main.c

#include <SDL3/SDL.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>

#include "structs.h"
#include "manipulation.h"
#include "rendering.h"

#define WINDOW_HEIGHT 1200
#define WINDOW_WIDTH 900
#define FPS 60
#define MAX_ANGULAR_SPEED 0.04

SDL_Window *window;
SDL_Surface *surface;
SDL_Renderer *renderer;

Point2D project_3d_to_2d(const Point3D *point_3d, float focal_length)
{
    float x_2d = (point_3d->x / point_3d->z) * focal_length + WINDOW_WIDTH / 2;
    float y_2d = (point_3d->y / point_3d->z) * focal_length + WINDOW_HEIGHT / 2;
    Point2D point_2d = {x_2d, y_2d};
    return point_2d;
}

float random_range(float min, float max)
{
    return min + ((float)rand() / RAND_MAX) * (max - min);
}

int main(void)
{
    srand(time(NULL));
    if (SDL_Init(SDL_INIT_VIDEO) < 0)
    {
        printf("SDL could not initialize! %s\n", SDL_GetError());
        return 1;
    }

    window = SDL_CreateWindow("Hello SDL3!", WINDOW_WIDTH, WINDOW_HEIGHT, 0);
    renderer = SDL_CreateRenderer(window, NULL);
    SDL_SetRenderDrawColor(renderer, 255, 255, 255, SDL_ALPHA_OPAQUE);

    float focal_length = 300.0;

    Point3D cube_3d[] = {
        {-1, -1, 2}, {1, -1, 2}, {1, 1, 2}, {-1, 1, 2}, {-1, -1, 4}, {1, -1, 4}, {1, 1, 4}, {-1, 1, 4}};

    int cube_edges[12][2] = {
        {0, 1}, {1, 2}, {2, 3}, {3, 0}, {4, 5}, {5, 6}, {6, 7}, {7, 4}, {0, 4}, {1, 5}, {2, 6}, {3, 7}};

    Point2D cube_2d[8];

    float angular_speed_x = 0.0, angular_speed_y = 0.0, angular_speed_z = 0.0;
    float angular_accel_x = 0.0, angular_accel_y = 0.0, angular_accel_z = 0.0;

    int frame = 0;
    SDL_Event event;
    int running = 1;

    while (running)
    {
        // Handle events
        while (SDL_PollEvent(&event))
        {
            if (event.type == SDL_EVENT_QUIT)
            {
                running = 0;
            }
        }

        if (frame % 30 == 0)
        {
            angular_accel_x = random_range(-0.0005f, 0.0005f);
            angular_accel_y = random_range(-0.0005f, 0.0005f);
            angular_accel_z = random_range(-0.0005f, 0.0005f);
        }

        if (angular_speed_x > MAX_ANGULAR_SPEED)
            angular_accel_x = -fabs(angular_accel_x);
        if (angular_speed_x < -MAX_ANGULAR_SPEED)
            angular_accel_x = fabs(angular_accel_x);
        if (angular_speed_y > MAX_ANGULAR_SPEED)
            angular_accel_y = -fabs(angular_accel_y);
        if (angular_speed_y < -MAX_ANGULAR_SPEED)
            angular_accel_y = fabs(angular_accel_y);
        if (angular_speed_z > MAX_ANGULAR_SPEED)
            angular_accel_z = -fabs(angular_accel_z);
        if (angular_speed_z < -MAX_ANGULAR_SPEED)
            angular_accel_z = fabs(angular_accel_z);

        Point3D center = {0, 0, 0};
        for (int i = 0; i < 8; i++)
        {
            center.x += cube_3d[i].x;
            center.y += cube_3d[i].y;
            center.z += cube_3d[i].z;
        }
        center.x /= 8.0f;
        center.y /= 8.0f;
        center.z /= 8.0f;

        for (int i = 0; i < 8; i++)
        {
            cube_3d[i].x -= center.x;
            cube_3d[i].y -= center.y;
            cube_3d[i].z -= center.z;
        }

        rotate_x(cube_3d, 8, angular_speed_x);
        rotate_y(cube_3d, 8, angular_speed_y);
        rotate_z(cube_3d, 8, angular_speed_z);

        angular_speed_x += angular_accel_x;
        angular_speed_y += angular_accel_y;
        angular_speed_z += angular_accel_z;

        for (int i = 0; i < 8; i++)
        {
            cube_3d[i].x += center.x;
            cube_3d[i].y += center.y;
            cube_3d[i].z += center.z;
        }

        for (int i = 0; i < 8; i++)
        {
            Point3D p = cube_3d[i];
            Point2D p_2d = project_3d_to_2d(&p, focal_length);
            cube_2d[i] = p_2d;
        }

        for (int i = 0; i < 12; i++)
        {
            draw_line(&cube_2d[cube_edges[i][0]], &cube_2d[cube_edges[i][1]], renderer);
        }

        SDL_RenderPresent(renderer);
        SDL_Delay(1000 / FPS);
        display_clear(renderer);

        frame++;
    }
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 0;
}