Some SDL Issues

[MarauderIIC]

I mean, I'm not sure you can draw to the front buffer (direct to the screen) when you're doublebuffering in SDL. If he can he would have had to make sure that he's not doing this.

[programmerinprogress]

Jesus. I was surprised as to how easy this SDL problem was to solve.

Here is the solution, thank me later

...Fail

Fail!

error!.png (18.32 KiB) Viewed 1579 times

Click here to see the hidden message (It might contain spoilers)

SDL's site wouldn't do that

As for the flickering problem, I hope that gets sorted, i'm sure there's a simple enough explanation.
I've never bothered with doublebuffering though.

[Chaos Clown]

AHA! Through the magic of camstudio, I caught the bugger in action! It is definitely screen-tearing, right?



Also, I looked at it bit more closely, and it turns out that I was double-buffering the whole time. Would tripple-buffering help, or am I doomed to failure?

[MarauderIIC]

SCREEN=SDL_SetVideoMode(SCREEN_W,SCREEN_H,0,SDL_DOUBLEBUF... ?

SDL_Flip(screen you were drawing to)?

Hm. Start posting relevant code sections, I think.

[Amarant]

AHA! Through the magic of camstudio, I caught the bugger in action! It is definitely screen-tearing, right?

Also, I looked at it bit more closely, and it turns out that I was double-buffering the whole time. Would tripple-buffering help, or am I doomed to failure?

That's weird, usually tearing only results in one visible tear.
Agrees with:

Hm. Start posting relevant code sections, I think.

[Chaos Clown]

Code: Select all

void Init()
{
	SDL_Init(SDL_INIT_EVERYTHING);
	Screen = SDL_SetVideoMode(ScreenWidth, ScreenHeight, ScreenBPP, SDL_DOUBLEBUF);
	SDL_WM_SetCaption("Tile Test", NULL);
}

Code: Select all

void player::DisplayPlayer()
{
	if(Direction == left)
	{
		if(XVel == 0 && YVel ==0)
			ApplySurface(X-ScrollX, Y, LSprite, Screen);
		else if(YVel !=0)
			ApplySurface(X-ScrollX, Y, LJumpSprite, Screen);
		else
			ApplySurface(X-ScrollX, Y, lWalkAnimation[CurFrame], Screen);
	}
	else
	{
		if(XVel == 0 && YVel ==0)
			ApplySurface(X-ScrollX, Y, RSprite, Screen);
		else if(YVel !=0)
			ApplySurface(X-ScrollX, Y, RJumpSprite, Screen);
		else
			ApplySurface(X-ScrollX, Y, rWalkAnimation[CurFrame], Screen);
	}
}

Code: Select all

SDL_Flip(Screen);

I'm seriously starting to think this is my monitor, or I'm hallucinating, and that screenshot was just a camstudio glitch or something.

[MarauderIIC]

Try

sceDisplayWaitVblankStart();

before your SDL_Flip() call just for the heck of it

[M_D_K]

Try

sceDisplayWaitVblankStart();

before your SDL_Flip() call just for the heck of it

Isn't sceDisplayWaitVblankStart() from the PSP SDK?

[MarauderIIC]

Probably. I'm not all here right now. I might have pasted the wrong thing. So nevermind.

[LeonBlade]

Try

sceDisplayWaitVblankStart();

before your SDL_Flip() call just for the heck of it

Isn't sceDisplayWaitVblankStart() from the PSP SDK?

LOL yeah it is.

[KuramaYoko10]

Try adding SDL_HWSURFACE....

Code: Select all

SDL_SetVideoMode(SCREEN_WIDTH, SCREEN_HEIGHT, SCREENBPP, SDL_HWSURFACE | SDL_DOUBLEBUF); 

That is the way I always did because of a website that I started learning SDL, and here it is its explanation:

SDL_DOUBLEBUF - Enable hardware double buffering; only valid with SDL_HWSURFACE. Calling SDL_Flip will flip the buffers and update the screen. All drawing will take place on the surface that is not displayed at the moment. If double buffering could not be enabled then SDL_Flip will just perform a SDL_UpdateRect on the entire screen.

My recommendation: give it SDL_HWSURFACE|SDL_DOUBLEBUF and in case of an error try again with SDL_SWSURFACE.

Hope it works

[MarauderIIC]

"And someone with a brain said..." ^

[Chaos Clown]

Tried it with both SDL_HWSURFACE and SDL_SWSURFACE. Made no difference. I also tried calling SDL_FillRect(blah) every frame before I draw all everything to the screen. Still no dice.

IMPORTANT EDIT: Running it in fullscreen (SDL_FULLSCREEN) makes the flickering disappear. I think this is because SDL has automatic V-Synching in fullscreen mode. Is there any way I can replicate this in windowed mode?

[Ginto8]

Tried it with both SDL_HWSURFACE and SDL_SWSURFACE. Made no difference. I also tried calling SDL_FillRect(blah) every frame before I draw all everything to the screen. Still no dice.

IMPORTANT EDIT: Running it in fullscreen (SDL_FULLSCREEN) makes the flickering disappear. I think this is because SDL has automatic V-Synching in fullscreen mode. Is there any way I can replicate this in windowed mode?

I have no clue.

But in SFML, they have sf::Window::UseVerticalSync, which sets v-synching.

[M_D_K]

V-sync in windowed mode is not supported on all platforms since in windowed mode the OS is in control of refresh rate.