stinger_transition.effect

uniform float4x4  ViewProj;
uniform texture2d a_tex;
uniform texture2d b_tex;

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

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

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

//Overlay "Top" on "Base"
float4 Overlay(float4 Base, float4 Top)
{
	float4 Res;
	half3 BaseVisible = Base.rgb * (1 - Top.a);
	half3 TopVisible = Top.rgb * (Top.a);
	
	float3 finalColor =  (BaseVisible + TopVisible);
	Res.rgb = finalColor;
	Res.a = 1.0f;
	return Res;
}

float4 PSStinger(VertData v_in) : TARGET
{
	float2 uv = v_in.uv;
	float4 a_color = a_tex.Sample(textureSampler, uv);
	float4 b_color = b_tex.Sample(textureSampler, uv);

	return Overlay(a_color, b_color);
}

technique Stinger
{
	pass
	{
		vertex_shader = VSDefault(v_in);
		pixel_shader = PSStinger(v_in);
	}
}