Error in the Collision of the Player Character

[solar river]

Hi! I hope you are having a good day or night or whatever. I come to you because I am currently working on a game project and I am stuck doing the collisions because for some reason the invisible rectangle made to serve has the collision box of the character is offset, like its not on the center of the character. When it collides with a tile on the right it creates a bigger gap than it does on the left.

I have been following this tutorial and so far it has been incredibly helpful, until now.
https://youtu.be/oPzPpUcDiYY?si=W98I88btmC0LyZrb

I also will provide my own code if necessary (Which I guess it is going to be), but it is not going to fit here so, yeah.

[uneven verge]

<@&987246883653156906> please have a look, thanks.

[solar river]

I will put here the code that is important for collisions

[soft rune]

can we see the code?

[solar river]

I am struggling to put it here 😭

[soft rune]

ah got it

[solar river]

First part of the Collision Checker

import Entity.Entity;
public class CollisionChecker {
    
    GameMenu gp;
    
    public CollisionChecker (GameMenu gp) {
        this.gp = gp;
    }
    
    public void checkTile (Entity entity) {
        int entityleftWorldX = entity.worldx + entity.solidArea.x;
        int entityrightWorldX = entity.worldx + entity.solidArea.x + entity.solidArea.width;
        int entitytopWorldY = entity.worldy + entity.solidArea.y;
        int entitybottomWorldY = entity.worldy + entity.solidArea.y + entity.solidArea.height;
        
        int entityleftcol = entityleftWorldX / gp.tileSize;
        int entityrightcol = entityrightWorldX / gp.tileSize;
        int entitytoprow = entitytopWorldY / gp.tileSize;
        int entitybottomrow = entitybottomWorldY / gp.tileSize;
        
        int tileNum1, tileNum2;```

            case "up":
                entitytoprow = (entitytopWorldY - entity.speed) / gp.tileSize;
                tileNum1 = gp.tileM.mapTileNum[entityleftcol][entitytoprow];
                tileNum2 = gp.tileM.mapTileNum[entityrightcol][entitytoprow];
                if (gp.tileM.tile[tileNum1].collision == true || gp.tileM.tile[tileNum2].collision == true) {
                    entity.collisionOn = true;
                }
                break;
            case "down":
                entitybottomrow = (entitybottomWorldY + entity.speed) / gp.tileSize;
                tileNum1 = gp.tileM.mapTileNum[entityleftcol][entitybottomrow];
                tileNum2 = gp.tileM.mapTileNum[entityrightcol][entitybottomrow];
                if (gp.tileM.tile[tileNum1].collision == true || gp.tileM.tile[tileNum2].collision == true) {
                    entity.collisionOn = true;
                }
                break;
            case "left":
                entityleftcol = (entityleftWorldX - entity.speed) / gp.tileSize;
                tileNum1 = gp.tileM.mapTileNum[entityleftcol][entitytoprow];
                tileNum2 = gp.tileM.mapTileNum[entityleftcol][entitybottomrow];
                if (gp.tileM.tile[tileNum1].collision == true || gp.tileM.tile[tileNum2].collision == true) {
                    entity.collisionOn = true;
                }
                break;
            case "right":
                entityrightcol = (entityrightWorldX + entity.speed) / gp.tileSize;
                tileNum1 = gp.tileM.mapTileNum[entityrightcol][entitytoprow];
                tileNum2 = gp.tileM.mapTileNum[entityrightcol][entitybottomrow];
                if (gp.tileM.tile[tileNum1].collision == true || gp.tileM.tile[tileNum2].collision == true) {
                    entity.collisionOn = true;
                }
                break;
        }
        
    }
    
}```

[uneven verge]

Detected code, here are some useful tools:

[solar river]

Second part

Player Character part 1

import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import main.GameMenu;
import main.KeyHandler;
public class Player extends Entity {
    GameMenu gp;
    KeyHandler keyH;
    
    public final int screenX;
    public final int screenY;
    
    public Player (GameMenu gp, KeyHandler keyH) {
        this.gp = gp;
        this.keyH = keyH;
        
        screenX = gp.screenWidth / 2 - (gp.tileSize / 2);
        screenY = gp.screenHeight / 2 - (gp.tileSize / 2);
        
        solidArea = new Rectangle();
        solidArea.x = 0;
        solidArea.y = 0;
        solidArea.width = 64;
        solidArea.height = 64;
        
        setDefaultValues();
        getPlayerImage();
    } 
    public void setDefaultValues() {
        worldx = gp.tileSize * 23;
        worldy = gp.tileSize * 21;
        speed = 4;
        direction = "down";
    }```

[uneven verge]

Detected code, here are some useful tools:

[solar river]

Player Part 2

        try {
            up1 = ImageIO.read(getClass().getResourceAsStream("/player/Fox_WalkF1.png"));
            up2 = ImageIO.read(getClass().getResourceAsStream("/player/Fox_WalkF2.png"));
            down1 = ImageIO.read(getClass().getResourceAsStream("/player/Fox_WalkB1.png"));
            down2 = ImageIO.read(getClass().getResourceAsStream("/player/Fox_WalkB2.png"));
            left1 = ImageIO.read(getClass().getResourceAsStream("/player/Fox_WalkL1.png"));
            left2 = ImageIO.read(getClass().getResourceAsStream("/player/Fox_WalkL2.png"));
            right1 = ImageIO.read(getClass().getResourceAsStream("/player/Fox_WalkR1.png"));
            right2 = ImageIO.read(getClass().getResourceAsStream("/player/Fox_WalkR2.png"));
            
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public void update() {
        if (keyH.upPressed == true || keyH.downPressed == true || keyH.leftPressed == true || keyH.rightPressed == true) {
           if (keyH.upPressed == true) {
            direction = "up";
            }
           if (keyH.downPressed == true) {
            direction = "down";
           }
           if (keyH.leftPressed == true) {
            direction = "left";
           }
           if (keyH.rightPressed == true) {
            direction = "right";
           }```

[uneven verge]

Detected code, here are some useful tools:

[soft rune]

can you show also what is wrong with running the code

with making invisible rectangles to visible

[solar river]

Thats the thing, the rectangle is not visible, there's a player character

I mean

theres a sprite

[soft rune]

in order to debug it, can you make it visible

then u can remove it back again

maybe it may be cause by the sprite image, in order to detect it

is your sprite is at center for sure?

[solar river]

I actually though about making it visible

But I dont know how to actually do that, I have some nebulous idea of it

And about the sprite, It seems to be at the center of the screen, it is the rectangle that is off.

But let me check

[soft rune]

you can add it to the scene

you just created but didnt add it to scene according to your code

so it stays invisible

[solar river]

Thats not all the code

[soft rune]

can i see the sprite / the code running with the problem

is your sprite at center?

[solar river]

I will try to make a video then

[soft rune]

okey

by the way its 3am in my country, so i may go to sleep soon

if i dont answer you, ping me and i will check in the mornnig

[solar river]

cool

I will also try to put a notebook doc with all the relevant code for this

[soft rune]

do u know is your sprite at center or not?

i think the problem is about sprite itself

if you correctly coded as in the video

you should fit the invisible rectangle to your own sprite but u said you dont know how to make it visible

if your sprite is not centered, then it causes problem

[solar river]

Had to do it on my phone

[soft rune]

can you show the sprite image

not necessary send it

i need to see the gaps

[solar river]

ok just let me open aseprite

but the sprite is a 32x32 image upscaled inside the game to be 64x64

[soft rune]

okey okey

we just need to check that is sprite centered or not

[solar river]

you meant this?

because by the sprite not being cetenred it may be the camera not being centered

[soft rune]

it seems no problem okey

now you need to fit the invisible rectangle according to this sprit

wait

is this red rectangle good for you?

[solar river]

yeah

[soft rune]

i couldnt find, where did you create and initialize the invisible rectangle, can you show

solidArea = new Rectangle();
solidArea.x = 0;
solidArea.y = 0;
solidArea.width = 64;
solidArea.height = 64;

oh here?

[solar river]

import java.awt.Rectangle;
import java.awt.image.BufferedImage;
public class Entity {
    public int worldx, worldy;
    public int speed;
    
    public BufferedImage up1, up2, down1, down2, left1, left2, right1, right2;
    public String direction;
    
    public int spriteCounter = 0;
    public int spriteNum = 1;
    
    public Rectangle solidArea;
    public boolean collisionOn = false;
}```

[uneven verge]

Detected code, here are some useful tools:

[soft rune]

okey

solidArea = new Rectangle();
solidArea.x = 10;
solidArea.y = 11;
solidArea.width = 12;
solidArea.height = 15;

can you try this?

in Player class i got them

[solar river]

ok I tried that and it is still weird

[soft rune]

is there a difference?

[solar river]

I will show

[soft rune]

okey

[solar river]

yes

the gaps are biger

[soft rune]

so at least we know the error is about fitting the rectangle to the sprite

so you must learn that how can you make the rectangle visible

[soft rune]

it is the same as how did all other things visible

[soft rune]

oh can you try -10 and -11 as x and y

and i think you need bigger width and height

height=22
width=12
x= -11
y= -7

i think it would be better

so the main logic is, fitting the invisible rectangle to your sprite.
so you need to make it visible until you find the best fitting rectangle.
until you find it, you must change x,y values etc

[solar river]

yeah I was thinking that

[sinful topaz]

Wouldn't you want the bounding box for just the feet/shadow area.

for positioning.

Not the 2d physical size

You want that shadow area to be able to get up into those corners of the walkway.

[soft rune]

good luck to you guys, have fun

i will go to sleep its 3:30am here

[solar river]

take care and thanks!

[solar river]

The idea for it is that is cover the feet and half of the body

Though right now I am just trying to figure out the correct numbers for it

Anyway I will put the code in notes here just in case

[sinful topaz]

https://en.wikipedia.org/wiki/Rubber_duck_debugging

Try writing out in english the problem you have in detail as if you were going to bother the busiest developer in the world your problem.

It often helps to write as comments what you think you are going to be doing. Later, you remove comments with real code.

[solar river]

so basically just explain the logic of the code?

[sinful topaz]

Yes, in a lot of detail. You will most likely discover your error that way.

Showing code without any explanation of what it's supposed to do doesn't really help anyone trying to help you.

It looks like your creating a 2.x dimensional game and so probably there is a technique for collision detection that is not just a 2d, this box overlaps that box, solution.

So research that.

https://www.reddit.com/r/gamedev/comments/5xst6w/efficient_collision_detection_for_characters_in_a/

[solar river]

Huh that is going to be hard.

Explaining myself I mean, researching not so much.

[uneven verge]

I uploaded your attachments as Gist. This makes them more accessible, for example to mobile users.

[solar river]

I will try to look up a little

there's the code tho

But I will try to look a method to draw the rectangle to see how offset it is and maybe find a way to circumvent that

[uneven verge]

@solar river

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With enough info, someone knows the answer for sure 👍

[soft rune]

@solar river did you solve it?

[real coral]

they will callback if they need further help 👍