i am using openscenegraph to show a bridge model.I use Texture2D to represent an image.Now,the problem is that the image is too large, about 1G .if i load the whole image at one time,it would be a waste of computer memory. I want to implement the effect similar to google map.Loading image of different quality according to distance of view sight. Is there any body know how to achieve that?
You want to be using something like osgEarth, which handles all of that sort of thing, and basically is a Google Earth clone.
Alternately, Virtual Planet Builder does some of the tiling and paging that Google Maps/Earth do. osgEarth was designed as an enhancement to the capabilities in VPB.
Related
We're trying to visualize a massive graph that transforms over time but we're unsure which platform would be powerful enough to do this.
We tried using Unity, but importing the 50.000 vertices was a big problem already. With static Batching we could get up to 100fps, but we want to change the vertices color depending on parameters. Therefore static Batching was not an option. We tried using other batching systems in combination with different rendering pipelines but then we could get 20 fps at most. We concluded that unity probably isn't the best platform for our purposes since there is so much stuff happening in the background.
try doing some optimizations like
I think your problem is all about performance these is some performance tips as i see 50K vertices are good
rendering only what camera see by using Occlusion culling
Make objects that dosnt move mark as static by selecting it and check static in top right corner in inpector
back light instead of realtime lighting & reflections
try use texture map to use same material on multiple objects and select material> inspector check Enable gpu instancing
good luck !
In my Vulkan backend implementation I currently check the supported usage flags for the Swapchain and then proceed to either use copy commands or a fall-back render pass to draw to the back buffer from an intermediary Render Target. I wanted to know whether this check is required or is it safe to assume that the Swapchain Images allow usage as a Transfer Destination on typical Desktop hardware.
Also, if anyone knows about Vulkan implementations that do not allow Copying to Swapchain Images, I'd appreciate it if you could share. This is mostly for the sake of curiosity rather than solving a problem.
You can look at the Vulkan Hardware Database.
I couldn't find anywhere which summarized the data, but if you click on a device from the list then click onto the surface tab, then on the surface properties tab you can see supportedUsageFlags in the table and look for TRANSFER_DST_BIT.
I only looked at a few and they all had TRANSFER_DST_BIT present. I believe the database and code for the viewer are open source, so perhaps you can find a better way to mine the particular information you're after.
I have a model that I am trying to use in a web game using three.js.
When I render an image of the scene in blender, the quality of the image is very good. Specifically, the quality of the textures is very high and they are very crisp and matte.
When I setup the scene in my game, they look very dull and almost plain.
I've looked up Raytracing, Ambient occlusion, lightmaps. But all of these effect the lighting. They should not affect the quality of the textures. What am I missing here?
What all does blender's offline renderer do that real time renderers (like threejs's webgl render) usually don't do?
Thanks alot in advance.
Merry Christmas,
i guess the best way is to use baking... That means you save the high qualitiy lightning information into an image texture. (This should solve your problem with plain looking textures)
I recommend to check out this tutorial by Andrew Price(blenderguru.com):
https://www.youtube.com/watch?v=sB09T--_ZvU
And make sure your realtime client uses a proper texture filtering, has support for normalmaps
etc and that the webclient does not downscale your images for some reason.
I've been studying 3D graphics on my own for a while now and I want to get a greater understanding of just how everything works. What I would like to do is to create a simple game without using DirectX or OpenGL. I understand most of the math I believe, but the problem I am running up against is I do not know how to get control of the pixels being displayed in a window.
How do I specify what color I want each pixel in my window to be?
I understand I will probably run into issues with buffers and image shearing and probably terrible efficiency problems, but I want to create my own program so that I could see from the very lowest level, of the high level language, how the rendering process works. I really have no idea where to start though. I've figured out how to output BMPs, but I would like to have a running program spitting out 20+ frames per second. How do I accomplish this?
You could pick a environment that allows you to fill an array with values for pixels and display it as a bitmap. This way you come closest to poking RGB values in video memory. WPF, Silverlight, HTML5/Javascript can do this. If you do not make it full screen these technologies should suffice for now.
In WPF and Silverlight, use the WriteableBitmap.
In HTML5, use the canvas
Then it is up to you to implement the logic to draw lines, circles, bezier curves, 3D projections.
This is a lot of fun and you will learn a lot.
I'm reading between the lines that you're more interested in having full control over the rendering process from a low level, rather than having a specific interest in how to achieve that on one specific platform.
If that's the case then you will probably get a good bang for your buck looking at a library like SDL which provides you with a frame buffer that you can render to directly but abstracts away a lot of the platform specifics issues. It has been around for quite a while and there are some good tutorials to give you an idea of whether it's the kind of thing you're looking for - see this tutorial and the subsequent one in the same series, which should be enough to get you up and running.
You say you want to create some kind of a rendering engine, meaning desinging you own Pipeline and matrice classes. Which you are to use to transform 3D coordinates to 2D points.
When you have got the 2D points you've been looking for. You can use say for instance on windows, you can select a brush and draw you triangle values while coloring them at the same time.
I do not know why you would need Bitmaps, but if you want to practice say Texturing you can also do that yourself although off course on a weak computer this might take your frames per second significantly.
If you aim is to understand how rendering works on the lowest level. This is with no doubt a good practice.
Jt Schwinschwiga
Let me describe the "battlefield" of my task:
Multi-room audio/video chat with more than 1M users;
Custom Direct3D renderer;
What I need to implement is a TextOverVideo feature. The Text itself goes via network and is to be rendered on the recipient side with Direct3D renderer. AFAIK, it is commonly used in game development to create your own texture with letters/numbers and draw this items. Because our application must support many languages, we ought to use a standard. That's why I've been working with ID3DXFont interface but I've found out some unsatisfied limitations.
What I've faced is a lack of scalability. E.g. if user is resizing video window I have to RE-create D3DXFont with new D3DXFONT_DESC while he's doing that. I think it is unacceptable.
That is why the ONLY solution I see (due to my skills) is somehow render the text to a texture and therefore draw sprite with scaling, translation etc.
So, I'm not sure if I go into the correct direction. Please help with advice, experience, literature, sources...
Your question is a bit unclear. As I understand it, you want easily scalable font.
I think it is unacceptable
As far as I know, this is standard behavior for fonts - even for system fonts. They aren't supposed to be easily scalable.
Possible solutions:
Use ID3DXRenderTarget for rendering text onto texture. Font will be filtered when you scale it up too much. Some people will think that it looks ugly.
Write custom library that supports vector fonts. I.e. - it should be able to extract font outline from font, and build text from it. It will be MUCH slower than ID3DXFont (which is already slower than traditional "texture" fonts). Text will be easily scalable. Using this way, you are very likely to get visible artifacts ("noise") for small text. I wouldn't use that approach unless you want huge letters (40+ pixels). Freetype library may have functions for processing font outlines.
Or you could try using D3DXCreateText. This will create 3D text for ONE string. Won't be fast at all.
I'd forget about it. As long as user is happy about overall performance, improving font rendering routines (so their behavior looks nice to you) is not worth the effort.
--EDIT--
About ID3DXRenderTarget.
EVen if you use ID3DXRenderTarget, you'll need ID3DXFont. I.e. you use ID3DXFont to render text onto texture, and then use texture to blit text onto screen.
Because you said that performance is critical, you can delay creation of new ID3DXFont until user stops resizing video. I.e. When user starts resizing video, you use old font, but upscale it using texture. There will be filtering, of course. Once user stops resizing, you create new font when you have time. you probably can do that in separate thread, but I'm not sure about it. OR you could simply always render text in the same resolution as video. This way you won't have to worry about resizing it (it still will be filtered - along with the video). Some video players work this way.
Few more things about ID3DXFont. There is one problem with ID3DXFont - it is slow in situations where you need a lot of text (but you still need it, because it supports unicode, and writing texturefont with unicode support is pain). Last time I worked with it I optimized things by caching commonly used strings in the textures. I.e. any string that was drawn more than 3 frames in the row were rendered onto D3DFMT_A8R8G8B8 texture/render target, and then I've been copying that string from texture instead of using ID3DXFont. Strings that weren't rendered for a while, were removed from texture. That gave some serious boost. This solution, however is tricky - monitoring empty space in the texture, removing unused strings, and defragmenting the texture isn't exactly trivial (there is nothing exceptionally complicated, but it is easy to make a mistake). You won't need such complicated system unless your screen is literally covered by text.
ID3DXFont fonts are flat, always parallel to the screen. D3DXCreateText are meshes that can be scaled and rotated.
Texture fonts are fuzzy and don't look very clear. Not good for an app that uses lots of small text.
I am writing an app that can create 500 text meshes, each mesh averaging 3,000-5,000 vertices. The text meshes are created once, then are static. I get 700 fps on a GeForce 8800.