highly appreciate it!
Thanks