// static methods
// collosion detection algorithm:
// first see if the the texture rectangles intersect
// if there is an intersection look at just the pixels in the intersection
// if the pixels in both textures in the intersection are not transparent, then it is a collision
public static bool CollisionBetween(Vector2 thatVector, Texture2DData thatTextureData, Vector2 theOtherVector, Texture2DData theOtherTextureData, bool calcPerPixel = true)
{
bool didItCollide = false;
Rectangle that = new Rectangle((int)thatVector.X, (int)thatVector.Y, thatTextureData.Texture.Width, thatTextureData.Texture.Height);
Rectangle theOther = new Rectangle((int)theOtherVector.X, (int)theOtherVector.Y, theOtherTextureData.Texture.Width, theOtherTextureData.Texture.Height);
didItCollide = that.Intersects(theOther);
if (calcPerPixel && didItCollide) // If simple intersection fails, don't even bother with per-pixel
{
didItCollide = PerPixelCollision(that, thatTextureData, theOther, theOtherTextureData);
} // end if
return didItCollide;
}
private static bool PerPixelCollision(Rectangle rectangleA, Texture2DData textureAData, Rectangle rectangleB, Texture2DData textureBData)
{
bool returnValue = false; // no intersection found
// find the bounds of the rectangle intersection
Rectangle rectangleOfCollision = Rectangle.Intersect(rectangleA, rectangleB);
// get the color data of just the part of the texture we are looking at
//Texture2D cropTextureA = new Texture2D(textureAData.Texture.GraphicsDevice, rectangleOfCollision.Width, rectangleOfCollision.Height);
//Color[] colorA = new Color[rectangleOfCollision.Width * rectangleOfCollision.Height];
//textureA.GetData(0, rectangleOfCollision, colorA, 0, colorA.Length);
//textureAData.Texture.GetData(0, rectangleOfCollision, colorA, 0, colorA.Length);
//cropTextureA.SetData(colorA);
// get the color data of just the part of the texture we are looking at
//Texture2D cropTextureB = new Texture2D(textureBData.Texture.GraphicsDevice, rectangleOfCollision.Width, rectangleOfCollision.Height);
//Color[] colorB = new Color[rectangleOfCollision.Width * rectangleOfCollision.Height];
//textureB.GetData(0, rectangleOfCollision, colorB, 0, colorB.Length);
//textureBData.Texture.GetData(colorB);
//cropTextureB.SetData(colorB);
//Color[] colorA = textureAData.GetTextureColors(rectangleOfCollision);
Color[] colorA = textureAData.ColorData;
Color[] colorB = textureBData.ColorData;
Color cA;
Color cB;
// get Color data of each Texture
//Color[] dataAA = new Color[textureA.Width * textureA.Height];
//textureA.GetData(dataAA);
//Color[] dataBB = new Color[textureB.Width * textureB.Height];
//textureB.GetData(dataBB);
// to find the color at a specific pixel
//Color colorAA;
//Color colorBB;
//Color cA;
//Color cB;
//foreach (Color cA in colorA)
//{
//} // end foreach loop
// check every point within the intersection bounds
//for (int color = 0; color < colorA.Length && !returnValue; color++)
//{
// if (colorA[color].A * colorB[color].A != 0) // if both pixels are not completely transparent
// {
// returnValue = true; // an intersection has been found
// } // end if
//} // end for loop
// check every point within the intersection bounds
for (int y = rectangleOfCollision.Top; y < rectangleOfCollision.Bottom && !returnValue; y++)
{
for (int x = rectangleOfCollision.Left; x < rectangleOfCollision.Right && !returnValue; x++)
{
// get the color of both pixels at this point
cA = colorA[(x - rectangleA.Left) + (y - rectangleA.Top) * rectangleA.Width];
cB = colorB[(x - rectangleB.Left) + (y - rectangleB.Top) * rectangleB.Width];
// if both pixels are not completely transparent,
if (cA.A * cB.A != 0)
{
returnValue = true; // an intersection has been found
} // end if
} // end for loop
} // end for loop
return returnValue;
}
