Per Pixel collision when animate sprites - xna

Question

This is what I have for detecting collision.
public static bool IntersectPixels(Rectangle rectangleA, Color[] dataA, Rectangle rectangleB, Color[] dataB)
{
int top = Math.Max(rectangleA.Top, rectangleB.Top);
int bottom = Math.Min(rectangleA.Bottom, rectangleB.Bottom);
int left = Math.Max(rectangleA.Left, rectangleB.Left);
int right = Math.Min(rectangleA.Right, rectangleB.Right);
for (int y = top; y < bottom; y++)
{
for (int x = left; x < right; x++)
{
Color colorA = dataA[(x - rectangleA.Left) + (y - rectangleA.Top) * rectangleA.Width];
Color colorB = dataB[(x - rectangleB.Left) + (y - rectangleB.Top) * rectangleB.Width];
if (colorA.A != 0 && colorB.A != 0)
{
return true;
}
}
}
return false;
}:
It work fine until I want to animate stuff. So I have a texture sprite that have about 12 frame. what I need to do is get the color data array of each frame. This is how I get the color data array:
Color[] playerColorArray = new Color[playerColorArray.X * playerColorArray.Y];
PlayerTexture.GetData(playerColorArray);
CData = playerColorArray;
Now my guess is that i have to update the textureData everytime the frame changes
Is there a way to get the the color data from each frame only?

Answer 1

You can get an array of the complete sprite sheet texture and only use the current frame.
Let's say you have a sprite sheet and stride is the offset of a pixel to the pixel below it. This can be the sprite sheet's width. Furthermore, you have the position x0, y0 of the first pixel of the current frame. Then you just have to modify the index calculation:
int posXInFrame = (x - rectangleA.Left);
int posYInFrame = (y - rectangleA.Top);
Color colorA = dataA[(posXInFrame + x0) + (posYInFrame + y0) * stride];
Probably, you have calculated x0 and y0 somewhere else and can pass those values to the function.