cosmopolitan/examples/asteroids.c
2024-11-22 08:52:49 -08:00

353 lines
10 KiB
C

// -*- mode:c; indent-tabs-mode:nil; c-basic-offset:4 -*-
// vi: set et ft=c ts=4 sts=4 sw=4 fenc=utf-8
// asteroids by tsotchke
// https://github.com/tsotchke/asteroids
// clang-format off
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>
#include <unistd.h>
#include <signal.h>
#include <termios.h>
#include <sys/select.h>
#define SCREEN_WIDTH 80
#define SCREEN_HEIGHT 24
#define MAX_ASTEROIDS 5
#define MAX_BULLETS 5
typedef struct {
float x, y;
} Vector2;
typedef struct {
Vector2 position;
Vector2 velocity;
float angle;
float radius;
} GameObject;
GameObject spaceship;
GameObject asteroids[MAX_ASTEROIDS];
GameObject bullets[MAX_BULLETS];
int score = 0;
time_t startTime;
int isGameOver = 0;
int shouldExit = 0;
int finalTime = 0; // To store final time at game over
char display[SCREEN_HEIGHT][SCREEN_WIDTH];
// Function to clear the screen buffer
void clearDisplay() {
memset(display, ' ', sizeof(display));
}
// Function to draw a pixel on the screen
void drawPixel(int x, int y) {
if (x >= 0 && x < SCREEN_WIDTH && y >= 0 && y < SCREEN_HEIGHT) {
display[y][x] = '*';
}
}
// Function to draw a line using Bresenham's algorithm
void drawLine(int x1, int y1, int x2, int y2) {
int dx = abs(x2 - x1), sx = (x1 < x2) ? 1 : -1;
int dy = -abs(y2 - y1), sy = (y1 < y2) ? 1 : -1;
int error = dx + dy, e2;
while (1) {
drawPixel(x1, y1);
if (x1 == x2 && y1 == y2) break;
e2 = 2 * error;
if (e2 >= dy) { error += dy; x1 += sx; }
if (e2 <= dx) { error += dx; y1 += sy; }
}
}
// Function to draw a circle
void drawCircle(int centerX, int centerY, int radius) {
int x = radius - 1, y = 0, dx = 1, dy = 1, err = dx - (radius << 1);
while (x >= y) {
drawPixel(centerX + x, centerY + y);
drawPixel(centerX + y, centerY + x);
drawPixel(centerX - y, centerY + x);
drawPixel(centerX - x, centerY + y);
drawPixel(centerX - x, centerY - y);
drawPixel(centerX - y, centerY - x);
drawPixel(centerX + y, centerY - x);
drawPixel(centerX + x, centerY - y);
if (err <= 0) {
y++;
err += dy;
dy += 2;
}
if (err > 0) {
x--;
dx += 2;
err += dx - (radius << 1);
}
}
}
// Initialize a game object
void initializeGameObject(GameObject *obj, float x, float y, float angle, float radius) {
obj->position = (Vector2){x, y};
obj->velocity = (Vector2){0, 0};
obj->angle = angle;
obj->radius = radius;
}
// Wrap position of the spaceship and asteroids within screen bounds
void wrapPosition(Vector2 *pos) {
if (pos->x < 0) pos->x = SCREEN_WIDTH - 1;
if (pos->x >= SCREEN_WIDTH) pos->x = 0;
if (pos->y < 0) pos->y = SCREEN_HEIGHT - 1;
if (pos->y >= SCREEN_HEIGHT) pos->y = 0;
}
// Check if two game objects are colliding
int checkCollision(GameObject *a, GameObject *b) {
float deltaX = a->position.x - b->position.x;
float deltaY = a->position.y - b->position.y;
return sqrt(deltaX * deltaX + deltaY * deltaY) < (a->radius + b->radius);
}
// Initialize game state
void initGame() {
score = 0; // Reset the score
initializeGameObject(&spaceship, SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2, 0, 2);
for (int i = 0; i < MAX_ASTEROIDS; i++) {
initializeGameObject(&asteroids[i],
rand() % SCREEN_WIDTH,
rand() % SCREEN_HEIGHT,
0,
2 + rand() % 3);
asteroids[i].velocity.x = ((float)rand() / RAND_MAX) * 2 - 1;
asteroids[i].velocity.y = ((float)rand() / RAND_MAX) * 2 - 1;
}
for (int i = 0; i < MAX_BULLETS; i++) {
bullets[i].position.x = -1; // Mark bullet as inactive
bullets[i].position.y = -1;
}
startTime = time(NULL);
isGameOver = 0;
finalTime = 0; // Reset final time
}
// Draw the spaceship on the screen
void drawSpaceship() {
int x = (int)spaceship.position.x;
int y = (int)spaceship.position.y;
int size = 3;
float cosAngle = cos(spaceship.angle);
float sinAngle = sin(spaceship.angle);
int x1 = x + size * cosAngle;
int y1 = y + size * sinAngle;
int x2 = x + size * cos(spaceship.angle + 2.5);
int y2 = y + size * sin(spaceship.angle + 2.5);
int x3 = x + size * cos(spaceship.angle - 2.5);
int y3 = y + size * sin(spaceship.angle - 2.5);
drawLine(x1, y1, x2, y2);
drawLine(x2, y2, x3, y3);
drawLine(x3, y3, x1, y1);
}
// Draw all entities on the screen
void drawEntities(GameObject *entities, int count, void (*drawFunc)(GameObject *)) {
for (int i = 0; i < count; i++) {
drawFunc(&entities[i]);
}
}
// Draw a bullet on the screen
void drawBullet(GameObject *bullet) { // Changed to non-const
if (bullet->position.x >= 0) {
drawPixel((int)bullet->position.x, (int)bullet->position.y);
}
}
// Draw an asteroid on the screen
void drawAsteroid(GameObject *asteroid) { // Changed to non-const
drawCircle((int)asteroid->position.x, (int)asteroid->position.y, (int)asteroid->radius);
}
// Refresh the display
void updateDisplay() {
clearDisplay();
if (!isGameOver) {
drawSpaceship();
drawEntities(asteroids, MAX_ASTEROIDS, drawAsteroid);
drawEntities(bullets, MAX_BULLETS, drawBullet);
}
// Print the screen buffer
printf("\033[H");
for (int y = 0; y < SCREEN_HEIGHT; y++) {
for (int x = 0; x < SCREEN_WIDTH; x++) {
putchar(display[y][x]);
}
putchar('\n');
}
// Display score and elapsed time
time_t currentTime = time(NULL);
int elapsedTime = isGameOver ? finalTime : (currentTime - startTime);
printf("Score: %d | Time: %02d:%02d | %s\n", score, elapsedTime / 60, elapsedTime % 60, isGameOver ? "Game Over!" : " ");
}
// Update the position of game objects
void updateGameObject(GameObject *obj, int isBullet) {
obj->position.x += obj->velocity.x;
obj->position.y += obj->velocity.y;
// If it's a bullet, check if it's out of bounds
if (isBullet) {
if (obj->position.x < 0 || obj->position.x >= SCREEN_WIDTH || obj->position.y < 0 || obj->position.y >= SCREEN_HEIGHT) {
obj->position.x = -1; // Deactivate bullet
obj->position.y = -1;
}
} else {
wrapPosition(&obj->position);
}
}
// Update the game state
void updateGame() {
if (isGameOver) return;
// Update spaceship and apply friction
updateGameObject(&spaceship, 0); // 0 indicates it's not a bullet
spaceship.velocity.x *= 0.98;
spaceship.velocity.y *= 0.98;
// Move asteroids and check for collisions
for (int i = 0; i < MAX_ASTEROIDS; i++) {
updateGameObject(&asteroids[i], 0);
if (checkCollision(&spaceship, &asteroids[i])) {
isGameOver = 1;
finalTime = time(NULL) - startTime;
return;
}
}
// Update bullet positions
for (int i = 0; i < MAX_BULLETS; i++) {
if (bullets[i].position.x >= 0) {
updateGameObject(&bullets[i], 1); // 1 indicates it's a bullet
}
}
// Check for bullet collisions with asteroids
for (int i = 0; i < MAX_BULLETS; i++) {
if (bullets[i].position.x >= 0) {
for (int j = 0; j < MAX_ASTEROIDS; j++) {
if (checkCollision(&bullets[i], &asteroids[j])) {
bullets[i].position.x = -1; // Deactivate bullet
bullets[i].position.y = -1;
asteroids[j].position.x = rand() % SCREEN_WIDTH;
asteroids[j].position.y = rand() % SCREEN_HEIGHT;
score += 100;
}
}
}
}
}
// Fire a bullet
void shootBullet() {
for (int i = 0; i < MAX_BULLETS; i++) {
if (bullets[i].position.x < 0) {
bullets[i].position = spaceship.position;
bullets[i].velocity.x = cos(spaceship.angle) * 2;
bullets[i].velocity.y = sin(spaceship.angle) * 2;
break;
}
}
}
// Check if a key was hit
int isKeyHit() {
struct timeval tv = { 0L, 0L };
fd_set fds;
FD_ZERO(&fds);
FD_SET(0, &fds);
return select(1, &fds, NULL, NULL, &tv);
}
// Configure terminal settings
void configureTerminal(struct termios *old_tio, struct termios *new_tio) {
tcgetattr(STDIN_FILENO, old_tio);
*new_tio = *old_tio;
new_tio->c_lflag &= (~ICANON & ~ECHO);
tcsetattr(STDIN_FILENO, TCSANOW, new_tio);
}
// Restore terminal settings
void restoreTerminal(struct termios *old_tio) {
tcsetattr(STDIN_FILENO, TCSANOW, old_tio);
}
void onSignal(int sig) {
shouldExit = 1;
}
// Main game loop
int main() {
signal(SIGINT, onSignal); // Capture ^C
srand(time(NULL)); // Seed the random number generator
initGame(); // Initialize the game state
struct termios old_tio, new_tio;
configureTerminal(&old_tio, &new_tio);
printf("\033[?25l"); // Hide the cursor
while (!shouldExit) {
if (isKeyHit()) {
char input = getchar();
if (input == 27) { // ESC key
if (getchar() == '[') { // Handle arrow keys
switch (getchar()) {
case 'A': // Up arrow
spaceship.velocity.x += cos(spaceship.angle) * 0.2;
spaceship.velocity.y += sin(spaceship.angle) * 0.2;
break;
case 'B': // Down arrow
spaceship.velocity.x -= cos(spaceship.angle) * 0.2;
spaceship.velocity.y -= sin(spaceship.angle) * 0.2;
break;
case 'D': spaceship.angle -= 0.2; break; // Left arrow
case 'C': spaceship.angle += 0.2; break; // Right arrow
}
}
} else if (input == ' ') {
shootBullet(); // Fire a bullet
} else if (input == 'q') {
break; // Quit the game
} else if (input == 'r' && isGameOver) {
initGame(); // Restart the game
}
}
updateGame(); // Update game state
updateDisplay(); // Refresh the display
usleep(50000); // Wait for 50ms (20 FPS)
}
printf("\033[?25h"); // Show the cursor
restoreTerminal(&old_tio); // Restore terminal settings
return 0;
}