Need help cleaning up code

I''m working on an isometric engine, and I want to make sure my code is as clean as possible (which it isn''t) before I move on. I''ve left out most of the initilization functions, because I''m fine with them.

//-----------------------------------------------------------------------------

// Name: InitVB()

// Desc: Creates a vertex buffer and fills it with the vertices

//-----------------------------------------------------------------------------

HRESULT CGame::InitVB(){


	if(FAILED(D3DXCreateTextureFromFileEx(g_pD3DDevice, "test.bmp", D3DX_DEFAULT, 
			D3DX_DEFAULT, D3DX_DEFAULT, D3DUSAGE_RENDERTARGET, D3DFMT_UNKNOWN,
			D3DPOOL_DEFAULT, D3DX_FILTER_NONE, D3DX_DEFAULT,
			D3DCOLOR_XRGB(0,0,0), NULL, NULL, &pTileTex)))

		return E_FAIL;

	charSprite.LoadTexture(g_pD3DDevice, "manatarms.bmp");

    return S_OK;

}


//-----------------------------------------------------------------------------

// Name: Scroll()

// Desc: Scrolls the map

//-----------------------------------------------------------------------------

void CGame::Scroll(){

	if(dir == RIGHT){
		scrollXOffset--;
		if(scrollXOffset < 1){
			scrollX++;
			scrollXOffset = 64;
			if(scrollX > 20) 
				dir = STATIONARY;
		};
	} 
	else if(dir == LEFT){
		scrollXOffset++;
		if(scrollXOffset > 64){
			scrollX--;
			scrollXOffset = 0;
			if(scrollX < 1) 
				dir = STATIONARY;
		};

	}
	else if(dir == UP){
		scrollYOffset++;
		if(scrollYOffset > 64){
			scrollY--;
			scrollYOffset = 0;
			if(scrollY < 1) 
				dir = STATIONARY;
		};

	}
	else if(dir == DOWN){
		scrollYOffset--;
		if(scrollYOffset < 1){
			scrollY++;
			scrollYOffset = 64;
			if(scrollY > 20) 
				dir = STATIONARY;
		};
	}
	else if(dir == STATIONARY){
		scrollX=scrollX;
		scrollXOffset=scrollXOffset;
	};

	DrawMap(scrollX, scrollY, scrollXOffset, scrollYOffset);
}

//-----------------------------------------------------------------------------

// Name: DrawMap()

// Desc: Draws the isometric map

//-----------------------------------------------------------------------------

void CGame::DrawMap(int worldX, int worldY, float offsetX, float offsetY)
{

	float screenX; // Where are we currently on the screen?

	float screenY=-16;
	int whereX=worldX; // Where are we currently rendering on the map?

	int whereY=worldY;

	int i, j=0, counter=0;
	
	static CUSTOMVERTEX vertices[4];

	// Setup texture alignment

	vertices[0].u = 0.0f;
	vertices[0].v = 0.0f;
	vertices[1].u = 1.0f;
	vertices[1].v = 0.0f;
	vertices[2].u = 0.0f;
	vertices[2].v = 1.0f;
	vertices[3].u = 1.0f;
	vertices[3].v = 1.0f;

	for(i=0; i<4; i++){
		vertices[i].color = D3DCOLOR_XRGB(1, 1, 1);
		vertices[i].z=1.0f;
		vertices[i].rhw=1.0f;
	}

	g_pD3DDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,0), 1.0f, 0);

    // Begin the scene

    g_pD3DDevice->BeginScene();
	
	if((whereX % 2)==1)
		screenY=-64;
	else
		screenY=-96;
	while(screenY < SCREENH){
		if((whereY % 2)==1)
			screenX=-64;
		else
			screenX=-96;
		while(screenX < SCREENW){
			vertices[0].x = screenX + offsetX;
			vertices[0].y = screenY+16 + offsetY;
			vertices[1].x = screenX+32 + offsetX;
			vertices[1].y = screenY + offsetY;
			vertices[2].x = screenX+32 + offsetX;
			vertices[2].y = screenY+32 + offsetY;
			vertices[3].x = screenX+64 + offsetX;
			vertices[3].y = screenY+16 + offsetY;
			
			if(j==0){
			g_pD3DDevice->CreateVertexBuffer(4*sizeof(CUSTOMVERTEX), 0, D3DFVF_CUSTOMVERTEX,
                                                  D3DPOOL_DEFAULT, &g_pVB, NULL);
			j++;
			}

			VOID* pVertices;
			if(FAILED(g_pVB->Lock(0, sizeof(vertices), (void**)&pVertices, 0)))
				MessageBox(NULL, "EREORER", "MEMCPY", NULL);
			memcpy(pVertices, vertices, sizeof(vertices));
			g_pVB->Unlock();
			
			Render();

			// Make sure locations are correct

			screenX+=64;
			whereX++;
		};

		whereY++;
		whereX=whereX;
		screenY+=16;
	};

	g_pD3DDevice->EndScene();

    // Present the backbuffer contents to the display

    g_pD3DDevice->Present(NULL, NULL, NULL, NULL);

}

//-----------------------------------------------------------------------------

// Name: Render()

// Desc: Draws the scene

//-----------------------------------------------------------------------------

void CGame::Render()
{
	ProcessKeyboard();
		
	g_pD3DDevice->SetRenderState(D3DRS_LIGHTING, FALSE);
	g_pD3DDevice->SetStreamSource(0, g_pVB, 0, sizeof(CUSTOMVERTEX));

        g_pD3DDevice->SetFVF(D3DFVF_CUSTOMVERTEX);
	g_pD3DDevice->SetTexture(0, pTileTex);
        g_pD3DDevice->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2);

}