WebGL Experiments: Texture Compression | Illyriad - Beneath the Misted Land 15 Nov 2011 Author: Ben Adams | Filed under: Development, Graphics Lilli Thompson from Google asked us how we were doing texture decompression in the pixel shaders and what algorithm we were using. Texture compression was a bit of journey – as no one at Illyriad had ever implemented anything in 3d before; to us texture compression was mostly a tick box on a graphics card. It started when we found out our 90MB of jpegs expanded to 2GB of on-board memory and we were worried we’d made a terrible mistake, as this was certainly beyond the possibilities of low-end hardware! Dropping the reference Three.js held after the texture was bound to WebGL resolved this. With 1GB of memory remaining we were faced with three choices – either deciding what were were trying to do wasn’t possible; reducing the texture sizes and losing fidelity or trying to implement texture de-compression in the shader. It took a while to divine the file format; which we load via XMLHttpRequest into an arraybuffer.
mostly shaders » Post process voxels filter This is a pixelshader that takes depth and outputs a new depth and normals that represent the scene made up of voxels. This can be useful for giving bone-animated objects a voxel style look. (animating with voxels is bothersome). It could also be applied to complete scenes. It roughly works like this: -Every screen pixel will belong to a cube (a cube can contain multiple pixels). -Each cube needs to be completely drawn (the tricky part- because the silhouette of the object(s) will change). -a pixel samples a number of pixels in an area that should be about as big as the biggest cube you would expect. -since the screen-area of a cube can be very large (say 64 * 64 = 4096 pixels) it is impossible to sample all pixels in that area to search for a cube that could be occluding the current pixel. -It is sampling with a grid with a spacing of 16 pixels. -it does a ray-cast against every samples containing cube.
Christopher Warnow / » A Thousand Milieus A Thousand Milieus Inspired by the article “Your choices reveal who you are” of Valdis Krebs in the book Beautiful Visualization, I am collecting the Amazon recommendations for a certain book, until a network of books is created..The tool I created as well as the source code can be downloaded here.. See it it in action: . . .
WebGL GPU Landscaping and Erosion A while ago I finished playing From Dust which I enjoyed a lot. What impressed me about that game was the application of landscape changes by erosion. One drawback of the tool Lithosphere I wrote earlier is that it can't do any form of hydraulic erosion. Contents Demo You can try the live demo. Video Screenshots At the start it looks like this. Starting the rain. After a while of raining and erosion. Mesh I am using vertex shader texture lookups to displace the Y axis of a flat plane to represent the terrain and water. The mesh is regularly tessellated into 512x512 cells. if(all(greaterThan(bc, vec3(0.02)))){ gl_FragColor = vec4(color, 1.0);}else{ gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);} Terrain The initial terrain is generated by layering 10 octaves of simplex noise. float h = 0.0;for(int i=0; i<10; i++){ float factor = pow(2.0, float(i)); h += snoise(vec3(uv*factor, delta*float(i+1)))/(pow(factor, 0.88)*10.0);} Snoise is a good implementation of simplex noise for WebGL by Ian McEwan. Lighting
Psychedelic Saturn storm! Late last year, a huge storm erupted in the clouds of Saturn’s northern hemisphere. Huge even at the beginning, it grew even larger rapidly and eventually wound itself all the way around the planet! It grew to the incredible length of 300,000 km (180,000 miles) — end-to-end, it would’ve stretched 3/4 the way from the Earth to the Moon! The folks at the Cassini mission have just released a treasure trove of new pictures of the storm, and they are very, very cool. Check this out: [Click to encronosenate.] It looks like it’s a ghost running from Pacman, doesn’t it? Taken in late December 2010, this image shows Saturn in the infrared using a combination of 3 different filters. But it grew. This time, 12 separate filters in the infrared were used, but the color scheme is largely the same. This next picture, though, is the one that made me really smile: More of these amazing images are available at the Cassini website. … and, of course, there’s no substitute for being there, too. Related posts:
Lossless and Transparency Encoding in WebP In September 2010 we announced the WebP image format with lossy compression. WebP was proposed as an alternative to JPEG, with 25–34% better compression compared to JPEG images at equivalent SSIM index. We received lots of feedback, and have been busy improving the format. Last month we announced WebP support for animation, ICC profile, XMP metadata and tiling. Today, we introduce a new mode in WebP to compress images losslessly, and support for transparency – also known as alpha channel – in both the lossless and lossy modes. With these new modes, you can now use WebP to better compress all types of images on the web. New lossless mode Our main focus for lossless mode has been in compression density and simplicity in decoding. New transparency mode Today, webmasters who need transparency must encode images losslessly in PNG, leading to a significant size bloat. You can find a more detailed compression study for these modes here and sample images in the WebP-Gallery.
Quantum theorem shakes foundations Andy Hair/iStockphoto Mathematical device or physical fact? The elusive nature of the quantum wavefunction may be pinned down at last. At the heart of the weirdness for which the field of quantum mechanics is famous is the wavefunction, a powerful but mysterious entity that is used to determine the probabilities that quantum particles will have certain properties. Now, a preprint posted online on 14 November1 reopens the question of what the wavefunction represents — with an answer that could rock quantum theory to its core. “I don't like to sound hyperbolic, but I think the word 'seismic' is likely to apply to this paper,” says Antony Valentini, a theoretical physicist specializing in quantum foundations at Clemson University in South Carolina. Action at a distance occurs when pairs of quantum particles interact in such a way that they become entangled. Historical debate The debate over how to understand the wavefunction goes back to the 1920s. Quantum information
HTML5 2D gaming performance analysis Update March 2012: read our updated benchmarks here Yesterday we released our new beta WebGL renderer in r68 . The release notes cover it briefly, but some of the technology is really cool, so I thought I would go in to more detail in a blog post - this is be pretty long and technical, but it's always good to know what's going on under the hood! What is WebGL ? How GPUs draw 2D First of all, let's cover the rendering process so you can understand what's happening in the tests. To efficiently draw lots of 2D sprites, you need to make a big list of the vertices of every sprite you want to draw. Graphics cards are sophisticated technology. Anyway, this has the interesting side effect that performance in 2D games is limited by how fast you can fill the vertex buffer . The performance test In order to test the performance of each renderer we've written a standard test. You might be wondering: why is performance so important? The Canvas 2D renderer The WebGL renderer Conclusion
Current Opinion in Neurobiology : Neuroaesthetics: a review Volume 19, Issue 6, December 2009, Pages 682–687 Motor systems • Neurology of behaviour Edited By Abdel El Manira, Krishna Shenoy, Catherine Dulac and Giacomo Rizzolatti Neuroaesthetics is a relatively young field within cognitive neuroscience, concerned with the neural underpinnings of aesthetic experience of beauty, particularly in visual art. Copyright © 2009 Elsevier Ltd. Man Builds $5,200 Hobbit House Last week, we saw a lodge in Chile that looked like a hobbit hotel and this week we bring you a woodland home with a similar aesthetic. Though this domain doesn't gush gallons of water, it is an alternative living space for a natural homestead. Photographer Simon Dale is responsible for the design and construction of this eco-home, despite his inexperience in architecture and carpentry. The 32-year-old photographer was tired of mortgage payments and had a passion for nature. The home, which was constructed for a grand total of £3,000 (approximately $5,200) features plenty of sustainable materials. Simon Dale's website via [Daily Mail]