20 months agoMake animation curve creation more generic
Mikko Rasa [Fri, 7 Jun 2019 22:30:11 +0000 (01:30 +0300)]
Make animation curve creation more generic

20 months agoReimplement Animation using splines
Mikko Rasa [Wed, 5 Jun 2019 22:02:41 +0000 (01:02 +0300)]
Reimplement Animation using splines

Transform interpolation is now performed on individual components rather
than entire matrices.  This produces more accurate rotations and later
will allow animations to only affect some components of the transform.

Currently linear splines are used and the slope parameters are ignored.
Pose matrices are also disabled for now because I don't have any suitable
data for testing them.  The old implementation was broken in various ways

20 months agoCheck for armature mismatches in Animation
Mikko Rasa [Tue, 4 Jun 2019 22:42:49 +0000 (01:42 +0300)]
Check for armature mismatches in Animation

Also set the armature if a keyframe with a pose is added and there is no
armature yet.

20 months agoStore a Transform in keyframes instead of a Matrix
Mikko Rasa [Tue, 4 Jun 2019 14:13:59 +0000 (17:13 +0300)]
Store a Transform in keyframes instead of a Matrix

This is the first step towards curve-based animations and finer control
over which values are animated.

20 months agoAdd more public methods to Transform
Mikko Rasa [Tue, 4 Jun 2019 11:11:45 +0000 (14:11 +0300)]
Add more public methods to Transform

20 months agoExport world transforms for scene objects
Mikko Rasa [Tue, 4 Jun 2019 10:39:27 +0000 (13:39 +0300)]
Export world transforms for scene objects

The location, rotation and scale properties contain transform components
relative to the somewhat arbitrary basis matrix.  Obtain the values from
the world matrix instead.  A drawback is that nonuniform or negative
scaling can produce inconsistent results.

20 months agoUse transform blocks to specify object transforms in exported scenes
Mikko Rasa [Tue, 4 Jun 2019 10:00:07 +0000 (13:00 +0300)]
Use transform blocks to specify object transforms in exported scenes

20 months agoMove transform loading to ObjectInstance
Mikko Rasa [Tue, 4 Jun 2019 09:26:54 +0000 (12:26 +0300)]
Move transform loading to ObjectInstance

20 months agoAdd a class to unify loading coordinate transforms
Mikko Rasa [Tue, 4 Jun 2019 07:39:17 +0000 (10:39 +0300)]
Add a class to unify loading coordinate transforms

It will also be useful for animations.  Euler angles are not the ideal
way of storing rotations but they are relatively easy to understand and
work with.  Other rotation types will be added in the future.

20 months agoDo not use the srgb flag for textures that explicitly define storage
Mikko Rasa [Tue, 4 Jun 2019 07:23:39 +0000 (10:23 +0300)]
Do not use the srgb flag for textures that explicitly define storage

Presumably the texture author knows which colorspace the texture uses.
In particular this made it impossible to load non-color textures such
as normal maps which require a linear colorspace if the srgb flag was
set in the containing resource collection.

20 months agoUpdate deprecated things
Mikko Rasa [Mon, 3 Jun 2019 16:43:41 +0000 (19:43 +0300)]
Update deprecated things

20 months agoBetter naming algorithm for objects in scene export
Mikko Rasa [Sat, 1 Jun 2019 12:55:28 +0000 (15:55 +0300)]
Better naming algorithm for objects in scene export

Arbitrary prefixes can cut words or numbers in silly places.  Only allow
truncating at common separator characters.

20 months agoAdd getters for RenderTarget width and height
Mikko Rasa [Fri, 31 May 2019 19:30:20 +0000 (22:30 +0300)]
Add getters for RenderTarget width and height

21 months agoFix a texture data indexing bug in AmbientOcclusion
Mikko Rasa [Thu, 30 May 2019 10:54:42 +0000 (13:54 +0300)]
Fix a texture data indexing bug in AmbientOcclusion

21 months agoRecognize displacement map textures when exporting
Mikko Rasa [Wed, 29 May 2019 17:19:41 +0000 (20:19 +0300)]
Recognize displacement map textures when exporting

21 months agoAlways export texture data inline if there's no image file
Mikko Rasa [Wed, 29 May 2019 17:17:56 +0000 (20:17 +0300)]
Always export texture data inline if there's no image file

This allows exporting packed or baked textures.

21 months agoInline functions in variable initialization expressions
Mikko Rasa [Tue, 28 May 2019 08:59:45 +0000 (11:59 +0300)]
Inline functions in variable initialization expressions

If the entire expression was a function call, it didn't get inlined
because VariableDeclaration wasn't being handled separately.

21 months agoAdd an exporter for Blender cameras
Mikko Rasa [Sun, 26 May 2019 18:18:01 +0000 (21:18 +0300)]
Add an exporter for Blender cameras

21 months agoMark datafile tokens as such
Mikko Rasa [Sun, 26 May 2019 18:17:42 +0000 (21:17 +0300)]
Mark datafile tokens as such

21 months agoSupport while loops in GLSL
Mikko Rasa [Sat, 25 May 2019 21:58:17 +0000 (00:58 +0300)]
Support while loops in GLSL

Loops with only a condition expression present are now emitted as while
loops, even if they were originally for loops.

21 months agoImprove formatting of an empty loop body
Mikko Rasa [Sat, 25 May 2019 21:55:10 +0000 (00:55 +0300)]
Improve formatting of an empty loop body

21 months agoAllow removing the initialization statement of a for loop
Mikko Rasa [Sat, 25 May 2019 21:53:05 +0000 (00:53 +0300)]
Allow removing the initialization statement of a for loop

Previously the compiler would recognize it as unused but couldn't remove
it, leading it to repeat the optimizer endlessly.

21 months agoMake all components of a for loop optional
Mikko Rasa [Sat, 25 May 2019 21:52:33 +0000 (00:52 +0300)]
Make all components of a for loop optional

21 months agoRemove an XXX because I no longer remember how to reproduce the issue
Mikko Rasa [Sat, 25 May 2019 21:25:34 +0000 (00:25 +0300)]
Remove an XXX because I no longer remember how to reproduce the issue

Next time I should include a test case.

21 months agoFix various issues with constant condition elimination
Mikko Rasa [Sat, 25 May 2019 21:00:54 +0000 (00:00 +0300)]
Fix various issues with constant condition elimination

It used to optimize based on the initial values of variables, ignoring
the fact that they may change between loop iterations.  A stop-gap fix
was implemented in 8e14c29, but it prevented optimizations of some
conditionals that could safely have been removed.  It also caused the
optimizer to ignore any assignments made to any variables after
declaration when evaluating the loop condition, potentially causing
entire loops to be erroneously removed.  Finally, unary expressions were
not being handled so ++ and -- operators did not mark the variable as

21 months agoProcess MemberAccess nodes in FunctionInliner
Mikko Rasa [Fri, 24 May 2019 22:32:17 +0000 (01:32 +0300)]
Process MemberAccess nodes in FunctionInliner

21 months agoCorrectly parse consecutive *s in a comment
Mikko Rasa [Fri, 24 May 2019 22:07:03 +0000 (01:07 +0300)]
Correctly parse consecutive *s in a comment

Parsing state must not be reset at ** because there may be a / after.

21 months agoDon't try to access a nonexistent return expression
Mikko Rasa [Fri, 24 May 2019 22:04:44 +0000 (01:04 +0300)]
Don't try to access a nonexistent return expression

21 months agoRemove useless using declarations
Mikko Rasa [Fri, 24 May 2019 19:26:34 +0000 (22:26 +0300)]
Remove useless using declarations

Scene no longer has any other overloads of render().

21 months agoDon't attempt to create a copy of null ProgramData
Mikko Rasa [Fri, 24 May 2019 19:26:10 +0000 (22:26 +0300)]
Don't attempt to create a copy of null ProgramData

21 months agoCopy the material slot of RenderPass
Mikko Rasa [Fri, 24 May 2019 19:25:57 +0000 (22:25 +0300)]
Copy the material slot of RenderPass

21 months agoRemember the camera given to Renderer constructor
Mikko Rasa [Fri, 24 May 2019 19:24:43 +0000 (22:24 +0300)]
Remember the camera given to Renderer constructor

And reapply it in end().  It may be necessary to call end() during
setup_frame in order to render nested content, but the camera must

21 months agoAdd OffscreenView class
Mikko Rasa [Fri, 24 May 2019 17:49:41 +0000 (20:49 +0300)]
Add OffscreenView class

This is a fairly thin wrapper around RenderTarget, mostly useful as an

21 months agoSome cleanup for View and WindowView
Mikko Rasa [Fri, 24 May 2019 17:49:07 +0000 (20:49 +0300)]
Some cleanup for View and WindowView

21 months agoAdd numberless versions of vertex array statements
Mikko Rasa [Fri, 24 May 2019 16:39:03 +0000 (19:39 +0300)]
Add numberless versions of vertex array statements

This should have accompanied 6ee541f, which changed the exporter to use
those keywords.

21 months agoAllow tagging objects in a scene file for retrieval after loading
Mikko Rasa [Fri, 24 May 2019 15:43:19 +0000 (18:43 +0300)]
Allow tagging objects in a scene file for retrieval after loading

21 months agoTry to simplify object names when exporting a scene
Mikko Rasa [Fri, 24 May 2019 15:27:50 +0000 (18:27 +0300)]
Try to simplify object names when exporting a scene

The exporter now tries to find the longest common prefix for objects
sharing the same prototype and exports the prototype using that name.
This avoids having randomly numbered object names.

21 months agoFixes and improvements to exporting materials
Mikko Rasa [Thu, 23 May 2019 21:20:26 +0000 (00:20 +0300)]
Fixes and improvements to exporting materials

21 months agoAdd a missing file
Mikko Rasa [Thu, 23 May 2019 21:06:05 +0000 (00:06 +0300)]
Add a missing file

It was supposed to be in bde3ec8.

21 months agoSet texture format according to sRGB colorspace setting
Mikko Rasa [Sun, 19 May 2019 23:20:06 +0000 (02:20 +0300)]
Set texture format according to sRGB colorspace setting

21 months agoImplement material maps for exporting objects with multiple materials
Mikko Rasa [Sun, 19 May 2019 23:03:41 +0000 (02:03 +0300)]
Implement material maps for exporting objects with multiple materials

This replaces the material texture feature which was removed earlier.  The
principle is similar (store material color values in a texture) but the
maps are global, making it possible for multiple objects to use the same

21 months agoImprove texture unit assignment when exporting meshes
Mikko Rasa [Sat, 18 May 2019 14:55:16 +0000 (17:55 +0300)]
Improve texture unit assignment when exporting meshes

21 months agoSome bugfixes to texture exporting
Mikko Rasa [Sat, 18 May 2019 07:54:44 +0000 (10:54 +0300)]
Some bugfixes to texture exporting

21 months agoSimplify the resource separation options
Mikko Rasa [Sat, 18 May 2019 07:45:23 +0000 (10:45 +0300)]
Simplify the resource separation options

Having different options for each resource type was getting unmanageable.
I don't see much value in such fine-grained control either.

21 months agoUse filtering options from Blender texture
Mikko Rasa [Thu, 16 May 2019 21:46:21 +0000 (00:46 +0300)]
Use filtering options from Blender texture

A new property has been added on textures to reference the original image
only and use default options at load time.

21 months agoRefactor texture handling in the material exporter
Mikko Rasa [Thu, 16 May 2019 19:56:37 +0000 (22:56 +0300)]
Refactor texture handling in the material exporter

21 months agoMove material and texture export to their own classes
Mikko Rasa [Thu, 16 May 2019 15:58:55 +0000 (18:58 +0300)]
Move material and texture export to their own classes

Also move technique properties from Object to Material.

21 months agoMake resource handling in the Blender exporter more flexible
Mikko Rasa [Thu, 16 May 2019 11:38:27 +0000 (14:38 +0300)]
Make resource handling in the Blender exporter more flexible

All resources are now collected into a dict and referenced or inlined as
necessary.  This makes it possible for SceneExporter to see the resources
used by objects and export them to the resource collection as separate

21 months agoRedesign file writing in the Blender exporter
Mikko Rasa [Wed, 15 May 2019 21:42:03 +0000 (00:42 +0300)]
Redesign file writing in the Blender exporter

Instead of writing statements directly to the file as string fragments,
construct an in-memory representation of the exported data first.  This
allows it to be manipulated and combined easier.

21 months agoCombine shared_mesh and shared_tech into a single option
Mikko Rasa [Wed, 15 May 2019 21:38:02 +0000 (00:38 +0300)]
Combine shared_mesh and shared_tech into a single option

21 months agoTemporarily remove the material texture feature from Blender exporter
Mikko Rasa [Wed, 15 May 2019 21:33:00 +0000 (00:33 +0300)]
Temporarily remove the material texture feature from Blender exporter

It gets in the way of other improvements and will be replaced by a
similar yet different feature later.

21 months agoOnly use texunit zero in exporter-generated techniques
Mikko Rasa [Sun, 12 May 2019 06:59:53 +0000 (09:59 +0300)]
Only use texunit zero in exporter-generated techniques

It does not make much sense to use anything else without shaders, and
accessing the mesh to find out unit numbers is getting in the way of
some other changes.

21 months agoSome cleanups to exporter code
Mikko Rasa [Sun, 12 May 2019 05:36:17 +0000 (08:36 +0300)]
Some cleanups to exporter code

21 months agoFix some errors in the triangulation algorithm
Mikko Rasa [Mon, 6 May 2019 06:08:19 +0000 (09:08 +0300)]
Fix some errors in the triangulation algorithm

Normals were reversed and edge links were not being updated properly.

21 months agoRewrite triangle strip generation in the Blender exporter
Mikko Rasa [Sun, 5 May 2019 13:54:37 +0000 (16:54 +0300)]
Rewrite triangle strip generation in the Blender exporter

The old algorithm had many of the right ideas but was too clever by half
and consequently very complex.  Use a simpler score-based algorithm
developed by Tom Forsyth.  Also reorder vertices to make memory accesses
to them occur in a more linear fashion.

Options related to cache optimization were removed since there's
no good reason not to optimize.

21 months agoExplicitly triangulate faces in the Blender exporter
Mikko Rasa [Sat, 4 May 2019 23:16:22 +0000 (02:16 +0300)]
Explicitly triangulate faces in the Blender exporter

Previously they were implicitly triangulated during strip generation,
with the idea that it would be more flexible.  However I have some
doubts of its benefits and existing strip generation algorithms tend
to deal exclusively in triangles.

21 months agoAdd a bunch of comments to the Mesh class in the Blender exporter
Mikko Rasa [Sat, 4 May 2019 20:34:15 +0000 (23:34 +0300)]
Add a bunch of comments to the Mesh class in the Blender exporter

21 months agoRename some variable to be a bit clearer
Mikko Rasa [Sat, 4 May 2019 20:29:11 +0000 (23:29 +0300)]
Rename some variable to be a bit clearer

21 months agoSimplify the vertex splitting algorithm
Mikko Rasa [Sat, 4 May 2019 20:16:58 +0000 (23:16 +0300)]
Simplify the vertex splitting algorithm

It now uses single-pass loops instead of temporary lists where feasible.

21 months agoMake the edge map transient
Mikko Rasa [Sat, 4 May 2019 20:11:47 +0000 (23:11 +0300)]
Make the edge map transient

It's only actually used to associate edges with faces so it's simpler if
it doesn't need to be maintained in other functions.

21 months agoMore post-refactoring bugfixes
Mikko Rasa [Sat, 4 May 2019 18:50:06 +0000 (21:50 +0300)]
More post-refactoring bugfixes

21 months agoImprove progress reporting in the Blender exporter
Mikko Rasa [Sat, 4 May 2019 13:42:34 +0000 (16:42 +0300)]
Improve progress reporting in the Blender exporter

Pushing and popping tasks now makes more sense.  The Progress object
always exists but it's possible to suppress reporting (see 9b57666) by
giving it a falsy context.  Progress reporting has been added to a few
places that previously lacked it.

21 months agoRemove extraneous semicolons from Python code
Mikko Rasa [Sat, 4 May 2019 13:40:59 +0000 (16:40 +0300)]
Remove extraneous semicolons from Python code

Sometimes I instinctively put one in because I'm used to writing C++.

21 months agoFix some errors introduced in the refactoring
Mikko Rasa [Sat, 4 May 2019 13:39:26 +0000 (16:39 +0300)]
Fix some errors introduced in the refactoring

21 months agoMajor rework of mesh handling in Blender exporter
Mikko Rasa [Fri, 3 May 2019 17:13:45 +0000 (20:13 +0300)]
Major rework of mesh handling in Blender exporter

All of the preprocessing has been moved out of the MeshExporter class and
into a utility function.  This should make it easier for other exporter
classes to use meshes.

21 months agoRemove the external tech exporter property
Mikko Rasa [Wed, 1 May 2019 09:29:11 +0000 (12:29 +0300)]
Remove the external tech exporter property

Always use an external technique if one is specified through the object

21 months agoRemove the compound property from exporter
Mikko Rasa [Wed, 1 May 2019 09:07:52 +0000 (12:07 +0300)]
Remove the compound property from exporter

It hasn't been very useful since objects got the compound with parent
property.  Removing it simplifies passing around the object to be

21 months agoMove most properties from exporters to the relevant types
Mikko Rasa [Tue, 30 Apr 2019 22:00:22 +0000 (01:00 +0300)]
Move most properties from exporters to the relevant types

These properties pertain to the things being exported and should retain
their values between exports.  It's getting especially difficult to
specify object-specific properties when exporting an entire scene.

2 years agoAllow multiple character ranges in the makefont script
Mikko Rasa [Sat, 7 Jul 2018 07:26:03 +0000 (10:26 +0300)]
Allow multiple character ranges in the makefont script

2 years agoBe less eager to optimize constant conditions in loops
Mikko Rasa [Sat, 7 Jul 2018 07:25:08 +0000 (10:25 +0300)]
Be less eager to optimize constant conditions in loops

It still requires more work to actually detect the scope in which
variables are set, but this at least solves the immediate problem I had.

2 years agoSupport the sample sampling qualifier
Mikko Rasa [Thu, 5 Jul 2018 21:03:35 +0000 (00:03 +0300)]
Support the sample sampling qualifier

Also add a version check for the centroid qualifier.

2 years agoAdd a utility class for switching renderables
Mikko Rasa [Thu, 5 Jul 2018 18:29:29 +0000 (21:29 +0300)]
Add a utility class for switching renderables

2 years agoAllow RED and RG pixel formats in RenderTargetFormat
Mikko Rasa [Wed, 4 Jul 2018 20:49:06 +0000 (23:49 +0300)]
Allow RED and RG pixel formats in RenderTargetFormat

2 years agoAdd support for GLSL interpolation qualifiers
Mikko Rasa [Tue, 3 Jul 2018 23:26:02 +0000 (02:26 +0300)]
Add support for GLSL interpolation qualifiers

2 years agoRearrange GLSL qualifier parsing
Mikko Rasa [Tue, 3 Jul 2018 23:22:56 +0000 (02:22 +0300)]
Rearrange GLSL qualifier parsing

GLSL 4.20 allows qualifiers to be in any order so there's no sense to
enforce a particular order here.  Always output them in a compatible
order though.

2 years agoHave Object provide an identity matrix from get_matrix
Mikko Rasa [Mon, 2 Jul 2018 21:00:28 +0000 (00:00 +0300)]
Have Object provide an identity matrix from get_matrix

It's often useful to have static geometry in a scene directly as an Object
without creating an instance.  Many features such as Z-sorting and culling
require a matrix to be available.

2 years agoDisable mipmaps from various render target textures
Mikko Rasa [Mon, 2 Jul 2018 15:00:30 +0000 (18:00 +0300)]
Disable mipmaps from various render target textures

2 years agoAllow the maximum mipmap level of a texture to be specified
Mikko Rasa [Mon, 2 Jul 2018 12:49:48 +0000 (15:49 +0300)]
Allow the maximum mipmap level of a texture to be specified

This doubles as a way to specify the number of mipmap levels to allocate
when the tetxure image is loaded from a Graphics::Image.

2 years agoExplicitly define the number of mipmap levels in textures
Mikko Rasa [Mon, 2 Jul 2018 12:46:13 +0000 (15:46 +0300)]
Explicitly define the number of mipmap levels in textures

Storage() no longer uses the minification filter to decide whether to
allocate mipmaps or not.  That functionality has been moved to image(),
specifically the version taking a Graphics::Image.

2 years agoThrow an exception if Texture*::allocate is called before storage
Mikko Rasa [Mon, 2 Jul 2018 12:39:45 +0000 (15:39 +0300)]
Throw an exception if Texture*::allocate is called before storage

2 years agoDon't link keyframes with zero interval
Mikko Rasa [Mon, 2 Jul 2018 11:44:23 +0000 (14:44 +0300)]
Don't link keyframes with zero interval

Fixes an issue where a lone instant keyframe at the end of the animation
would produce bad values as the iterator tries to divide by zero.

2 years agoDon't allow iterators on empty animations
Mikko Rasa [Mon, 2 Jul 2018 11:43:49 +0000 (14:43 +0300)]
Don't allow iterators on empty animations

2 years agoRequire the first keyframe of an animation to be at zero offset
Mikko Rasa [Mon, 2 Jul 2018 11:43:02 +0000 (14:43 +0300)]
Require the first keyframe of an animation to be at zero offset

Having empty space at the start of an animation produces unexpected

2 years agoAdd getter for animation duration
Mikko Rasa [Sun, 1 Jul 2018 22:10:58 +0000 (01:10 +0300)]
Add getter for animation duration

2 years agoAdd a speed parameter for animation playback
Mikko Rasa [Sun, 1 Jul 2018 22:10:41 +0000 (01:10 +0300)]
Add a speed parameter for animation playback

2 years agoSupport slopes in keyframe interpolation
Mikko Rasa [Sun, 1 Jul 2018 22:01:27 +0000 (01:01 +0300)]
Support slopes in keyframe interpolation

2 years agoSupport animations on Placeables
Mikko Rasa [Sun, 1 Jul 2018 20:58:02 +0000 (23:58 +0300)]
Support animations on Placeables

Only matrix animations work for obvious reasons.

2 years agoAdd functions to control environment map updates
Mikko Rasa [Sun, 1 Jul 2018 10:05:39 +0000 (13:05 +0300)]
Add functions to control environment map updates

If the environment changes only very slowly or not at all, it may be
desirable to not update the map every frame.

2 years agoAdd a function to set depth clip of EnvironmentMap
Mikko Rasa [Sun, 1 Jul 2018 10:05:11 +0000 (13:05 +0300)]
Add a function to set depth clip of EnvironmentMap

2 years agoDo not attempt to legacy-bind texture targets which do not support it
Mikko Rasa [Sun, 1 Jul 2018 09:53:08 +0000 (12:53 +0300)]
Do not attempt to legacy-bind texture targets which do not support it

2 years agoBind textures in the modern way when shaders are used
Mikko Rasa [Sun, 1 Jul 2018 09:52:07 +0000 (12:52 +0300)]
Bind textures in the modern way when shaders are used

2 years agoUse DSA for binding textures if available
Mikko Rasa [Sun, 1 Jul 2018 09:15:17 +0000 (12:15 +0300)]
Use DSA for binding textures if available

2 years agoRecognize in and out qualifiers for function parameters
Mikko Rasa [Sun, 1 Jul 2018 07:55:31 +0000 (10:55 +0300)]
Recognize in and out qualifiers for function parameters

2 years agoFix a stupid error with PixelStore parameter mask
Mikko Rasa [Tue, 26 Jun 2018 23:14:09 +0000 (02:14 +0300)]
Fix a stupid error with PixelStore parameter mask

2 years agoFix shadowing warnings from older gcc versions
Mikko Rasa [Mon, 25 Jun 2018 21:20:02 +0000 (00:20 +0300)]
Fix shadowing warnings from older gcc versions

2 years agoAdditional overloads for creating pipelines
Mikko Rasa [Sat, 23 Jun 2018 09:12:26 +0000 (12:12 +0300)]
Additional overloads for creating pipelines

2 years agoPlug a memory leak in PipelineTemplate
Mikko Rasa [Sat, 23 Jun 2018 00:57:40 +0000 (03:57 +0300)]
Plug a memory leak in PipelineTemplate

2 years agoMake grid texture coordinates relative to the grid origin
Mikko Rasa [Wed, 20 Jun 2018 10:40:17 +0000 (13:40 +0300)]
Make grid texture coordinates relative to the grid origin

Instead of the world origin, which doesn't make much sense.

2 years agoAdd default texture anisotropy to Resources
Mikko Rasa [Wed, 20 Jun 2018 10:39:00 +0000 (13:39 +0300)]
Add default texture anisotropy to Resources

2 years agoMinor fixes to texture anisotropy handling
Mikko Rasa [Wed, 20 Jun 2018 10:38:16 +0000 (13:38 +0300)]
Minor fixes to texture anisotropy handling

Initialize the anisotropy parameter and don't try to set it unless the
extension is supported.