几何变换_屏幕范围检测

Shader "Unlit/V2f34"
{
    SubShader{
            pass{
                
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            struct a2v
            {
                 float4 vertex : POSITION;
            };


            struct v2f {                
                float4 pos:POSITION;
                float4 color:COLOR;
            };          

            v2f vert(appdata_base v )
                {
                    v2f o;

                    o.pos= UnityObjectToClipPos(v.vertex);      
                    float x= o.pos.x / o.pos.w;

                        if(x<-1)

                            o.color=fixed4(1,0,0,1);
                        else if(x>1)
                            o.color=fixed4(0,0,1,1);
                        else
                            o.color = fixed4(x/2+0.5,x/2+0.5,x/2+0.5,1);

                    return o; 
                }   

            fixed frag(v2f i):SV_TARGET
                {
                    return i.color;
                }
            ENDCG
            }
    }
    
}