Java Community | Help. Code. Learn.•2y ago

Collision with slopes in a game

can someone help me describe how sloped tiled collision should work for my game? say i have a sloped tile on the tile value 40, how do i handle a sloped tile, like how do i set the hitbox x, the hitbox y, how do i avoid others methods clashing, how do i update the height of the player? i only have two slopes which are both 45 degrees diagonally and cover the entire tile.

5 Replies

JavaBot•2y ago

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ErkyOP•2y ago

this is my current collision handling:

// ====== Entity collision with tiles ======

    protected boolean canMoveToPosition(float x, float y, float width, float height, Level level) {
    // Get x, y, width and height position for player and see if he can move to the next position or not
    boolean isTopLeftSolid = isSolid(x, y, level);
    boolean isTopRightSolid = isSolid(x + width, y, level);
    boolean isBottomLeftSolid = isSolid(x, y + height, level);
    boolean isBottomRightSolid = isSolid(x + width, y + height, level);

    // If neither corner is solid, the entity can move here
    if (!isTopLeftSolid && !isTopRightSolid && !isBottomLeftSolid && !isBottomRightSolid)
        return true;

    // Returns false by default, meaning cannot move to the position
    return false;
    }

    protected boolean isSolid(float x, float y, Level level) {
    int tileX = (int) (x / TILES_SIZE);
    int tileY = (int) (y / TILES_SIZE);

    if (isTileSolid(tileX, tileY, level))
        return true;
    else
        return false;
    }

    protected boolean isTileSolid(int tileX, int tileY, Level level) {
    // Get every tile value from the level
    int tileValue = level.getLevelData()[tileY][tileX];

    // sloped tile
    if (tileValue == SLOPED_TILE) {
        slope = true;
        return false;
    }

    return switch (tileValue) {
        case TRANSPARENT_TILE -> false;
        default -> true;
    };
    }

// ====== Entity collision with tiles ======

    protected boolean canMoveToPosition(float x, float y, float width, float height, Level level) {
    // Get x, y, width and height position for player and see if he can move to the next position or not
    boolean isTopLeftSolid = isSolid(x, y, level);
    boolean isTopRightSolid = isSolid(x + width, y, level);
    boolean isBottomLeftSolid = isSolid(x, y + height, level);
    boolean isBottomRightSolid = isSolid(x + width, y + height, level);

    // If neither corner is solid, the entity can move here
    if (!isTopLeftSolid && !isTopRightSolid && !isBottomLeftSolid && !isBottomRightSolid)
        return true;

    // Returns false by default, meaning cannot move to the position
    return false;
    }

    protected boolean isSolid(float x, float y, Level level) {
    int tileX = (int) (x / TILES_SIZE);
    int tileY = (int) (y / TILES_SIZE);

    if (isTileSolid(tileX, tileY, level))
        return true;
    else
        return false;
    }

    protected boolean isTileSolid(int tileX, int tileY, Level level) {
    // Get every tile value from the level
    int tileValue = level.getLevelData()[tileY][tileX];

    // sloped tile
    if (tileValue == SLOPED_TILE) {
        slope = true;
        return false;
    }

    return switch (tileValue) {
        case TRANSPARENT_TILE -> false;
        default -> true;
    };
    }

// ====== Entity falling on spawn ======

    protected boolean isEntityInAir(Rectangle2D.Float hitbox, Level level) {
    slope = false;

    // check the bottom left and bottom right corner of the hitbox
    boolean isBottomLeftSolid     = isSolid(hitbox.x, hitbox.y + hitbox.height + 1, level);
    boolean isBottomRightSolid     = isSolid(hitbox.x + hitbox.width, hitbox.y + hitbox.height + 1, level);

    // returns false if either hitbox for bottom left and bottom right corner is colliding with a solid tile
    if (isBottomLeftSolid || isBottomRightSolid)
        return false;
    else
        return true;
    }

    protected void updateFallingStatus(Level level) {
    if (isEntityInAir(hitbox, level))
        falling = true;
    }

    protected void startFalling(Level level) {
    if(canMoveToPosition(hitbox.x, hitbox.y + ySpeed, hitbox.width, hitbox.height, level)) {
        // Start falling, move Y downwards
        hitbox.y += ySpeed;
        ySpeed += GRAVITY;
    } else {
        // Stop falling, reset jump
        if (ySpeed > 0) {
        ySpeed = 0;
        jumping = false;
        falling = false;
        } else {
        // Hit roof, start falling downwards fast!
        ySpeed = GRAVITY * 10;
        }
    }
    }

// ====== Entity falling on spawn ======

    protected boolean isEntityInAir(Rectangle2D.Float hitbox, Level level) {
    slope = false;

    // check the bottom left and bottom right corner of the hitbox
    boolean isBottomLeftSolid     = isSolid(hitbox.x, hitbox.y + hitbox.height + 1, level);
    boolean isBottomRightSolid     = isSolid(hitbox.x + hitbox.width, hitbox.y + hitbox.height + 1, level);

    // returns false if either hitbox for bottom left and bottom right corner is colliding with a solid tile
    if (isBottomLeftSolid || isBottomRightSolid)
        return false;
    else
        return true;
    }

    protected void updateFallingStatus(Level level) {
    if (isEntityInAir(hitbox, level))
        falling = true;
    }

    protected void startFalling(Level level) {
    if(canMoveToPosition(hitbox.x, hitbox.y + ySpeed, hitbox.width, hitbox.height, level)) {
        // Start falling, move Y downwards
        hitbox.y += ySpeed;
        ySpeed += GRAVITY;
    } else {
        // Stop falling, reset jump
        if (ySpeed > 0) {
        ySpeed = 0;
        jumping = false;
        falling = false;
        } else {
        // Hit roof, start falling downwards fast!
        ySpeed = GRAVITY * 10;
        }
    }
    }

// ====== Entity X direction ======

    protected void startMovingWithDirection(float xDirection, Level level) {
    // Update the player hitbox if not colliding with a solid block on the next X position
    if (canMoveToPosition(hitbox.x + xDirection, hitbox.y, hitbox.width, hitbox.height, level))
        hitbox.x += xDirection;
    }

    protected void updateXDirection() {
    xDirection = 0;
    if (direction == LEFT)
        xDirection = -xSpeed;
    if (direction == RIGHT)
        xDirection = xSpeed;
    }

// ====== Entity X direction ======

    protected void startMovingWithDirection(float xDirection, Level level) {
    // Update the player hitbox if not colliding with a solid block on the next X position
    if (canMoveToPosition(hitbox.x + xDirection, hitbox.y, hitbox.width, hitbox.height, level))
        hitbox.x += xDirection;
    }

    protected void updateXDirection() {
    xDirection = 0;
    if (direction == LEFT)
        xDirection = -xSpeed;
    if (direction == RIGHT)
        xDirection = xSpeed;
    }

public class Player extends Entity {
    public void update() {
    // ====== Update level data =======
    level = game.getPlaying().getLevelManager().getLevel();

    // ====== Update player X position =======
    updateXDirection();
    startMovingWithDirection(xDirection, level);

    // ====== Update player Y position =======
    updateFallingStatus(level);

    if (falling)
        startFalling(level);
    else if (jumping)
        startJumping();

private void startJumping() {
    falling = true;
    ySpeed = -jumpHeight;
    SoundLoader.tryPlaySound("player_jump.wav", VOLUME / 2, false);
    }

public class Player extends Entity {
    public void update() {
    // ====== Update level data =======
    level = game.getPlaying().getLevelManager().getLevel();

    // ====== Update player X position =======
    updateXDirection();
    startMovingWithDirection(xDirection, level);

    // ====== Update player Y position =======
    updateFallingStatus(level);

    if (falling)
        startFalling(level);
    else if (jumping)
        startJumping();

private void startJumping() {
    falling = true;
    ySpeed = -jumpHeight;
    SoundLoader.tryPlaySound("player_jump.wav", VOLUME / 2, false);
    }

Kyo-chan•2y ago

I mean, dude, that sort of things is why there are game engines out there, with features such as handling slopes. While I imagine the problem of slopes has gotten fairly standardized, the entire concept is that you design the physics of it, not that others do it for you. Treat it like any things that you put in your game and isn't in all games.

Unknown User•2y ago

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JavaBot•2y ago

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Collision with slopes in a game

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