c++ - 从游戏中的可移动空间中删除矩形

Question

我有一个简单的设置，其中有一个球在屏幕上弹跳，我希望能够为对象提供它无法在内部移动的矩形(它们将充当障碍物)。目前有以下逻辑来尝试完成这个。

void AnimatableObject::ExcludeRects(AnimatableObject *obj) {
        for (int i = 0; i < obj->numberOfExclusionBounds; i++) {
            SDL_Rect bounds = obj->exclusionBounds[i];

            /* TOUCHING SIDES OF THE RECT*/
            bool touchingTopOfRect = obj->m_dY + obj->m_dHeight > bounds.y &&
                obj->m_dY < bounds.y + bounds.h &&
                obj->m_dX > bounds.x &&
                obj->m_dX + obj->m_dWidth < bounds.x + bounds.w;

            bool touchingBottomOfRect = obj->m_dY < bounds.y + bounds.h &&
                obj->m_dY > bounds.y &&
                obj->m_dX > bounds.x &&
                obj->m_dX + obj->m_dWidth < bounds.x + bounds.w;

            bool touchingRightOfRect = obj->m_dX < bounds.x + bounds.w &&
                obj->m_dX > bounds.x &&
                obj->m_dY > bounds.y &&
                obj->m_dY + obj->m_dHeight < bounds.y + bounds.h;

            bool touchingLeftOfRect = obj->m_dX + obj->m_dWidth > bounds.x &&
                obj->m_dX + obj->m_dWidth < bounds.x + bounds.w &&
                obj->m_dY > bounds.y &&
                obj->m_dY + obj->m_dHeight > bounds.y + bounds.h;


            // Top of a rect.
            if (touchingTopOfRect) {
                obj->m_dY = bounds.y - obj->m_dHeight;
                obj->bottomContact = true;
            }

            // Bottom of Rect
            if (touchingBottomOfRect) {
                obj->m_dY = bounds.y + bounds.h;
                obj->topContact = true;
            }

            // Left Side of rect.
            if (touchingLeftOfRect) {
                obj->m_dX = bounds.x - obj->m_dWidth;
                obj->rightContact = true;
            }

            // Right Side of rect
            if (touchingRightOfRect) {
                printf("HIT RIGHT OF A OBSTACLE %d\n", bounds.w);

                obj->m_dX = bounds.x + bounds.w;
                obj->leftContact = true;
            }
        }
}

所以这会在每一帧调用，并将循环遍历一个数组，该数组存储我想从对象可移动区域中排除的矩形。

使用这种方法开始工作变得非常棘手，很多时候条件句在它们不应该触发的时候触发。但是我的主要问题是这对我来说似乎不必要地复杂。有没有更好的方法来解决这个问题？

Answer 1

您应该能够使用 SDL_HasIntersection

大大简化此操作

基本的伪代码将遵循

for each collider rect
  if HasIntersection( bounds, colliderBounds )
    find the centre points of each rect (x+w/2, y+h/2)
    bool touchingLeft = ( bounds_centre.x < collider_centre.x )
    bool touchingRight = ( bounds_cenre.x > collider_centre.x )
    ... etc ...

看

http://wiki.libsdl.org/SDL_HasIntersection

编辑:另一种选择是自己跳过任何碰撞检测，而是使用出色的 Box2D:

http://box2d.org/