Hola amigosss,
el siguiente simple código creará una ventana (secundaria al Formulario) con sólo las funciones externas de la librería SDL.
La ventana contendrá una imagen, un cuadrado de color amarillo y un texto.

Public Struct SDL_Rect
x As Short
y As Short
w As Short
h As Short
End Struct

Private Const SDL_INIT_VIDEO As Byte = 32
Private Const SDL_HWSURFACE As Byte = 1
Private Const SDL_DOUBLEBUF As Integer = 1073741824
Private video As Pointer

Library "libSDL-1.2:0.11.4"
Private Extern SDL_Init(flags As Integer) As Integer
Private Extern SDL_SetVideoMode(width As Integer, height As Integer, bitsperpixel As Integer, flags As Integer) As Pointer
Private Extern SDL_Delay(ms As Integer)
Private Extern SDL_FreeSurface(surface As Pointer)
Private Extern SDL_Quit()

Private Extern SDL_RWFromFile($file As String, mode As String) As Pointer
Private Extern SDL_LoadBMP_RW(image As Pointer, freesrc As Integer) As Pointer
Private Extern SDL_UpperBlit(image As Pointer, srcrect As Pointer, dst As Pointer, dstrect As SDL_Rect) As Integer In "libSDL_image-1.2:0.8.4"
Private Extern SDL_UpdateRect(sdlsurface As Pointer, x As Integer, y As Integer, w As Integer, h As Integer)
Private Extern SDL_Flip(sdlsurface As Pointer)
Private Extern SDL_FillRect(sdlsurface As Pointer, dstrect As SDL_Rect, color As Integer)

Library "libSDL_ttf-2.0:0.10.1"
Private Extern TTF_Init() As Integer
Private Extern TTF_OpenFont(nomefont As String, ptsize As Integer) As Pointer
Private Extern TTF_RenderText_Blended(fontP As Pointer, text As String, fg As Integer) As Pointer
Private Extern SDL_WM_SetCaption(title As String, icon As String)
Private Extern TTF_Quit()


Public Sub Button1_Click()

Dim fl, imago, font, testo As Pointer
Dim riquadro As New SDL_Rect


SDL_Init(SDL_INIT_VIDEO)

video = SDL_SetVideoMode(640, 480, 32, SDL_HWSURFACE Or SDL_DOUBLEBUF)

' Carga un imagen en la ventana:
fl = SDL_RWFromFile("/direccion/de/la/imagen.bmp", "rb")

imago = SDL_LoadBMP_RW(fl, 1)

SDL_UpperBlit(imago, Null, video, Null)

SDL_UpdateRect(video, 0, 0, 0, 0)


' Fija un titulo textual a la ventana:
SDL_WM_SetCaption("Titulo de la ventana", Null)


' Se procede con la configuración de un texto sobre la superficie de la ventana:
TTF_Init()

font = TTF_OpenFont("/direccion/del/font.ttf", 15)

testo = TTF_RenderText_Blended(font, "texto cualquier", 3329329)


' Se procede a la fijación de 300x300 píxeles en la ventana y por encima de la imagen:
With riquadro
.x = 0
.y = 0
.w = 300
.h = 300
End With

' El cuadrado será de color amarillo:
SDL_FillRect(video, riquadro, &FFFF00)

' El cuadrado que contiene el texto, sin embargo, se colocará en la superficie de la ventana a una posición determinada por las coordenadas X e Y:
With riquadro
.x = 30
.y = 50
End With

SDL_UpperBlit(testo, Null, video, riquadro)

SDL_Flip(video)

End


Public Sub Button2_Click() ' Cierra todas las interfaces de SDL y destruye la ventana

TTF_Quit()

SDL_FreeSurface(video)

SDL_Quit()

End



Referencias:
La página que escribí (en italiano) en la wiki de gambas-it.org:
http://www.gambas-it.org/wiki/index..._del_API_di_SDL