Shader "Hide/HIDE_DrawTex"
{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
        _MainColor ("Color", Color) = (1,1,1,1)
    }
    SubShader
    {
        
        Tags { 
            "RenderType"="Transparent"
            "RenderPipeline" = "UniversalPipeline"
        }

        Pass
        {
            Name "DrawTex"
            Cull Off
            ZTest Off
            ZClip Off
            ZWrite Off
            // BlendOp Multiply
            Blend SrcAlpha DstColor
            HLSLPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #include "Packages/com.unity.render-pipelines.universal/ShaderLibrary/Core.hlsl"

            // #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float3 color : COLOR;
            };

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

            TEXTURE2D(_MainTex);
            SAMPLER(sampler_MainTex);
            
            CBUFFER_START(UnityPerMaterial)
                float4 _MainTex_ST;
                float4 _MainColor;
            CBUFFER_END

            // 投影参数
            // float4 _ProjectionParams;

            // 屏幕参数
            // float4 _ScreenParams;

            v2f vert (appdata v)
            {
                v2f o;
                o.vertex = v.vertex;
                o.uv = v.color.xy;
                o.color.a = v.color.z;
                // 判断 Y 轴是否需要取反
                float flipY = _ProjectionParams.x;
                o.vertex.y *= flipY;
                return o;
            }

            float4 frag (v2f i) : SV_Target
            {
                // sample the texture
                float4 col = SAMPLE_TEXTURE2D_LOD(_MainTex, sampler_MainTex, i.uv, 200);
                col.a *= i.color.a;
                // col.a *= 200.0 / 255.0 * col.a;
                col.xyz *= _MainColor.xyz;
                col.a *= _MainColor.a;
                // return float4(1,0,0,1);
                // if (col.a < 0.001) discard;
                return col;
            }
            ENDHLSL
        }
    }
}