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#include "raytracer/raytracer.h"
glm::vec4 RayTracer::illuminationFromPointLight(
const SceneLightData &light,
glm::vec4 intersectionWorld,
glm::vec4 normalWorld,
glm::vec4 directionToCamera,
const RenderShapeData &shape,
const RayTraceScene &scene
)
{
auto directionFromIntersectionToLight = light.pos - intersectionWorld;
directionFromIntersectionToLight = glm::normalize(directionFromIntersectionToLight);
// check if this light is blocked by an object
auto distanceToLight = glm::distance(light.pos, intersectionWorld);
bool isShadow = RayTracer::isShadowed(
light.pos,
distanceToLight,
glm::vec4(directionFromIntersectionToLight),
glm::vec4(intersectionWorld),
scene);
if (isShadow)
{
// if this is a shadow, then no light contribution
return glm::vec4(0.f);
}
// calculate attenuation
float c1 = light.function.x;
float c2 = light.function.y;
float c3 = light.function.z;
float attenuation = std::min(1.f, 1.f / (c1 + distanceToLight * c2 + (distanceToLight * distanceToLight) * c3));
return phong(
light.color,
attenuation,
directionFromIntersectionToLight,
directionToCamera,
intersectionWorld,
normalWorld,
shape,
scene);
}
glm::vec4 RayTracer::illuminationFromSpotLight(
const SceneLightData &light,
glm::vec4 intersectionWorld,
glm::vec4 normalWorld,
glm::vec4 directionToCamera,
const RenderShapeData &shape,
const RayTraceScene &scene
)
{
auto distance = glm::distance(light.pos, intersectionWorld);
// calculate the angle from the shape to the spot light
auto directionFromIntersectionToLight = glm::normalize(light.pos - intersectionWorld);
// calculate intensity, based on angle. apply falloff if necessary
auto lightDirection = glm::normalize(light.dir);
// invert the direction of the intersection to light for dot product to work correctly
auto cosTheta = glm::dot(-directionFromIntersectionToLight, lightDirection);
auto theta = glm::acos(cosTheta);
// determine intensity, based on location on spot cone
glm::vec4 intensity;
float inner = light.angle - light.penumbra;
if (theta <= inner)
{
intensity = light.color;
}
else if
(
theta > inner
&& theta <= light.angle
)
{
// inside the penumbra, need to apply falloff
float falloff = -2 * std::pow(theta - inner, 3) / std::pow(light.penumbra, 3) +
3 * std::pow(theta - inner, 2) / std::pow(light.penumbra, 2);
intensity = light.color * (1 - falloff);
}
else // theta > light.angle
{
return glm::vec4(0.f);
}
// if the light is within the cone, see if it's a shadow
auto distanceToLight = glm::distance(light.pos, intersectionWorld);
bool isShadow = RayTracer::isShadowed(
light.pos,
distanceToLight,
glm::vec4(directionFromIntersectionToLight),
glm::vec4(intersectionWorld),
scene);
if (isShadow)
{
// if this is a shadow, then no light contribution
return glm::vec4(0.f);
}
// calculate attenuation
float c1 = light.function.x;
float c2 = light.function.y;
float c3 = light.function.z;
float attenuation = std::min(1.f, 1.f / (c1 + distance * c2 + (distance * distance) * c3));
return phong(
intensity,
attenuation,
directionFromIntersectionToLight,
directionToCamera,
intersectionWorld,
normalWorld,
shape,
scene);
}
glm::vec4 RayTracer::illuminationFromDirectionalLight(
const SceneLightData &light,
glm::vec4 intersectionWorld,
glm::vec4 normalWorld,
glm::vec4 directionToCamera,
const RenderShapeData &shape,
const RayTraceScene &scene
)
{
// define direction and distance of directional light
auto directionFromIntersectionToLight = - light.dir;
directionFromIntersectionToLight = glm::normalize(directionFromIntersectionToLight);
float distanceToLight = FINF; // directional light infinitely far away
// check if an object blocks ours
bool isShadow = RayTracer::isShadowed(
light.pos,
distanceToLight,
directionFromIntersectionToLight,
glm::vec4(intersectionWorld),
scene);
if (isShadow)
{
// if this is a shadow, then no light contribution
return glm::vec4(0.f);
}
float attenuation = 1.f; // directional lights don't attenuate
return phong(
light.color,
attenuation,
directionFromIntersectionToLight,
directionToCamera,
intersectionWorld,
normalWorld,
shape,
scene);
}
// Calculates the RGBA of a pixel from intersection infomation and globally-defined coefficients
glm::vec4 RayTracer::illuminatePixel(
glm::vec4 intersectionWorld,
glm::vec4 normalWorld,
glm::vec4 directionToCamera,
const RenderShapeData& shape,
const RayTraceScene &scene,
int depth)
{
// Normalizing directions
normalWorld = glm::normalize(normalWorld);
directionToCamera = glm::normalize(directionToCamera);
// to be summed then returned
glm::vec4 illumination(0, 0, 0, 1.f);
// add the ambient term
float ka = scene.getGlobalData().ka;
illumination += ka*shape.primitive.material.cAmbient;
for (const SceneLightData &light : scene.getLights()) {
switch (light.type) {
case LightType::LIGHT_POINT:
illumination +=
illuminationFromPointLight(light, intersectionWorld, normalWorld, directionToCamera, shape, scene);
continue;
case LightType::LIGHT_DIRECTIONAL:
illumination +=
illuminationFromDirectionalLight(light, intersectionWorld, normalWorld, directionToCamera, shape, scene);
continue;
case LightType::LIGHT_SPOT:
illumination +=
illuminationFromSpotLight(light, intersectionWorld, normalWorld, directionToCamera, shape, scene);
continue;
case LightType::LIGHT_AREA:
illumination +=
illuminationFromAreaLight(light, intersectionWorld, normalWorld, directionToCamera, shape, scene);
continue;
default:
continue;
}
}
auto incidentDir = -directionToCamera;
// recursive raytracing for the reflection and refraction (see reflect.cpp)
illumination += refract(intersectionWorld, normalWorld, incidentDir, shape, scene, depth + 1);
illumination += reflect(intersectionWorld, normalWorld, incidentDir, shape, scene, depth + 1);
return illumination;
}
// helper function to handle the diffuse and specular terms
// also handles the texture within that diffuse term
glm::vec4 RayTracer::phong(
glm::vec4 lightColor,
float attenuation,
glm::vec4 directionFromIntersectionToLight,
glm::vec4 directionToCamera,
glm::vec4 intersectionWorld,
glm::vec4 normalWorld,
const RenderShapeData &shape,
const RayTraceScene &scene)
{
float kd = scene.getGlobalData().kd;
float ks = scene.getGlobalData().ks;
auto material = shape.primitive.material;
glm::vec4 illumination(0.f);
// calculate diffuse term
auto dotDiffuse = glm::dot(normalWorld, directionFromIntersectionToLight);
if (dotDiffuse > 0) // ensure not facing away
{
auto diffuse = (kd * material.cDiffuse);
// commenting out texture stuff bc 4d textures??????
// if (material.textureMap.isUsed)
// {
// glm::vec4 pObject = shape.inverseCTM * glm::vec4(intersectionWorld, 1.f);
// diffuse = interpolateTexture(pObject, shape, diffuse);
// }
illumination += (attenuation * lightColor) * dotDiffuse * diffuse;
}
// add specular term
auto reflectedDirOverNormal =
2 * glm::dot(directionFromIntersectionToLight, normalWorld) * normalWorld -
directionFromIntersectionToLight;
auto dotSpecular = glm::dot(reflectedDirOverNormal, directionToCamera);
auto toPow = std::pow(dotSpecular, material.shininess);
if (dotSpecular > 0) {
illumination += (attenuation * lightColor) * toPow * (ks * material.cSpecular);
}
return illumination;
}
// EXTRA CREDIT -> AREA LIGHT
glm::vec4 RayTracer::illuminationFromAreaLight(
const SceneLightData &light,
glm::vec4 intersectionWorld,
glm::vec4 normalWorld,
glm::vec4 directionToCamera,
const RenderShapeData &shape,
const RayTraceScene &scene
) {
// select a random point within the light's height and width
float width = light.width;
float height = light.height;
float x = ((float) rand() / (float) RAND_MAX) * width - width / 2.f;
float y = ((float) rand() / (float) RAND_MAX) * height - height / 2.f;
glm::vec4 lightPosition = light.pos + glm::vec4(x, y, 0.f, 0.f);
auto directionFromIntersectionToLight = lightPosition - intersectionWorld;
directionFromIntersectionToLight = glm::normalize(directionFromIntersectionToLight);
// check if this light is blocked by an object
auto distanceToLight = glm::distance(lightPosition, intersectionWorld);
bool isShadow = RayTracer::isShadowed(
lightPosition,
distanceToLight,
glm::vec4(directionFromIntersectionToLight),
glm::vec4(intersectionWorld),
scene);
if (isShadow)
{
// if this is a shadow, then show a ray to a random point in the light
return glm::vec4(0.f);
}
// calculate attenuation
float c1 = light.function.x;
float c2 = light.function.y;
float c3 = light.function.z;
float attenuation = std::min(1.f, 1.f / (c1 + distanceToLight * c2 + (distanceToLight * distanceToLight) * c3));
return phong(
light.color,
attenuation,
directionFromIntersectionToLight,
directionToCamera,
intersectionWorld,
normalWorld,
shape,
scene);
}
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