108 lines
2.8 KiB
C++
108 lines
2.8 KiB
C++
#include "camera.h"
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#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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Material &material, ColorF32 &intensity);
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static ColorF32 ComputeDiffuseLight(
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Material &material, ColorF32 &intensity, Vertex &vert, Light &light);
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static ColorF32 ComputeSpecularLight(
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Material &material, ColorF32 &intensity, Vertex &vert, Light &light,
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Camera &camera);
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// PUBLIC FUNCTIONS
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ColorF32 ComputeLight(
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Vertex &vert, Material &material, Light &light, Camera &camera)
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{
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// Distance from light to vertex
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Vector direction = light.position - vert.position;
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float distance = VectorLength(direction);
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// Point light 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(material, intensity);
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// Compute diffuse light
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ColorF32 diffuseLight = ComputeDiffuseLight(material, intensity, vert, light);
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// Compute specular light
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ColorF32 specularLight = ComputeSpecularLight(material, intensity, vert, light, camera);
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// Total light is sum of all lights
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ColorF32 result = ambientLight + diffuseLight + specularLight;
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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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Material &material, ColorF32 &intensity)
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{
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// light = Kd * I
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ColorF32 result = material.ambient * intensity;
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return result;
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}
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static ColorF32 ComputeDiffuseLight(
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Material &material, ColorF32 &intensity, Vertex &vert, Light &light)
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{
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// Vector from the light to the vertex
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Vector direction = light.position - vert.position;
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VectorNormalize(direction);
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float normalDotDirection = VectorDot(vert.normal, direction);
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// light = Kr * I * n.d
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ColorF32 result = material.diffuse * intensity * normalDotDirection;
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return result;
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}
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static ColorF32 ComputeSpecularLight(
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Material &material, ColorF32 &intensity, Vertex &vert, Light &light,
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Camera &camera)
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{
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// Vector from the camera to the vertex
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Vector view = camera.position - vert.position;
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VectorNormalize(view);
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// Vector from the light to the vertex
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Vector direction = light.position - vert.position;
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VectorNormalize(direction);
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// Reflection vector of the light vector across the vertex normal
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float normalDotDirection = VectorDot(vert.normal, direction);
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Vector reflection = (2.0f * normalDotDirection * vert.normal) - direction;
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float reflectDotView = MAX(VectorDot(reflection, view), 0.0f);
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// light = Ks * I * (r.v)^sp
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ColorF32 result =
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material.specular * intensity * powf(reflectDotView, material.specularExp);
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return result;
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}
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