AABB 碰撞使实际精灵的大小翻倍

Question

所以，我让这段代码用于 AABB 碰撞，直到我决定在 Y 轴上使精灵比在 X 轴上更大。我试图修复代码，但现在它只是将冲突大小比实际精灵大小翻了一番。例如，精灵 1 iVec2(50,100( 的大小，精灵 2 iVec2(30,30( 的大小。

CollisionData Collision::DoCollision(GameObject &object1, GameObject &object2) {
iVec2 center(object1.Position.x + object1.Size.x / 2, object1.Position.y + object1.Size.y / 2);
iVec2 half_extents(object2.Size.x / 2, object2.Size.y / 2);
iVec2 aabb_center(object2.Position.x + half_extents.x, object2.Position.y + half_extents.y);
iVec2 difference = center - aabb_center;
iVec2 difference2 = center - aabb_center;
iVec2 clamped = glm::clamp(difference, -half_extents, half_extents);
iVec2 clamped2 = glm::clamp(difference2, -iVec2(object1.Size.x / 2, object1.Size.y / 2), iVec2(object1.Size.x / 2, object1.Size.y / 2));
iVec2 closest = aabb_center + clamped;
iVec2 closest2 = aabb_center + clamped2;
difference = closest - center;
difference2 = closest2 - center;
if (glm::length(difference) <= object1.Size.x / 2 || glm::length(difference2) <= object1.Size.y / 2)
return std::make_tuple(GL_TRUE, VectorDirection(difference), difference);
else return std::make_tuple(GL_FALSE, UP, glm::vec2(0, 0));
}

Answer 1

我建议做一个简单的重叠检查。

如果 2 段重叠，可以通过以下方式进行检查：

overlap = (x1+w1) > x2 && (x2+w2) > x1

其中x1是起点，w1第一段的宽度。x2是 2n 段的起点和宽度w2。

如果要检查轴对齐的边界框是否重叠，则ypu必须对两个维度进行测试

bool overlap = 
(object1.Position.x + object1.Size.x) > object2.Position.x) &&
(object2.Position.x + object2.Size.x) > object1.Position.x) &&
(object1.Position.y + object1.Size.y) > object2.Position.y) &&
(object2.Position.y + object2.Size.y) > object1.Position.y);

如果你想知道重叠的数量，你必须计算盒子的中心点，并将中心点的距离与盒子的常见一半大小进行比较：

CollisionData Collision::DoCollision(GameObject &object1, GameObject &object2) {
iVec2 center1(
object1.Position.x + object1.Size.x / 2,
object1.Position.y + object1.Size.y / 2);
iVec2 center2(
object2.Position.x + object2.Size.x / 2,
object2.Position.y + object2.Size.y / 2);
iVec2 dist = center1 - center2;
iVec2 size((object1.Size.x + object2.Size.x) / 2, (object1.Size.y + object2.Size.y) / 2);

iVec2 difference = size - iVec2(abs(dist.x), abs(dist.y));
bool overlap = difference.x > 0 && difference.y > 0;
if ( overlap )
{
iVec2 min1 = object1.Position;
iVec2 min2 = object2.Position;
iVec2 max1 = object1.Position + object1.Size;
iVec2 max2 = object2.Position + object2.Size;
bool horizontal = difference.x > difference.y;
if ( min2.x > min1.x && max1.x < max2.x || min1.x > min2.x && max2.x < max1.x )
horizontal = false;
else if ( min2.y > min1.y && max1.y < max2.y || min1.y > min2.y && max2.y < max1.y )
horizontal = true;
return std::make_tuple(
GL_TRUE, !horizontal ? (dist.x < 0 ? LEFT: RIGHT) : (dist.y < 0 ? UP : DOWN), difference );
}
return std::make_tuple(GL_FALSE, UP, glm::vec2(0, 0));
}