HP Workstation zx2000 OpenGL 1.1 Reference for HP-UX 11.x - Page 376

R glRasterPos 376 glRasterPos3 specifies object coordinate x, y, and z explicitly, while w is implicitly set to 1. glRasterPos2 uses the argument values for x and y while implicitly setting z and w to 0 and 1. The object coordinates presented by glRasterPos are treated just like those of a glVertex command: They are transformed by the current modelview and projection matrices and passed to the clipping stage. If the vertex is not culled, then it is projected and scaled to window coordinates, which become the new current raster position, and the GL_CURRENT_RASTER_POSITION_VALID flag is set. If the vertex is culled, then the valid bit is cleared and the current raster position and associated color and texture coordinates are undefined. The current raster position also includes some associated color data and texture coordinates. If lighting is enabled, then GL_CURRENT_RASTER_COLOR (in RGBA mode) or GL_CURRENT_RASTER_INDEX (in color index mode) is set to the color produced by the lighting calculation (see glLight, glLightModel, and glShadeModel). If lighting is disabled, current color (in RGBA mode, state variable GL_CURRENT_COLOR) or color index (in color index mode, state variable GL_CURRENT_INDEX) is used to update the current raster color. Likewise, GL_CURRENT_RASTER_TEXTURE_COORDS is updated as a function of GL_CURRENT_TEXTURE_COORDS, based on the texture matrix and the texture generation functions (see glTexGen). Finally, the distance from the origin of the eye coordinate system to the vertex as transformed by only the modelview matrix replaces GL_CURRENT_RASTER_DISTANCE. Initially, the current raster position is (0, 0, 0, 1), the current raster distance is 0, the valid bit is set, the associated RGBA color is (1, 1, 1, 1), the associated color index is 1, and the associated texture coordinates are (0, 0, 0, 1). In RGBA mode, GL_CURRENT_RASTER_INDEX is always 1; in color index mode, the current raster RGBA color always maintains its initial value. Notes The raster position is modified both by glRasterPos and by glBitmap. When the raster position coordinates are invalid, drawing commands that are based on the raster position are ignored (that is, they do not result in changes to GL state). Calling glDrawElements may leave the current color or index indeterminate. If glRasterPos is executed while the current color or index is indeterminate, the current raster color or current raster index remains indeterminate. To set a valid raster position outside the viewport, first set a valid raster position, then call glBitmap with NULL as the bitmap parameter. Errors • GL_INVALID_OPERATION is generated if glRasterPos is executed between the execution of glBegin and the corresponding execution of glEnd. Associated Gets glGet with argument GL_CURRENT_RASTER_POSITION glGet with argument GL_CURRENT_RASTER_POSITION_VALID glGet with argument GL_CURRENT_RASTER_DISTANCE Chapter 16