Program Listing for File ViewFrustumCulling.ixx

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module;

#include <glad/glad.h>

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <memory>
#include <vector>

#include "host_device/GlobalValues.hpp"

export module kataglyphis.opengl.view_frustum_culling;

import kataglyphis.shared.scene.camera;
import kataglyphis.opengl.aabb;
import kataglyphis.opengl.texture;

export class ViewFrustumCulling
{
  public:
    ViewFrustumCulling();

    bool is_inside(GLfloat aspect_ratio,
      const Camera &main_camera,
      AABB &bounding_box,
      const glm::mat4 &model);

    void render_view_frustum() const;

    ~ViewFrustumCulling();

  private:
    // render view frustum
    unsigned int VBO, VAO, EBO;

    unsigned int m_drawCount;

    // we get that as input
    GLfloat near_plane, far_plane, fov, ratio;

    // calculate as soon as we become params
    GLfloat tan, near_height, near_width, far_height, far_width;

    glm::vec3 dir, near_center, far_center;

    // all corners of the frustum
    // near plane
    glm::vec3 near_top_left, near_top_right, near_bottom_left, near_bottom_right;
    // far plane
    glm::vec3 far_top_left, far_top_right, far_bottom_left, far_bottom_right;

    // planes in Hesse normal form
    // layout: [0]: near plane, [1] far plane, [2] front, [3] bottom, [4]: left,
    // [5]: right
    struct frustum_plane
    {
        glm::vec3 normal;
        glm::vec3 position;
    };

    frustum_plane frustum_planes[NUM_FRUSTUM_PLANES];

    void init(const std::vector<glm::vec3> &frustum_corner);

    bool corners_outside_plane(const std::vector<glm::vec3> &aabb_corners, frustum_plane plane, GLuint outcode_pattern);

    static GLfloat plane_point_distance(frustum_plane plane, glm::vec3 corner);

    void update_frustum_param(GLfloat cam_near,
      GLfloat cam_far,
      GLfloat cam_fov,
      GLfloat aspect_ratio,
      const Camera &main_camera);
};