79 lines
1.8 KiB
C++
79 lines
1.8 KiB
C++
#include "color.h"
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#include "light.h"
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// PRIVATE PROTOTYPES
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static ColorF32 ComputeAmbientLight(
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ColorF32 surfaceReflectivity, ColorF32 lightIntensity);
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static ColorF32 ComputeDiffuseLight(
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ColorF32 surfaceReflectivity, ColorF32 lightIntensity,
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Point &vertPosition, Vector &vertNormal,
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Point &lightPosition);
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// PUBLIC FUNCTIONS
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ColorF32 ComputeLight(Vertex &vert, Material &material, Light &light)
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{
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// Distance from light to vertex
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Vector d = light.position - vert.point;
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float distance = d.Length();
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// Intensity is a function of the falloff factors and the distance
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ColorF32 intensity =
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(light.intensity * light.color)
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/ (light.falloffConstant + light.falloffLinear * distance);
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// Compute ambient light
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ColorF32 ambientLight = ComputeAmbientLight(
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material.ambient, intensity);
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// Compute diffuse light
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ColorF32 diffuseLight = ComputeDiffuseLight(
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material.diffuse, intensity,
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vert.point, vert.normal,
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light.position);
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// Total light is sum of all lights
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ColorF32 result = ambientLight + diffuseLight;
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return result;
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}
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// PRIVATE FUNCTIONS
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static ColorF32 ComputeAmbientLight(
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ColorF32 surfaceReflectivity, ColorF32 lightIntensity)
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{
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ColorF32 result;
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result = surfaceReflectivity * lightIntensity;
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return result;
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}
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static ColorF32 ComputeDiffuseLight(
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ColorF32 surfaceReflectivity, ColorF32 lightIntensity,
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Point &vertPosition, Vector &vertNormal,
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Point &lightPosition)
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{
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// Light is a function of the position of the light source and the surface
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Vector direction = lightPosition - vertPosition;
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direction.Normalize();
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float dot = Vector::Dot(vertNormal, direction);
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ColorF32 result = surfaceReflectivity * lightIntensity * dot;
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return result;
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}
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