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#include <GLFW/glfw3.h>
#include <stdio.h>
#include <math.h>
// TODO: move to implicit map definition with level editor in future
#define MAP_HEIGHT 20
#define MAP_WIDTH 20
int world_map[MAP_HEIGHT][MAP_WIDTH] = {
{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 0, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 4, 0, 1},
{1, 0, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 4, 0, 1},
{1, 0, 3, 3, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 4, 0, 1},
{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
{1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
};
// TODO: move player code to dedicated file after complication demands it
// TODO: implement y-shearing to allow players to look vertically
typedef struct {
float pos_x, pos_y;
float dir_x, dir_y;
float plane_x, plane_y;
float move_speed;
float rot_speed;
} Player;
typedef struct {
unsigned char r, g, b;
} ColorRGB;
// honest- this function can from chatgpt- cross-reference this with other raycasting guides
void raycast(Player *player) {
int screen_width = 800;
int screen_height = 600;
for (int x = 0; x < screen_width; ++x) {
// Calculate ray position and direction
double camera_x = 2.0 * x / (double)screen_width - 1; // x-coordinate in camera space
double ray_dir_x = player->dir_x + player->plane_x * camera_x;
double ray_dir_y = player->dir_y + player->plane_y * camera_x;
// Which box of the map we're in
int map_x = (int)player->pos_x;
int map_y = (int)player->pos_y;
// Length of ray from one x or y-side to next x or y-side
double delta_dist_x = fabs(1 / ray_dir_x);
double delta_dist_y = fabs(1 / ray_dir_y);
// Length of ray from current position to next x or y-side
double side_dist_x;
double side_dist_y;
// Direction to step in x or y-direction (either +1 or -1)
int step_x;
int step_y;
// Was a wall hit?
int hit = 0;
// Was the wall hit a wall facing north, east-west, or south?
int side;
if (ray_dir_x < 0) {
step_x = -1;
side_dist_x = (player->pos_x - map_x) * delta_dist_x;
} else {
step_x = 1;
side_dist_x = (map_x + 1.0 - player->pos_x) * delta_dist_x;
}
if (ray_dir_y < 0) {
step_y = -1;
side_dist_y = (player->pos_y - map_y) * delta_dist_y;
} else {
step_y = 1;
side_dist_y = (map_y + 1.0 - player->pos_y) * delta_dist_y;
}
// Perform DDA
while (hit == 0) {
// Jump to next map square
if (side_dist_x < side_dist_y) {
side_dist_x += delta_dist_x;
map_x += step_x;
side = (ray_dir_x > 0) ? 0 : 2;
} else {
side_dist_y += delta_dist_y;
map_y += step_y;
side = 1;
}
// Check if ray has hit a wall
if (world_map[map_x][map_y] > 0) { hit = 1; }
}
// calculate distance projected on camera direction
double perp_wall_dist;
if (side == 0 || side == 2) { perp_wall_dist = (map_x - player->pos_x + (1 - step_x) / 2) / ray_dir_x; }
else { perp_wall_dist = (map_y - player->pos_y + (1 - step_y) / 2) / ray_dir_y; }
// fog effect
float fog_distance = 20.0f;
float scale_factor = 1.0f - perp_wall_dist / fog_distance;
if (scale_factor < 0.0f) { scale_factor = 0.0f; }
// calculate height of line on screen
int line_height = (int)(screen_height / perp_wall_dist);
int draw_start = -line_height / 2 + screen_height / 2;
if (draw_start < 0) { draw_start = 0; }
int draw_end = line_height / 2 + screen_height / 2;
if (draw_end >= screen_height) { draw_end = screen_height - 1; }
// colors :)
// TODO: currently, this effects both inside and outside faces
// which creates some awkward coloring issues with the outer walls.
// this may not be an issue in the final release, depending how walls
// are handled, but worth noting now.
ColorRGB color;
if (world_map[map_x][map_y] == 1) color = (ColorRGB){.r = 255, .g = 255, .b = 255};
else if (world_map[map_x][map_y] == 2) color = (ColorRGB){.r = 255, .g = 0, .b = 0};
else if (world_map[map_x][map_y] == 3) color = (ColorRGB){.r = 0, .g = 255, .b = 0};
else if (world_map[map_x][map_y] == 4) color = (ColorRGB){.r = 0, .g = 0, .b = 255};
else color = (ColorRGB){.r = 0, .g = 0, .b = 0};
if (side == 1) {
color.r /= 2;
color.g /= 2;
color.b /= 2;
} else if (side == 2) {
color.r /= 4;
color.g /= 4;
color.b /= 4;
}
// scale brightness in accordance with distance (for fog)
color.r *= scale_factor;
color.g *= scale_factor;
color.b *= scale_factor;
// TODO: recommended to put this in its own function or something at some point,
// as it deals with library calls outside of this function's scope
glBegin(GL_LINES);
glColor3ub(color.r, color.g, color.b);
glVertex2i(x, draw_start);
glVertex2i(x, draw_end);
glEnd();
}
}
int main(int argc, char *argv[]) {
GLFWwindow* window;
// init player
Player player;
player.pos_y = 2.0f;
player.pos_x = 2.0f;
player.dir_x = 1.0f; // facing right
player.dir_y = 0.0f; // facing right
player.plane_x = 0.0f; // FOV related
player.plane_y = 0.66f; // FOV related
player.move_speed = 0.05f;
player.rot_speed = 0.1f;
// initiate glfw library
if (!glfwInit()){
printf("Failed to initiate GLFW.\n");
return -1;
}
// create glfw window
window = glfwCreateWindow(800, 600, "raycaster", NULL, NULL);
if (!window){
printf("Failed to create GLFW window.\n");
glfwTerminate();
return -1;
}
// make window current
glfwMakeContextCurrent(window);
// setup orthographic projection camera
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0, 800, 600, 0.0, -1.0, 1.0);
glMatrixMode(GL_MODELVIEW);
// TODO: move timers into a header
double last_time = glfwGetTime();
int nb_frames = 0;
// TODO: render FPS with freetype or something as opposed to updating title
char title[200];
while (!glfwWindowShouldClose(window)) {
// timing section
double current_time = glfwGetTime();
nb_frames++;
if (current_time - last_time >= 1.0) {
sprintf(title, "FPS: %d", nb_frames);
glfwSetWindowTitle(window, title);
nb_frames = 0;
last_time += 1.0;
}
// clear window
glClear(GL_COLOR_BUFFER_BIT);
glLoadIdentity();
// main raycast function
raycast(&player);
// movement and camera rotation
// TODO: eventually translate movement from a header
if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS) {
player.pos_x += player.dir_x * player.move_speed;
player.pos_y += player.dir_y * player.move_speed;
}
if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS) {
player.pos_x -= player.dir_x * player.move_speed;
player.pos_y -= player.dir_y * player.move_speed;
}
if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS) {
// this changes where we're casting our rays
double old_dir_x = player.dir_x;
player.dir_x = player.dir_x * cos(-player.rot_speed) - player.dir_y * sin(-player.rot_speed);
player.dir_y = old_dir_x * sin(-player.rot_speed) + player.dir_y * cos(-player.rot_speed);
// this updates perspective
double old_plane_x = player.plane_x;
player.plane_x = player.plane_x * cos(-player.rot_speed) - player.plane_y * sin(-player.rot_speed);
player.plane_y = old_plane_x * sin(-player.rot_speed) + player.plane_y * cos(-player.rot_speed);
}
if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS) {
double old_dir_x = player.dir_x;
player.dir_x = player.dir_x * cos(player.rot_speed) - player.dir_y * sin(player.rot_speed);
player.dir_y = old_dir_x * sin(player.rot_speed) + player.dir_y * cos(player.rot_speed);
double old_plane_x = player.plane_x;
player.plane_x = player.plane_x * cos(player.rot_speed) - player.plane_y * sin(player.rot_speed);
player.plane_y = old_plane_x * sin(player.rot_speed) + player.plane_y * cos(player.rot_speed);
}
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
printf("Terminating program...\n");
return 0;
}
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