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Messages - Vogtinator

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661
TI-Nspire / Re: nGL - a fast (enough) 3D engine for the nspire
« on: November 28, 2013, 03:47:51 pm »
So, I fixed a few bugs in nGL (fewer crashes) and converted my snake game (I made exactly one year ago) to 3D.
No special features, just plain snake.
You can still move around and look.
The apple is just a cube with apple texture (I found on the internet), I couldn't find a suitable 3D model of an apple and I can't use blender.
Every block on the screen is drawn and textured completely, the game isn't optimized at all (walls between two wall blocks) but still runs smooth.
Sorry, but I'm more programmer than game designer and I just couldn't do it any better...

Controls: 8-6-4-2: Move snake
                WASD: Move around (for testing with nspire_emu)
                touchpad: Look around

662
Other / Re: I *HAVE* a new computer
« on: November 28, 2013, 09:42:58 am »
Try to run memtest and the usual "time echo 'scale=5000;4*a(1)' | bc -l" cpu burn-in trick in linux.
If it's somthing hardware related, you'll notice it.

663
TI-Nspire / Re: nGL - a fast (enough) 3D engine for the nspire
« on: November 26, 2013, 01:57:17 pm »
That depends entirely on the features it uses, if it's only immediate mode or vertex arrays/VBOs a simple abstraction could be enough.
Then there's the problem with the viewport, nGL doesn't have a function to define the viewport or the frustrum yet.
The accuracy of my fixed-point type is also too bad for most programs which use a 1 unit = 1 meter base. Sometimes a glScale3f is sufficient, but if it isn't, you'll have to scale manually or increase the accuracy of the fixed-point type (which may lead to strange errors if it overflows).
Textures aren't bound by ids anymore and other major features are missing (lighting, materials, transparency) mostly for performance reasons.

tl;dr: It depends.

664
TI-Nspire / Re: nGL - a fast (enough) 3D engine for the nspire
« on: November 26, 2013, 01:34:59 pm »
Yeah, right. I started nGL some days before Chockosta published nCraft here.
The same that happened to Levak now :P

665
TI-Nspire / Re: nGL - a fast (enough) 3D engine for the nspire
« on: November 26, 2013, 01:31:16 pm »
Quote from: Levak on November 26, 2013, 01:22:26 pm
Are you serious ? x)
I started nAk3D two months ago with an openGL like api !
Yours is obviously finished. ^^
I started nGL some days before nCraft..

Quote
Whats strange, is that I started using fixed point numbers and had a headache when multiplying matrices (int overflows) and then went to floating point and didn't seemed to lost any performances.
Weird. I'm using int_fast32_t as storage and the lowest 8 bits as fractional part. (~0.004 accuracy).
Also weird that you didn't lose any performance. For me it was a significant difference (the CPU doesn't have a FPU)

Quote
The only difference with nAk3D is that it uses nGC and an heap sort face algorithm instead or your zBuffer.
Z-Buffer has some advantages: constant performance, overlapping triangles and you can maybe use the depth image for e.g. lighting.
And the most obvious one: It's very easy to implement.

666
TI-Nspire / nGL - a fast (enough) 3D engine for the nspire
« on: November 26, 2013, 01:11:43 pm »
Hi,

I started this program a long while ago and it never really advanced. But now I'm making progress again!
It's basically a little library (but not intended to be a library to link with) which handles the basic stuff you need for 3D:
-Rotation
-Translation ;D
-Scaling
-Colors  :hyper:
-Drawing triangles and quads
-Perspective
-Z-Buffering
-Backface culling
-Bad wireframe mode
-Matrix stack (glPushMatrix, glPopMatrix)
-Textures O.O
-sin and cos LUT for the fixed point datatype with highest possible accuracy (degrees)
-OpenGL immediate-mode like API
-Written in C++ (operator overloading) but C-style API if needed

At first I tried to implement it with float, but that was ridiculously slow and laggy. Especially the z-buffering was painful to watch..
But after I implemented fixed point arithmetic things changed: The attached demo runs at ~100fps (1 degree rotation per frame) in the emulator and a bit slower on a real calc. I was curious how fast it really was, so I tried loading some .obj files and it was smooth until 2000 triangles. I'm sure it can be optimized further, it doesn't use a single line of assembler yet.

I tried to port glxgears but a quick and dirty port had some issues with the blue gear.

Known issues:
-No triangle-based clipping: pixel based is a bit slower (depends on the objects on screen) and if you're near a triangle, it may look weird or even crash
-Bad integer division algorithm (gcc's own): division through a small number takes ages
-Drawing triangles is still a bit slow, two increments, one multiplication and several comparisions per pixel (without textures)
-glRotatef not yet implemented
-Sometimes it tries to divide through zero and it hangs, I don't know why  >:(
-Textures lack perspective (difficult to optimize)
-Viewport is fixed: bottom: y=0 top: y=239 left: x=0 right: x=320, in OpenGL it's most times -1-1, so a scaling factor is needed

But nevertheless, I'm going to implement a simple 3D game (no, not minecraft) with this lib, but I don't know what kind of game:
- 3D Tetris (boring..)
- Motor race in 3D (how should the cars and the environment look like, also: collision detection)
- 3D snake (even more boring..)

Edit: Ok, it seems like I made a minecraft game nevertheless...
Latest release of crafti: v1.2 GitHub
Source code and tutorial for nGL are on GitHub as well

Demo controls:
-touchpad: camera rotation
-8-4-6-2: camera position
-x: rotate the four cubes

Do you think this is useful or will it stay an experiment forever?

667
TI-Nspire / Re: Calling all Linux Kernel developers!
« on: November 23, 2013, 06:31:05 pm »
make dtb and make zImage, the usual way. You just have to copy the suitable dtb for your model as well.

668
Other / Re: Wanting to get a desktop
« on: November 20, 2013, 08:52:40 am »
With the newer 3.12 kernel the open source radeon driver is almost (90%) as fast as the proprietrary fglrx.
With fglrx the console is at the native resolution sometimes, sometimes it isn't. But with the open source driver you won't get annoying flickering if you switch the tty.

669
TI-Nspire / Re: Windows for nSpire
« on: November 17, 2013, 04:14:04 pm »
Actually, dosbox has been ported to the playstation portable, which also made gpsp_nspire possible.
(Guess what the psp in gpsp_nspire stands for :P )

670
TI-Nspire / Re: Windows for nSpire
« on: November 17, 2013, 03:03:27 pm »
Why not port dosbox and run a real Win95?

671
TI-Nspire / Re: Calling all Linux Kernel developers!
« on: November 11, 2013, 04:35:24 pm »
The newest for armv5. Probably without any X.org stuff.

672
TI-Nspire / Re: Calling all Linux Kernel developers!
« on: November 11, 2013, 04:28:49 pm »
You have to be able to boot from USB and put your redhat arm image onto it. Couldn't be any easier.

673
TI-Nspire / Re: Calling all Linux Kernel developers!
« on: November 11, 2013, 04:17:49 pm »
Anything which supports the ARM (v5) 3.x-Kernel should run fine.
openSUSE runs, so if redhat also has a special ARM release, it will very likely work.

674
TI-Nspire / Re: Calling all Linux Kernel developers!
« on: October 12, 2013, 07:00:08 pm »
You have to enable support for them in the kernel config.

675
TI-Nspire / Re: Calling all Linux Kernel developers!
« on: October 12, 2013, 12:44:04 pm »
If you're trying to compile the version with DTB support, you have to configure it yourself.
Basically, enable everything with "NSPIRE" or "ZEVIO" in its name and also "SP804" watchdog and "CLCD" LCD driver.
Execute make dtbs and copy the dtb appropriate for your nspire onto the device.

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