Hello guys, this is my first post in this forum. So, I am maintaining an old game, written in C++ and using DirectX9b. In order to use shader model 3 I decided to update the source code to Directx9c. The issue I am trying to fix right now is exactly what the title suggests.

To make a long story short, here is the function I am currently using to replace the old functionality:

HRESULT SpriteDrawFix(
	LPD3DXSPRITE pSprite,				// The sprite
	LPDIRECT3DTEXTURE9 pSrcTexture,		// The texture to draw.
	CONST RECT* pSrcRect,				// The src rect 
	CONST D3DXVECTOR2* pScaling,		// Scaling
	CONST D3DXVECTOR2* pRotationCenter,	// The rotation center if rotation is used.
	FLOAT Rotation,						// Rotation in radians.
	CONST D3DXVECTOR2* pTranslation,	// Translation, i.e. moving the object to this place.
	D3DCOLOR Color)						// Color to module the image pixels.
{
	D3DXVECTOR3 vScale = pScaling != nullptr ? D3DXVECTOR3{ pScaling->x, pScaling->y, 1 } : D3DXVECTOR3{ 1, 1, 1 };
	D3DXVECTOR3 vCenter = pRotationCenter != nullptr ? D3DXVECTOR3{ pRotationCenter->x, pRotationCenter->y, 0 } : D3DXVECTOR3{ 0, 0, 0 };
	D3DXVECTOR3 vTrans = pTranslation != nullptr ? D3DXVECTOR3{ pTranslation->x, pTranslation->y, 0 } : D3DXVECTOR3{ 0, 0, 0 };

	D3DXMATRIXA16 s, r, t, total;

	D3DXMatrixScaling(&s, vScale.x, vScale.y, 1);
	D3DXMatrixRotationZ(&r, Rotation);
	D3DXMatrixTranslation(&t, vTrans.x + vCenter.x * vScale.x, vTrans.y + vCenter.y * vScale.y, 0);

	total = s * r * t;

	pSprite->SetTransform(&total);

	pSprite->Begin(D3DXSPRITE_ALPHABLEND);
	HRESULT hr = pSprite->Draw(pSrcTexture, pSrcRect, &vCenter, nullptr, Color);
	pSprite->End();

	return hr;
}

It works for most cases, however, there seems to be a problem with rotation. This screenshot speaks for itself:

With Directx9b and using the old method, this renders as expected. I would appreciate it if someone knows what causes this bug or how the original method was implemented. Thanks in advance.

PS: I just noticed IDirectXSprite never existed, well, you got the picture anyway.

Sorry for double posting, I just want to share the solution, which was pretty simple after:

D3DXMatrixTransformation2D(&m, nullptr, 0, pScaling, pRotationCenter, -Rotation, pTranslation);

The thing is, I still don't understand what this function does differently compared to my initial approach.