//-----------------------------------------------------------------------------
// Clouds.fx
//
// Microsoft XNA Community Game Platform
// Copyright (C) Microsoft Corporation. All rights reserved.
//-----------------------------------------------------------------------------


// the relative position for the texture coordinates, inducing a slight parallax
float2 Position;


// modify the sampler state on the zero texture sampler, used by SpriteBatch
sampler TextureSampler : register(s0) = 
sampler_state
{
    AddressU = Wrap;
    AddressV = Wrap;
};


float4 PixelShaderFunction(float2 texCoord : TEXCOORD0) : COLOR0
{
    // sample from the cloud texture for the blue component
    texCoord.x += Position.x * 0.00025f;
    texCoord.y += Position.y * 0.00025f;
    texCoord *= 0.5f;
    float4 results = float4(0,0,1,0.25) * tex2D(TextureSampler, texCoord);

    // sample from the cloud texture for the green component
    texCoord.x += Position.x * 0.00025f + 0.25f;
    texCoord.y += Position.y * 0.00025f - 0.15;
    texCoord *= 0.4f;
    results += float4(0,1,0,0.15) * tex2D(TextureSampler, texCoord);
        
    return results;
}


technique Technique1
{
    pass Pass1
    {
        PixelShader = compile ps_2_0 PixelShaderFunction();
    }
}