#include "color.effect"

uniform float4x4 ViewProj;
uniform texture2d image;
uniform float multiplier;

sampler_state def_sampler {
	Filter   = Linear;
	AddressU = Clamp;
	AddressV = Clamp;
};

struct VertInOut {
	float4 pos : POSITION;
	float2 uv  : TEXCOORD0;
};

VertInOut VSDefault(VertInOut vert_in)
{
	VertInOut vert_out;
	vert_out.pos = mul(float4(vert_in.pos.xyz, 1.0), ViewProj);
	vert_out.uv  = vert_in.uv;
	return vert_out;
}

float4 PSDrawForMacDrawPen(VertInOut vert_in) : TARGET
{
    float4 rgba = image.Sample(def_sampler, vert_in.uv);
    
    if (rgba.a < 1.0) {
        rgba.rgb = srgb_linear_to_nonlinear(rgba.rgb);
        rgba.rgb *= max(1. / rgba.a, 0.);
        rgba.rgb = srgb_nonlinear_to_linear(rgba.rgb);
    } else {
        rgba.rgb = srgb_nonlinear_to_linear(rgba.rgb);
        rgba.rgb *= multiplier;
    }
    return rgba;
}

technique DrawForMacDrawPen
{
    pass
    {
        vertex_shader = VSDefault(vert_in);
        pixel_shader  = PSDrawForMacDrawPen(vert_in);
    }
}