tHeBloG

Howdy! Do you remember the time before HD, amoled etc. super sharp screens? When pixels were so big that you could easily count them and any colors were luxury? This is your ticket back to these good ol' times: LedScreen Qt5 & QtQuick 2.0 component! Here is a video presenting it with example applications: This component allows you to use any QML content as the source for the ledscreen, define led size and color or use colors from the source item. So it doesn't contain kitchen sink yet, but there's only so much you can fit into 60 lines of QML + GLSL with API documentation.. ;-) Feel free to grab sources from here & modify & use as you want! PS: Hoping to be able to develop & demo Qt5 soon on Raspberry Pi!

Smoke the Bugs is now available to download from Nokia Store for Harmattan N9 and for Anna/Belle . No bugs (except software bugs!) were harmed while developing the game, but to know whether this virtual bug smoking is suitable for you, check this video of game play on N9: As explained here earlier , this was partly an expedition on making a game with pure QML + JavaScript + shader effects. Plan was to make it totally without C++ (excluding the launcher which Qt SDK generates automatically) and to see what the outcome would be. So summing up some random development notes here: Harmattan version of the game utilizes Qt-components for portrait main window and for disabling swipe while playing. Symbian version does not use Qt-components as pure QML was enough. It's good to use Loader for separating rest of the UI from initial "splash screen" for faster startup. Another option on Harmattan would be to show static splash screen image with invoker . In this game, loaders are...

Catchy title right? Don't worry, content partly matches to that description... ;) It seems that I quite often include videos in my blog posts. There is no reason to stray away from that habit now, so here's a video showing a beta version of "Smoke the Bugs!" game on N950 & N8: By looking at the graphics, effects, dynamic lights etc. what you saw was a pretty average OpenGL (ES 2.0) game, right? Well yes and no... Yes, GLSL shaders have been used for the effects. But no, there is zero lines of OpenGL and in fact also zero lines of C/C++ in the game. It's all QML + GLSL + JavaScript. To work on current Harmattan & Symbian devices, game uses Qt 4.7 with the shaders plugin. This is an okay-ish platform, as you see from the video: N8@680MHz runs at smooth ~60fps. But I have also smelled, tasted and floated in the sweet velvet of Qt5 and can tell you as a fact that it will be much better. With Qt5 & QtQuick 2.0, applications will get a healthy boost of perfo...

Hey! Qt Developer Days '11 are over and I want to thank all organizers & attendees, what a great event again!! For fresh owners of N9 (congratulations!), I'll say that 5inarow game is now available through Nokia Store. Here's how to get beaten by medium level: Symbian version may follow later, but for now game is only available on N9/N950. It's free and contains no ads so if you feel like it, go grab it from here . PS. If this tickles your "How to implement a Qt game like that?" or "I could do much better than that!" -nerves, source codes and Qt Quick Game Programming tutorial are still available from here . These are for the older N900 version, without e.g. sounds and computer AI. But an idea of updating the document for Qt5 & shader effects is floating in my mind, we'll see, we'll see...

Yoann Lopes blogged recently about Text Rendering in the QML Scene Graph using distance field alpha testing. This technique brings smoothly scalable fonts with fast OpenGL rendering to Qt5. Distance field is of course not limited for just fonts (although they are the most usual use-case), same technique can be used also with suitable images. Here is a video of an example application running on PC and N950 which demonstrates the effect: As you can see, the original image becomes quite pixelated when zooming in, which is expected as image is only 256x160 pixels (smiley 64x64 pixels). But enabling smoothing with distance field shader makes it very scalable with nice anti-aliasing, outline and transparency. As the pixmap required for this is so small, GPU / fragment shader has less to process leading to better performance. Like with fonts, adding effects such as outline, smoothing, glow and shadow can be implemented very effectively. This application is under 300 lines of QM...

I will be mostly interested in discussions about Qt5 graphics stack, qml-box2d, QtQuick 2.0 and of course QML Scene Graph. So whenever something related to these is going on, please grab me in!

Kimi, the man with excellent genes, blogged few days ago in here about QML extension plugin that provides shader effects for QGraphicsView based Qt Quick 1.x. What makes this magnificent, is the fact that API matches to what QML Scene Graph (at least currently) has, making it a perfect solution to start experimenting with the future. Also, as it is a separate plugin sitting on top of standard Qt 4.7.x, it turns "Qt everywhere" to "shaders everywhere" right now while waiting for the full Scene Graph glory. All you need is 1) Qt 4.7 installed in suitable environment (Linux, Windows, Symbian etc.) 2) the qml1-shadersplugin and 3) imagination for writing QML & GLSL. What I came up with using the plugin is something they call metaballs : Source codes are available in here , go wild! And kudos to Nokia/Qt team for providing this plugin!