Unity实现在3D模型上涂鸦

http://docs.unity3d.com/ScriptReference/GL.html

Paste_Image.png

using System.Collections.Generic;using UnityEngine;using UnityEngine.EventSystems;public class DrawOnModel : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler{    public Color color = Color.red;    public float thickness = 0.02f;    private List<Vector3> points = new List<Vector3>();    private List<Vector3> normals = new List<Vector3>();    private List<int> splits = new List<int>();//分割索引    static Material lineMaterial;    static void CreateLineMaterial()    {        if (!lineMaterial)        {            // Unity has a built-in shader that is useful for drawing            // simple colored things.            var shader = Shader.Find("Hidden/Internal-Colored");            lineMaterial = new Material(shader);            lineMaterial.hideFlags = HideFlags.HideAndDontSave;            // Turn on alpha blending            lineMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.SrcAlpha);            lineMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.OneMinusSrcAlpha);            // Turn backface culling off            lineMaterial.SetInt("_Cull", (int)UnityEngine.Rendering.CullMode.Off);            // Turn off depth writes            lineMaterial.SetInt("_ZWrite", 0);        }    }    public void OnRenderObject()    {        CreateLineMaterial();        lineMaterial.SetPass(0);        GL.PushMatrix();        GL.MultMatrix(transform.localToWorldMatrix);        GL.Begin(GL.LINES);        int index = 0;        for(int i=1; i<points.Count; i++)        {            if (index < splits.Count && i == splits[index])            {                index++;                continue;            }            GL.Color(color);            var from = points[i-1] + normals[i-1] * thickness;            GL.Vertex3(from.x, from.y, from.z);            var worldNormal = transform.TransformDirection(normals[i]);            var to = points[i] + worldNormal * thickness;            GL.Vertex3(to.x, to.y, to.z);        }        GL.End();        GL.PopMatrix();    }    public void OnBeginDrag(PointerEventData eventData)    {    }    public void OnDrag(PointerEventData eventData)    {        if (!eventData.pointerCurrentRaycast.isValid)        {            SplitPoints();            return;        }        var localPosition = transform.InverseTransformPoint(eventData.pointerCurrentRaycast.worldPosition);        points.Add(localPosition);        var localNormal = transform.InverseTransformDirection(eventData.pointerCurrentRaycast.worldNormal);        normals.Add(localNormal);    }    public void OnEndDrag(PointerEventData eventData)    {        SplitPoints();    }    void SplitPoints()    {        if (splits.Count == 0 && points.Count != 0 || splits[splits.Count - 1] != points.Count)            splits.Add(points.Count);    }}