Topics

1

General / Vector of Vectors Collision Detection

« on: May 28, 2018, 04:28:06 am »

Hello,

I am having issues with collision detection of player bullets against enemies.

I have three "types" of enemies and plan on having many more with distinct characteristics.

enemyOne(sf::Color::Yellow, 20.f, 20.f)
enemyTwo(sf::Color::Red, 40.f, 40.f)
enemyThree(sf::Color::Cyan, 80.f, 80.f)

that feed into

std::vector<Enemy> enemiesOne;
std::vector<Enemy> enemiesTwo;
std::vector<Enemy> enemiesThree;

I currently have a not so elegant function that won't scale very well with my goal...however it does work.

void Bullet::BulletEnemyCollision(sf::RectangleShape playerBulletShape, std::vector<Enemy>& enemyVectorsOne, std::vector<Enemy>& enemyVectorsTwo, std::vector<Enemy>& enemyVectorsThree)
{
        for (unsigned int i = 0; i < enemyVectorsOne.size(); i++)
        {
                if (playerBulletShape.getGlobalBounds().intersects(enemyVectorsOne[i].enemyShape.getGlobalBounds()))
                {
                        enemyVectorsOne.erase(enemyVectorsOne.begin() + i);
                }
        }
        for (unsigned int i = 0; i < enemyVectorsTwo.size(); i++)
        {
                if (playerBulletShape.getGlobalBounds().intersects(enemyVectorsTwo[i].enemyShape.getGlobalBounds()))
                {
                        enemyVectorsTwo.erase(enemyVectorsTwo.begin() + i);
                }
        }
        for (unsigned int i = 0; i < enemyVectorsThree.size(); i++)
        {
                if (playerBulletShape.getGlobalBounds().intersects(enemyVectorsThree[i].enemyShape.getGlobalBounds()))
                {
                        enemyVectorsThree.erase(enemyVectorsThree.begin() + i);
                }
        }
}

An idea I have is to feed each enemy vector into a vector and simply have the function iterate through that vector of vectors. This currently does not work.

std::vector<std::vector<Enemy> >& enemyVectors

void Bullet::BulletEnemyCollision(sf::RectangleShape playerBulletShape, std::vector<std::vector<Enemy> >& enemyVectors)
{
        for (unsigned int i = 0; i < enemyVectors.size(); i++)
        {
                for (unsigned int j = 0; j < enemyVectors[i].size(); j++)
                {
                        if (playerBulletShape.getGlobalBounds().intersects(enemyVectors[i][j].enemyShape.getGlobalBounds()))
                        {
                                enemyVectors[i].erase(enemyVectors[i].begin() + j);
                        }
                }
        }
}

Below is a brief recording of the game with the not so elegant code in place.

https://gfycat.com/gifs/detail/LivelySpottedChevrotain

You may notice the lack of pointers and keywords like auto...etc. This game for me is an exercise in learning classes & functions at a basic level. The next game I plan on taking a stab at utilizing pointers and super useful keywords. The last game I made I was using header files for implementation...baby steps.

Thanks for reading and I appreciate the help.

2

General / Fire Bullet At Angle

« on: April 22, 2018, 03:31:14 am »

Hello,

I am working on a game that so far has:

• A square moving around with a basic velocity system (wasd)
• The Square also rotates based on mouse position

I am now trying to implement bullets that will fire in the direction the square (player) is rotated, I made a very simple system with the last game I made (thanks again Hapax) that only went in one direction.

The bullets fire (yay), just not at the right angle (boo). I debugged and looked at the rotation each time and the numbers matched....it just doesn't come out correctly visually.

Thanks!

This is main.cpp (I chopped a major chunk of code to isolate what the issue may be)

#include "Player.h"
#include "Bullet.h"
#include <iostream>

int main()
{
        //declare
        float delta, deltaCd, bulletTime, bulletCd, bulletSpeed, bulletAngle;
        float& dCd = deltaCd;
        sf::Clock gameClock, bulletClock;
        Player playerOne;
        Player& pO = playerOne;
        Bullet playerBullet;
        Bullet& pB = playerBullet;
        std::vector<sf::RectangleShape> bulletVector;
        std::vector<float> bulletAngleVector;

        //initialize
        delta = .0f;
        deltaCd = .25f;
        bulletTime = 1.0f;
        bulletCd = 2.0f;
        bulletSpeed = 1.5f;
        bulletAngle = .0f;

        playerBullet.bulletShape.setPosition(sf::Vector2f(playerOne.playerShape.getPosition().x,
       
        //window loop
        //TODO: Create game loop
        while (win.isOpen())
        {
                window.clear();
                delta = gameClock.restart().asSeconds();
                playerOne.PlayerRotation(win, pO.playerShape);
                playerBullet.BulletAngle(win, pB.bulletShape);

                if (sf::Mouse::isButtonPressed(sf::Mouse::Left) && bulletTime > bulletCd)
                {
                        bulletTime = bulletClock.restart().asSeconds();
                        playerBullet.bulletShape.setPosition(sf::Vector2f(playerOne.playerShape.getPosition().x, playerOne.playerShape.getPosition().y));
                        bulletAngle = playerBullet.bulletShape.getRotation();
                        bulletVector.push_back(playerBullet.bulletShape);
                        bulletAngleVector.push_back(bulletAngle);
                }              

                for (unsigned int i = 0; i < bulletVector.size(); i++)
                {
                        bulletVector[i].move(cos(bulletAngleVector[i]), sin(bulletAngleVector[i]));
                        window.draw(bulletVector[i]);
                }
               
                bulletTime = bulletClock.getElapsedTime().asSeconds();

                window.draw(pO.playerShape);
                window.display();
        }
}

bullet.cpp

#include "Bullet.h"

Bullet::Bullet()
{
        bulletSizeX = 5.f;
        bulletSizeY = 5.f;
        bulletShape.setSize(sf::Vector2f(bulletSizeX, bulletSizeY));
        bulletShape.setOrigin(sf::Vector2f(bulletShape.getGlobalBounds().width / 2.f, bulletShape.getGlobalBounds().height / 2.f));
        bulletShape.setFillColor(sf::Color::Red);
}

void Bullet::BulletAngle(sf::RenderWindow& win, sf::RectangleShape& bS)
{
        dx = 0.f;
        dy = 0.f;
        mouse = sf::Mouse::getPosition(win);
        mouseWorld = win.mapPixelToCoords(mouse);
        dx = mouseWorld.x - bS.getPosition().x;
        dy = mouseWorld.y - bS.getPosition().y;
        rotation = atan2(dy, dx) * 180 / PI;
        bS.setRotation(rotation);
}

bullet.h

#pragma once
#include <SFML/Graphics.hpp>

class Bullet
{
public:
        float bulletSizeX, bulletSizeY, dx, dy, rotation;
        const float PI = 3.14159265f;
        sf::Vector2i mouse;
        sf::Vector2f mouseWorld;
        sf::RectangleShape bulletShape;
        void BulletAngle(sf::RenderWindow& win, sf::RectangleShape& bS);
        Bullet();
};

3

General / Multiple bullets with isKeyPressed

« on: February 13, 2017, 12:41:56 am »

The bolded section is the area of concern. I am having a hard time wrapping my head around making a great bullet system that is easy to work with and manipulate when needed.

bullet_sprites is a vector of sprites, a new bullet sprite is pushed back into the vector when spacebar is pressed. I originally didn't have "&& bullet_sprites.size() == 0" in the first if statement, but it would create a stream of bullets and cause performance issues (see attached pic).

The bullet is erased when it is off screen and the issue I am having now is for one space bar keypress, two bullets are fired. When i say two, I mean one is fired and moved off screen and then a consecutive bullet is fired and moves off screen with only one keypress.

Thanks for any help, i can provide more code as well (like the header files being used). I watched youtube tutorials and even made a stripped down basic project that is having the same exact issue.

   while (main_window.isOpen())
   {      
      float delta = delta_clock.restart().asSeconds();
      if (sf::Keyboard::isKeyPressed(sf::Keyboard::Space))
      {
         fired_bullet = true;
      }
      //clear...draw...
      main_window.clear();
      move_the_background(main_background, main_background2, delta, main_window);
      start_level.level_one(asteroid_sprites, main_window, delta, space_ship);
      start_level.level_two(asteroid_sprites, main_window, delta, space_ship);
      main_window.draw(space_ship);

      //keypress
      key_check.w_key(space_ship.getPosition(), space_ship);
      key_check.s_key(space_ship.getPosition(), space_ship);
      key_check.a_key(space_ship.getPosition(), space_ship);
      key_check.d_key(space_ship.getPosition(), space_ship);
      key_check.esc_key(main_window);

      if (fired_bullet == true && bullet_sprites.size() == 0)
      {
         sf::Sprite new_bullet = create_bullet.create_sprite("bullet.png", true);
         new_bullet.setPosition(space_ship.getPosition().x + 145.f, space_ship.getPosition().y + 0.f);
         bullet_sprites.push_back(new_bullet);
         fired_bullet = false;
      }

      for (int j = 0; j < bullet_sprites.size(); j++)
      {
         main_window.draw(bullet_sprites[j]);
         create_bullet.move_sprite(1500.f, 0.f, delta, bullet_sprites[j], false, 0.f, false, 0.f, 0.f, "pos");
         if (bullet_sprites[j].getPosition().x > 1940)
         {
            bullet_sprites.erase (bullet_sprites.end() - 1);
         }   
      }

      //display...
      main_window.display();
      
      //check to see if main window is closed
      close_event_checker(main_window);
   }