Question

JavaScript => public static function Begin(mode: int): void;
C# => public static void Begin(int mode);

Parameters 参数

mode	Primitives to draw: can be TRIANGLES, TRIANGLE_STRIP, QUADS or LINES. 主绘制参数。

Description 描述

Begin drawing 3D primitives.

开始绘制3d图元。

In OpenGL this matches glBegin; on other graphics APIs the same functionality is emulated. Between GL.Begin and GL.End it is valid to call GL.Vertex, GL.Color, GL.TexCoord and other immediate mode drawing functions.

这和OpenGL中的glBegin函数一样。其它的图形API中也有类似的函数。在GL.Begin 和 GL.End之间放置GL操作函数。

You should be careful about culling when drawing primitives yourself. The culling rules may be different depending on which graphics API the game is running. In most cases the safest way is to use Cull Off command in the shader.

在用到裁剪函数时特别注意，这依赖于特定的图形API，不同的API裁剪方式不同。在多数情况下最好是用shader 中Cull Off命令。

See Also: GL.End.

JavaScript:

	// Draws a Triangle, a Quad and a line
	// with different colors
 
	var mat : Material;
	function OnPostRender() {
		if (!mat) {
			Debug.LogError("Please Assign a material on the inspector");
			return;
		}
		GL.PushMatrix();
		mat.SetPass(0);
		GL.LoadOrtho();
		GL.Begin(GL.TRIANGLES); // Triangle
		GL.Color(Color(1,1,1,1));
		GL.Vertex3(0.50,0.25,0);
		GL.Vertex3(0.25,0.25,0);
		GL.Vertex3(0.375,0.5,0);
		GL.End();
		GL.Begin(GL.QUADS); // Quad
		GL.Color(Color(0.5,0.5,0.5,1));
		GL.Vertex3(0.5,0.5,0);
		GL.Vertex3(0.5,0.75,0);
		GL.Vertex3(0.75,0.75,0);
		GL.Vertex3(0.75,0.5,0);
		GL.End();
		GL.Begin(GL.LINES); // Line
		GL.Color(Color(0,0,0,1));
		GL.Vertex3(0,0,0);
		GL.Vertex3(0.75,0.75,0);
		GL.End();
		GL.PopMatrix();
	}

C#:

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(0);
        GL.LoadOrtho();
        GL.Begin(GL.TRIANGLES);
        GL.Color(new Color(1, 1, 1, 1));
        GL.Vertex3(0.5F, 0.25F, 0);
        GL.Vertex3(0.25F, 0.25F, 0);
        GL.Vertex3(0.375F, 0.5F, 0);
        GL.End();
        GL.Begin(GL.QUADS);
        GL.Color(new Color(0.5F, 0.5F, 0.5F, 1));
        GL.Vertex3(0.5F, 0.5F, 0);
        GL.Vertex3(0.5F, 0.75F, 0);
        GL.Vertex3(0.75F, 0.75F, 0);
        GL.Vertex3(0.75F, 0.5F, 0);
        GL.End();
        GL.Begin(GL.LINES);
        GL.Color(new Color(0, 0, 0, 1));
        GL.Vertex3(0, 0, 0);
        GL.Vertex3(0.75F, 0.75F, 0);
        GL.End();
        GL.PopMatrix();
    }
}

GL