Tremulous animations played from MD3 file

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Tremulous MD3 animation - Marauder
Tremulous MD3 animation - Tyrant

New example split_long_md3_animation_into_logical_pieces shows how to play subanimations in MD3 files. In a broader context, it shows how to use TCastleSceneCore.ForceAnimationPose to manually “drive” the animation, picking the animation frames you want.

The MD3 format comes from Quake 3 and it’s used by various games sharing that game engine. In particular I’m a big fan of Tremulous so this example naturally shows Tremulous cool low-poly aliens rendered and animated using Castle Game Engine πŸ™‚

The MD3 file itself doesn’t specify particular animations, it is essentially one long animation that in practice usually contains glued a number of “subanimations” in our terminology. The accompanying animation.cfg specifies the “subanimations”, where do they start and finish. The example code defined a ready class that loads animation.cfg, and allows to query and easily play “subanimations” specified there.

If you use MD3 files with accompanying animation.cfg files, you will find the class TSceneSubAnimations to be a ready-to-use component that allows you to deal with MD3 animations easily.

If you’re looking into more general “how can I manually control the animation” then look under the hood and see how is the TCastleSceneCore.ForceAnimationPose used there.

Here’s a quick demo:

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New component to place Tiled map in a viewport

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Tiled snow map
Tiled beach map
Tiled map - layers
Tiled map in 3D
Tiled map

Following the Tiled improvements and optimizations done in January, it was most natural to introduce a dedicated class TCastleTiledMap that represents a Tiled map in a viewport. It descends from TCastleTransform and thus can be moved, rotated, scaled (in 2D or 3D), just like anything else in the viewport.

The usage demo, along with many sample maps, is in examples/tiled/map_viewer_in_viewport.

Most important Tiled-specific API:

The full documentation is in Tiled map manual page.

Many thanks go to Freedomax for implementing animations on Tiled maps and providing a lot of Tiled fixes (seams fix, ForceTilesetSpacing, proper Z-order of tiles in all situations, relative URL fix…) and examples!

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Cache to speedup loading multiple instances of the same scene URL

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Occlusion query demo on desktop

New TCastleSceneCore.Cache property allows to load the scene contents through a shared cache. If you have multiple TCastleScene loaded from the same URL, this is a sure way to speedup loading of them.

Testcase: examples/viewport_and_scenes/occlusion_culling, where I set up multiple buildings and creatures from the same glTF.

Alternative: You can actually achieve even more optimization (loading time, memory use) using TCastleTransformReference or (equivalent internally) just adding the same TCastleScene instance multiple times to the viewport. These techniques allow to really have one instance and just draw it multiple times — this is a much more powerful optimization, but also puts more constraints: all the referenced things must have the same animation, occlusion culling doesn’t work on them etc.

In contrast, using TCastleSceneCore.Cache is much safer, it doesn’t really change how things work at all from the developer perspective. Each scene may be in a different state, play different animation etc. We just internally load them faster. And it is simpler to use, just toggle the Cache checkbox and observe the speed boost.

Related: Do you want to measure the loading speed, e.g. to compare what do you gain by cache? See the advise about “profiling” in our manual. To cut the long story short, I advise to do Profiler.Enabled := true in your initialization, and observe the report about what takes time at initialization in the log. For more about TCastleProfiler, see the API docs.

How this cache works now, and what is the future: Right now, it works by internally storing the nodes graph in the cache, and instead of loading a file again — we can just do TX3DNode.DeepCopy to clone the graph. This is nice, but actually in the future it could be even better: if we change how our animations work to do not modify the graph, then actually all cached scenes could just use one and the same graph. This is a possible future optimization.

If you like this, please support us on Patreon!

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Join our 5th Open Meeting (“Spring 2023”) on Discord this Saturday (March 18)

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"Lynch" game in CGE editor

You know the drill — our quarterly meeting on Discord, open to everyone, is this weekend! Join us and talk about Castle Game Engine πŸ™‚

The meeting will happen at 15:00 (UTC timezone) this Saturday, March 18th, 2023.

Simply join our Discord chat and go to the #open_meeting channel.

You can just visit this link to land in the channel directly. Or use this link to see the event details (click on β€œβ€¦β€ to see options to add it to your calendar, mark it β€œI am interested” etc.).


  1. Presentation of new CGE features. We have a lot of stuff from lately done features and I actually hope to add some more before Saturday πŸ™‚

  2. Our plans for the immediate future.

  3. Your turn! Everyone is welcome to take the stage!

    Show what you are working on. Show your project, component, game, anything even loosely related to CGE is OK.

    Do you have any questions? We will be happy to answer them live.

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Mobile (OpenGLES) rendering upgrades: occlusion culling, anisotropic filtering, 3D textures, shadows; plus new occlusion query demo

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Occlusion query demo on Android
Occlusion query demo
Occlusion query demo on desktop

Our OpenGL and OpenGLES code is now more streamlined, which allowed to “unlock” various rendering features on OpenGLES.

This means we will use some features from OpenGL ES 3.0, if it is available:

Note that we still require only OpenGL ES 2.0. The OpenGL ES 3.0 features are optional for us.


  • Anisotropic filtering is now supported on OpenGLES, through an almost universally-available extension, just like on the desktop. See e.g. anisotropic_filtering demo. (Yeah, we should have a more comfortable way to adjust anisotropic filtering visually — I have 2 ideas about this, will explore them.)

  • We also fixed support for rendering shapes that require 32-bit indexes. While OpenGLES 2.0 guarantees only 16-bit indexes (OpenGLES 3.0 bumps it to 32-bit), we now automatically deal with it inside a renderer, if necessary doing additional processing to enable bigger meshes even for OpenGLES 2.0. This can be tested using fps_game on mobile.

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We now use dedicated GPU automatically for all new projects

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"Lynch" game in CGE editor

Many laptops come now with 2 GPUs: a slower one that consumes less battery and a “dedicated” GPU consuming more battery but capable of much better speeds, esp. when used with non-trivial 3D data. The CGE editor and your applications automatically use the “dedicated” GPU now.

More information about this feature, the documentation how to disable it, and how to upgrade your existing projects to follow: Dedicated GPU.

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User interface features: render with mask (new TCastleMask component), better slider default look, new option ProtectedSidesScaling

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Mask at runtime
Mask at design-time
view3dcene new sliders
  1. New component TCastleMask allows to define a mask (using an arbitrary UI control) and use this mask to limit rendering the children.

    The mask may be any UI control (or a composition of it). The colors do not matter, only which pixels are drawn by the mask. E.g. you can define a mask using

    The masked children, in turn, can also be any UI control. So you can filter rendering of anything, even if it’s interactive (like a button) or 3D (like a viewport).

    TCastleMask.MaskRendering determines if the children are rendered where the mask is visible or (on the contrary) where the mask is not visible.

    See the example examples/user_interface/mask for demonstration.

  2. I improved the default look of our sliders (TCastleFloatSlider, TCastleIntegerSlider).

    These sliders are quite useful, esp. for various demos and tools (view3dscene uses them to test animations and lights). Well, they no longer look ugly πŸ™‚ and their design allows an optional label inside (useful to communicate to user exact numerical value behind the slider).

  3. I implemented a special way of treating protected sides for images. By default they do normal 9-slice scaling but a new option allows to scale corners horizontally to match the image height: TCastleImagePersistent.ProtectedSidesScaling, pssMatchHeight.

    Admittedly it’s a bit easier to see than to explain with words, so if you’re curious, just try it out with an image like SliderBackground that has exactly circular left and right endings. Thanks to the new option, they will stay circular, no matter how you resize the slider.

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Convert SVG to X3D using X_ITE, to display SVG as geometry in Castle Game Engine

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Zrzut ekranu z 2023-02-25 00-59-48
Zrzut ekranu z 2023-02-25 00-59-28
Zrzut ekranu z 2023-02-25 00-59-58
Zrzut ekranu z 2023-02-25 01-00-15

X_ITE is an open-source JavaScript library to display X3D (and a number of other formats) in a web browser, using WebGL. It was recently extended to import additional formats, and render them straight away or convert to X3D. The supported formats are now: X3D, VRML, glTF (GLB), OBJ, STL, and SVG.

There is an accompanying online converter to X3D and a command-line converter x3d-tidy that perform the conversion using X_ITE underneath.

In a way, this is similar to what we do in Castle Game Engine, where we also load everything (like glTF) to X3D nodes, give you an online converter and a command-line and GUI converter.

But there’s also a big added value: X_ITE supports SVG. SVG (scalable graphics, create it e.g. in Inkscape) gets converted into proper geometry in X3D, so it remains scalable and can be used as part of your 2D or 3D game in CGE! This is what I enjoy about being part of an ecosystem and open formats like X3D — we get new features “for free” thanks to cooperation with others.

Note that in the generated X3D file, all objects will be placed at the same depth, Z = 0, at least right now. You may have to fix it to avoid Z-fighting in case SVG layers overlap. For simple cases, it is possible to do this by just manually editing the X3D file in any text editor. Assigning meaningful names to your objects in SVG, e.g. using Inkscape “Object Properties”, also helps. I have done it with a non-trivial SVG file (our engine logo) and the manual effort was ~easy πŸ™‚

See the result of my play in demo-models/svg. It shows how to fix Z, I also add a shader effect to discard pixels outside of a circle in the middle, to “cut off” stuff that should not be visible in a circular engine logo.

I encourage you to test the converter and explore X_ITE in general. Many thanks go to Holger Seelig for an amazing work on this!

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Rendering of lines and points from glTF, more options for line nodes in X3D

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Lines from glTF, test model from
Points in glTF
Lines in glTF

This is probably not the most sexy graphic effect announcement :), but the lines and points are useful to visualize a lot of things.

We have improved our glTF support to properly import points, lines (lines, line strips, line loops), and their materials.

We have also improved our X3D nodes capabilities by introducing TIndexedLineSetNode.Mode and TLineSetNode.Mode. This allows to comfortably and efficiently define lines, line strips, line loops in X3D.

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Using OpenGL “core” profile by default on macOS

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fps_game example on mac
System Information with OpenGL 4.1 on mac
shadow maps on mac
shadow volumes on mac
shaders on mac
view3dscene on mac with OpenGL 4.1

Thanks to recent rendering code improvements, we can finally request “core” profile on macOS, to get latest OpenGL version (4.1 in my case) instead of being stuck with legacy OpenGL 2.1 on mac.

We request now a modern context on mac, both with TCastleWindow and TCastleControl. This applies to all our software — CGE editor, view3dscene, all your applications you build with CGE.

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