So I’ve been a busy little bee the last couple of days adding a couple new features to Gorgon.
One of the things I’ve been wondering about is how I could possibly improve performance. To understand, I should explain how Gorgon does its “thing”. When you draw a sprite to the screen using the Draw() method the actual data doesn’t go to the current render target (screen for our purposes) right away. What happens is the vertices for that sprite are added to a dynamic vertex buffer. If the next sprite you draw has the same texture and states as the previous (which will most likely be the case if you perform batching properly) it will just add that sprite to the dynamic buffer and the process continues over and over until the end of the frame. When the end of frame is reached the buffer is drawn to the screen and the buffer is ‘reset’, that is, all data in it is overwritten with our next frame. This is all well and good if you only use the same texture and render states (Smoothing, Blending, etc…) But let’s say we have 3 sprites. The first 2 sprites share a texture and the last uses a seperate texture. When the first two are drawn they get added to the vertex buffer and then when the 3rd sprite is drawn the system detects a change in state (in this case it’s the texture) and the buffer is flushed and process starts over with our third sprite. As you can imagine this can be very inefficient, but if you batch sensibly you’ll see excellent speeds.
I’ve actually been working on Gorgon off and on (mostly off) throughout the last 2 weeks and I’ve sent a few new changes to the svn repository:
- Modified the bump in the night sample (-again-) to allow better results when rendering specular maps and also to update a stupid mistake that I made. That is, I added unicode symbols directly into the source code instead of using their respective codes. While this hasn’t given me trouble yet, there’s always that possibility.
- Modified the TextSprite object to fix an issue where the MeasureText function was not calculating the correct height for a block of text. Also fixed an issue where the alignment settings would sometimes place the text in between pixels and cause the text to look jagged and unreadable.
- Removed Mount()/Unmount() from the public interface of the FileSystem object. These functions didn’t really serve any purpose and just made more work for the user. Internally Mount() is still available as a protected method for plug-ins so that the file system index can be built after a root is assigned. Sorry if this breaks anything.
- Added support for MRT (multiple render targets)! Finally! This allows a pixel shader to output to multiple targets at the same time and should help out in performance situations where multiple passes are being used to achieve the same thing. To manipulate the additional render targets you can call Gorgon.SetAdditionalRenderTarget to add/update/remove a render target or Gorgon.GetAdditonalRenderTarget to return one. The previous property: CurrentRenderTarget is still in place and uses the SetAdditionalRenderTarget internally and is available for use if you’re only looking to switch the primary target.
- Font objects can now load external TTF files. While you could always do this by hand by using PrivateFontCollection and then creating a Gorgon Font object from the resulting GDI+ font, it was a pain the ass. This new functionality will allow the reading of TTF fonts from various sources such as: A TTF file on the disk, an embedded resource, from a stream, or from a Gorgon file system. To load a font you just call: Font.From* (were * = Resource, File, FileSystem, or Stream) and it’ll import the font. For luddites: You can still create fonts directly from GDI+ font objects if you wish.
- And finally, the one that caused the most cursing: GorgonZipFileSystem.dll. What’s that? It’s a file system that allows you to manipulate zip files (you know, the files that Winzip generates). Now using this plug-in the file system editor can open/create/update your zip files. Or you can forego the file system editor completely and just use winzip. There are some caveats however: You cannot use a password, you cannot use encryption and the file format must be the legacy zip file format (Zip 2.0). But yeah, awesome.
So there you have it. Hopefully the zip file support will be a plus. I have no idea when a packaged release will be available, but when it is I’ll make sure to announce it.
Small update. I’ve updated Gorgon’s code in the subversion repository to use the March 09 version of SlimDX.
- Made some small fixes to handle a change to the FillTexture callback and to work around a bug in Texture.FromStream.
- Updated the ShadersInSpaaace to draw the film grain crap properly.
- Updated bump in the night sample to include specular mapping and included the specular map (yes it’s supposed to look that grainy). Updated normal map for more accurate lighting. Crazy bump is the shiznit.
- Fixed bugs in the file system editor that caused the whole file system to be exported to explorer even if only a single file was selected. Fixed bug in file system editor where if root wasn’t selected the export file system button would break. Changed export button to be more clear about its function.
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Just a quick notice. I think it’s great when I get questions about Gorgon. And I do my very best to answer what I can as accurately as I can.
However. I do NOT want questions about how to use libraries created by other groups/people. I have no problems explaining Gorgon’s inner workings for this purpose, but that’s as far as it goes. I won’t be transforming it into any other library, that’s your job. I am not tech support for any other library. If you want support for another graphics library go to their forums and ask the creators of that library. If they don’t support their stuff, then that’s tough, take it up with them through whatever means available to you.
Don’t take this as trying to be secretive/anti-competitive about Gorgon or its inner workings. If I wanted it to be secretive I wouldn’t have released it or the source for it.
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