flower/source/engine/utils/camera_interface.h

#pragma once

#include "math.h"
#include <array>
#include <common_header.h>

namespace engine
{
	struct Frustum
	{
		std::array<math::vec4, 6> planes;
		enum ESide
		{
			eLeft,
			eDown,
			eRight,
			eTop,
			eFront,
			eBack
		};

		// Build frustum from viewproject matrix.
		static Frustum build(const math::mat4& viewprojMatrix);
	};

	class CameraInterface
	{
	public:
		virtual void fillPerframe(PerFrameData& outPerframe);

		// return camera aspect.
		float getAspect() const { return (float)m_width / (float)m_height; }

		// return camera fov y.
		float getFovY() const { return m_fovy; }

		// Set fov y value in radians.
		bool setFovY(float v);

		// return camera z near plane.
		float getZNear() const { return m_zNear; }

		// return camera z far plane.
		float getZFar() const { return m_zFar; }

		// return camera view matrix.
		virtual math::mat4 getViewMatrix() const = 0;

		// return camera project matrix.
		virtual math::mat4 getProjectMatrix() const = 0;

		// return camera worldspcae position.
		const math::vec3& getPosition() const { return m_position; }

		// Compute world frustum.
		Frustum computeWorldFrustum() const;

	protected:
		// world space position.
		math::vec3 m_position = { 25.0f, 25.0f, 25.0f};

		// fov y.
		float m_fovy = math::radians(45.0f);

		// z near.
		float m_zNear = 0.001f;

		// z far.
		float m_zFar = 10'000.0f;

		// render width.
		size_t m_width;

		// render height.
		size_t m_height;

		// camera front direction.
		math::vec3 m_front = { -0.5f, -0.6f, 0.6f };

		// camera up direction.
		math::vec3 m_up;

		// camera right direction;
		math::vec3 m_right;
	};
}