UGUI教程之-UGUI 实现刮刮卡橡皮擦

 

有个朋友问我怎么在Unity中使用 UGUI 实现刮刮卡功能,之前确实没有做过,但我想了下,应该使用 Shader 可以达到。于是花了点时间实现了下改功能。看下最终效果图

UGUI 实现刮刮卡

下面说下实现方式。

这里我主要使用到一个脚本和一个Shader。


Shader "Unlit/Transparent Colored Eraser"
{
Properties
{
_MainTex ("Base (RGB), Alpha (A)", 2D) = "white" {}
_RendTex ("Base (RGB), Alpha (A)", 2D) = "white" {}
}

SubShader
{
LOD 200

Tags
{
"Queue" = "Transparent"
"IgnoreProjector" = "True"
"RenderType" = "Transparent"
}

Pass
{
Cull Off
Lighting Off
ZWrite Off
Fog { Mode Off }
Offset -1, -1
ColorMask RGB
AlphaTest Greater .01
Blend SrcAlpha OneMinusSrcAlpha
ColorMaterial AmbientAndDiffuse

CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"

sampler2D _MainTex;
float4 _MainTex_ST;
sampler2D _RendTex;

struct appdata_t
{
float4 vertex : POSITION;
half4 color : COLOR;
float2 texcoord : TEXCOORD0;
};

struct v2f
{
float4 vertex : POSITION;
half4 color : COLOR;
float2 texcoord : TEXCOORD0;
};

v2f vert (appdata_t v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
o.color = v.color;
o.texcoord = v.texcoord;
return o;
}

half4 frag (v2f IN) : COLOR
{
// Sample the texture
half4 col = tex2D(_MainTex, IN.texcoord) * IN.color;
half4 rnd = tex2D(_RendTex, IN.texcoord) * IN.color;
col.a =  rnd.a;
return col;
}
ENDCG
}
}
}

另一个脚本


using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using System.Collections;

public class UIEraserTexture : MonoBehaviour ,IPointerDownHandler,IPointerUpHandler{

public  RawImage image;
public  int brushScale = 4;

Texture2D texRender;
RectTransform mRectTransform;
Canvas canvas;

void Awake(){
mRectTransform = GetComponent<RectTransform> ();
canvas = GameObject.Find("Canvas").GetComponent<Canvas>();
}

void Start () {

texRender = new Texture2D(image.mainTexture.width, image.mainTexture.height,TextureFormat.ARGB32,true);

Reset ();

}

bool isMove = false;

public void OnPointerDown(PointerEventData data){
Debug.Log ("OnPointerDown..."+data.position);
start = ConvertSceneToUI (data.position);
isMove = true;
}

public void OnPointerUp(PointerEventData data){
isMove = false;
Debug.Log ("OnPointerUp..."+data.position);
OnMouseMove (data.position);
start = Vector2.zero;
}

void Update(){
if (isMove) {
OnMouseMove (Input.mousePosition);
}
}

Vector2 start = Vector2.zero;
Vector2 end = Vector2.zero;

Vector2 ConvertSceneToUI(Vector3 posi){
Vector2 postion;
if(RectTransformUtility.ScreenPointToLocalPointInRectangle(mRectTransform , posi, canvas.worldCamera, out postion)){
return postion;
}
return Vector2.zero;
}

void OnMouseMove(Vector2 position)
{

end = ConvertSceneToUI (position);

Draw (new Rect (end.x+texRender.width/2, end.y+texRender.height/2, brushScale, brushScale));

if (start.Equals (Vector2.zero)) {
return;
}

Rect disract = new Rect ((start+end).x/2+texRender.width/2, (start+end).y/2+texRender.height/2, Mathf.Abs (end.x-start.x), Mathf.Abs (end.y-start.y));

for (int x = (int)disract.xMin; x < (int)disract.xMax; x++) {
for (int y = (int)disract.yMin; y < (int)disract.yMax; y++) {
Draw (new Rect (x, y, brushScale, brushScale));
}
}

start = end;
}

void Reset(){

for (int i = 0; i < texRender.width; i++) {

for (int j = 0; j < texRender.height; j++) {

Color color = texRender.GetPixel (i,j);
color.a = 1;
texRender.SetPixel (i,j,color);
}
}

texRender.Apply ();
image.material.SetTexture ("_RendTex",texRender);

}

void Draw(Rect rect){

for (int x = (int)rect.xMin; x < (int)rect.xMax; x++) {
for (int y = (int)rect.yMin; y < (int)rect.yMax; y++) {
if (x < 0 || x > texRender.width || y < 0 || y > texRender.height) {
return;
}
Color color = texRender.GetPixel (x,y);
color.a = 0;
texRender.SetPixel (x,y,color);
}
}

texRender.Apply();
image.material.SetTexture ("_RendTex",texRender);
}

}

怎么使用请看效果图哦。

UGUI 实现刮刮卡

 

UGUI 实现刮刮卡

 

 

 

自己PS一张遮挡图吧,我随便P的。

UGUI 实现刮刮卡

 

新建一个材质球,给他选择上面的Shader,可以不需给它预设纹理,等下在脚本里赋予。 挂在UGUI的Image上,脚本也挂在Image上面,RawImage和Image随便吧,我没试过。大家可以试下。