Shader "XRLineRenderer/MeshChain - Alpha Blended"
{
    Properties
    {
        _Color("Color Tint", COLOR) = (1,1,1,1)
        _lineSettings ("Line Thickness Settings", VECTOR) = (0, 1, .5, 1)

        _lineRadius("Line Radius Scale, Min, Max", VECTOR) = (1, 0, 100)

        // Local space or world space data
        [HideInInspector] _WorldData("__worlddata", Float) = 0.0

        // Depth effects line width
        [HideInInspector] _LineDepthScale("__linedepthscale", Float) = 1.0
    }
    SubShader
    {
        Tags{ "RenderType" = "Transparent" "Queue" = "Transparent" }
        LOD 100

        // We don't want the line segments and caps to draw over top
        // one another as it breaks the continuous segment illusion
        // To alpha blend with the background, we use a three-pass technique
        Pass
        {
            // In the first pass we 'clear' the alpha channel to 1, 
            // so that the inner segments can mask this out
            Blend One One
            BlendOp Max
            Cull Off
            Lighting Off
            ZWrite Off
            ColorMask A
            Offset 0, -.1

            CGPROGRAM

                #pragma vertex vert
                #pragma fragment fragColor
                #pragma multi_compile LINE_PERSPECTIVE_WIDTH LINE_FIXED_WIDTH
                #pragma multi_compile LINE_MODEL_SPACE LINE_WORLD_SPACE

                #include "UnityCG.cginc"
                #include "MeshChain.cginc"

            ENDCG
        }
        Pass
        {
            // Next we write the line shape and fade only to the alpha channel.
            // This lets us punch a hole in the background that our
            // line color then shows through
            Blend One One
            BlendOp Min
            Cull Off
            Lighting Off
            ZWrite Off
            ColorMask A
            Offset 0, -.1

            CGPROGRAM

                #pragma vertex vert
                #pragma fragment fragAlphaMask
                #pragma multi_compile LINE_PERSPECTIVE_WIDTH LINE_FIXED_WIDTH
                #pragma multi_compile LINE_MODEL_SPACE LINE_WORLD_SPACE

                #include "UnityCG.cginc"
                #include "MeshChain.cginc"

            ENDCG
        }
        Pass
        {
            // In this second pass, we write our line color only as much
            // as the alpha value we wrote before allows through.  To
            // prevent overlapping lines from adding too much color,
            // we set the alpha value to one after visiting a pixel.
            Blend OneMinusDstAlpha DstAlpha, One One
            BlendOp Add, Max
            Cull Off
            Lighting Off
            ZWrite Off
            Offset 0, -.1

            CGPROGRAM

                #pragma vertex vert
                #pragma fragment fragColor
                #pragma multi_compile LINE_PERSPECTIVE_WIDTH LINE_FIXED_WIDTH
                #pragma multi_compile LINE_MODEL_SPACE LINE_WORLD_SPACE

                #include "UnityCG.cginc"
                #include "MeshChain.cginc"

            ENDCG
        }
    }
    FallBack "Diffuse"
    CustomEditor "Unity.XRTools.Rendering.MeshChainShaderGUI"
}