«SDL question»

No. With OpenGL however you can play with the texture co-ordinates or the vertices to achieve that.

Not sure how appropriate this question is for this forum.

 

Yes. It's quite trivial as image transforms go...

Code:

	SDL_LockSurface(m_pSurface);

	int nHH = m_pSurface->h / 2;
	int nPitch = m_pSurface->pitch;

	byte* pBuf = new byte[nPitch];
	byte* pSrc = (byte*) m_pSurface->pixels;
	byte* pDst = (byte*) m_pSurface->pixels + nPitch*(m_pSurface->h - 1);

	while (nHH--)
	{
		memcpy(pBuf, pSrc, nPitch);
		memcpy(pSrc, pDst, nPitch);
		memcpy(pDst, pBuf, nPitch);

		pSrc += nPitch;
		pDst -= nPitch;
	}

	delete[] pBuf;
	SDL_UnlockSurface(m_pSurface);

(Yeah, yeah, it could be optimized in assembler with SSE and MMX, unrolled, and written in Haskell, but you shouldn't be doing flips too often in realtime, nor optimizing prematurely!)

 

On a slightly related note, I thought I'd mention the following easy (but not always obvious) trick:

glScalef(1.0f, -1.0f, 1.0f);