PathTracing/Light.hpp at main · marko176/PathTracing · GitHub

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#pragma once
#include "Interaction.hpp"
#include "Shape.hpp"
#include <functional>

struct LightSample{
    glm::vec3 L;
    SurfaceInteraction interaction;
    glm::vec3 dir;

    bool isDeltaInteraction() const{
        return interaction.n == glm::vec3 { 0,0,0 };
    }
};

class Light{
public:
    virtual ~Light() = default;
    virtual bool isDelta() const = 0;
    virtual glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const = 0;
    virtual LightSample sample(const glm::vec2& uv, float time) const = 0;
    virtual float PDF(const GeometricInteraction& interaction, float time) const = 0;
    virtual float PDF(const GeometricInteraction& interaction, const Ray& ray) const = 0;
    virtual float Power() const = 0;
    virtual void PreProcess(const AABB& bbox){}
};

//infinite light has Le which doesnt need interaction!
//faraway / infinite directional
//uniform infinite
//texture infinite


//should remove InfiniteLight!
class InfiniteLight : public Light{
public:
    virtual ~InfiniteLight() = default;

    virtual glm::vec3 Le(const Ray& ray) const = 0;
    bool isDelta() const override;
    float PDF(const GeometricInteraction& interaction, float time) const override;
    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;
    void PreProcess(const AABB& bbox) override;
protected:
    float sceneRadius;
};

class UniformInfiniteLight : public InfiniteLight{
public:
    virtual ~UniformInfiniteLight() = default;

    UniformInfiniteLight(const glm::vec3& light_color, const std::function<float(float)>& powerFunc = [](float r) -> float{ return std::sqrt(r); }) : color { light_color }, powerFunction { powerFunc }{}

    glm::vec3 Le(const Ray& ray) const override;

    glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const override;

    LightSample sample(const glm::vec2& uv, float time) const override;

    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;


    float Power() const override;

private:
    glm::vec3 color;
    std::function<float(float)> powerFunction;
};

class FunctionInfiniteLight : public InfiniteLight{
public:
    virtual ~FunctionInfiniteLight() = default;

    FunctionInfiniteLight(const std::function<glm::vec3(const Ray& ray)>& lightFunc, const std::function<float(float)>& powerFunc = [](float r) -> float{ return std::sqrt(r); }) : lightFunction(lightFunc), powerFunction { powerFunc }{}

    glm::vec3 Le(const Ray& ray) const override;

    glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const override;

    LightSample sample(const glm::vec2& uv, float time) const override;

    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;

    float Power() const override;

    void PreProcess(const AABB& bbox) override;

private:
    std::function<glm::vec3(const Ray& ray)> lightFunction;
    std::function<float(float)> powerFunction;
    float cachedPower;//need to implement
};

class TextureInfiniteLight : public InfiniteLight{
public:
    virtual ~TextureInfiniteLight() = default;

    TextureInfiniteLight(const std::shared_ptr<Texture>& tex, float LeScale = 1.0f, const std::function<float(float)>& powerFunc = [](float r) -> float{ return std::sqrt(r); }) : tex { tex }, LeScale(LeScale), powerFunction { powerFunc }{}

    glm::vec3 Le(const Ray& ray) const override;

    glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const override;

    LightSample sample(const glm::vec2& uv, float time) const override;

    float Power() const override;

    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;

    void PreProcess(const AABB& bbox) override;

private:
    std::shared_ptr<Texture> tex;
    float LeScale;
    float cachedPower;
    std::vector<float> weights;
    std::vector<float> accWeights;
    double totalWeight;
    std::function<float(float)> powerFunction;// no_unique_address ?
    static constexpr int spp = 500;//HIGH MEMORY USAGE
    static constexpr int xSamples = 1920;
    static constexpr int ySamples = 1080;
};


//distantLight : InfiniteLIght?
class DistantLight : public Light{
public:
    virtual ~DistantLight() = default;

    DistantLight(const glm::vec3& light_dir, const glm::vec3& light_color, const std::function<float(float)>& powerFunc = [](float r) -> float{ return std::sqrt(r); }) : dir { light_dir }, color { light_color }, powerFunction { powerFunc }{}

    bool isDelta() const final;

    glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const override;

    LightSample sample(const glm::vec2& uv, float time) const override;

    float PDF(const GeometricInteraction& interaction, float time) const override;

    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;

    float Power() const override;

    void PreProcess(const AABB& bbox) override;
private:
    glm::vec3 dir;
    glm::vec3 color;
    float sceneRadius;
    std::function<float(float)> powerFunction;
};

class PointLight : public Light{
public:
    virtual ~PointLight() = default;

    PointLight(const glm::vec3& p, const glm::vec3& light_color, const std::function<float(float)>& powerFunc = [](float r) -> float{ return 4 * r; }) : p { p }, color { light_color }, powerFunction { powerFunc }{}

    bool isDelta() const final;

    glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const override;

    LightSample sample(const glm::vec2& uv, float time) const override;

    float PDF(const GeometricInteraction& interaction, float time) const override;

    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;

    float Power() const override;

    void PreProcess(const AABB& bbox) override;
private:
    glm::vec3 p;
    glm::vec3 color;
    float sceneRadius;
    std::function<float(float)> powerFunction;
};

class AreaLight : public Light{
public:
    virtual ~AreaLight() = default;

    AreaLight(const std::shared_ptr<Shape>& light_shape, const glm::vec3& light_color, bool oneSided = false) : shape { light_shape }, emissiveTexture { std::make_shared<SolidColor>(light_color) }, cachedPower { 0 }, oneSided { oneSided }{}
    AreaLight(const std::shared_ptr<Shape>& light_shape, const std::shared_ptr<Texture>& emissiveTex, bool oneSided = false) : shape { light_shape }, emissiveTexture { emissiveTex }, cachedPower { 0 }, oneSided { oneSided }{}

    bool isDelta() const final;

    glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const override;

    LightSample sample(const glm::vec2& uv, float time) const override;

    float PDF(const GeometricInteraction& interaction, float time) const override;

    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;

    float Power() const override;

    void PreProcess(const AABB& bbox) override;

    std::shared_ptr<Shape> getShape() const;
private:
    std::shared_ptr<Shape> shape;
    std::shared_ptr<Texture> emissiveTexture; //switch to texture/image
    float cachedPower;
    bool oneSided;
    //add alpha mask
};

class TransformedLight : public Light{
public:
    virtual ~TransformedLight() = default;

    TransformedLight(const std::shared_ptr<Light>& light, const glm::mat4& transform) : light(light), transform(transform), normalMatrix(glm::transpose(glm::inverse(glm::mat3(transform)))), invTransform(glm::inverse(transform)){}

    bool isDelta() const final;

    glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const override;

    LightSample sample(const glm::vec2& uv, float time) const override;

    float PDF(const GeometricInteraction& interaction, float time) const override;

    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;

    void PreProcess(const AABB& bbox) override;

    float Power() const override;

private:
    std::shared_ptr<Light> light;
    glm::mat4 transform;
    glm::mat3 normalMatrix;
    glm::mat4 invTransform;
};

class AnimatedLight : public Light{
public:
    virtual ~AnimatedLight() = default;

    AnimatedLight(const std::shared_ptr<Light>& light, const glm::vec3& direction, const glm::vec2& timeBounds) : light(light), dir(direction), timeBounds(timeBounds){}

    bool isDelta() const final;

    glm::vec3 L(const SurfaceInteraction& interaction, const Ray& ray) const override;

    LightSample sample(const glm::vec2& uv, float time) const override;

    float PDF(const GeometricInteraction& interaction, float time) const override;

    float PDF(const GeometricInteraction& interaction, const Ray& ray) const override;

    void PreProcess(const AABB& bbox) override;

    float Power() const override;

private:
    std::shared_ptr<Light> light;
    glm::vec3 dir;
    glm::vec2 timeBounds;
};