/// <summary>
/// Determines if there is overlap of the non-transparent pixels between two
/// sprites.
/// 检查两个精灵是否发生碰撞
/// </summary>
/// <returns>True if non-transparent pixels overlap; false otherwise</returns>
public static CollisionResult IntersectPixels(Sprite spriteA, Sprite spriteB)
{
if (!spriteA.mSupportIntersectDect || !spriteB.mSupportIntersectDect)
{
throw new Exception("At lest one of the two sprite doesn't support IntersectDect!");
}
spriteA.UpdateTransformBounding();
spriteB.UpdateTransformBounding();
CollisionResult result = new CollisionResult();
if (!spriteA.mBounding.Intersects(spriteB.mBounding))
{
result.IsCollided = false;
return(result);
}
int widthA = spriteA.mTexture.Width;
int heightA = spriteA.mTexture.Height;
int widthB = spriteB.mTexture.Width;
int heightB = spriteB.mTexture.Height;
// Calculate a matrix which transforms from A's local space into
// world space and then into B's local space
Matrix transformAToB = spriteA.mTransform * Matrix.Invert(spriteB.mTransform);
// When a point moves in A's local space, it moves in B's local space with a
// fixed direction and distance proportional to the movement in A.
// This algorithm steps through A one pixel at a time along A's X and Y axes
// Calculate the analogous steps in B:
Vector2 stepX = Vector2.TransformNormal(Vector2.UnitX, transformAToB);
Vector2 stepY = Vector2.TransformNormal(Vector2.UnitY, transformAToB);
// Calculate the top left corner of A in B's local space
// This variable will be reused to keep track of the start of each row
Vector2 oriPosInB = Vector2.Transform(Vector2.Zero, transformAToB);
CircleList <BorderPoint> list = spriteA.mBorder.BorderCircle;
CircleListNode <BorderPoint> cur = list.First;
bool justStart = true;
bool find = false;
CircleListNode <BorderPoint> firstNode = cur;
int length = 0;
#region 找出第一个相交点和该连续相交线的长度
for (int i = 0; i < list.Length; i++)
{
Point bordPointA = cur.value.p;
if (SpriteBBlockAtPos(spriteB, oriPosInB, stepX, stepY, bordPointA))
{
if (!justStart)
{
if (!find)
{
find = true;
firstNode = cur;
}
else
{
length++;
}
}
else
{
CircleListNode <BorderPoint> temp = cur.pre;
while (SpriteBBlockAtPos(spriteB, oriPosInB, stepX, stepY, temp.value.p))
{
temp = temp.pre;
}
cur = temp;
i--;
justStart = false;
}
}
else
{
justStart = false;
if (find)
{
break;
}
}
cur = cur.next;
}
#endregion
if (find)
{
cur = firstNode;
for (int i = 0; i < Math.Round((float)length / 2); i++)
{
cur = cur.next;
}
Point bordPointA = cur.value.p;
result.IsCollided = true;
Vector2 InterPos = Vector2.Transform(new Vector2(bordPointA.X, bordPointA.Y), spriteA.mTransform);
result.NormalVector = Vector2.Transform(spriteA.mBorder.GetNormalVector(cur, spriteA.mAverageSum), spriteA.mTransform)
- Vector2.Transform(Vector2.Zero, spriteA.mTransform);
result.NormalVector.Normalize();
result.InterPos = InterPos;
return(result);
}
// No intersection found
result.IsCollided = false;
return(result);
}
/// <summary>
/// Determines if there is overlap of the non-transparent pixels between two
/// sprites.
/// 检查两个精灵是否发生碰撞
/// </summary>
/// <returns>True if non-transparent pixels overlap; false otherwise</returns>
public static CollisionResult IntersectPixels ( Sprite spriteA, Sprite spriteB )
{
if (!spriteA.mSupportIntersectDect || !spriteB.mSupportIntersectDect)
throw new Exception( "At lest one of the two sprite doesn't support IntersectDect!" );
spriteA.UpdateTransformBounding();
spriteB.UpdateTransformBounding();
CollisionResult result = new CollisionResult();
if (!spriteA.mBounding.Intersects( spriteB.mBounding ))
{
result.IsCollided = false;
return result;
}
int widthA = spriteA.mTexture.Width;
int heightA = spriteA.mTexture.Height;
int widthB = spriteB.mTexture.Width;
int heightB = spriteB.mTexture.Height;
// Calculate a matrix which transforms from A's local space into
// world space and then into B's local space
Matrix transformAToB = spriteA.mTransform * Matrix.Invert( spriteB.mTransform );
// When a point moves in A's local space, it moves in B's local space with a
// fixed direction and distance proportional to the movement in A.
// This algorithm steps through A one pixel at a time along A's X and Y axes
// Calculate the analogous steps in B:
Vector2 stepX = Vector2.TransformNormal( Vector2.UnitX, transformAToB );
Vector2 stepY = Vector2.TransformNormal( Vector2.UnitY, transformAToB );
// Calculate the top left corner of A in B's local space
// This variable will be reused to keep track of the start of each row
Vector2 oriPosInB = Vector2.Transform( Vector2.Zero, transformAToB );
CircleList<BorderPoint> list = spriteA.mBorder.BorderCircle;
CircleListNode<BorderPoint> cur = list.First;
bool justStart = true;
bool find = false;
CircleListNode<BorderPoint> firstNode = cur;
int length = 0;
#region 找出第一个相交点和该连续相交线的长度
for (int i = 0; i < list.Length; i++)
{
Point bordPointA = cur.value.p;
if (SpriteBBlockAtPos( spriteB, oriPosInB, stepX, stepY, bordPointA ))
{
if (!justStart)
{
if (!find)
{
find = true;
firstNode = cur;
}
else
{
length++;
}
}
else
{
CircleListNode<BorderPoint> temp = cur.pre;
while (SpriteBBlockAtPos( spriteB, oriPosInB, stepX, stepY, temp.value.p ))
{
temp = temp.pre;
}
cur = temp;
i--;
justStart = false;
}
}
else
{
justStart = false;
if (find)
{
break;
}
}
cur = cur.next;
}
#endregion
if (find)
{
cur = firstNode;
for (int i = 0; i < Math.Round( (float)length / 2 ); i++)
{
cur = cur.next;
}
Point bordPointA = cur.value.p;
result.IsCollided = true;
Vector2 InterPos = Vector2.Transform( new Vector2( bordPointA.X, bordPointA.Y ), spriteA.mTransform );
result.NormalVector = Vector2.Transform( spriteA.mBorder.GetNormalVector( cur, spriteA.mAverageSum ), spriteA.mTransform )
- Vector2.Transform( Vector2.Zero, spriteA.mTransform );
result.NormalVector.Normalize();
result.InterPos = InterPos;
return result;
}
// No intersection found
result.IsCollided = false;
return result;
}
