/////////////
// GLOBALS //
/////////////
cbuffer MatrixBuffer
{
    matrix worldMatrix;
    matrix viewMatrix;
    matrix projectionMatrix;
};

cbuffer CameraBuffer
{
    float3 cameraPosition;
    float padding;
};

cbuffer SunLightBuffer
{
    float4 ambientColor;
    float4 diffuseColor;
    float3 lightDirection;
    float intensity;
};

//////////////
// TYPEDEFS //
//////////////
struct VertexInputType
{
    float4 position : POSITION;
    float2 tex : TEXCOORD0;
    float3 normal : NORMAL;
};

struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
    float3 normal : NORMAL;
    float3 lightDir : TEXCOORD1;
    float intensity : TEXCOORD2;
};

////////////////////////////////////////////////////////////////////////////////
// Vertex Shader
////////////////////////////////////////////////////////////////////////////////
PixelInputType SunLightVertexShader(VertexInputType input)
{
    PixelInputType output;

    // Change the position vector to be 4 units for proper matrix calculations.
    input.position.w = 1.0f;

    // Calculate the position of the vertex against the world, view, and projection matrices.
    output.position = mul(input.position, worldMatrix);
    output.position = mul(output.position, viewMatrix);
    output.position = mul(output.position, projectionMatrix);
    
    // Store the texture coordinates for the pixel shader.
    output.tex = input.tex;
    
    // Calculate the normal vector against the world matrix only.
    output.normal = mul(input.normal, (float3x3) worldMatrix);
	
    // Normalize the normal vector.
    output.normal = normalize(output.normal);

    // Use the light direction directly.
    output.lightDir = normalize(lightDirection);
    
    output.intensity = intensity;

    return output;
}