Aha! I had tried using D3DXMatrixTransformation2D before, but I was using it only for the scaling, not for the position as well. It apparently works better if you do it all at once. Also, now that it's doing it this way, setting the center to the actual center doesn't mess things up.
....However, although the sprite is now visible, it has somehow done both a horizontal flip and a vertical flip, and has moved up . Or, more accurately, a 180 degree rotation. Here's what the adjusted code snippet looks like:
D3DXVECTOR2 vCenter( s_sprite.width/2.0f, s_sprite.height/2.0f ); D3DXVECTOR2 vPosition( s_sprite.xPosit, s_sprite.yPosit ); D3DXVECTOR2 vScale(1.0f, 1.0f); D3DXMATRIX transMatrix; s_sprite.lpSprite->Begin( D3DXSPRITE_ALPHABLEND ); if(s_sprite.flipHoriz) vScale.x = -1.0f; D3DXMatrixTransformation2D(&transMatrix, &vCenter, 0.0f, &vScale, NULL, 0.0f, &vPosition); s_sprite.lpSprite->SetTransform(&transMatrix); s_sprite.lpSprite->Draw( t_texture.lpTexture, &srcRect, NULL, NULL, D3DCOLOR_COLORVALUE(1.0f,1.0f,1.0f,1.0f) );
It's possible I'm just using D3DXMatrixTransformation2D incorrectly. Before I changed the center to the real center, it was as if it flipped horizontally, and then reflected vertically over the top line bounding the sprite rectangle. Now it stays in the same place, it's just upside-down.
Edit: Nevermind! I had it making the y value of the scaling vector negative, when it seems it should have been the x value in this case.
Thanks for the help, guys.