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Saturday, February 13, 2010

Coding a 4k intro for Breakpoint 2010

I'm going to be quite busy here until the demoparty Breakpoint 2010, as I want to release a small 4k intro for this great event! I didn't plan anything few weeks ago and was slowly working on d3d10/d3d11, working on some effects for a 16k/64k intro to release later this year... but BP2010 is supposed to be the last one and I don't want to miss this experience, first time to go there... and probably last time, so I have decided to go to this party and try to contribute to it, yep!

I have started to work with d3d10, as i wanted to add some direct2D nice layout text over 2-3 raymarching scenes... but I have found that direct2D is bit too costly for a 4k, specially if you want to avoid the basic white logo... so I have to switch back to a plain d3d9 and forget about some cool text. I will use this direct2D technique for a bigger intro. Due to my lack of investment in all the d3d apis until now, I had to manage the API from the ground up... and it took me a while... To facilitate the d3d10/d3d11 coding experience, I have developed a lightweight c++ wrapper around d3d10/11 APIs, almost exactly in the same way (naming conventions,enums) SlimDx has done the job, and I'm really happy with it. The d3d10/d3d11 API is very clean but due to some verbose API contraints (ugly enums mixed sometimes with some #define, HRESULT to check from every function return, a famous windows programming philosophy), It's really worth to wrap this API around something that transparently hide all those things, rename and rearrange enum/methods/interface. Currently, It's working great with this SlimDx's like wrapper, much easier to program, much easier to read, and It does generate almost exactly the same code than a straight d3d10/d3d11 code, with the capability to remove the HRESULT check and so on... I will probably release this wrapper ( a single .h with a bunch of inline methods) around codeplex later this year, as it should probably help people like me that prefer a syntax much more closer to the C# coding experience than c/c++.

During my small d3d11 incursion, I have also discovered that the DirectX Effect framework (fx syntax files, with techniques, pass) is no longer available as part of the D3DX runtime! Yep, you need to go to the Utility directory in the DirectX SDK to find that you can compile this framework yourself... It means that for all intros, you can forget about the DirectX Effect framework and program a much lighter Effect framework. One good thing about this change is that I had to better understand the d3d10 philosophy with the constant buffers access and so on... In fact, It's much easier to work directly with constant buffer, and surprisingly, It gives a smaller code. As soon as I'm done with the 4k intro for BP2010, I will publish a small post about this along the SlimDx like wrapper.

Last thing is that I didn't have time to finish my softsynth, because I was more targeting a 16k/64k, with a more complex synth... so we should go with the great 4klang gopher's synth... but I have two problems with it : 1) ulrick (my old friend, main FRequency musician) is unable to use it under Renoise. It burns its notebook's CPU and we don't know why, as it's a pretty standard core 2 duo intel processor... we did check lost of 4klang/renoise/system parameters without any success. 2) 4klang is great, but, the total code is often close to 900 bytes... I know that some of the top's 4k softsynth are around 500 to 700 bytes, so I'm not completely sure that I will use 4klang. The other idea is to take part of the work I did already for the bigger synth (that is developped in assembler x86), and try to plumb it into a fixed pipeline (and not a stackbased as 4klang)... I'm not sure, but I suspect that I could save a substantial amount of bytes... but still, not sure, and I need to check it... but It's going to be really hard to make it on time for BP... so we'll see...

Currently, I have only coded one scene for the 4k intro, I'm quite happy with it... but that doesn't make a full intro! I need to add at least 3 scenes, work on the transitions, overall design, synch with synth & so on... even for a 4k, that's a lots of work, moreover when you consider that this is my first prod on my own (I mean, first prod for the PC, after the 3 prods i released 20 years ago on Amiga! ;) ) but It's possible in less than 2 month to do it, so I'll try to do my best!

1 comment:

  1. Okay @lx, it seems that the problem is now solved (http://www.pouet.net/prod.php?which=53398). Let us now do a good tune, and let's hope it will be well optimized to let you have enough free space for your code :)


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