简单定向边界框OBB碰撞检测解释

的变换矩阵箱知道两个OBB碰撞你使用SAT（分离轴定理）：你必须投影这两个点的所有点在两个形状的每个法线上形状。然后你会看到两个形状的投影是否重叠在每个法线上都有碰撞。如果至少有一个没有重叠的法线，它们不会相互碰撞。所有这一切，你需要一种方法来做一个矢量在另一个上的正交投影，并返回一个标量，并且用一个方法来检查两个区间是否重叠。 我有一些代码，但它的Java：

/** 
* Vec u is projected on Vec v 
* @param u 2d point 
* @param v 2d axe 
* @return the orthogonal projection 
*/ 
public static float orthagonalProjectionOf(Vector2f u, Vector2f v){ 
    float norme_u = u.lenght(); 
    float norme_v = v.lenght(); 
    float dot_u_v = dot(u, v); 
    float buffer = (dot_u_v/(norme_u*norme_v))*norme_u; 
    if(Float.isNaN(buffer))return 0;//If the vector u is null, then is orthogonal projection is 0, not a NaN 
    else return buffer; 
} 

重叠两类区间的：

/** 
* Get the overlapping of two interval on an axis. 
* @param minA 
* @param maxA 
* @param minB 
* @param maxB 
* @return true overlapping. false if there is no overlapping 
*/ 
public static boolean isOverlapping(float minA, float maxA, float minB, float maxB) { 
    float minOverlap = Float.NaN; 
    float maxOverlap = Float.NaN; 
    //If B contain in A 
    if(minA <= minB && minB <= maxA) { 
     if(Float.isNaN(minOverlap) || minB < minOverlap)minOverlap = minB; 
    } 
    if(minA <= maxB && maxB <= maxA) { 
     if(Float.isNaN(maxOverlap) || maxB > minOverlap)maxOverlap = maxB; 
    } 
    //If A contain in B 
    if(minB <= minA && minA <= maxB) { 
     if(Float.isNaN(minOverlap) || minA < minOverlap)minOverlap = minA; 
    } 
    if(minB <= maxA && maxA <= maxB) { 
     if(Float.isNaN(maxOverlap) || maxA > minOverlap)maxOverlap = maxA; 
    } 
    if(Float.isNaN(minOverlap) || Float.isNaN(maxOverlap))return false; //Pas d'intersection 
    else return true;//Intersection 
} 

随着你都能够做到的方法来测试的U开V

Orthagonal投影两个OBB之间的碰撞：

public boolean OBBwOBB(RigidBody bodyA, RigidBody bodyB) { 
    Shape shapeA = bodyA.getObb().getShape(); 
    Shape shapeB = bodyB.getObb().getShape(); 
    short overlapCompt = 0; 
    //We test for each normal the projection of the two shape 
     //Shape A : 
    for(int i = 0; i < shapeA.getNbrOfNormals(); i++) { 
     Vector2f normal = shapeA.getNormal(i, bodyA.getAngle()); 
     boolean overlap = overlapOnThisNormal(bodyA, bodyB, normal); 
     if(overlap) { 
      overlapCompt++; 
     } 
    } 
     //Shape B : 
    for(int i = 0; i < shapeB.getNbrOfNormals(); i++) { 
     Vector2f normal = shapeB.getNormal(i, bodyB.getAngle()); 
     boolean overlap = overlapOnThisNormal(bodyA, bodyB, normal); 
     if(overlap){ 
      overlapCompt++; 
     } 
    } 
    //Now we see if there is a collision 
    short howManyNormals = (short) (shapeA.getNbrOfNormals() + shapeB.getNbrOfNormals()); 
    if(overlapCompt == howManyNormals){//If the number of overlap equal the number of normal in both shape : 
     return true; 
    } 
    else return false; 
} 

而且您将需要它t为两个形式投影在向量的投影的最小值和最大值：

/** 
* Test if the orthogonal projection of two shape on a vector overlap. 
* @param bodyA 
* @param bodyB 
* @param normal 
* @return null if no overlap, else Vector2f(minOverlaping, maxOverlaping). 
*/ 
public static boolean overlapOnThisNormal(RigidBody bodyA, RigidBody bodyB, Vector2f normal) { 
    Shape shapeA = bodyA.getObb().getShape(); 
    Shape shapeB = bodyB.getObb().getShape(); 
    //We test each vertex of A 
    float minA = Float.NaN; 
    float maxA = Float.NaN; 
    for(short j = 0; j < shapeA.getNbrOfPoint(); j++){ 
     Vector2f vertex = shapeA.getVertex(j, bodyA.getScale().x, bodyA.getScale().y, bodyA.getPosition().x, bodyA.getPosition().y, bodyA.getAngle()); 
     float bufferA = Vector2f.orthagonalProjectionOf(vertex, normal); 
     if(Float.isNaN(minA) || bufferA < minA)minA = bufferA;//Set min interval 
     if(Float.isNaN(maxA) || bufferA > maxA)maxA = bufferA;//Set max interval 
    } 
    //We test each vertex of B 
    float minB = Float.NaN; 
    float maxB = Float.NaN; 
    for(short j = 0; j < shapeB.getNbrOfPoint(); j++){ 
     Vector2f vertex = shapeB.getVertex(j, bodyB.getScale().x, bodyB.getScale().y, bodyB.getPosition().x, bodyB.getPosition().y, bodyB.getAngle()); 
     float bufferB = Vector2f.orthagonalProjectionOf(vertex, normal); 
     if(Float.isNaN(minB) || bufferB < minB)minB = bufferB;//Set min interval 
     if(Float.isNaN(maxB) || bufferB > maxB)maxB = bufferB;//Set max interval 
    } 
    //We test if there overlap 
    boolean overlap = isOverlapping(minA, maxA, minB, maxB); 
    return overlap; 
} 

我希望这个帮你;）