Shader 实现位移、缩放、旋转

2023-05-23 | 分类游戏开发之unity 好好玩游戏 | 标签游戏 Unity URP Shader SubShader 外边框风格化渲染 PBR

unityShader简单示例——利用shader实现3d图像平移、缩放、旋转

在上面几篇关于外边框渲染的方案中，就有利用模型的缩放来实现外边框渲染的，对应可以理解缩放的实现和应用。在3D 游戏引擎中最基础的变换就是位移、旋转、缩放，下面分别再介绍一下

摘抄自上面的博客，做一个记录，方便后续随时查阅

Shader "Unlit/CustomChange(Blend)"
{
    Properties
    {
        _Translational("Translational", vector) = (0.0, 0.0, 0.0, 0.0)
        _Scale("Scale", vector) = (1.0, 1.0, 1.0, 1.0)
        _Rotation("Rotation", vector) = (0.0, 0.0, 0.0, 1.0)
    }
    SubShader
    {
        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            //uniform float _Transform;
            uniform float4 _Translational;
            uniform float4 _Scale;
            uniform float4 _Rotation;

            struct appdata
            {
                float4 vertex : POSITION;
            };

            struct v2f
            {
                float4 color:COLOR;
                float4 vertex : SV_POSITION;
            };

            //平移矩阵
            float4x4 Translational(float4 translational)
            {
                return float4x4(1.0, 0.0, 0.0, translational.x,
                                0.0, 1.0, 0.0, translational.y,
                                0.0, 0.0, 1.0, translational.z,
                                0.0, 0.0, 0.0, 1.0);
            }
            //缩放矩阵
            float4x4 Scale(float4 scale)
            {
                return float4x4(scale.x, 0.0, 0.0, 0.0,
                                0.0, scale.y, 0.0, 0.0,
                                0.0, 0.0, scale.z, 0.0,
                                0.0, 0.0, 0.0, 1.0);
            }
            //旋转矩阵
            float4x4 TRSBlend(float4 rotation)
            {
                float radX = radians(rotation.x);
                float radY = radians(rotation.y);
                float radZ = radians(rotation.z);
                float sinX = sin(radX);
                float cosX = cos(radX);
                float sinY = sin(radY);
                float cosY = cos(radY);
                float sinZ = sin(radZ);
                float cosZ = cos(radZ);
                float4x4 r= float4x4(cosY*cosZ, -cosY * sinZ, sinY, 0.0,
                                     cosX*sinZ + sinX * sinY*cosZ, cosX*cosZ - sinX * sinY*sinZ, -sinX * cosY, 0.0,
                                     sinX*sinZ - cosX * sinY*cosZ, sinX*cosZ + cosX * sinY*sinZ, cosX*cosY, 0.0,
                                     0.0, 0.0, 0.0, 1.0);
                float4x4 tr = mul(Translational(_Translational), r);
                return mul(tr, Scale(_Scale));
            }

            v2f vert(appdata v)
            {
                v2f o;
                //在模型空间计算
                v.vertex = mul(TRSBlend(_Rotation), v.vertex);
                o.vertex = UnityObjectToClipPos(v.vertex);//将坐标从模型空间转到裁切空间
                o.color = float4(1, 0, 0, 1);
                return o;
            }

            fixed4 frag(v2f i) : COLOR
            {
                return i.color;
            }
            
            ENDCG
        }
    }
}

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