39 lines
1.5 KiB
C++
39 lines
1.5 KiB
C++
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#include "light/spotlight.h"
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#include "scene/scene.h"
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SpotLight::SpotLight(Vector3d const &position, Vector3d const &direction, float alphaMin, float alphaMax, float intensity, Color const &color)
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: Light(intensity, color), position(position), direction(normalized(direction)), alphaMin(alphaMin), alphaMax(alphaMax) {}
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Light::Illumination SpotLight::illuminate(Scene const &scene, Ray const &ray) const {
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Vector3d const target = ray.origin + (ray.length - LGT_EPS) * ray.direction;
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// Illumination object
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Illumination illum;
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illum.direction = normalized(target - this->position);
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// Precompute the distance from the light source
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float const distance = length(target - this->position);
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// Define a secondary ray from the surface point to the light source
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Ray lightRay;
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lightRay.origin = target;
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lightRay.direction = -illum.direction;
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lightRay.length = distance - LGT_EPS;
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// Determine the angle of the inner cone
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float const alpha = std::fabs(std::acos(dotProduct(illum.direction, this->direction)) * 180.0f / float(PI));
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// If the target is within the cone...
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if (this->alphaMax > alpha) {
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// ... and not in shadow ...
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if (!scene.findOcclusion(lightRay)) {
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// ... compute the attenuation and light color ...
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illum.color = 1.0f / (distance * distance) * this->color * this->intensity;
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// ... then compute the falloff towards the edge of the cone
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if (this->alphaMin < alpha)
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illum.color *= 1.0f - (alpha - this->alphaMin) / (this->alphaMax - this->alphaMin);
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}
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}
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return illum;
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}
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