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GL_EXT_fragment_lighting
INCOMPLETE - DO NOT RELEASE IMPLEMENTATIONS OF THIS EXTENSION
EXT_fragment_lighting
Name Strings
GL_EXT_fragment_lighting
Version
$Date: 1998/09/26 02:49:31 $ $Revision: 1.26 $
Number
102
Dependencies
OpenGL 1.1 is required.
Overview
This extension adds a new lighting stage to the OpenGL pipeline. This
stage occurs during fragment processing after the texture environment
has been applied and before fog has been applied. The extension
provides a mechanism for computing 'per-pixel lighting'. Fragment lighting
applies to fragments generated by all primitives including pixel images.
This extension doesn't eliminate vertex lighting, but can be used to
complement it. For example, the diffuse contribution can be evaluated
at each vertex, and the specular contribution can be evaluated at each
fragment with the results being summed together to generate the final
result.
Ct Cf
| |-------------------------------+
| | |
---------- |
| | |
| TexEnv | |
| | |
---------- |
| |
---------- |
| Clamp | Nf Lf Hf Ff |
---------- | | | | | FragmentColorMaterial
| ----------------- |
| | | v
Cf' | FragmentLight |<-o-<- Material {Am,Em,Dm,Sm,Nm,...}
| | |
| -----------------
| |
| ---------
| | Clamp |
| ---------
| Cl |
| +----------------
v v
------------
| |
| LightEnv |
| |
------------
|
---------
| Clamp |
---------
|
Cf''
|
v
-------
| |
| Fog |
| |
-------
|
v
Patent Note
To the extent that SGI has patent rights that are unavoidably
infringed by all implementations of this extension, SGI will, upon
request, grant a license under such patent rights to the requesting
party subject to reasonable terms and conditions, and without
incremental charge or fee. Such license shall be non-exclusive, and
non-transferable, and shall be limited to implementations of the
extension in combination with any conformance certified
implementation of the OpenGL API. Such license is expressly
contingent upon a grant back of a non-exclusive, royalty-free,
perpetual, worldwide license to SGI and its OpenGL licensees under
the requesting party's patent rights that are unavoidably infringed
by all implementations of this extension or OpenGL.
Issues
* We specify a complete model and don't allow subsetting. if
portions of the model aren't supported with hardware acceleration
then a software implementation of the complete model is
necessary. There should be sufficient mechanism for an
implementation to include partial acceleration and easily
identify when it can be used. The alternative is to
allow subsetting and a mechanisms for enumerating the capability
would this be any better?
I don't think so. Lighting will be an important area of
growth for OpenGL. I think we owe it to our developers
to force a consistent growth direction by trying to look
ahead a little.
* We apply texture environment before lighting so that decals
can be lighted correctly. The spec does not provide a
mechanism for applying texture after lighting. There are
applications where it would be useful to apply texture after
lighting (e.g. shadows or spotlight effects), but we deliberately
leave them out. Instead we will add binding posts in another
extension to allow textures to be bound to the attenuation
term, specular exponent, environment term, normal perturbation,
etc.
* Should the FragmentColorMaterial command really be done through
texture binding posts and TexEnv moved after lighting?
No.
* New LightModel parameters?
yes, NORMAL_INTERPOLATION control
* We deliberately chose to decouple the control of normal interpolation
for fragment lighting from ShadeModel, choosing to put it in the
FragmentLightModel command. We chose not to provide any mechanism to
allow flat coloring before vertex lighting, so FlatShading continues
to mean that the vertex color after vertex lighting is used to
provide a constant color across the face of a primitive.
* Material parameters are not interpolated. If FragmentMaterial is
enabled then the interpolated color parameter will be used as one or
more of the material parameters, but there is no equivalent notion
to per-vertex materials. If a material change occurs between a
Begin/End sequence, then only the last material specified before the
provoking vertex will affect the shading computation.
* overload ColorMaterial & Material face param with FRAGMENT_FRONT,
FRAGMENT_BACK, and FRAGMENT_FRONT_AND_BACK rather than separate commands?
since the behaviour is somewhat different (not persistent) so it feels
like it should be a different command
* proxy mechanism for subsetting? proxy mechanism for determining
what is supported in hardware. NO.
* add some comments about where lighting parameters are sampled
(fragment centers, pixel centers, ...)
* shadow term is not quite right. removed it.
* should the material be undefined after color material is disabled
it should be well defined. fragment color material should be
thought of as a switch which causes the material parameters to be
sourced from the fragment material 'register' or from the fragment
color. At all times queries to the fragment material refer to the
material 'register' and whenever fragment color material is
disabled, material parameters are sourced from the unperturbed
fragment material 'register'
* disallow fragment material changes between begin/end?
seems okay, since we added a new command! - DONE
* add a total number of lights so that implementations can
share state between vertex and fragment lights yet be more flexible
about whether the state is used for a vertex or fragment light
(vimal).
Yes. MAX_ACTIVE_LIGHTS_EXT
* is the flatshading definition correct? unlike flatshading for
vertex lighting, the color will not be constant, just the normal
so N.L will vary across the face. Yes, it is what we want.
There is now a mechanism which allows flat or smooth color with
flat or smooth fragment lighting (flat or smooth normals).
* treatment of alpha?
alpha comes from the diffuse material if fragment lighting
is enabled.
* the state of FrontFace affects the interpretation of two-sided
lighting. Should there be separate state for vertex and fragment
lighting?
No. its a property of the geometry and shouldn't different for the
two light source types.
void FragmentLightModeliEXT(enum pname, int param);
void FragmentLightModelfEXT(enum pname, float param);
void FragmentLightModelivEXT(enum pname, int *params);
void FragmentLightModelfvEXT(enum pname, float *params);
void FragmentLightiEXT(enum light, enum pname, int param);
void FragmentLightfEXT(enum light, enum pname, float param);
void FragmentLightivEXT(enum light, enum pname, int *params);
void FragmentLightfvEXT(enum light, enum pname, float *params);
void GetFragmentLightivEXT(enum light, enum pname, int *params);
void GetFragmentLightfvEXT(enum light, enum pname, float *params);
void FragmentMaterialfEXT(enum face, enum pname, const float param);
void FragmentMaterialiEXT(enum face, enum pname, const int param);
void FragmentMaterialfvEXT(enum face, enum pname, const float *params);
void FragmentMaterialivEXT(enum face, enum pname, const int *params);
void FragmentColorMaterialEXT(enum face, enum mode);
void GetFragmentMaterialfvEXT(enum face, enum pname, const float *params);
void GetFragmentMaterialivEXT(enum face, enum pname, const int *params);
void LightEnviEXT(enum pname, int param);
Accepted by the <cap> parameter of Enable, Disable, and IsEnabled, by
the <pname> parameter of GetBooleanv, GetIntegerv, GetFloatv, and
GetDoublev:
FRAGMENT_LIGHTING_EXT 0x8400
FRAGMENT_COLOR_MATERIAL_EXT 0x8401
Accepted by the <pname> parameter of GetBooleanv, GetIntegerv, GetFloatv,
and GetDoublev:
FRAGMENT_COLOR_MATERIAL_FACE_EXT 0x8402
FRAGMENT_COLOR_MATERIAL_PARAMETER_EXT 0x8403
MAX_FRAGMENT_LIGHTS_EXT 0x8404
MAX_ACTIVE_LIGHTS_EXT 0x8405
CURRENT_RASTER_NORMAL_EXT 0x8406
Accepted by the <pname> parameter of LightEnviEXT, by
the <pname> parameter of GetBooleanv, GetIntegerv, GetFloatv, and
GetDoublev:
LIGHT_ENV_MODE_EXT 0x8407
Accepted by the <pname> parameter of FragmentLightModeliEXT,
FragmentLightModelfEXT, FragmentLightModelivEXT,
FragmentLightModelfvEXT, GetBooleanv, GetIntegerv, GetFloatv, and
GetDoublev:
FRAGMENT_LIGHT_MODEL_LOCAL_VIEWER_EXT 0x8408
FRAGMENT_LIGHT_MODEL_TWO_SIDE_EXT 0x8409
FRAGMENT_LIGHT_MODEL_AMBIENT_EXT 0x840A
FRAGMENT_LIGHT_MODEL_NORMAL_INTERPOLATION_EXT 0x840B
Accepted by the <light> parameter of FragmentLightfEXT,
FragmentLightiEXT, FragmentLightfvEXT, and FragmentLightivEXT, and by
the <cap> parameter of Enable, Disable, and IsEnabled, and by the <light>
parameter of GetFragmentLightfvEXT and GetFragmentLightivEXT:
FRAGMENT_LIGHT0_EXT 0x840C
.
.
.
FRAGMENT_LIGHT7_EXT 0x8413
<reserve enums for 32>
Additions to Chapter 2 of the 1.1 Specification (OpenGL Operation)
Section 2.12 Current Raster Position
... <paragraph 2>
The current raster position consists of three window coordinates xw, yw,
and zw, a clip corrdinate wc value, an eye coordinate distance, a valid
bit, and associated data consisting of a color, normal, and texture
coordinates. It is set ...
... <paragraph 5>
The current raster position requires five single-precision floating point
values for its xw, yw, and zw window coordinates, its wc clip coordinate,
and its eye coordinate distance, a single valid bit, a color (RGBA and color
index), normal, and texture coordinates for associated data. In the initial
state, the coordinates and texture coordinates are both (0,0,0,1), the eye
coordinate 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 normal is
(0,0,1). In RGBA mode, the associated color index always has its initial
value; in color index mode, the RGBA color always maintains its initial
value.
Section 2.13 Colors and Coloring
...
Next vertex lighting, if enabled produces a color. If vertex lighting is
disabled, the current color is used in further processing. After vertex
lighting, RGBA colors are clamped to the range [0,1]. A color index is
converted to fixed-point and then its integer portion is masked (see
section 2.13.16). After clamping or masking, a primitive may be flatshaded,
indicating that all vertices of the primitive are to have the same color
(and normal). Finally, a primitive is clipped, then colors (texture
coordinates and normals) must be computed at the vertices introduced or
modified by clipping.
Additions to Chapter 3 of the 1.1 Specification (Rasterization)
Section 3.6.3 Rasterization of Pixel Rectangles
Conversion to Fragments
... <paragraph 2>
A fragment arising from a group consisting of color data takes on the color
index or color components of the group; the depth, normal and texture
coordinates are taken from the current raster position's associated data.
A fragment arising from a depth component takes the component's depth
value; the color, normal, and texture coordinate are given by those associated
with the current raster position. In both cases texture coordinates s, t,
and r are preplaced with s/q, t/q, and r/q, respectively. If q is less than
or equal to zero the results are undefined. Groups arising from DrawPixels
with a <format> of STENCIL_INDEX are treated specially and are described in
section 4.3.1.
Before Section 3.9 Fog insert:
Section 3.9 Fragment Lighting
If enabled, fragment lighting computes a color for each rasterized fragment
by applying an equation defined by a client-specified lighting model to
a collection of parameters that can include the fragment coordinates, the
coordinates of one or more light sources, the fragment normal, and
parameters defining the characteristics of the light source and current
fragment material. Fragment lighting is only defined for RGBA mode, it
has no effect in color index mode.
Fragment lighting may be in one of two states:
1. Lighting Off. In this state the color assigned to a fragment is the
rasterized fragment's post-texturing color.
2. Lighting On. In this state the color assigned to a fragment is the
result of combining the rasterized fragment's post-texturing color and
a color computed from the current fragment lighting parameters. The
two colors are combined according to the function defined
by Lighting Environment described below.
Fragment lighting is turned either on or off using the generic Enable or
Disable commands with the symbolic value FRAGMENT_LIGHTING_EXT.
3.9.1 Lighting Environment
The command
void LightEnviEXT(enum pname, int param);
sets parameters of the lighting environment that specifies how the computed
illumination value is combined with the post-texturing fragment color.
<pname> is a symbolic constant indicating the parameter to be set, <param>
is a value to which to set a single valued parameter. The possible
environment parameter is LIGHT_ENV_MODE_EXT. LIGHT_ENV_MODE_EXT may be
set to one of REPLACE, MODULATE, or ADD.
The value of LIGHT_ENV_MODE_EXT specifies an environment function.
The result of this function depends on the post-texturing fragment color
(Cf) and the color computed (Cl) in equation (3.2) below. The functions
are specified in Table 3.3
REPLACE MODULATE ADD
Rv = Rl Rv = RfRl Rv = Rf+Rl
Gv = Gl Gv = GfGl Gv = Gf+Gl
Bv = Bl Bv = BfBl Bv = Bf+Bl
Av = Al Av = AfAl Av = Af+Al
Table 3.3 Light environment functions
3.9.2 Lighting Operation
The equation for the fragment illumination model is:
C = Em emissive
+ Am*As ambient material*scene ambient color
SUM{_i = 0 through Nf-1} {
+ Atten_i*SpotL_i*{ distance/spot light attenuation
+ Am*Al_i ambient material*ambient light
+ Dm*Dl_i*(N.L_i) diffuse material*diffuse light
+ Sm*Sl_i*(f_i)(N.H_i)^n specular material*specular light
}
}
Nf is the number of fragment light sources
N is the fragment normal vector
L_i is the direction vector from the fragment position to the light source
H_i is the half angle vector
f_i is as defined in equation (2.2)
n is the specular exponent (shininess)
Rewrite the equation as:
I[i] = Atten_i*SpotL_i*(Am*Al_i + Dm*Dl_i*(N.L_i) + Sm*Sl*(f_i)(N.H_i)^n) (3.1)
and
I' = SUM{i = 0 through Nf-1} I[i]
C = Em + Am*As + I' (3.2)
Equation (3.1) is the same as the vertex lighting equation described in
section 2.13.1 for a single light source. Similar to vertex lighting,
equation 3.2 is only evaluated for the R, G, and B components and the A
component of C is determined from the alpha component of Dm.
In order to compute the illumination terms for each fragment, the eye
coordinates of the fragment can be used to compute the light direction,
half angle vector, and attenuation factor in a manner similar to that
used in the vertex lighting computations. It is permissible for an
implementation to approximate these by computing these values as well
as the normal vector at the vertices and interpolating and
renormalizing the results.
Fragment material state is maintained which is distinct from the
vertex material state. The fragment material state consists of
emission, ambient, diffuse, specular and shininess terms for both
the front and back face of a primitive. Unlike vertex lighting, the
fragment material state is constant across a primitive since
it is resolved during rasterization. The results of the back face
computation described in section 3.5.1 are used to determine whether
the front material or back material is used when two sided lighting
is enabled.
There is separate state for each fragment light source. The
fragment light source parameters are the same as the vertex light
source parameters described in section 2.13.1. The minimum number of
fragment light sources is 1. The number of available fragment light
sources can be queried by issuing the Get command with the <pname>
parameter set to MAX_FRAGMENT_LIGHTS_EXT.
Distinct lighting model state is also maintained for vertex lighting and
fragment lighting. The lighting model state is described in section
2.13.1. Fragment lighting model state includes one additional parameter,
FRAGMENT_LIGHT_MODEL_NORMAL_INTERPOLATION_EXT, which controls how normals
are selected for use in the fragment lighting computations for a primitive.
If FLAT is selected for the lighting model, the normal from the provoking
vertex (as described in Section 2.13.7 Flatshading) of the primitive for all
fragment lighting computations for the primitive. If SMOOTH is specified
a normal is computed for each fragment using the normals from all of the
vertices of the primitive.
Fragment lighting differs from vertex lighting in that all components
of lighting parameters which are of type color in Table 2.7 are clamped
to the range [0,1] when they are specified.
Equation 3.1 is evaluated for each light source and the resulting
colors are summed. This result is added to the material emissive and
scene ambient terms as in equation 3.2 to produce the R, G, and B
color components. The A component is determined from the diffuse
material's A component. The resulting color components
are clamped to the range [0,1] and then passed to the lighting
environment computation.
3.9.3 Lighting Parameter Specification
The fragment material state can be set with the commands
FragmentMaterialfEXT, FragmentMaterialfvEXT, FragmentMaterialiEXT,
FragmentMaterialivEXT using the values AMBIENT, DIFFUSE, SPECULAR,
SHININESS and EMISSION. This state can be queried using the commands
GetFragmentMaterialfvEXT and GetFragmentMaterialivEXT.
Lighting parameters for fragment light i can be modified by issuing the
commands FragmentLightfEXT, FragmentLightiEXT, FragmentLightfvEXT, and
FragmentLightivEXT with the <light> parameter
set to FRAGMENT_LIGHTi_EXT. The lighting parameters for fragment light i
can be queried by issuing the commands GetFragmentLightfvEXT and
GetFragmentLightivEXT with the <light> parameter set to FRAGMENT_LIGHTi_EXT.
Lighting model parameters for fragment lighting can be modified using the
commands FragmentLightModel{T}EXT, FragmentLightModel{T}vEXT. The
lighting model parameters can be queried by issuing the Get command <pname>
parameter set to the appropriate fragment lighting model parameter:
FRAGMENT_LIGHT_MODEL_LOCAL_VIEWER_EXT, FRAGMENT_LIGHT_MODEL_TWO_SIDE_EXT,
FRAGMENT_LIGHT_MODEL_AMBIENT_EXT or FRAGMENT_LIGHT_MODEL_NORMAL_INTERPOLATION_EXT.
3.9.4 FragmentColorMaterial
One or more fragment material properties in Equation 3.2 can be
replaced with the fragment's pre-texturing color, causing these color
values to be used during the lighting computation. This behavior is enabled
and disabled by calling Enable and Disable with the symbolic value
FRAGMENT_COLOR_MATERIAL.
The command that controls which of these modes is selected is
void FragmentColorMaterial(enum face, enum mode);
<face> is one of FRONT, BACK, or FRONT_AND_BACK, indicating whether
the front material, back material, or both are affected by the
pre-texturing color. <mode> is one of EMISSION, AMBIENT, DIFFUSE,
SPECULAR, or AMBIENT_AND_DIFFUSE and specifies which material property
or properties are subsituted with the pre-texturing color. The substutions
do not affect the material state. When FragmentColorMaterial
is disabled the values in the fragment material state are used.
GetFragmentMaterial returns the fragment material last specified with
FragmentMaterial, regardless of whether FragmentColorMaterial is enabled.
3.9.5 Interactions with Vertex Lighting
In order to allow implementions to share resources for vertex lighting and
fragment lighting, an implementation may limit the maximum number of combined
vertex and fragment lights to a number less than the sum of MAX_LIGHTS and
MAX_FRAGMENT_LIGHTS_EXT. This limit can be queried using the Get command
with <pname> parameter MAX_ACTIVE_LIGHTS_EXT. State for all
fragment and vertex lights is always maintained. When multiple
lights are enabled, priority is given to vertex lights starting with
LIGHT0 through LIGHT<n> where <n> is equal to MAX_LIGHTS, followed by
FRAGMENT_LIGHT0_EXT through FRAGMENT_LIGHT<m>_EXT where <m> is equal
to MAX_FRAGMENT_LIGHTS_EXT.
Additions to Chapter 4 of the 1.1 Specification (Per-Fragment Operations
and the Frame Buffer)
None
Additions to Chapter 5 of the 1.1 Specification (Special Functions)
None
Additions to Chapter 6 of the 1.1 Specification (State and State Requests)
TBD
Additions to the GLX Specification
TBD
Errors
INVALID_ENUM is generated if FragmentMaterial{T}EXT,
FragmentMaterial{T}vEXT, or FragmentColorMaterialEXT, parameter <face> is
not FRONT, BACK or FRONT_AND_BACK.
INVALID_ENUM is generated if FragmentMaterial{T}EXT or
FragmentMaterial{T}vEXT parameter <pname> is not AMBIENT, DIFFUSE,
SPECULAR, EMISSION, SHININESS, or AMBIENT_AND_DIFFUSE.
INVALID_ENUM is generated if GetFragmentMaterial{T}vEXT parameter <face>
is not FRONT or BACK.
INVALID_ENUM is generated if GetFragmentMaterial{T}vEXT parameter <pname>
is not AMBIENT, DIFFUSE, SPECULAR, EMISSION, or SHININESS,
INVALID_ENUM if FragmentColorMaterialEXT parameter <mode> is not EMISSION,
AMBIENT, DIFFUSE, SPECULAR, or AMBIENT_AND_DIFFUSE
INVALID_ENUM if LightEnviEXT parameter <pname> is not LIGHT_ENV_MODE_EXT
or if parameter <mode> is not REPLACE, MODULATE, or ADD.
INVALID_ENUM is generated if FragmentLightModel{T}EXT <pname> is not
FRAGMENT_LIGHT_MODEL_LOCAL_VIEWER_EXT, FRAGMENT_LIGHT_MODEL_TWO_SIDE_EXT
or FRAGMENT_LIGHT_MODEL_NORMAL_INTERPOLATION_EXT or if
FragmentLightModel{T}vEXT, parameter <pname> is not
FRAGMENT_LIGHT_MODEL_AMBIENT_EXT, FRAGMENT_LIGHT_MODEL_LOCAL_VIEWER_EXT
FRAGMENT_LIGHT_MODEL_TWO_SIDE_EXT or
FRAGMENT_LIGHT_MODEL_NORMAL_INTERPOLATION_EXT.
INVALID_ENUM is generated if FragmentLight{T}EXT, FragmentLight{T}vEXT,
or GetFragmentLight{T}vEXT parameter <light> is not FRAGMENT_LIGHT0_EXT
... FRAGMENT_LIGHT<n>_EXT where n is one minus the number of supported
fragment lights, or if FragmentLight{T}EXT parameter <pname> is not
SPOT_EXPONENT, SPOT_CUTOFF, CONSTANT_ATTENUATION, LINEAR_ATTENUATION, or
QUADRATIC_ATTENUATION, or if FragmentLight{T}vEXT or
GetFragmentLight{T}vEXT parameter <pname> is not AMBIENT, DIFFUSE,
SPECULAR, POSITION, SPOT_DIRECTION, SPOT_EXPONENT, SPOT_CUTOFF,
CONSTANT_ATTENUATION, LINEAR_ATTENUATION, or QUADRATIC_ATTENUATION.
INVALID_VALUE is generated if FragmentLight{T}EXT or FragmentLight{T}vEXT
parameter <param> if a spot exponent value is specified outside the range
[0,128], or if spot cutoff is specified outside the range [0,90] (except
for the special value 180), or if a negative attenuation factor is
specified.
INVALID_OPERATION is generated if FragmentMaterial{T}EXT,
FragmentMaterial{T}vEXT, FragmentColorMaterialEXT,
GetFragmentMaterial{T}vEXT, LightEnviEXT, FragmentLight{T}EXT,
FragmentLight{T}vEXT, FragmentLightModel{T}EXT,
FragmentLightModel{T}vEXT or GetFragmentLight{T}vEXT is executed between
execution of Begin and the corresponding execution of End.
New State
Get Value Get Command Type Initial Value Attribute
--------- ----------- ---- ------------- ---------
FRAGMENT_LIGHTING_EXT IsEnabled B False lighting/enable
FRAGMENT_COLOR_MATERIAL_EXT IsEnabled B False lighting/enable
FRAGMENT_COLOR_MATERIAL_PARAMETER_EXT GetIntegerv Z5 AMBIENT_AND_DIFFUSE lighting
FRAGMENT_COLOR_MATERIAL_FACE_EXT GetIntegerv Z3 FRONT_AND_BACK lighting
AMBIENT GetFragmentMaterialfvEXT 2xC (0.2,0.2,0.2,1.0) lighting
DIFFUSE GetFragmentMaterialfvEXT 2xC (0.8,0.8,0.8,1.0) lighting
SPECULAR GetFragmentMaterialfvEXT 2xC (0.0,0.0,0.0,1.0) lighting
EMISSION GetFragmentMaterialfvEXT 2xC (0.0,0.0,0.0,1.0) lighting
SHININESS GetFragmentMaterialfvEXT 2xR 0.0 lighting
FRAGMENT_LIGHT_MODEL_AMBIENT_EXT GetFloatv C (0.2,0.2,0.2,0.2) lighting
FRAGMENT_LIGHT_MODEL_LOCAL_VIEWER_EXT GetBooleanv B False lighting
FRAGMENT_LIGHT_MODEL_TWO_SIDE_EXT GetBooleanv B False lighting
FRAGMENT_LIGHT_MODEL_NORMAL_INTERPOLATION_EXT GetIntegerv Z2 SMOOTH lighting
AMBIENT GetFragmentLightfvEXT 1*xC (0.0,0.0,0.0,1.0) lighting
DIFFUSE GetFragmentLightfvEXT 1*xC see 3.x lighting
SPECULAR GetFragmentLightfvEXT 1*xC see 3.x lighting
POSITION GetFragmentLightfvEXT 1*xP (0.0,0.0,1.0,0.0) lighting
CONSTANT_ATTENUATION GetFragmentLightfvEXT 1*xR 1.0 lighting
LINEAR_ATTENUATION GetFragmentLightfvEXT 1*xR+ 0.0 lighting
QUADRATIC_ATTENUATION GetFragmentLightfvEXT 1*xR+ 0.0 lighting
SPOT_DIRECTION GetFragmentLightfvEXT 1*xD (0.0,0.0,-1.0) lighting
SPOT_EXPONENT GetFragmentLightfvEXT 1*xR+ 0.0 lighting
SPOT_CUTOFF GetFragmentLightfvEXT 1*xR+ 180.0 lighting
FRAGMENT_LIGHTi_EXT IsEnabled 1*xB False lighting/enable
LIGHT_ENV_MODE_EXT GetIntegerv Z3 REPLACE lighting
CURRENT_RASTER_NORMAL_EXT GetFloatv N (0,0,1) current
New Implementation Dependent State
Get Value Get Command Type Minimum Value
--------- ----------- ---- -------------
MAX_FRAGMENT_LIGHTS_EXT GetIntegerv Z+ 1
MAX_ACTIVE_LIGHTS_EXT GetIntegerv z+ MAX_LIGHTS
Implementation Support
List of OpenGL implementations supporting the GL_EXT_fragment_lighting extension
Original File
Original text file for the GL_EXT_fragment_lighting extension
Page generated on Sun Nov 20 18:37:37 2005