GL.MultiTexCoord3

Description

Sets current texture coordinate (x,y,z) to the actual texture unit.

In OpenGL this matches glMultiTexCoord for the given texture unit if multi-texturing is available. On other graphics APIs the same functionality is emulated.

The Z component is used only when:
1. You access a cubemap (which you access with a vector coordinate, hence x,y & z).
2. You do "projective texturing", where the X & Y coordinates are divided by Z to get the final coordinate. This would be mostly useful for water reflections and similar things.

This function can only be called between GL.Begin and GL.End functions.

    // Changes between two textures assigned to a material
    // When pressed space
    var mat : Material;
    private var flagTex : boolean = true;
    function Update() {
        if (Input.GetKeyDown(KeyCode.Space)) {
            if(flagTex) {
                flagTex = false;
            } else {
                flagTex = true;
            }
        }
    }

    function OnPostRender() {
        if (!mat) {
            Debug.LogError("Please Assign a material on the inspector");
            return;
        }
        GL.PushMatrix();
        mat.SetPass(1);
        GL.LoadOrtho();
        GL.Begin(GL.QUADS);
        if (flagTex) {
            GL.MultiTexCoord3(0,0,0,0); // main texture
        } else {
            GL.MultiTexCoord3(1,0,0,0); // second texture
        }
        GL.Vertex3(0.25,0.25,0);
        if (flagTex) {
            GL.MultiTexCoord3(0,0,1,0);
        } else {
            GL.MultiTexCoord3(1,0,1,0);
        }
        GL.Vertex3(0.25,0.75,0);
        if (flagTex) {
            GL.MultiTexCoord3(0,1,1,0);
        } else {
            GL.MultiTexCoord3(1,1,1,0);
        }
        GL.Vertex3(0.75,0.75,0);
        if (flagTex) {
            GL.MultiTexCoord3(0,1,0,0);
        } else {
            GL.MultiTexCoord3(1,1,0,0);
        }
        GL.Vertex3(0.75,0.25,0);
        GL.End();
        GL.PopMatrix();
    }

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public Material mat;
    private bool flagTex = true;
    void Update() {
        if (Input.GetKeyDown(KeyCode.Space))
            if (flagTex)
                flagTex = false;
            else
                flagTex = true;
        
    }
    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);
        if (flagTex)
            GL.MultiTexCoord3(0, 0, 0, 0);
        else
            GL.MultiTexCoord3(1, 0, 0, 0);
        GL.Vertex3(0.25F, 0.25F, 0);
        if (flagTex)
            GL.MultiTexCoord3(0, 0, 1, 0);
        else
            GL.MultiTexCoord3(1, 0, 1, 0);
        GL.Vertex3(0.25F, 0.75F, 0);
        if (flagTex)
            GL.MultiTexCoord3(0, 1, 1, 0);
        else
            GL.MultiTexCoord3(1, 1, 1, 0);
        GL.Vertex3(0.75F, 0.75F, 0);
        if (flagTex)
            GL.MultiTexCoord3(0, 1, 0, 0);
        else
            GL.MultiTexCoord3(1, 1, 0, 0);
        GL.Vertex3(0.75F, 0.25F, 0);
        GL.End();
        GL.PopMatrix();
    }
}