/// <summary>
/// Check to see if two Rotated Rectangls have collided
/// </summary>
/// <param name="theRectangle"></param>
/// <returns></returns>
public bool Intersects(RotatedRectangle theRectangle)
{
//Calculate the Axis we will use to determine if a collision has occurred
//Since the objects are rectangles, we only have to generate 4 Axis (2 for
//each rectangle) since we know the other 2 on a rectangle are parallel.
List <Vector2> aRectangleAxis = new List <Vector2>();
aRectangleAxis.Add(UpperRightCorner() - UpperLeftCorner());
aRectangleAxis.Add(UpperRightCorner() - LowerRightCorner());
aRectangleAxis.Add(theRectangle.UpperLeftCorner() - theRectangle.LowerLeftCorner());
aRectangleAxis.Add(theRectangle.UpperLeftCorner() - theRectangle.UpperRightCorner());
//Cycle through all of the Axis we need to check. If a collision does not occur
//on ALL of the Axis, then a collision is NOT occurring. We can then exit out
//immediately and notify the calling function that no collision was detected. If
//a collision DOES occur on ALL of the Axis, then there is a collision occurring
//between the rotated rectangles. We know this to be true by the Seperating Axis Theorem
foreach (Vector2 aAxis in aRectangleAxis)
{
if (!IsAxisCollision(theRectangle, aAxis))
{
return(false);
}
}
return(true);
}
/// <summary>
/// Draw the sprite
/// </summary>
public void Draw()
{
PositionRect = new Rectangle((int)Position.X, (int)Position.Y, spriteWidth, spriteHeight);
RotatedRect = new RotatedRectangle(PositionRect, 0f);
Rectangle aPositionAdjusted = new Rectangle(rotatedRect.X + (rotatedRect.Width / 2), rotatedRect.Y + (rotatedRect.Height / 2), rotatedRect.Width, rotatedRect.Height);
spriteBatch.Draw(Texture, aPositionAdjusted, SourceRect, Color.White, Rotation, new Vector2((int)PositionRect.Width / 2, (int)PositionRect.Height / 2), SpriteEffects.None, 0);
}
/// <summary>
/// Constructor for the AnimatedSprite.
/// </summary>
/// <param name="texture"></param>
/// <param name="currentFrame"></param>
/// <param name="spriteWidth"></param>
/// <param name="spriteHeight"></param>
/// <param name="totalFrames"></param>
/// <param name="spriteBatch"></param>
public AnimatedSprite(Texture2D texture, Vector2 position, int currentFrame, int spriteWidth, int spriteHeight, int totalFrames, SpriteBatch spriteBatch, float interval, Single initialRotation)
{
// When a new animated sprite is created, these variables must be initialized.
this.spriteTexture = texture; // The sprite sheet we will be drawing from.
this.currentFrame = currentFrame; // The current frame that we are drawing.
this.spriteWidth = spriteWidth; // The width of the individual sprite.
this.spriteHeight = spriteHeight; // The height of the individual sprite.
this.totalFrames = totalFrames; // The total amount of frames in the sprite sheet.
this.spriteBatch = spriteBatch; // The spriteBatch that we will use to draw the AnimatedSprite.
this.interval = interval; // The amount of time it takes before the sprite moves to the next frame.
this.position = position;
this.positionRect = new Rectangle((int)Position.X, (int)Position.Y, spriteWidth, spriteHeight);
this.rotatedRect = new RotatedRectangle(PositionRect, initialRotation);
}
/// <summary>
/// Determines if a collision has occurred on an Axis of one of the
/// planes parallel to the Rectangle
/// </summary>
/// <param name="theRectangle"></param>
/// <param name="aAxis"></param>
/// <returns></returns>
private bool IsAxisCollision(RotatedRectangle theRectangle, Vector2 aAxis)
{
//Project the corners of the Rectangle we are checking on to the Axis and
//get a scalar value of that project we can then use for comparison
List <int> aRectangleAScalars = new List <int>();
aRectangleAScalars.Add(GenerateScalar(theRectangle.UpperLeftCorner(), aAxis));
aRectangleAScalars.Add(GenerateScalar(theRectangle.UpperRightCorner(), aAxis));
aRectangleAScalars.Add(GenerateScalar(theRectangle.LowerLeftCorner(), aAxis));
aRectangleAScalars.Add(GenerateScalar(theRectangle.LowerRightCorner(), aAxis));
//Project the corners of the current Rectangle on to the Axis and
//get a scalar value of that project we can then use for comparison
List <int> aRectangleBScalars = new List <int>();
aRectangleBScalars.Add(GenerateScalar(UpperLeftCorner(), aAxis));
aRectangleBScalars.Add(GenerateScalar(UpperRightCorner(), aAxis));
aRectangleBScalars.Add(GenerateScalar(LowerLeftCorner(), aAxis));
aRectangleBScalars.Add(GenerateScalar(LowerRightCorner(), aAxis));
//Get the Maximum and Minium Scalar values for each of the Rectangles
int aRectangleAMinimum = aRectangleAScalars.Min();
int aRectangleAMaximum = aRectangleAScalars.Max();
int aRectangleBMinimum = aRectangleBScalars.Min();
int aRectangleBMaximum = aRectangleBScalars.Max();
//If we have overlaps between the Rectangles (i.e. Min of B is less than Max of A)
//then we are detecting a collision between the rectangles on this Axis
if (aRectangleBMinimum <= aRectangleAMaximum && aRectangleBMaximum >= aRectangleAMaximum)
{
return(true);
}
else if (aRectangleAMinimum <= aRectangleBMaximum && aRectangleAMaximum >= aRectangleBMaximum)
{
return(true);
}
return(false);
}
