LibGDX - Orthogonal Camera won't stop at edge of map

Question

i'm fairly new to libgdx and java but am learning everything I can! I'm working on an orthogonal 2d tiled game. Basically, i've got my character walking around and the camera following him. I am trying to set it up so the camera stops when the character is near the edge of the map so no black space is seen. The camera should stop at the edge and the player should continue moving.

This is my code for moving the camera. It's a bit messy now as i've been trying everything. The map is 30x30.

if (mainPlayer.getPosition().x >= 15 && mainPlayer.getPosition().x <= 30) {
    camera.position.x = mainPlayer.getPosition().x;     
}

camera.position.y = mainPlayer.getPosition().y;

camera.update();
camera.apply(gl);

This is inside my render method. I've only messed with the x part, so ignore the y for now.

EDIT I think I need to reword that. I know how to make it stop..It works using my code, but I can't figure out how to determine where to stop it. I'm using 15 in my code above which is half the map..which of course doesn't work.

Answer 1

You need to fix the bounds of the Camera rectangle to inside the world rectangle. A function such as below would help:

public void fixBounds() {
    float scaledViewportWidthHalfExtent = viewportWidth * zoom * 0.5f;
    float scaledViewportHeightHalfExtent = viewportHeight * zoom * 0.5f;

    // Horizontal
    if (position.x < scaledViewportWidthHalfExtent)
        position.x = scaledViewportWidthHalfExtent;
    else if (position.x > xmax - scaledViewportWidthHalfExtent)
        position.x = xmax - scaledViewportWidthHalfExtent;

    // Vertical
    if (position.y < scaledViewportHeightHalfExtent)
        position.y = scaledViewportHeightHalfExtent;
    else if (position.y > ymax - scaledViewportHeightHalfExtent)
        position.y = ymax - scaledViewportHeightHalfExtent;
}

Answer 2

EDIT I think I need to reword that. I know how to make it stop..It works using my code, but I can't figure out how to determine where to stop it. I'm using 15 in my code above which is half the map..which of course doesn't work.

The minimum x would need to be:

map.position.x + camera.viewportWidth/2;

And the maximum x would need to be:

map.position.x+mapwidth-camera.viewportWidth/2;

Assuming the map position is in (0,0) you can just ignore the map.position.x part.