ogltest/src/drawing.h

#pragma once
#include <memory>
#include <glm/glm.hpp>
#include "mesh.h"
#include <set>
#include "glutil.h"
#include <GL/glu.h>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include "entity.h"

void  draw_objects(Shader *shader, const std::vector<physics_model> positions, std::shared_ptr<Model> m, const glm::mat4 view, const glm::mat4 projection) ;

void setup_shader(Shader *shader, const glm::mat4 view, const glm::mat4 projection, const glm::vec3 position, const glm::mat4 orientation);

namespace drawing {

    struct instanced_renderer {
        GLuint vbo;
        Shader * shader;
    };

    struct position {
        glm::vec3 position;
        glm::mat4 orientation;
    };

    instanced_renderer instanced_setup(Shader* shader, const std::vector<position> &positions);
    void instanced_update(const instanced_renderer r, const std::vector<position> &positions);
    void instanced_draw(const instanced_renderer r, const glm::mat4 view, const glm::mat4 projection);
    void noninstanced_set_camera(Shader *shader, const glm::mat4 view, const glm::mat4 projection);
    void  noninstanced_draw(std::vector<position> objects, Model * model, Shader *shader, const glm::mat4 view, const glm::mat4 projection);
};

struct object {
    glm::vec3 position;
    glm::mat4 orientation;
    std::shared_ptr<Model> model;
};

// handles shaders, models, meshes for drawing a collection of similar objects
class drawing_object_handle {
    public:
    virtual void  draw(const glm::mat4 view, const glm::mat4 projection) = 0;
    virtual void  draw(int i, const glm::mat4 view, const glm::mat4 projection) = 0;
};


class simple_object_draw_system : public drawing_object_handle {
    Shader *shader;



    public:
    std::vector<object> objects;
    std::set<int> do_not_draw;
    simple_object_draw_system(Shader *shader);
    
    int add(std::shared_ptr<Model> model, glm::vec3 position, glm::mat4 orientation);


    void remove(int i);

    void return_to_draw_list(int i);

    void  draw(int i, const glm::mat4 view, const glm::mat4 projection) override;


    void  draw(const glm::mat4 view, const glm::mat4 projection) override;

};


/* Draw  a lot of the same object. */
class instanced_drawing : public drawing_object_handle {
    public:
        struct object {
            glm::vec3 position;
            glm::mat4 model;
        };
    private:

    std::vector<object> models;

    Model *model;
    Shader *shader;

    unsigned int instance_VBO;
    public:
    instanced_drawing (Model *model, Shader *shader, std::vector<object> obj_models); 
    instanced_drawing (Model *model, Shader *shader);

    int finalize ();
    int add(glm::vec3 position, glm::mat4 orientation);
    void  draw(const glm::mat4 view, const glm::mat4 projection) override;
};