如何使用GL功能在Unity3D上显示纹理

Question

I tried to show an image to a GL.QUADS. But nothing but a black rect show on the screen. How can I fix it.

Here is my script code and I add the component to MainCamera.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public Material mat;
    void OnPostRender() {
        if (!mat) {
            Debug.LogError("Please Assign a material on the inspector");
            return;
        }
        GL.PushMatrix();
        mat.SetPass(1);
        GL.LoadOrtho();
        GL.Begin(GL.QUADS);
        GL.TexCoord2(0, 0);
        GL.Vertex3(0.25F, 0.25F, 0);
        GL.TexCoord2(0, 1);
        GL.Vertex3(0.25F, 0.75F, 0);
        GL.TexCoord2(1, 1);
        GL.Vertex3(0.75F, 0.75F, 0);
        GL.TexCoord2(1, 0);
        GL.Vertex3(0.75F, 0.25F, 0);
        GL.End();
        GL.PopMatrix();
    }
}

I created a custom material named 'CrossHairMaterial' using 'standard' shader:

Finally it showed a black rectangle.

Answer 1

Unity's GL API requires vertex shader to work. The default standard shader that is used when new material is created will not work because it's not a vertex shader.

Any vertex shader in Unity should also work.

First of all, change mat.SetPass(1); to mat.SetPass(0); .

These are the supported Shaders:

1 .Particles --> VertexLit Blended.

2 .Unlit-->Color

3 .Unlit-->Texture

4 .Unlit-->Transparent

Lagacy Shaders that should work:

5 .Legacy Shaders-->Transparent-->VertexLit.

6 .Legacy Shaders-->VertexLit.

I recommend you use #2 , #3 or #4 depending on if you need Texture or Transparency in the material.

Test with Unlit-->Texture: