OpenGL State Variables and Inventor

If you need to combine Inventor and OpenGL calls, Table 28.1, “OpenGL State Variables: Current Values and Associated Data” through Table 28.9, “OpenGL State Variables: Miscellaneous” list the OpenGL state variables and describe which Inventor nodes (or actions) change those variables. If Inventor uses the current value of an OpenGL state variable and never changes it, the variable is omitted from this set of tables. See the OpenGL Programming Guide for a complete list of all OpenGL state variables and their default values. The recommended value for these variables is the default value, with two exceptions: turn on z-buffering and use RGB color mode.

Remember, the constructor for SoGLRenderAction takes a parameter that specifies whether to inherit the current OpenGL values. If you specify TRUE, Inventor inherits values from OpenGL. If you specify FALSE (the default), Inventor sets up its own reasonable default values (see Applying Actions).

To save and restore OpenGL state, use the OpenGL pushAttributes() and popAttributes() commands. For example, if you change variables in the OpenGL state in a callback node, you need to restore the state when the callback node is finished. Note that if your callback node begins with a pushAttributes() and ends with a popAttributes(), but a render abort occurs in between, popAttributes() is never called and the state is not restored.

Table 28.1. OpenGL State Variables: Current Values and Associated Data

OpenGL State Variable	Inventor Nodes That Change This Variable
GL_CURRENT_COLOR	Shapes, Material, Base Color
GL_CURRENT_INDEX	Color Index node, Shapes
GL_CURRENT_TEXTURE_COORDS	Shapes, TextureCoordinate2
GL_CURRENT_NORMAL	Shapes, Normal
GL_CURRENT_RASTER_POSITION	Text2
GL_CURRENT_RASTER_COLOR	Text2
GL_CURRENT_RASTER_INDEX	Text2
GL_CURRENT_RASTER_POSITION_- VALID	Text2

Table 28.2. OpenGL State Variables: Transformation State

OpenGL State Variable	Inventor Nodes That Change This Variable
GL_MODELVIEW_MATRIX	Transformation nodes, Cameras
GL_PROJECTION_MATRIX	Cameras
GL_TEXTURE_MATRIX	Texture2Transform
GL_VIEWPORT	Cameras
GL_DEPTH_RANGE	Cameras
GL_MODELVIEW_STACK_DEPTH	Transformation nodes
GL_TEXTURE_STACK_DEPTH	Texture2Transform
GL_MATRIX_MODE	Cameras, Texture2Transform

Table 28.3. OpenGL State Variables: Coloring

OpenGL State Variable	Inventor Nodes That Change This Variable
GL_FOG_COLOR	Environment node
GL_FOG_INDEX	Environment node
GL_FOG_DENSITY	Environment node
GL_FOG_START	Environment node
GL_FOG_END	Environment node
GL_FOG_MODE	Environment node
GL_FOG	Environment node
GL_SHADE_MODEL	Light Model, if in color index mode

Table 28.4. OpenGL State Variables: Lighting

OpenGL State Variable	Inventor Nodes That Change This Variable
GL_LIGHTING	Light Model
GL_COLOR_MATERIAL	Shapes
GL_MATERIAL_PARAMETER	Shapes
GL_MATERIAL_FACE	Shapes
GL_AMBIENT	Shapes, Material
GL_DIFFUSE	Shapes, Material
GL_SPECULAR	Shapes, Material
GL_EMISSION	Shapes, Material
GL_SHININESS	Shapes, Material
GL_LIGHT_MODEL_AMBIENT	Shapes, Material
GL_LIGHT_MODEL_LOCAL_VIEWER	Shapes, Material
GL_LIGHT_MODEL_TWO_SIDE	Shape Hints
GL_AMBIENT	Lights
GL_DIFFUSE	Lights
GL_SPECULAR	Lights
GL_POSITION	Lights
GL_CONSTANT_ATTENUATION	Environment
GL_LINEAR_ATTENUATION	Environment
GL_QUADRATIC_ATTENUATION	Environment
GL_SPOT_DIRECTION	Lights
GL_SPOT_EXPONENT	Lights
GL_SPOT_CUTOFF	Lights
GL_LIGHT*i*	Lights
GL_COLOR_INDEXES	Lights

Table 28.5. OpenGL State Variables: Rasterization

OpenGL State Variable	Inventor Nodes That Change This Variable
GL_POINT_SIZE	Draw Style
GL_POINT_SMOOTH	Render action
GL_LINE_WIDTH	Draw Style
GL_LINE_SMOOTH	Render Action
GL_LINE_STIPPLE_PATTERN	Draw Style
GL_LINE_STIPPLE	Draw Style
GL_CULL_FACE	Shape Hints
GL_CULL_FACE_MODE	Shape Hints
GL_POLYGON_MODE	Draw Style
GL_POLYGON_STIPPLE	Shapes if SCREEN_DOOR transparency

Table 28.6. OpenGL State Variables: Texturing

OpenGL State Variable	Inventor Nodes That Change This Variable
GL_TEXTURE_*x*	Texture2 node
GL_TEXTURE	Texture2 node
GL_TEXTURE_WIDTH	Texture2 node
GL_TEXTURE_HEIGHT	Texture2 node
GL_TEXTURE_COMPONENTS	Texture2 node
GL_TEXTURE_MIN_FILTER	Complexity node
GL_TEXTURE_MAG_FILTER	Complexity node
GL_TEXTURE_WRAP_*x*	Texture2 node
GL_TEXTURE_ENV_MODE	Texture2 node
GL_TEXTURE_ENV_COLOR	Texture2 node
GL_TEXTURE_GEN_*x*	Texture Coordinate Function nodes
GL_EYE_LINEAR	Texture Coordinate Function nodes
GL_OBJECT_LINEAR	Texture Coordinate Function nodes
GL_TEXTURE_GEN_MODE	Texture Coordinate Function nodes

Table 28.7. OpenGL State Variables: Pixel Operations

| GL_BLEND | Render action, Texture2 node | | GL_BLEND_SRC | Render action, Texture2 node | | GL_BLEND_DST | Render action, Texture2 node |

Table 28.8. OpenGL State Variables: Pixels

OpenGL State Variable	Inventor Nodes That Change This Variable
GL_UNPACK_ALIGNMENT	Texture2 node
GL_*_SCALE (* = RED; GREEN; BLUE; ALPHA)	Texture2 node
GL_*_BIAS (* = RED; GREEN; BLUE; ALPHA)	Texture2 node

Table 28.9. OpenGL State Variables: Miscellaneous

OpenGL State Variable	Inventor Nodes That Change This Variable
GL_LIST_BASE	Text2, Text3 nodes
GL_LIST_INDEX	Separator, Text2, Text3 nodes
GL_LIST_MODE	Separator, Text2, Text3 nodes