help with black screen

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danibus
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Joined: Sat Feb 03, 2018 12:41 pm

help with black screen

Post by danibus » Thu Dec 02, 2021 11:25 am

Hi there

I'm currently developing my own game. Every stage is already done and I can start game from beginning and finish it (I call this "first game loop").

But then when I start again to play ( "2nd game loop"), sooner or later, I found a black screen, with no sprites loaded in VRAM (but background tiles are loaded). CPU is working, I check 68k and it's working in a sort of loop. Then game is active, but nothing happens.

I tried to modify code. When I "fix/change" something in one stage, black screen appears in another stage.

I'm not using dynamic memory. Just in the begining I load my own config.h file with some global variables and some global structs, after that every stage.c has its local variables and they are destroyed after leaving function.

Also I track every sprite created and release before finishing stage. Also using VPP_init() after finishing every stage.
I though about tileSets, but I'm releasing ( Mem_free()/free() functions ) before leaving every stage using tilesets so.... I'm lost

Would you be so kind to help me?
  • At this moment only solution is making a hard reset when finishing game... but I want to know what is wrong and where is the problem.
    Take note still don't using music/sfx, not using Z80 at all.
    Take note using old sgdk release, I modify code to use lastest sgdk, problem still there, so I return to old sgdk as it0s not sgdk related.


This is my skeleton stage function:

Code: Select all

void stageXX(){

    SYS_disableInts();
    VDP_setScreenWidth320();
    SPR_init();
    Game.time = 0;
    Game.level = XX;

    VDP_setPaletteColors(0, (u16*) palette_black, 64);
    memcpy(&Game.palette[ 0],  stage1.palette->data,          16 * 2);
    memcpy(&Game.palette[16], sprite_player.palette->data, 16 * 2);
    memcpy(&Game.palette[32], sprite_xxxxx.palette->data,  16 * 2);
    memcpy(&Game.palette[48], sprite_yyyyyy.palette->data, 16 * 2);

    VDP_drawImageEx(PLAN_B, &stage1,  TILE_ATTR_FULL(PAL0, FALSE, FALSE, FALSE, Game.index_planB), 0, 0, FALSE, TRUE);
    Game.index_planA   = Game.index_planB + stage1.tileset->numTile;

    ..similar to PLAN_A...

    create_IU();
    create_player();          
    ....all create_functions() here...

    VDP_fadeIn(0, (4 * 16) - 1, Game.palette, 60, FALSE);
    VDP_waitFadeCompletion();

    SYS_enableInts();

	//main stage loop
	while (1) {
        control_IU();
        control_read_pad();
        control_player();
        ...all control_functions()... here

        Game.time++;

        if(Game.points>LIMIT) break; //to NEXT stage

        SPR_update();
        VDP_waitVSync();
	}

	//borra todo antes de terminar la fase
	delete_player();
        ...all delete_functions();... here  //release sprites

      //free memory tilesets (only if necessary)
      MEM_free(Game.tileset01);
      Game.Estructura1 = NULL;


    VDP_setHilightShadow(0);    //Disable HL/S mode (only if necessary)

    //reset VDP indexs
    Game.index_planA   = 1;
    Game.index_planB   = 1;
    Game.index_planTop = 1;

    VDP_init();
}

cloudstrifer
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Joined: Mon Feb 19, 2018 7:31 pm

Re: help with black screen

Post by cloudstrifer » Fri Dec 03, 2021 7:50 pm

Its not easy.

I'm using Gens Kmod for debugging.
I can try to help you using Teamviewer or AnyDesk.

Stef
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Joined: Thu Nov 30, 2006 9:46 pm
Location: France - Sevres
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Re: help with black screen

Post by Stef » Sat Dec 04, 2021 10:21 pm

I will say it's probably an issue with variable initialization / initialized state.
But why just don't do a "hard reset" on completion ? so you're sure to restart in a perfect initialized state :)

danibus
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Posts: 139
Joined: Sat Feb 03, 2018 12:41 pm

Re: help with black screen

Post by danibus » Sat Dec 04, 2021 11:21 pm

cloudstrifer wrote:
Fri Dec 03, 2021 7:50 pm
Its not easy.

I'm using Gens Kmod for debugging.
I can try to help you using Teamviewer or AnyDesk.
Thanks for your help, also use GensKmod. No need to Teamviewer, just wanna some clue to solve by myself.

danibus
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Posts: 139
Joined: Sat Feb 03, 2018 12:41 pm

Re: help with black screen

Post by danibus » Sat Dec 04, 2021 11:22 pm

Stef wrote:
Sat Dec 04, 2021 10:21 pm
I will say it's probably an issue with variable initialization / initialized state.
But why just don't do a "hard reset" on completion ? so you're sure to restart in a perfect initialized state :)
Thanks, I will check every variable.
I can do hard reset, but I want to save high score.
Also want to know where is the problem, sure a silly mistake.

Stef
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Re: help with black screen

Post by Stef » Sun Dec 05, 2021 2:26 pm

To be honest handling correctly soft reset without resetting everything can be tricky, it's easy to miss some uninitialized variables !

danibus
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Re: help with black screen

Post by danibus » Sun Dec 05, 2021 11:03 pm

Reset was last option.

First attempt was just end game (just finishing game or player dead), and then start main loop but no way so I try to reset.
Very very strange. I think my C is rusty, because I think all variable all properly initialized.
Will do a second check but... if there is some "crazy" variable, why is working well first time? :mrgreen: I know I know....

Stef
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Re: help with black screen

Post by Stef » Mon Dec 06, 2021 4:01 pm

Note that recent SGDK version are also more stable in general, so here depending on which version you are, you may also work with the old SGDK bugs too :-/

danibus
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Joined: Sat Feb 03, 2018 12:41 pm

Re: help with black screen

Post by danibus » Mon Dec 06, 2021 10:27 pm

I know, but I think is not SGDK fault, just my rusty C.
One month ago I make all necessary changes to use last SGDK version but the result was the same.
Then I back to "old SGDK" because I want to finish this game and after that start new project with lastest version.

I'm afraid I have to start with C from scratch, because I use to make small programs (1 file) and now have lot of .c and .h files, small mess, maybe this is what is going wrong.

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