Newton Game Dynamics - Linux Version

[Sascha Willems]

Ah well, KDevelop + FreePascal is very nice and SDL seems to be very handy too (I wish there was something similar to KDevelop under Win32)

I finished my Newton/SDL/GL-template yesterday and as it uses SDL it should be cross-platform as long as the target platform supports newton. The template compiles and works fine under Windows and also under Linux (when I comment out the Newton-part, since the dynamic lib isn't available). And as I unterstand it then also should compile fine under MacOS, or is there anything I need to know that's different from Linux/Win32 under MacOS?

And after NGD 1.35 with the dynamic lib for Linux is released I'll also update all the developer samples for Newton on my page to SDL and FP so they're cross-platform too.

[savage]

Great stuff, look forward to seeing it.

btw, any chance of a small tutorial on setting up FPC and KDevlop.

[Sascha Willems]

btw, any chance of a small tutorial on setting up FPC and KDevlop.

It was so easy, at least after I figured out how to do it, that it's too little for a tutorial. In my Linux installation, which is the HD-install of Kanotix (means it's a Debian distro or so) there is a graphical package-manager included, called Synaptic which allows you to easily install packages. It get's a current packages list from the net and even automaticllay selects and installs all needed package if you choose some package that needs some others.

So I used Synaptic to install the newest packages for KDevelop, for SDL and also for FreePascal and after it was finished installing the packages I was able to write and compile FPC (2.0.0) apps.


P.S. : I saw that some ODE-demos are included in JEDI-SDL. So is it possible that later on the SDL versions of my newton demos (right now it's three of them) also will be included in SDL? I'd love to contribute them.

[savage]

P.S. : I saw that some ODE-demos are included in JEDI-SDL. So is it possible that later on the SDL versions of my newton demos (right now it's three of them) also will be included in SDL? I'd love to contribute them.

Absolutely, that was the plan all along .

Ideally, I would also like to create a demo where you could dynamically change between, ODE, Newton and even Havok if they will let us create a Pascal unit for it . What's definately needed for both are step by step demos showing how to use each and how all the bits fit together.

[Sly]

...and even Havok if they will let us create a Pascal unit for it .

Have you seen the licensing costs for Havok? At Krome we have considered Havok for large commercial projects and we still baulk at the costs involved.

[savage]

Have you seen the licensing costs for Havok? At Krome we have considered Havok for large commercial projects and we still baulk at the costs involved.

I know they are expensive, but have no idea how much it costs. So what does Krome use for physics? Is it all in house?

[Sascha Willems]

Forget about Havok, it's nowhere in reach for free or indy-developers and I'm sure they have about zero interest in a "pascal-market". So even asking them about it would be a waste of time.

But with Newton and ODE in JEDI-SDL, you have the most important two physics engine on board. Though there are some more free engines on the market, like Tokamak, Novodex (free for personal use), but seems that no one is using them with Pascal.

[Sly]

I know they are expensive, but have no idea how much it costs. So what does Krome use for physics? Is it all in house?

Last I remember, it was about $20,000 per license. For one title.

For Krome's current generation games, we are using in-house solutions for rag-doll, cloth and leg IK simulations. They do what we need for our current games, but for future titles we may need more heavyweight physics solutions.

[Sascha Willems]

What's definately needed for both are step by step demos showing how to use each and how all the bits fit together.

So now the count is at five demos that I'll release which are all commeted very extensive, so that after looking at the source and reading the comments anyone should be able to do at least some basic stuff with Newton :

• SDLBasic
  This is as basic as it can get. It only uses a single callback for applying gravity onto some boxes.
  
• SDLJoints
  Newton has different kinds of joints to offer to stick bodies together. This demo shows the most simple usage of each joint type (ball-and-socket, hinge, slider corkscrew, universal). This is the first demo (all demos below include that feature too) that also includes the possibility to drag bodies around, which is done by using a special spring force in a special callback.
  
• SDLBuoyancy
  Shows how to use Newton's buoyancy features to simulate bodies immersed in a fluid.
  
• SDLVehicle
  Let's you drive around a very basic vehicle made by using Newton's vehicle container.
  
• SDLRagDoll
  RagDolls should be a known term for 3d coders/gamers. This demo shows how to put a human ragdoll together by using Newton's ragdoll container. You can drop some of them down and also pick them up and throw them around.

Most of the demos are based on the one that are on my newton-page already, but all of them use SDL and are also compileable (tested this already) with FPC (2.0.0). I've also changed physics timing for all demos to a method called "accumulative timeslicing", which gives the same physics-calculations no matter what FPS the demo/game is running at.

As soon as NGD1.35 is released I'll upload those demos. But since that can still be one or two (or even more) weeks away, if anyone of you likes to see an additional demo that I should add to that collection, just tell me.

And one last question : How about licensing when my stuff goes into JEDI-SDL? The demos itself are all using MPL 1.1, but some of them include helper units I wrote which are GPL. Is that a problem, or doesn't it matter?

[savage]

All those demos sound great. I will need to delete, my poor attempts at creating Newton demos. Are you able to email me a preview version of your demos to me?

JEDI-SDL is MPL and I personally don't have a problem with GPLed stuff, but then I am not a lawyer and don't know anything about the intricasies of mixing the 2 licenses.