#ifndef LIGHT_CLASS
#define LIGHT_CLASS

#include <glm/glm.hpp>

// These have to match the sizes in deferred_lighting.frag and default.frag
static constexpr int MAX_DIRECTIONAL_LIGHTS = 4;
static constexpr int MAX_POINT_LIGHTS = 16;
static constexpr int MAX_SPOT_LIGHTS = 8;

// Spot and point shadows share one depth texture cut into tiles.
// A spot light takes 1 tile, a point light takes 6. Lights past the limit just don't cast shadows.
static constexpr int SHADOW_ATLAS_COLUMNS = 6;   // has to match the shaders too
static constexpr int SHADOW_ATLAS_TILES = SHADOW_ATLAS_COLUMNS * SHADOW_ATLAS_COLUMNS;
static constexpr int SHADOW_ATLAS_TILE_SIZE = 640;

class Light {
public:
	glm::vec3 color = glm::vec3(1.0f);   // linear rgb
	float intensity = 1.0f;
	bool castShadow = true;   // spot and point lights, the sun always has its own shadow map
	int shadowTile = -1;      // first atlas tile, set each frame by the render system
};

// Parallel rays with no position, so it lights the whole scene from one direction
class DirectionalLight : public Light {
public:
	glm::vec3 direction = glm::vec3(0.0f, -1.0f, 0.0f);   // the way the light travels
};

// Fades with distance and reaches nothing past radius
class PointLight : public Light {
public:
	glm::vec3 position = glm::vec3(0.0f);
	float radius = 10.0f;
};

// A cone from a point. Full brightness inside innerAngle, fading to nothing at outerAngle.
class SpotLight : public Light {
public:
	glm::vec3 position = glm::vec3(0.0f);
	glm::vec3 direction = glm::vec3(0.0f, -1.0f, 0.0f);   // the way the cone points
	float radius = 20.0f;
	float innerAngle = 20.0f;   // degrees from the center of the cone
	float outerAngle = 30.0f;
};

#endif