While some sprite libraries come with the option to flip horizontally or vertically, the ID3DXSprite interface does not. If you're rolling your own sprite class using a quad, you can easily add this functionality by inverting the texture co-ordinates.
Another method of flipping, which works for ID3DXSprites as well, is to inverse the scale on the flipped axis.
Here's a simple pseudo code example:
D3DXVECTOR2 scale; D3DXVECTOR2 position; ... if(FlippedOnX) { scale.x = -scale.x; //Invert the sprite on the x axis position.x += spriteWidth; //Shift the sprite by the amount of 'width' to re-position after the mirror flip } if(FlippedOnY) { scale.y = -scale.y; position.y += spriteHeight; }
Of course, you can get rid of the two if statements:
D3DXVECTOR2 scale; D3DXVECTOR2 position; ... scale.x = (scale.x * !FlippedOnX) + (-scale.x * FlippedOnX); scale.y = (scale.y * !FlippedOnY) + (-scale.y * FlippedOnY); position.x = posixion.x + (spriteWidth * FlippedOnX); position.y = posixion.y + (spriteHeight * FlippedOnY);
This is far from secret knowledge, but when I was looking for an answer to this question, I found mostly short forum responses, such as: "Just invert the scale". While this is to the point and it's easy enough to try for yourself, I figured an example and a brief explanation could have been of some use.
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