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Diffstat (limited to 'examples/ray_casting.c')
| -rw-r--r-- | examples/ray_casting.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/examples/ray_casting.c b/examples/ray_casting.c new file mode 100644 index 0000000..32a382b --- /dev/null +++ b/examples/ray_casting.c @@ -0,0 +1,218 @@ +#define FBGL_IMPLEMENTATION +#include "fbgl.h" + +#include <math.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <stdbool.h> +#include <unistd.h> + +#define MAP_WIDTH 8 +#define MAP_HEIGHT 8 +#define TILE_SIZE 64 +#define PLAYER_SPEED 2 +#define TURN_SPEED 0.1f + +uint32_t get_pixel(const fbgl_t *framebuffer, int x, int y) { + return framebuffer->pixels[y * framebuffer->width + x]; +} + + +void save_frame_as_ppm(const fbgl_t *framebuffer, const char *filename) { + FILE *file = fopen(filename, "wb"); + if (!file) { + fprintf(stderr, "Failed to save frame as PPM.\n"); + return; + } + + // Write PPM header + fprintf(file, "P6\n%d %d\n255\n", framebuffer->width, framebuffer->height); + + // Write pixel data + for (int y = 0; y < framebuffer->height; ++y) { + for (int x = 0; x < framebuffer->width; ++x) { + uint32_t color = get_pixel(framebuffer, x, y); + uint8_t r = (color >> 16) & 0xFF; + uint8_t g = (color >> 8) & 0xFF; + uint8_t b = color & 0xFF; + fwrite(&r, 1, 1, file); + fwrite(&g, 1, 1, file); + fwrite(&b, 1, 1, file); + } + } + + fclose(file); +} + + +// World map +const char WORLD_MAP[MAP_WIDTH][MAP_HEIGHT] = { + {'#', '#', '#', '#', '#', '#', '#', '#'}, + {'#', ' ', ' ', ' ', ' ', ' ', ' ', '#'}, + {'#', ' ', '#', '#', ' ', '#', ' ', '#'}, + {'#', ' ', '#', ' ', ' ', '#', ' ', '#'}, + {'#', ' ', '#', ' ', '#', '#', ' ', '#'}, + {'#', ' ', ' ', ' ', ' ', ' ', ' ', '#'}, + {'#', ' ', '#', '#', '#', '#', ' ', '#'}, + {'#', '#', '#', '#', '#', '#', '#', '#'} +}; + +// Player structure +typedef struct { + float x, y; // Player position + float angle; // Viewing angle + float fov; // Field of view +} Player; + +// Player instance +Player player = {128.0f, 128.0f, 0.0f, M_PI / 4.0f}; + +// Framebuffer instance +fbgl_t framebuffer; + +// Calculate shaded color based on distance +uint32_t calculate_shaded_color(uint32_t base_color, float distance) { + float shade_factor = 1.0f / (distance + 1.0f); + return FBGL_RGB( + (int)((base_color >> 16 & 0xFF) * shade_factor), + (int)((base_color >> 8 & 0xFF) * shade_factor), + (int)((base_color & 0xFF) * shade_factor) + ); +} + +// Draw a solid vertical slice for a wall +void draw_wall_slice(int x, int wall_height, uint32_t color) { + int top = (framebuffer.height / 2) - (wall_height / 2); + int bottom = (framebuffer.height / 2) + (wall_height / 2); + + // Clip the top and bottom to the framebuffer boundaries + if (top < 0) top = 0; + if (bottom >= framebuffer.height) bottom = framebuffer.height - 1; + + fbgl_point_t top_left = {x, top}; + fbgl_point_t bottom_right = {x + 1, bottom}; + fbgl_draw_rectangle_filled(top_left, bottom_right, color, &framebuffer); +} + +int frame_counter = 0; +// Perform ray-casting to render the 3D view +void cast_rays() { + for (int ray = 0; ray < framebuffer.width; ray++) { + float ray_angle = player.angle - player.fov / 2 + player.fov * ray / framebuffer.width; + + float distance_to_wall = 0.0f; + bool hit_wall = false; + bool vertical_hit = false; + + float eye_x = cos(ray_angle); + float eye_y = sin(ray_angle); + + while (!hit_wall && distance_to_wall < 16.0f) { + distance_to_wall += 0.1f; + int test_x = (int)(player.x / TILE_SIZE + eye_x * distance_to_wall); + int test_y = (int)(player.y / TILE_SIZE + eye_y * distance_to_wall); + + // Check if the ray is out of bounds + if (test_x < 0 || test_x >= MAP_WIDTH || test_y < 0 || test_y >= MAP_HEIGHT) { + hit_wall = true; + distance_to_wall = 16.0f; + break; + } + + // Check if the ray hit a wall + if (WORLD_MAP[test_x][test_y] == '#') { + hit_wall = true; + + // Determine if the hit was on a vertical wall + if (fabs(eye_x) > fabs(eye_y)) { + vertical_hit = true; + } + } + } + + // Calculate wall height + int wall_height = (int)(framebuffer.height / distance_to_wall); + + // Choose base wall color + uint32_t base_color = vertical_hit + ? FBGL_RGB(150, 150, 255) // Bluish for vertical walls + : FBGL_RGB(255, 150, 150); // Reddish for horizontal walls + + // Calculate shaded color + uint32_t shaded_color = calculate_shaded_color(base_color, distance_to_wall); + + // Render the wall slice + draw_wall_slice(ray, wall_height, shaded_color); + } +} + +// Main program +int main() { + // Initialize framebuffer + if (fbgl_init(NULL, &framebuffer) < 0) { + fprintf(stderr, "Failed to initialize framebuffer.\n"); + return 1; + } + + // Initialize keyboard + if (fbgl_keyboard_init() != 0) { + fprintf(stderr, "Failed to initialize keyboard.\n"); + fbgl_destroy(&framebuffer); + return 1; + } + + // Main game loop + while (true) { + // Set the background color to black + fbgl_set_bg(&framebuffer, FBGL_RGB(0, 0, 0)); + + // Perform ray-casting and render the scene + cast_rays(); + char filename[64]; + snprintf(filename, sizeof(filename), "frame_%04d.ppm", frame_counter++); + save_frame_as_ppm(&framebuffer, filename); + // Get key input + fbgl_key_t key = fbgl_get_key(); + + // Handle player movement + if (key == FBGL_KEY_UP) { + float next_x = player.x + cos(player.angle) * PLAYER_SPEED; + float next_y = player.y + sin(player.angle) * PLAYER_SPEED; + + // Prevent moving into walls + if (WORLD_MAP[(int)(next_x / TILE_SIZE)][(int)(player.y / TILE_SIZE)] != '#') { + player.x = next_x; + } + if (WORLD_MAP[(int)(player.x / TILE_SIZE)][(int)(next_y / TILE_SIZE)] != '#') { + player.y = next_y; + } + } else if (key == FBGL_KEY_DOWN) { + float next_x = player.x - cos(player.angle) * PLAYER_SPEED; + float next_y = player.y - sin(player.angle) * PLAYER_SPEED; + + // Prevent moving into walls + if (WORLD_MAP[(int)(next_x / TILE_SIZE)][(int)(player.y / TILE_SIZE)] != '#') { + player.x = next_x; + } + if (WORLD_MAP[(int)(player.x / TILE_SIZE)][(int)(next_y / TILE_SIZE)] != '#') { + player.y = next_y; + } + } else if (key == FBGL_KEY_LEFT) { + player.angle -= TURN_SPEED; + } else if (key == FBGL_KEY_RIGHT) { + player.angle += TURN_SPEED; + } else if (key == FBGL_KEY_ESCAPE) { + // Exit the game loop + break; + } + + // Frame delay for ~60 FPS + usleep(16666); + } + + // Cleanup resources + fbgl_destroy(&framebuffer); + fbgl_destroy_keyboard(); + return 0; +} |