Making the monsters attack

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  1. Tutorials

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  2. Introduction to coding

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  3. Making the monsters attack

Making the monsters attack

To keep track of the health and the amount of gold and potions the player has, we define 3 variables:

int playerGoldAmount = 0, playerPotionAmount = 0, playerHealthAmount = 3;

How the monsters attack

The monsters attack by casting an aura of shadow around them. Basically, when the character is close to a monster, he takes damage over time.

We define a variable to keep track of the amount of time the player has been around a monster and a variable storing whether he is close to a monster or not.

sf::Clock monsterAttackClock; bool isPlayerNearMonster = false;

Handling the attack of the monsters

We define a variable representing whether the character is currently close to a monster. By default, we assume he is not.

bool isPlayerCurrentlyNearMonster = false;

For each monster:

for(int c=0; c < 4; c++) {

If it is not dead:

if(monstersDead[c] == false) {

We define a sf::FloatRect of 3 times the size of the monster, located around it, that we consider to be the range in which it can deal damage to the player:

// We copy the sf::FloatRect representing the bounds of the monster. sf::FloatRect nearMonsterRect(monsters[c].getGlobalBounds()); // We center it. nearMonsterRect.left -= nearMonsterRect.width; nearMonsterRect.top -= nearMonsterRect.height; // We scale it by 3. nearMonsterRect.width *= 3; nearMonsterRect.height *= 3;

If the player is in the range of attack of the monster:

if(player.getGlobalBounds().intersects(nearMonsterRect)) {

We set the variable indicating if he is currently close to a monster to true:

isPlayerCurrentlyNearMonster = true;

If, before, he was already in the range of attack of the monster:

if(isPlayerNearMonster) {

Then, if the player had been in the range of the aura of the monster for at least 1 second and that he is not already dead:

if(monsterAttackClock.getElapsedTime().asSeconds() >= 1 && playerHealthAmount > 0) {

We subtract 1 from the amount of health of the player:

playerHealthAmount--;

We restart the attack clock of the monsters so there is an other 1 second lap of time before the player loses an other health point:

monsterAttackClock.restart();

Then, we update the texture of the heart icon:

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if(playerHealthAmount == 0) // He is dead, its last 'heart' is empty. hearts[0].setTexture(emptyHeartTex); else if(playerHealthAmount == 1) // He lost its second 'heart'. hearts[1].setTexture(emptyHeartTex); else // He lost its first 'heart'. hearts[2].setTexture(emptyHeartTex);

If the character was not close to a monster before now, we, instead, restart the attack clock of the monsters (From now, if he stays in the range for at least 1 second, he will lose health) and we set the variable indicating whether he is close to a monster to true:

else { isPlayerNearMonster = true; monsterAttackClock.restart(); }

After that, if the variable ' isPlayerCurrentlyNearMonster' kept the value 'false' (The monster is not currently close to a monster), we set the variable ' isPlayerNearMonster' to 'false', so the next time the player is found to be in the attack range of a monster, we know he just entered it:

if(isPlayerCurrentlyNearMonster == false) isPlayerNearMonster = false;

The monsters can now deal damage to the player:

The player has lost health

The code of the game so far

main.cpp

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#include <SFML/Graphics.hpp> int main() { sf::RenderWindow win(sf::VideoMode(800, 600), "Introduction to coding", sf::Style::Close); // Grass sf::Texture grassTex; grassTex.loadFromFile("resources/grass.png"); grassTex.setRepeated(true); sf::Sprite grass; grass.setTexture(grassTex); grass.setScale(5, 5); grass.setTextureRect(sf::IntRect(0,0,160,120)); // Dirt tiles sf::Texture dirtTex; dirtTex.loadFromFile("resources/dirt.png"); sf::Sprite dirtTiles[10]; dirtTiles[0].setPosition(300, 60); dirtTiles[1].setPosition(660, 300); dirtTiles[2].setPosition(390, 480); dirtTiles[3].setPosition(660, 60); dirtTiles[4].setPosition(720, 420); dirtTiles[5].setPosition(180, 300); dirtTiles[6].setPosition(60, 180); dirtTiles[7].setPosition(60, 420); dirtTiles[8].setPosition(240, 420); dirtTiles[9].setPosition(480, 120); for(int c = 0; c < 10; c++) { dirtTiles[c].setTexture(dirtTex); dirtTiles[c].setScale(5, 5); } // Trees sf::Texture treeTex; treeTex.loadFromFile("resources/tree.png"); sf::Sprite trees[8]; trees[0].setPosition(50, 60); trees[1].setPosition(600, 150); trees[2].setPosition(630, 456); trees[3].setPosition(300, 600); trees[4].setPosition(720, 40); trees[5].setPosition(460, 500); trees[6].setPosition(20, 370); trees[7].setPosition(340, 240); for(int c = 0; c < 8; c++) { trees[c].setTexture(treeTex); trees[c].setScale(3, 3); } // Stones sf::Texture stoneTex; stoneTex.loadFromFile("resources/stone.png"); sf::Sprite stones[3]; stones[0].setPosition(304, 64); stones[1].setPosition(664, 304); stones[2].setPosition(180, 300); for(int c = 0; c < 3; c++) { stones[c].setTexture(stoneTex); stones[c].setScale(3, 3); } // Player sf::Texture playerTex; playerTex.loadFromFile("resources/player.png"); sf::Texture playerAttackingTex; playerAttackingTex.loadFromFile("resources/playerAttacking.png"); sf::Sprite player; player.setTexture(playerTex); player.setPosition(400, 300); player.setScale(3, 3); float playerMovementSpeed = 200.0; sf::Clock playerMovementClock; sf::Clock playerAttackClock; int playerGoldAmount = 0, playerPotionAmount = 0, playerHealthAmount = 3; // Monsters sf::Texture monsterTexs[3]; monsterTexs[0].loadFromFile("resources/monster1.png"); monsterTexs[1].loadFromFile("resources/monster2.png"); monsterTexs[2].loadFromFile("resources/monster3.png"); sf::Sprite monsters[4]; monsters[0].setPosition(500, 40); monsters[1].setPosition(100, 170); monsters[2].setPosition(400, 450); monsters[3].setPosition(690, 160); bool monstersDead[4]; for(int c = 0; c < 4; c++) { monsters[c].setTexture(monsterTexs[0]); monsters[c].setScale(3, 3); monstersDead[c] = false; } sf::Clock monstersAnimationClock; sf::Clock monsterRespawnClocks[4]; sf::Clock monsterAttackClock; bool isPlayerNearMonster = false; // Gold sf::Texture goldTex; goldTex.loadFromFile("resources/gold.png"); sf::Sprite gold; gold.setTexture(goldTex); gold.setScale(2, 2); gold.setPosition(15, 10); sf::Font font; font.loadFromFile("resources/LinuxBiolinum.ttf"); sf::Text goldAmountText; goldAmountText.setFont(font); goldAmountText.setString("0"); goldAmountText.setFillColor(sf::Color::White); goldAmountText.setCharacterSize(24); goldAmountText.setPosition(60, 10); // Potions sf::Texture healthPotionTex; healthPotionTex.loadFromFile("resources/healthPotion.png"); sf::Texture emptyVialTex; emptyVialTex.loadFromFile("resources/emptyVial.png"); sf::Sprite potion; potion.setTexture(emptyVialTex); potion.setScale(2, 2); potion.setPosition(350, 10); sf::Text potionAmountText; potionAmountText.setFont(font); potionAmountText.setString("0"); potionAmountText.setFillColor(sf::Color::White); potionAmountText.setCharacterSize(24); potionAmountText.setPosition(395, 10); // Health of the player sf::Texture heartTex; heartTex.loadFromFile("resources/heart.png"); sf::Texture emptyHeartTex; emptyHeartTex.loadFromFile("resources/emptyHeart.png"); sf::Sprite hearts[3]; hearts[0].setPosition(800 - 130, 10); hearts[1].setPosition(800 - 90, 10); hearts[2].setPosition(800 - 50, 10); for(int c = 0; c < 3; c++) { hearts[c].setTexture(heartTex); hearts[c].setScale(2, 2); } // Game loop sf::Event event; while(win.isOpen()) { while(win.pollEvent(event)) { if(event.type == sf::Event::Closed) win.close(); } // Player movements sf::Vector2f trans; float mouv = playerMovementClock.getElapsedTime().asSeconds() * playerMovementSpeed; if(sf::Keyboard::isKeyPressed(sf::Keyboard::W)) trans.y -= mouv; if(sf::Keyboard::isKeyPressed(sf::Keyboard::S)) trans.y += mouv; if(sf::Keyboard::isKeyPressed(sf::Keyboard::A)) trans.x -= mouv; if(sf::Keyboard::isKeyPressed(sf::Keyboard::D)) trans.x += mouv; player.setPosition(player.getPosition().x+trans.x, player.getPosition().y+trans.y); playerMovementClock.restart(); // Collision testing for(int c=0; c < 8; c++) { if(player.getGlobalBounds().intersects(trees[c].getGlobalBounds())) player.setPosition(player.getPosition().x-trans.x, player.getPosition().y-trans.y); } for(int c=0; c < 3; c++) { if(player.getGlobalBounds().intersects(stones[c].getGlobalBounds())) player.setPosition(player.getPosition().x-trans.x, player.getPosition().y-trans.y); } // Animation of the monsters int index = monstersAnimationClock.getElapsedTime().asMilliseconds() / 333; if(index > 2) { monstersAnimationClock.restart(); index = 0; } for(int c=0; c < 4; c++) { monsters[c].setTexture(monsterTexs[index]); } // Player attacking if((sf::Keyboard::isKeyPressed(sf::Keyboard::Space) || sf::Mouse::isButtonPressed(sf::Mouse::Left)) && playerAttackClock.getElapsedTime().asMilliseconds() > 1000) { playerAttackClock.restart(); player.setTexture(playerAttackingTex); // Testing if the attack reaches a monster sf::FloatRect attackRect(player.getPosition()+sf::Vector2f((player.getGlobalBounds().width/4), -player.getGlobalBounds().height/3), sf::Vector2f(player.getGlobalBounds().width/4, player.getGlobalBounds().height/3)); for(int c=0; c < 4; c++) { if(monstersDead[c] == false && attackRect.intersects(monsters[c].getGlobalBounds())) { monstersDead[c] = true; monsterRespawnClocks[c].restart(); } } } if(playerAttackClock.getElapsedTime().asMilliseconds() > 1000) player.setTexture(playerTex); // Monster attacking bool isPlayerCurrentlyNearMonster = false; for(int c=0; c < 4; c++) { if(monstersDead[c] == false) { sf::FloatRect nearMonsterRect(monsters[c].getGlobalBounds()); nearMonsterRect.left -= nearMonsterRect.width; nearMonsterRect.top -= nearMonsterRect.height; nearMonsterRect.width *= 3; nearMonsterRect.height *= 3; if(player.getGlobalBounds().intersects(nearMonsterRect)) { isPlayerCurrentlyNearMonster = true; if(isPlayerNearMonster) { if(monsterAttackClock.getElapsedTime().asSeconds() >= 1 && playerHealthAmount > 0) { playerHealthAmount--; monsterAttackClock.restart(); if(playerHealthAmount == 0) hearts[0].setTexture(emptyHeartTex); else if(playerHealthAmount == 1) hearts[1].setTexture(emptyHeartTex); else hearts[2].setTexture(emptyHeartTex); } } else { isPlayerNearMonster = true; monsterAttackClock.restart(); } } } } if(isPlayerCurrentlyNearMonster == false) isPlayerNearMonster = false; // Respawn of the monsters for(int c=0; c < 4; c++) { if(monsterRespawnClocks[c].getElapsedTime().asSeconds() >= 8) monstersDead[c] = false; } // Rendering win.clear(); win.draw(grass); for(int c = 0; c < 10; c++) win.draw(dirtTiles[c]); for(int c = 0; c < 8; c++) win.draw(trees[c]); for(int c = 0; c < 3; c++) win.draw(stones[c]); win.draw(player); for(int c = 0; c < 4; c++) { if(monstersDead[c] == false) win.draw(monsters[c]); } win.draw(gold); win.draw(goldAmountText); win.draw(potion); win.draw(potionAmountText); for(int c = 0; c < 3; c++) win.draw(hearts[c]); win.display(); } return 0; }