Different ways of interpreting vertices when drawing.
FIXME, equivalent to GL_LINES
FIXME, equivalent to GL_LINE_LOOP
FIXME, equivalent to GL_LINE_STRIP
FIXME, equivalent to GL_POINTS
FIXME, equivalent to GL_TRIANGLES
FIXME, equivalent to GL_TRIANGLE_FAN
FIXME, equivalent to GL_TRIANGLE_STRIP
Different ways of interpreting vertices when drawing.