3D physics/collision libraries that work on DC?

[bbmario]

Does anyone know any physics/collision libraries that can work or easily be ported to DC? I tried Tokamak, but seemed like a huge effort.

[bogglez]

CubicVR is a game engine that runs on the Dreamcast, they seem to have used Bullet..
https://github.com/cjcliffe/CubicVR/tre ... /dreamcast

[Tvspelsfreak]

ODE has been ported over. It's from 2003 though.
http://www.boob.co.uk/devtools.html

[bbmario]

CubicVR seems abandoned... has anyone used it?

[bogglez]

CubicVR seems abandoned... has anyone used it?

I'm afraid I have not, but it's a sign that bullet should be usable.

[Chilly Willy]

Funny, I was going to mention a port of Bullet I helped with on the PSP. The biggest problem that port ran into was the HUGE amount of stack you can wind up using. The issue I helped track down was the demo the guy was using was using almost 1MByte of stack space (the default PSP stack was 64K).

[BlueCrab]

Funny, I was going to mention a port of Bullet I helped with on the PSP. The biggest problem that port ran into was the HUGE amount of stack you can wind up using. The issue I helped track down was the demo the guy was using was using almost 1MByte of stack space (the default PSP stack was 64K).

Wow... That's more than a bit ridiculous stack space wise.

Also on that note, the default stack size in KOS is 32KiB (set at compile-time in <arch/arch.h>). I've been pondering the idea of making that configurable at run-time on a per-thread basis, as POSIX allows.

[bogglez]

Seems like they have an object pool on the stack, but the size can be configured.

[bbmario]

Tokamak seems lighter than Bullet, so, i'll start trying to port that. Are there any common caveats when porting libraries to DC?

[Bouz]

ODE has been ported over. It's from 2003 though.
http://www.boob.co.uk/devtools.html

DC-ODE is used in DC-Stunt-Racer:
http://dcstuntracer.sourceforge.net/

Here is a video of this little game:
https://www.youtube.com/watch?v=q9EPQCd5ZY8

[Indiket]

I did some time ago (2011) a newer ODE quick port to Dreamcast (ODE 0.11.1 with OPCODE).
http://www.dreamcast.es/downloads.php?c ... oad_id=276

It is used in a little homebrew game (Skunks) that I used to test it
http://www.dreamcast.es/news.php?readmore=429

[PH3NOM]

Tokamak seems lighter than Bullet, so, i'll start trying to port that. Are there any common caveats when porting libraries to DC?

Tonight, I decided to compile Chipmunk (2D Physics) Engine for DC.
http://en.wikipedia.org/wiki/Physics_engine

I wrote a makefile for dc-kos:

Code: Select all

OBJS = cpVect.o cpSweep1D.o cpSpatialIndex.o cpSpaceStep.o cpSpaceQuery.o
OBJS += cpSpaceHash.o cpSpaceComponent.o cpSpace.o cpShape.o 
OBJS += cpPolyShape.o cpHashSet.o cpCollision.o cpBody.o 
OBJS += cpBBTree.o cpBB.o cpArray.o cpArbiter.o chipmunk.o

OBJS += constraints/cpConstraint.o
OBJS += constraints/cpDampedRotarySpring.o
OBJS += constraints/cpDampedSpring.o
OBJS += constraints/cpGearJoint.o
OBJS += constraints/cpGrooveJoint.o
OBJS += constraints/cpPinJoint.o
OBJS += constraints/cpPivotJoint.o
OBJS += constraints/cpRatchetJoint.o
OBJS += constraints/cpRotaryLimitJoint.o
OBJS += constraints/cpSimpleMotor.o
OBJS += constraints/cpSlideJoint.o

KOS_CFLAGS += -I. -I../include/chipmunk

CFLAGS += -O3 -std=c99

all: libchipmunk.a

libchipmunk.a: $(OBJS)
	$(KOS_AR) rcs libchipmunk.a $(OBJS)

include $(KOS_BASE)/Makefile.rules

Quite simple, really.
I only had to make a modification to cpCollision.c, because the code did not compile as-is.
I simply added the code

Code: Select all

/* DC-KOS Begin (C) PH3NOM 2014 */
#include <malloc.h>
#define alloca(n) memalign(32, n) 
/* End (C) PH3NOM 2014 */

Everything works fine on DC, I tested using some of the provided examples in the Chipmunk source.

However, just because the code compiles for DC, does not necessarily mean the code has been "ported" to the DC.
I see a lot of places in the code that the DC's fast vector math instructions should be implemented instead of the plain C code, for a true "port".

[Ayla]

Why is that hack necesary? Including <alloca.h> does not work?

[BlueCrab]

Also, replacing alloca() with malloc(), memalign(), or anything else of the like will leak all kinds of memory.

That said, as far as I know, <alloca.h> should work fine.

[PH3NOM]

Right, thanks for that correction.

The only change needed was to #include <alloca.h> on cpCollision.c.

Not sure if it will be that easy with other libs, but I guess that's a start

But my main point is that for optimized performance of a physics library, some of the code should be re-written to take advantage of the SH4's fast vector math instructions...

[bbmario]

Does anyone know a port of Box2D? Also, regarding DC's math functions, is there an API doc on them?

[bogglez]

What kind of physics are you trying to do anyway, just collision or more? How many objects are we talking here?

[bbmario]

As of Box2D, i was just curious about it's port. Regarding Bullet and Tokamak, i'm looking for simple ball physics since i'm planning to work on a Marble Blast clone.