Sound engine improvements, paper about Tornado statistics in Ukraine, other news

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  1. Sound engine improvements:
    • Easy additional simultaneous music tracks, for easily playing looping sounds, using the new LoopingChannel property.

    • Added a <group> element to group your sounds in “sound repository” XML files. See the manual about “Sound”.

    • We auto-detect extension (.wav, .ogg) if no URL is specified for <sound> in “sound repository” XML files (previously we assumed .wav).

  2. The paper Tornado statistics in Ukraine based on new data is using Castle Game Engine for visualizations!

  3. Our scripts now just call the build tool. See this commit log for numerous reasons why this is better.

  4. Our website is now protected by Cloudflare. In case of outage, you will see a cached version.

Sorry for being so quiet lately, lots of work! A big announcement about a big new feature is on the horizon, but I am not ready yet. 🙂

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User-defined clipping planes, TInputShortcut example

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  1. ClipPlane allows you to define custom clipping planes.

    See our documentation of nodes, X3D documentation of ClipPlane, and a simple demo or very complicated demo.

    Remember that this node can be specified in an X3D file (which you can open using e.g. view3dscene or load to TCastleScene), or it can be added and changed using Pascal code (use TClipPlaneNode class).

    While we already had this feature in the past, it was broken in the modern shader pipeline. It is fixed now, and will work both in modern OpenGL and on mobile OpenGLES 🙂

    • in OpenGL >= 3: use built-in gl_ClipDistance

    • in OpenGL < 3, keep using gl_ClipVertex,

    • in OpenGLES: use own castle_ClipDistance, discard in fragment shader.

  2. We also have a new example showing how to use TInputShortcut and save it to a config file.

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New Screen Effects API and Demo, Text Node Optimizations, Multi-texture Modes Fixes

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Screenshot of selection at 2018-07-29 05:15:01
Screenshot of selection at 2018-07-29 05:16:00
  1. New class TCastleScreenEffects offers easier, and at the same time more flexible API to control screen effects.

    • It has a simple AddScreenEffect method that takes X3D node graph with TScreenEffectNode.

    • New demo showing screen effects is in examples/screen_effects_demo.

    • The screen effects can now be applied over any other UI control output (placed as children of TCastleScreenEffects). E.g. trivial TCastleImageControl or complicated TCastleSceneManager.

      For the special case when using with TCastleAbstractViewport (TCastleSceneManager, TCastleViewport), it is even easier, as TCastleAbstractViewport now descends from TCastleScreenEffects, and exposes AddScreenEffect method immediately.

    • We have also added new (float-based) GLSL functions available for screen effects authors. The documentation how to create screen effects shader code is here.

  2. An important optimization of Text node memory usage. Previously a scene with many Text nodes could really eat a lot of memory.

  3. BLEND* multi-texture modes fixed, and many multi-texture modes that can work only on RGB/alpha channels implemented in the shader pipeline. The specification of all supported multi-texturing modes is here.

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Easy mirrors on flat surfaces: more progress

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The implementation of our “easy mirrors on flat surfaces” is more-or-less complete now. I’ll be working on a documentation and better demos soon. For now, see the description below.


  • Setting up the mirror is a matter of using X3D node ViewpointMirror with RenderedTexture (to get a texture containing mirror), and applying this texture with generated coordinates by TextureCoordinateGenerator { mode "MIRROR-PLANE" }.
  • A working demo is in viewpoint_mirror.x3dv. Just get the demo-models repository and open viewpoint_mirror.x3dv inside with view3dscene from snapshots or any Castle Game Engine 3D example. A better demo will follow shortly, showing also how to use this with Blender and Pascal, without hand-crafting an X3D file.

  • Multiple mirrors work nicely and can produce recursive reflections (when a mirror is visible in a mirror). Each frame updates the mirrors based on their previous contents, so the recursion depth is practically unlimited with zero cost.

  • A mirror texture can be mixed with material and other textures using multi-texturing, just like any other texture.

  • The mirror geometry can be any complicated shape. It doesn’t have to be a simple quad! However, it should be more-or-less planar (we automatically calculate a best fit plane looking at geometry) in order to get sensible results.

  • The texture mapping TextureCoordinateGenerator is done by shaders on GPU. So it remains fast even for complicated objects. The mirror itself is rendered using FBO.

This work is sponsored by the Castle Game Engine supporters on Patreon, in particular thanks go to Robert Daniel Murphy for requesting this feature. If you like what I’m doing, please consider supporting me! Thank you.

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New trailer of “The Unholy Society”

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We proudly present a new trailer for our game “The Unholy Society”:

It’s all in-game footage, everything is done using Castle Game Engine. Most of the graphics is done in Spine, and rendered and animated using TCastle2DScene (see more info about using Spine in Castle Game Engine). The UI (fight symbols, items) is using standard CGE UI (TUIControl descendants). We have a simple custom language for conversations and scripting (see also Google Doc version of this post).

You can wishlist the game on Steam!

The game is developed by Cat-astrophe Games, an indie game studio in which Michalis is the main (and only, although that may change soon) developer. Coincidentally, we’re doing all our projects using Castle Game Engine 🙂

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NURBS, simplified license (just LGPL out-of-the-box)

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  1. The need to define symbol CASTLE_ENGINE_LGPL to get LGPL engine (otherwise you only had GPL) disappears. The whole engine can be used on a permissive LGPL terms out-of-the-box now, there is no point in defining the CASTLE_ENGINE_LGPL symbol anymore.

    I have clarified and simplified our license terms on . In short: we’re exactly like FPC and Lazarus. Yes, you can make closed-source applications using CGE.

  2. We have a new NURBS implementation, developed by Michalis from scratch. I deleted the old (GPL-only, copyright by White Dune developers) implementation in this commit, and later implemented new one (LGPL, copyright by me) in subsequent commits. So the LGPL engine supports NURBS now.

    The new implementation also got some serious optimizations (utilizing the fact that we usually calculate not one point on a curve/surface, but a number of such points in a series).

    The new implementation also features a helper method TNurbsCurveNode.Point. See this test for a quick usage example. This allows you to use NURBS curves calculation for any purposes, not necessarily by placing the NURBS nodes inside TCastleScene.

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Fixes, demo switching projection, website and API documentation improvements

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Busy month! Partially due to developing the last chapter of our game The Unholy Society, in which a certain-special-someone is scheduled to appear 🙂

New stuff in the engine:

  • Important bugfix: Changing the FullScreen property of the window is now more reliable. The actual change (which may involve recreating OpenGL context) happens with delay, not immediately at the point you assign the “FullScreen” property. This makes it safe to use always, even during Window.OnOpen / Application.OnInitialize. Thanks for Ninjamida from Discord for finding this nasty bug.
  • SceneManager.OnProjection event along with a demo switch_projection.lpr showing how to use it to toggle between orthographic/perspective projection.

  • TAbstractBindableNode.Bound property.

  • More reliable on-screen keyboard on Android thanks to Benedikt Magnus!

New website improvements:

  • You can now comfortably switch between viewing API documentation for engine stable version (6.4) and unstable (6.5). The currently viewed version is clearly visible, and when switching we try to show the same identifier (if it exists in the other version).

  • The “search” in our documentation is better now (highlights found terms, no messed up HTML) as I improved the “tipue search” functionality in PasDoc.

  • I have adjusted our analytics (Piwik) settings to be compliant with GDPR and anonymize the IP addresses and delete old data. Our privacy policy was reflected about this.

    P.S. Have you seen a new pretty webpage of our studio Cat-astrophe Games ? 🙂 My cats are there!

Retired: GitHub -> SourceForge SVN synchronization

Our GitHub -> SourceForge SVN synchronization (using forked sync2git) started to have problems.

(Details: The synchronization repository got into a state unexpected for git-svn. Possibly the underlying reason was a random SourceForge connectivity issue, but that’s speculation.)

Since I don’t think anyone is using SourceForge SVN anymore, I just turned it off, and I made sure no links to SourceForge SVN repository exist anymore on our website. Please use only CGE repositories on GitHub from now on, in particular the main Castle Game Engine repository.

Note that you can still use either GIT or SVN client to get Castle Game Engine. GitHub supports doing “svn checkout” on a GitHub repository (or a subdirectory of it).

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Engine improvements: CommonSurfaceShader with shadow maps fix, demo of mouse picking 3D/2D objects, view3dscene without console

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  1. We added a simple demo how to detect which scene (TCastleScene) was clicked with the mouse: .

  2. The behavior of shadow maps when combined with CommonSurfaceShader is now correct. Testcase:

  3. view3dscene no longer uses console for various messages. Instead we display our own message box, with contents that can be copied to clipboard with Ctrl+C. This makes it more comfortable to use as a normal GUI program, in particular on Windows. Remember that you can always download the latest view3dscene snapshots from here. (Or you can compile view3dscene from source, of course.)

  4. Our website supports now IPV6, HTTP/2, has better redirects (from www domain to non-www), and is HTTPS-only (non-secure HTTP merely redirects to HTTPS, and we use HSTS). Thanks to Raul Tambre for suggesting and testing these improvements!

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