Showing OBJs?

Have you tried the Wiki? If you have, try it again. I just finished editing it for clarity.

DogP’s post notwithstanding, I think there are definite uses for OBJs in a game. A large part of what makes “gamers” (i.e. those whose cable boxes are permanently set to G4TV :-P) ooh and ahh over modern games is the use of particle effects.

Some VB games (Panic Bomber, for one) already feature OBJ-based particle effects and there is no reason they can’t be used to great effect in homebrew, too, IMHO.

Also, as I hope my new Wiki article will show, it’s really not that confusing to use OBJs. Although, for particles and most other uses, I would steer clear of the “SetObject” routine. Using an optimized loop to edit OAM entries directly is a much better idea.

Make sure and post any specific questions if you still can’t get it working.

It’s basically the same thing slightly rearranged, but you’re quite welcome! 😀

RunnerPack and Fwirt: Yes, there definitely are good uses for OBJs (and I was also going to mention particle effects), and I didn’t mean to imply that they’re useless… I was just making a suggestion that if you’re just starting out, most “beginner” apps/games don’t need to make use of OBJs since they’re typically more complex/difficult to work with, and have fewer well documented examples of using them.

If you’re wanting to use them just for the sake of learning how to use OBJs, or if you have a specific reason that you want to use OBJs, that’s great… and just you bringing this up caused RunnerPack to update the Wiki with some good info… so thanks for that! I just wanted to make sure you’re not making it more complex than you needed to by thinking that BGMaps could only be used for Backgrounds.

DogP

Affine is nice and all, but hbias and vbias should be much faster to make some simple 3d worlds (look at DonkeyKong Country backrounds, imagin that in both directions). I actually found a demo for something like that, but it didnt have source code, and it was for some browser java stuff.

No, that would be just simple paralax scroll. Im talking about that special scroll that you can also do with HiBias (the water surfaces,etc… in the DKC backrounds)

Fwirt wrote:
Actually, to be honest, I did always wonder how they pulled that trick off in those DKC games.

The equivalent of H and V Bias is done on the SNES by using an interrupt that happens on every scanline. When the interrupt occurs, the scrolling registers (among others, like the palettes, etc.) are changed to make waves, etc.

I’m not an SNES dev’er, but I think this is how “Mode 7” effects work, too. (But I could be mistaken…)

Updated code:

#include "libgccvb.h"
#include "chartest.h"
#include "maptest.h"

//Screen is 384 X 224

int main()
{
    int objX=0, objY=0;
    vbDisplayOn();
    copymem((void*)CharSeg0, (void*)CHARTEST, 256*16);
    copymem((void*)BGMap(0), (void*)MAPTEST, 256*16);
    vbSetWorld(31, WRLD_ON, 108, 0, 76, 0, 0, 0, 168, 72);
    VIP_REGS[SPT3] = 0x100;
    VIP_REGS[SPT2] = 0x1;
    vbSetObject(2, OBJ_ON, objX, 0, objY, 9);
    vbSetWorld(30, WRLD_OBJ | WRLD_ON, 0, 0, 0, 0, 0, 0, 0, 0);
    vbSetWorld(29, WRLD_END, 0, 0, 0, 0, 0, 0, 0, 0);
    vbDisplayShow();
    while(1) {
        if (vbReadPad() & (K_LR)) objX++;
        if (vbReadPad() & (K_LL)) objX--;
        if (vbReadPad() & (K_LU)) objY--;
        if (vbReadPad() & (K_LD)) objY++;
        vbSetObject(1, OBJ_ON, objX, 0, objY, 9);
        vbWaitFrame(40);
    }

Look in the libgccvb.h file. Those constants near SPTx are used in the VIP_REGS[] array to get the real address.

Sorry for the confusion. (I guess it’s time for another round of updates to the wiki… Unless we change that in the new official library.)