Skip to content
Field Guide

Fly Catch

The C/C++ version of the Fly Catch is provided below. Use this if you get stuck converting this code yourself, but make sure you understand it!

#include "splashkit.h"


int main()
{
    const string GAME_TIMER = "GameTimer";


    const int SCREEN_WIDTH = 800;
    const int SCREEN_HEIGHT = 600;
    const int SPIDER_RADIUS = 25;
    const int SPIDER_SPEED = 3;


    const int FLY_RADIUS = 10;


    // Set the spider in the center of the screen
    int spiderX = SCREEN_WIDTH / 2;
    int spiderY = SCREEN_HEIGHT / 2;


    // Create the fly
    int flyX = rnd(SCREEN_WIDTH), flyY = rnd(SCREEN_HEIGHT);
    bool flyAppeared = false;
    long appearAtTime = 1000 + rnd(2000);
    long escapeAtTime = 0;


    open_window("Fly Catch", SCREEN_WIDTH, SCREEN_HEIGHT);


    create_timer(GAME_TIMER);
    start_timer(GAME_TIMER);


    // The event loop
    while (!quit_requested())
    {
        // Handle Input
        if (key_down(RIGHT_KEY) && spiderX + SPIDER_RADIUS < SCREEN_WIDTH)
        {
            spiderX += SPIDER_SPEED;
        }
        if (key_down(LEFT_KEY) && spiderX - SPIDER_RADIUS > 0)
        {
            spiderX -= SPIDER_SPEED;
        }


        // Update the Game
        // Check if the fly should appear
        if (! flyAppeared && timer_ticks(GAME_TIMER) > appearAtTime)
        {
            // Make the fly appear
            flyAppeared = true;


            // Give it a new random position
            flyX = rnd(SCREEN_WIDTH);
            flyY = rnd(SCREEN_HEIGHT);


            // Set its escape time
            escapeAtTime = timer_ticks(GAME_TIMER) + 2000 + rnd(5000);
        }
        else if (flyAppeared && timer_ticks(GAME_TIMER) > escapeAtTime)
        {
            flyAppeared = false;
            appearAtTime = timer_ticks(GAME_TIMER) + 1000 + rnd(2000);
        }


        // Test if the spider and fly are touching
        if (circles_intersect(spiderX, spiderY, SPIDER_RADIUS, flyX, flyY, FLY_RADIUS))
        {
            flyAppeared = false;
            appearAtTime = timer_ticks(GAME_TIMER) + 1000 + rnd(2000);
        }


        // Draw the game
        clear_screen(color_white());
        // Draw the spider
        fill_circle(color_black(), spiderX, spiderY, SPIDER_RADIUS);


        if (flyAppeared)
        {
            // Draw the fly
            fill_circle(color_dark_green(), flyX, flyY, FLY_RADIUS);
        }


        // Show it to  the user
        refresh_screen(60);


        // Get any new user interactions
        process_events();
    }
}