我正在使用LibGDX为Android开发游戏。我已经添加了捏合缩放和平移功能。我的问题是如何防止越过游戏区域的边界。目前，你可以将屏幕拖动到黑色区域之外。当完全缩小时，我知道如何处理这个问题，我只需要做：
if(camera.zoom == 1.0f) ;
else {
}
但是，如果放大视图，我该怎么做呢？我知道这并不复杂，只是似乎想不出方法。在创建对象时，我将相机设置在屏幕中央。我知道如何平移，我正在使用camera.translate(-input.deltaX, -input.deltaY, 0)，我只需要在此调用之前进行测试，以查看位置是否超出了游戏区域。当我放大视图时，如何测试自己是否位于屏幕边缘？
BoundingBox left, right, top, bottom = null;
public void setWorldBounds(int left, int bottom, int width, int height) {
int top = bottom + height;
int right = left + width;
this.left = new BoundingBox(new Vector3(left - 2, 0, 0), new Vector3(left -1, top, 0));
this.right = new BoundingBox(new Vector3(right + 1, 0, 0), new Vector3(right + 2, top, 0));
this.top = new BoundingBox(new Vector3(0, top + 1, 0), new Vector3(right, top + 2, 0));
this.bottom = new BoundingBox(new Vector3(0, bottom - 1, 0), new Vector3(right, bottom - 2, 0));
}
Vector3 lastPosition = new Vector3();
@Override
public void translate(float x, float y) {
lastPosition.set(position.x, position.y, 0);
super.translate(x, y);
}
public void translateSafe(float x, float y) {
translate(x, y);
update();
ensureBounds();
update();
}
public void ensureBounds() {
if (frustum.boundsInFrustum(left) || frustum.boundsInFrustum(right) || frustum.boundsInFrustum(top) || frustum.boundsInFrustum(bottom)) {
position.set(lastPosition);
}
}
camera.setWorldBounds()
camera.translateSafe(x, y);
应该将您的相机限制在范围内
您可以使用以下之一：
camera.frustum.boundsInFrustum(BoundingBox box)
camera.frustum.pointInFrustum(Vector3 point)
camera.frustum.sphereInFrustum(Vector3 point, float radius)
检查一个点/盒子/球是否在相机的视野内。
我通常会定义4个围绕我的世界的盒子，玩家不应该看到这些盒子。如果相机移动并且其中一个盒子在视锥体中，我将相机移回到上一个位置。
编辑：AAvering已经在代码下面实现了此功能。
这是我在我的2D游戏中使用正交相机进行平移或缩放后更新相机位置后调用的代码。它会校正相机位置，使其不显示游戏区域边界之外的任何内容。
float camX = camera.position.x;
float camY = camera.position.y;
Vector2 camMin = new Vector2(camera.viewportWidth, camera.viewportHeight);
camMin.scl(camera.zoom/2); //bring to center and scale by the zoom level
Vector2 camMax = new Vector2(borderWidth, borderHeight);
camMax.sub(camMin); //bring to center
//keep camera within borders
camX = Math.min(camMax.x, Math.max(camX, camMin.x));
camY = Math.min(camMax.y, Math.max(camY, camMin.y));
camera.position.set(camX, camY, camera.position.z);
camMin 是相机最低的左下角位置，相机不能显示游戏区域之外的任何内容，并且还是从相机到中心的一个角落的偏移量。
camMax 是相机可以到达的相反的最高右侧位置。
我猜你可能缺少的关键部分是按缩放级别缩放相机大小。
float minCameraX = camera.zoom * (camera.viewportWidth / 2);
float maxCameraX = worldSize.x - minCameraX;
float minCameraY = camera.zoom * (camera.viewportHeight / 2);
float maxCameraY = worldSize.y - minCameraY;
camera.position.set(Math.min(maxCameraX, Math.max(targetX, minCameraX)),
Math.min(maxCameraY, Math.max(targetY, minCameraY)),
0);
含义：
targetX 和 targetY 是你的目标所在的世界坐标。worldSize 是世界的大小，它是一个 Vector2 类型的变量。我没有足够的声望来写评论，所以我会指向一些先前的答案。
AAverin使用Matsemann的想法制作的边界框解决方案不好，因为当您靠近一个边缘（边界）并尝试对角线移动时，它会令人恼火地减慢速度，在这种情况下，您正在向一侧移动超出范围，而另一侧则是正确的方向。
我强烈建议您尝试handleInput方法底部呈现的解决方案。
那个程序运行顺畅，与之前的答案有些相似，但这个使用了MathUtils.clamp，更加直观简洁。对于这个问题，非常适合使用这个类（部分感谢AAverin）。
这个类不仅限制了边界，而且在缩放时自动吸附到边界。
调用这些方法来设置边界并移动摄像机。
camera.setWorldBounds()
camera.translateSafe(x, y);
camera.attemptZoom();
以下是这个类：
public class CustomCamera extends OrthographicCamera
{
public CustomCamera() {}
public CustomCamera(float viewportWidth, float viewportHeight)
{
super(viewportWidth, viewportHeight);
}
BoundingBox left, right, top, bottom = null;
public void setWorldBounds(int left, int bottom, int width, int height) {
int top = bottom + height;
int right = left + width;
this.left = new BoundingBox(new Vector3(left - 2, 0, 0), new Vector3(left -1, top, 0));
this.right = new BoundingBox(new Vector3(right + 1, 0, 0), new Vector3(right + 2, top, 0));
this.top = new BoundingBox(new Vector3(0, top + 1, 0), new Vector3(right, top + 2, 0));
this.bottom = new BoundingBox(new Vector3(0, bottom - 1, 0), new Vector3(right, bottom - 2, 0));
}
Vector3 lastPosition;
@Override
public void translate(float x, float y) {
lastPosition = new Vector3(position);
super.translate(x, y);
}
public void translateSafe(float x, float y) {
translate(x, y);
update();
ensureBounds();
update();
}
public void ensureBounds()
{
if(isInsideBounds())
{
position.set(lastPosition);
}
}
private boolean isInsideBounds()
{
if(frustum.boundsInFrustum(left) || frustum.boundsInFrustum(right) || frustum.boundsInFrustum(top) || frustum.boundsInFrustum(bottom))
{
return true;
}
return false;
}
public void attemptZoom(float newZoom)
{
this.zoom = newZoom;
this.snapCameraInView();
}
private void snapCameraInView()
{
float halfOfCurrentViewportWidth = ((viewportWidth * zoom) / 2f);
float halfOfCurrentViewportHeight = ((viewportHeight * zoom) / 2f);
//Check the vertical camera.
if(position.x - halfOfCurrentViewportWidth < 0f) //Is going off the left side.
{
//Snap back.
float amountGoneOver = position.x - halfOfCurrentViewportWidth;
position.x += Math.abs(amountGoneOver);
}
else if(position.x + halfOfCurrentViewportWidth > viewportWidth)
{
//Snap back.
float amountGoneOver = (viewportWidth - (position.x + halfOfCurrentViewportWidth));
position.x -= Math.abs(amountGoneOver);
}
//Check the horizontal camera.
if(position.y + halfOfCurrentViewportHeight > viewportHeight)
{
float amountGoneOver = (position.y + halfOfCurrentViewportHeight) - viewportHeight;
position.y -= Math.abs(amountGoneOver);
}
else if(position.y - halfOfCurrentViewportHeight < 0f)
{
float amountGoneOver = (position.y - halfOfCurrentViewportHeight);
position.y += Math.abs(amountGoneOver);
}
}
}