light.ps

////////////////////////////////////////////////////////////////////////////////
// Filename: light.ps
////////////////////////////////////////////////////////////////////////////////


/////////////
// GLOBALS //
/////////////
Texture2D shaderTexture;
SamplerState SampleType;

cbuffer LightBuffer
{
	float4 diffuseColor;
	float3 lightDirection;
};


//////////////
// TYPEDEFS //
//////////////
struct PixelInputType
{
    float4 position : SV_POSITION;
    float2 tex : TEXCOORD0;
	float3 normal : NORMAL;
};


////////////////////////////////////////////////////////////////////////////////
// Pixel Shader
////////////////////////////////////////////////////////////////////////////////
float4 LightPixelShader(PixelInputType input) : SV_TARGET
{
	float4 textureColor;
	float3 lightDir;
	float lightIntensity;
	float4 color;
	

	// Sample the texture pixel at this location.
	textureColor = shaderTexture.Sample(SampleType, input.tex);
	
	// Invert the light direction for calculations.
	lightDir = -lightDirection;

	// Calculate the amount of light on this pixel.
	lightIntensity = saturate(dot(input.normal, lightDir));

	// Determine the final diffuse color based on the diffuse color and the amount of light intensity.
	color = saturate(diffuseColor * lightIntensity);

	// Multiply the texture pixel and the input color to get the final result.
	color = color * textureColor;
	
	return color;
}