[002-Déplacement du shader-vertex]

// 顶点位移
Shader "Study/ImageShader2"
{
    
    
    Properties
    {
    
    
        _MainTex ("Texture", 2D) = "white" {
    
    }
    }
    SubShader
    {
    
    
        // No culling or depth
        Cull Off ZWrite Off ZTest Always
        Blend SrcAlpha OneMinusSrcAlpha

        Pass
        {
    
    
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"

            struct appdata
            {
    
    
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
    
    
                float2 uv : TEXCOORD0;
                float4 vertex : SV_POSITION;
            };

            /**
            坐标转换
            local(object) -> world -> camera(view) -> screen(project)
            vector(x,y,z,w)

            局部到全局 world = o2w_mat * local
            世界到相机 camera = w2c_mat * world
            相机到屏幕 screen = c2s_mat * camera

            UnityObjectToClipPos：已经完成了 local-> screen 的转换

            mul(UNITY_MATRIX_MVP,v.vertex) = UnityObjectToClipPos(v.vertex) MVP: M-局部到全局 V:世界到相机 P:相机到屏幕

            M =  mul(unity_ObjectToWorld,v.vertex)

            // 位置矩阵
            // 百度左手坐标系坐标变换
            float4x4 = {
    
    
                1,0,0,x,
                0,1,0,y,
                0,0,1,z,
                0,0,0,1
            }
            // 缩放 -> 旋转 -> 平移
            float4x4 = {
    
    
                _Scale.x,0,0,_Position.x,
                0,_Scale.y,0,_Position.y,
                0,0,_Scale.z,_Position.z,
                0,0,0,1
            }

            **/
            v2f vert (appdata v)
            {
    
    
                // 在这些坐标变换
                v2f o;

                // o.vertex = UnityObjectToClipPos(v.vertex);
                // o.vertex = mul(UNITY_MATRIX_MVP,v.vertex);

                float4 worldPos = mul(unity_ObjectToWorld,v.vertex);
                o.vertex = mul(UNITY_MATRIX_VP,worldPos);



                o.uv = v.uv;
                return o;
            }

            sampler2D _MainTex;

            fixed4 frag (v2f i) : SV_Target
            {
    
    
                fixed4 col = tex2D(_MainTex, i.uv);
                // just invert the colors
                // col.rgb = 1 - col.rgb;
                return col;
            }
            ENDCG
        }
    }
    Fallback "Sprites/Default"
}