Like IRIS GL, OpenGL lets you switch between smooth (Gouraud) shading and flat shading. The following table lists the IRIS GL shading and dithering functions and their equivalent OpenGL functions.
| IRIS GL Function | OpenGL Function | Meaning |
|---|---|---|
| shademodel(FLAT) | glShadeModel(GL_FLAT) | Do flat shading. |
| shademodel(GOURAUD) | glShadeModel(GL_SMOOTH) | Do smooth shading. |
| getsm | glGet(GL_SHADE_MODEL) | Return current shade model. |
| dither(DT_ON) dither(DT_OFF) |
glEnable(GL_DITHER) glDisable(GL_DITHER) |
Turn dithering on/off. |