How Fast?

[Quiest]

How fast is SDL on the gp2x?

I mean, at which fps should a game run for example on my
1.6ghz laptop, to be running at a constant 60fps on the gp2x?


Thanks in advance,
and I hope it hasnt been asked already, as I was to lazy to
search. (I`m finished at work now, just finishing this post,
and I`m off to drive home.)


EDIT:
I got yet another thing to ask and I dont wanna open a new
thread again, so I`m asking here:

Why does this work:

SDL_Surface *water_effect(SDL_Surface *back)
{
	[b]for(int y=1; y<y_res-1; y++)[/b]
	{
		for(p.x=1; p.x<x_res-1; p.x++)
		{
			p.y=y;

			wave[j][p.x][p.y]=((wave[i][p.x-1][p.y]
							   +wave[i][p.x+1][p.y]
							   +wave[i][p.x][p.y-1]
							   +wave[i][p.x][p.y+1])>>1)-wave[j][p.x][p.y];

			wave[j][p.x][p.y]-=wave[j][p.x][p.y]>>4;


			if(wave[i][p.x][p.y]!=0)
			{
				p_mod.x=p.x+(wave[j][p.x+1][p.y]+wave[j][p.x-1][p.y])/50;
				p_mod.y=p.y+(wave[j][p.x][p.y+1]+wave[j][p.x][p.y-1])/50;
				SDL_BlitSurface(back,&p_mod,water,&p);
			}
		}
	}
	if(i){i=0;j=1;}else{i=1;j=0;}
	return water;
}

but this doesn`t:

SDL_Surface *water_effect(SDL_Surface *back)
{
	[b]for(p.y=1; p.y<y_res-1; p.y++)[/b]
	{
		for(p.x=1; p.x<x_res-1; p.x++)
		{
			wave[j][p.x][p.y]=((wave[i][p.x-1][p.y]
							   +wave[i][p.x+1][p.y]
							   +wave[i][p.x][p.y-1]
							   +wave[i][p.x][p.y+1])>>1)-wave[j][p.x][p.y];

			wave[j][p.x][p.y]-=wave[j][p.x][p.y]>>4;


			if(wave[i][p.x][p.y]!=0)
			{
				p_mod.x=p.x+(wave[j][p.x+1][p.y]+wave[j][p.x-1][p.y])/50;
				p_mod.y=p.y+(wave[j][p.x][p.y+1]+wave[j][p.x][p.y-1])/50;
				SDL_BlitSurface(back,&p_mod,water,&p);
			}
		}
	}
	if(i){i=0;j=1;}else{i=1;j=0;}
	return water;
}

p is a rect, btw (as is p_mod). I`m as confused as ever ^^
The for loop works for p.x but something is not right with p.y.
It totally renders the effect uneffectful
(tho there shouldn`t be any difference to the first version,
or should there?)

And please dont tell me that this`ll be slow on the gp2x.
I know. I`m already trying to make it faster.


EDIT2:
Hmm, bold tags in code tags dont work so please look at the
parts surrounded by the tags.

 

[Quiest]

Come on people Am I that annoying?

 

[Parkydr]

Come on people sad.gif Am I that annoying?

Yes

It's not really possible to do a direct fps translation, it's a different processor and the frame rate most probably is not limited by the processor speed on the PC. You may get 60 fps on the GP2X but it depends how processor intensive your code is.

You just have to try it and see.

I can't see anything obviously wrong with your code. It won't necessarily be too slow - it depends on what else you're doing.

 

[Dr_Ian]

I guess both bits of code should be the same.
Does it make a difference if p.y = y is placed before the x loop?

 

[Parkydr]

From SDL wiki

The final blit rectangle is saved in dstrect after all clipping is performed (srcrect is not modified).

So p is being modified by SDL_BlitSurface

 

[Quiest]

Okay, thanks a lot. ^^