Unity&Shader基础篇-绘制网格+圆盘

时间:2023-02-06 22:15:02

一、前言

尊重原创,转载请注明出处凯尔八阿哥专栏

上一章点击打开链接中已经画出了一个棋盘网格,首先来完善一下这个画网格的Shader,添加属性,属性包括网格的线的宽度,网格的颜色等。代码如下:

Shader "Unlit/Chapter2-2"
{
Properties
{
_backgroundColor("面板背景色",Color) = (1.0,1.0,1.0,1.0)
_axesColor("坐标轴的颜色",Color) = (0.0,0.0,1.0)
_gridColor("网格的颜色",Color) = (0.5,0.5,0.5)
_tickWidth("网格的密集程度",Range(0.1,1))=0.1
_gridWidth("网格的宽度",Range(0.0001,0.01))=0.008
_axesXWidth("x轴的宽度",Range(0.0001,0.01))=0.006
_axesYWidth("y轴的宽度",Range(0.0001,0.01))=0.007
}
SubShader
{
//去掉遮挡和深度缓冲
Cull Off
ZWrite Off
//开启深度测试
ZTest Always

CGINCLUDE
//添加一个计算方法
float mod(float a,float b)
{
//floor(x)方法是Cg语言内置的方法,返回小于x的最大的整数
return a - b*floor(a / b);
}
ENDCG

Pass
{
CGPROGRAM
//敲代码的时候要注意:“CGPROGRAM”和“#pragma...”中的拼写不同,真不知道“pragma”是什么单词
#pragma vertex vert
#pragma fragment frag

#include "UnityCG.cginc"

uniform float4 _backgroundColor;
uniform float4 _axesColor;
uniform float4 _gridColor;
uniform float _tickWidth;
uniform float _gridWidth;
uniform float _axesXWidth;
uniform float _axesYWidth;

struct appdata
{
float4 vertex:POSITION;
float2 uv:TEXCOORD0;
};
struct v2f
{
float2 uv:TEXCOORD0;
float4 vertex:SV_POSITION;
};
v2f vert(appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP,v.vertex);
o.uv = v.uv;
return o;
}

fixed4 frag(v2f i) :SV_Target
{
//将坐标的中心从左下角移动到网格的中心
fixed2 r = 2.0*fixed2(i.uv.x - 0.5,i.uv.y - 0.5);
fixed3 backgroundColor = _backgroundColor.xyz;
fixed3 axesColor = _axesColor.xyz;
fixed3 gridColor = _gridColor.xyz;

fixed3 pixel = backgroundColor;

//定义网格的的宽度
const float tickWidth = _tickWidth;
if (mod(r.x, tickWidth) < _gridWidth)
{
pixel = gridColor;
}
if (mod(r.y, tickWidth) < _gridWidth)
{
pixel = gridColor;
}

//画两个坐标轴
if (abs(r.x) < _axesXWidth)
{
pixel = axesColor;
}
if (abs(r.y) < _axesYWidth)
{
pixel = axesColor;
}

return fixed4(pixel, 1.0);
}
ENDCG
}

}

}

通过以下代码将网格的轴心移动到中心位置

fixed2 r = 2.0*fixed2(i.uv.x - 0.5,i.uv.y - 0.5);
效果图如图所示:

Unity&Shader基础篇-绘制网格+圆盘

二、画一个圆盘

原理:圆的方程为(x-a)^2+(y-b)^2=r^2,根据方程即可以添加如下方法来计算预定圆盘的颜色值信息

//添加第二个计算方法,根据半径,原点、原点的偏移量r和颜色来绘制圆盘
fixed3 disk(fixed2 r,fixed2 center,fixed radius,fixed3 color,fixed3 pixel)
{
fixed3 col=pixel;
if (length(r - center) < radius)
{
col = color;
}
return col;
}
效果如图所示:

Unity&Shader基础篇-绘制网格+圆盘 完整的代码如下:
Shader "Unlit/Chapter3-2"
{
Properties
{
_backgroundColor("面板背景色",Color) = (1.0,1.0,1.0,1.0)
_col1("圆盘1的颜色",Color) = (0.216, 0.471, 0.698) // blue
_col2("圆盘2的颜色",Color) = (1.00, 0.329, 0.298) // red
_col3("圆盘3的颜色",Color) = (0.867, 0.910, 0.247) // yellow

_center2X("第三个圆盘的原点X的位置",Range(0.0,1.0)) = 0.9
_center2Y("第三个圆盘的原点Y的位置",Range(0.0,1.0)) = -0.4

_radius1("第一个圆盘的半径",Range(0.1,1)) = 0.8
_radius2("第二个圆盘的半径", Range(0.1, 1)) = 0.3
_radius3("第三个圆盘的半径", Range(0.1, 1)) = 0.6

}
SubShader
{
//去掉遮挡和深度缓冲
Cull Off
ZWrite Off
//开启深度测试
ZTest Always

CGINCLUDE
//添加一个计算方法
float mod(float a,float b)
{
//floor(x)方法是Cg语言内置的方法,返回小于x的最大的整数
return a - b*floor(a / b);
}

//添加第二个计算方法,根据半径,原点、原点的偏移量r和颜色来绘制圆盘
fixed3 disk(fixed2 r,fixed2 center,fixed radius,fixed3 color,fixed3 pixel)
{
fixed3 col=pixel;
if (length(r - center) < radius)
{
col = color;
}
return col;
}
ENDCG

Pass
{
CGPROGRAM
//敲代码的时候要注意:“CGPROGRAM”和“#pragma...”中的拼写不同,真不知道“pragma”是什么单词
#pragma vertex vert
#pragma fragment frag

#include "UnityCG.cginc"

uniform float4 _backgroundColor;
uniform float4 _col1;
uniform float4 _col2;
uniform float4 _col3;
uniform float _radius1;
uniform float _radius2;
uniform float _radius3;
uniform float _center2X;
uniform float _center2Y;

struct appdata
{
float4 vertex:POSITION;
float2 uv:TEXCOORD0;
};
struct v2f
{
float2 uv:TEXCOORD0;
float4 vertex:SV_POSITION;
};
v2f vert(appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP,v.vertex);
o.uv = v.uv;
return o;
}

fixed4 frag(v2f i) :SV_Target
{
float2 r = 2.0*(i.uv - 0.5);
float aspectRatio = _ScreenParams.x / _ScreenParams.y;
r.x *= aspectRatio;

fixed3 backgroundColor = _backgroundColor.xyz;
fixed3 col1 = _col1.xyz;
fixed3 col2 = _col2.xyz;
fixed3 col3 = _col3.xyz;

fixed3 pixel = _backgroundColor;

//画第一个圆盘
pixel = disk(r,fixed2(0.1,0.3), _radius1,col3,pixel);
//画第二个圆盘
pixel= disk(r, fixed2(_center2X, _center2Y), _radius2, col2, pixel);
//画第三个圆盘
pixel= disk(r, fixed2(-0.8, 0.6), _radius3, col1, pixel);
return fixed4(pixel, 1.0);
}

ENDCG
}

}

}

三、在网格中绘制圆盘

1、根据2中绘制圆盘的原理,只要将a和b通过C#代码传递参数给Shader来控制即可,这个参数就是鼠标点击时候的坐标位置。当然这个位置要经过计算才能应用到网格坐标中,网格坐标的范围为-1~1,通过代码来转换:
void Update () {

if(Input.GetMouseButtonDown(0))
{
vec_mouseBtnPos = Input.mousePosition;

//将鼠标的位置除以屏幕参数得到范围为0~1的坐标范围
vec_mouseBtnPos = new Vector2(vec_mouseBtnPos.x / Screen.width, vec_mouseBtnPos.y / Screen.height);
//设定坐标原点为中点
vec_mouseBtnPos -= new Vector2(0.5f,0.5f);
vec_mouseBtnPos *= 2;
vec_mouseBtnPos.y = -vec_mouseBtnPos.y;}
基本上和Shader代码中的计算方法相同,得到的效果图如图所示:
Unity&Shader基础篇-绘制网格+圆盘2、将点固定在网格交叉点上 看到这里,各位看官你会想到我要做一个什么?哈哈,没错就是一个五子棋,用Shader来写一个五子棋,想想都很激动。好,回归正题,有了上一步的基础,现在我们只需要将鼠标点击的点和附近网格交叉点之间做一个判断,看看是否达到了阈值范围内,如果是,就让这个红色点固定绘制在这个交叉点上。完整的代码如下:
using UnityEngine;
using System.Collections;
using System.Collections.Generic;

/// <summary>
/// 这个脚本实现的点击单个点的效果
/// </summary>
public class GameControl : MonoBehaviour {
public Material mat;
//设置点中的最小误差
public float clickMinError;

//网格点的坐标集
private List<Vector2> list_gridIntersectionPos = new List<Vector2>();

//网格点的数量
private int gridIntersectionNums;
private float gridSpace;
private Vector2 vec_mouseBtnPos;
// Use this for initialization
void Start()
{

gridSpace = mat.GetFloat("_tickWidth");

//单个坐标轴上网格点的数量等于横轴坐标间距除以网格间距
gridIntersectionNums = (int)Mathf.Floor(1.0f / gridSpace); //这里不能只用强制类型转换,如果使用强制类型转换会丢失数据,比如1.0/0.1最后的结果是9

for (int i = -gridIntersectionNums; i <= gridIntersectionNums; i++)
{
float x = gridSpace * i;


for (int j = -gridIntersectionNums; j <= gridIntersectionNums; j++)
{
float y = gridSpace * j;
list_gridIntersectionPos.Add(new Vector2(x, y));

}

}
}

// Update is called once per frame
void Update () {

if(Input.GetMouseButtonDown(0))
{
vec_mouseBtnPos = Input.mousePosition;

//将鼠标的位置除以屏幕参数得到范围为0~1的坐标范围
vec_mouseBtnPos = new Vector2(vec_mouseBtnPos.x / Screen.width, vec_mouseBtnPos.y / Screen.height);
//设定坐标原点为中点
vec_mouseBtnPos -= new Vector2(0.5f,0.5f);
vec_mouseBtnPos *= 2;
vec_mouseBtnPos.y = -vec_mouseBtnPos.y;

/* mat.SetFloat("_MouseBtnPosX", vec_mouseBtnPos.x);
mat.SetFloat("_MouseBtnPosY", vec_mouseBtnPos.y);*/
//如果点中了网格的交叉点出就显示圆点
int index = CheckClikedIntersection(vec_mouseBtnPos);
if (index != -1)
{
//将准确的网格点的位置赋值给vec_mouseBtnPos
vec_mouseBtnPos = list_gridIntersectionPos[index];
mat.SetFloat("_MouseBtnPosX", vec_mouseBtnPos.x);
mat.SetFloat("_MouseBtnPosY", vec_mouseBtnPos.y);
}
Debug.Log("x:" + vec_mouseBtnPos.x + "y:" + vec_mouseBtnPos.y);


}

}
/// <summary>
/// 判断鼠标点中的地方是否在网格的交叉点处
/// </summary>
/// <param name="vec2"></param>
/// <returns></returns>
private int CheckClikedIntersection(Vector2 vec2)
{
int clickIndex = -1;
for (int i = 0; i < list_gridIntersectionPos.Count; i++)
{
float errorx = Mathf.Abs(vec2.x- list_gridIntersectionPos[i].x);
float errory = Mathf.Abs(vec2.y - list_gridIntersectionPos[i].y);
//如果误差的值小于预设的值则判定点中了
float error = Mathf.Sqrt(errorx * errorx + errory * errory);
if(error<clickMinError)
{
clickIndex = i;
break;
}
}
return clickIndex;
}
}
这里使用了“CheckClikedIntersection”方法来进行判断和校正,并设置了一个最小误差“clickMinError”。
效果图如图所示: Unity&Shader基础篇-绘制网格+圆盘3、完整的Shader代码如下:
Shader "Unlit/Backgammon"
{
Properties
{
_backgroundColor("面板背景色",Color) = (1.0,1.0,1.0,1.0)
_axesColor("坐标轴的颜色",Color) = (0.0,0.0,1.0)
_gridColor("网格的颜色",Color) = (0.5,0.5,0.5)
_tickWidth("网格的间距",Range(0.1,1)) = 0.1
_gridWidth("网格的宽度",Range(0.0001,0.01)) = 0.008
_axesXWidth("x轴的宽度",Range(0.0001,0.01)) = 0.006
_axesYWidth("y轴的宽度",Range(0.0001,0.01)) = 0.007
_MouseBtnPosX("鼠标点击的X方向位置",float) = 0.0
_MouseBtnPosY("鼠标点击的Y方向位置",float) = 0.0
_MouseBtnRadius("鼠标点中位置圆盘的半径",float) = 0.001
_MouseDownColor("鼠标点中的颜色",Color) = (1.00, 0.329, 0.298,1.0)
}
SubShader
{
//去掉遮挡和深度缓冲
Cull Off
ZWrite Off
//开启深度测试
ZTest Always

CGINCLUDE
//添加一个计算方法
float mod(float a,float b)
{
//floor(x)方法是Cg语言内置的方法,返回小于x的最大的整数
return a - b*floor(a / b);
}

//添加第二个计算方法,根据半径,原点和颜色来绘制圆盘
fixed3 disk(fixed2 r,fixed2 center,fixed radius,fixed3 color,fixed3 pixel)
{
fixed3 col = pixel;
if (length(r - center) < radius)
{
col = color;
}
return col;
}
ENDCG

Pass
{
CGPROGRAM
//敲代码的时候要注意:“CGPROGRAM”和“#pragma...”中的拼写不同,真不知道“pragma”是什么单词
#pragma vertex vert
#pragma fragment frag

#include "UnityCG.cginc"

uniform float4 _backgroundColor;
uniform float4 _axesColor;
uniform float4 _gridColor;
uniform float _tickWidth;
uniform float _gridWidth;
uniform float _axesXWidth;
uniform float _axesYWidth;

uniform float _MouseBtnPosX;
uniform float _MouseBtnPosY;
uniform float _MouseBtnRadius;
uniform float4 _MouseDownColor;


struct appdata
{
float4 vertex:POSITION;
float2 uv:TEXCOORD0;
};
struct v2f
{
float2 uv:TEXCOORD0;
float4 vertex:SV_POSITION;
};
v2f vert(appdata v)
{
v2f o;
o.vertex = mul(UNITY_MATRIX_MVP,v.vertex);
o.uv = v.uv;
return o;
}

fixed4 frag(v2f i) :SV_Target
{
//将坐标的中心从左下角移动到网格的中心
float2 r = 2.0*(i.uv - 0.5);
float aspectRatio = _ScreenParams.x / _ScreenParams.y;
//r.x *= aspectRatio;
fixed3 backgroundColor = _backgroundColor.xyz;
fixed3 axesColor = _axesColor.xyz;
fixed3 gridColor = _gridColor.xyz;

fixed3 pixel = backgroundColor;

//定义网格的的间距
const float tickWidth = _tickWidth;
if (mod(r.x, tickWidth) < _gridWidth)
{
pixel = gridColor;
}
if (mod(r.y, tickWidth) < _gridWidth)
{
pixel = gridColor;
}

//画两个坐标轴
if (abs(r.x) < _axesXWidth)
{
pixel = axesColor;
}
if (abs(r.y) < _axesYWidth)
{
pixel = axesColor;
}


//画一个点
pixel = disk(r, fixed2(_MouseBtnPosX, _MouseBtnPosY), _MouseBtnRadius, _MouseDownColor, pixel);
return fixed4(pixel, 1.0);
}
ENDCG
}

}

}
代码中添加了用来接收C#脚本传递的鼠标点击的位置
“uniform float _MouseBtnPosX;uniform float_MouseBtnPosY;” 到了这一步还是不能说可以完整的做出一个五子棋,因为现在只能画一个点,当然你可以通过在Shader代码中增加画点的代码来实现画多个点,然而并不能达到我们理想的状况。下一节将会给出一个技巧来实现C#脚本怎么向Shader中传数组来实现Shader代码画多个点。 附上本节的工程下载地址百度网盘工程下载地址,使用的是Unity5.3.3版本