[solved] 512x512 backgrounds not displaying

[awesomejuice]

Hi there, I'm working with a team trying to make an NDS game, and we're stumped trying to get 512x512 backgrounds displaying. Our code is below; we have no idea what we're doing wrong or simply not doing what we should be because the documentation we've found is sparse and tutorials covering this all seem to stop immediately before making this work. Any help is appreciated.

Code: Select all

#include <nds.h>
#include <stdio.h>
#include "rah.h" // our grit-generated graphics header

int main(void)
{
   // Turn on 2d graphics core
   powerOn ( POWER_ALL_2D );
   
   // Video mode
   videoSetMode ( MODE_5_2D | DISPLAY_BG3_ACTIVE );

   // Tried these three as well as vramSetMainBanks, equally unsuccessful:
   //
   //vramSetBankA ( VRAM_A_MAIN_BG_0x06000000 );
   //vramSetBankA(VRAM_A_MAIN_BG);
   //vramSetBankB(VRAM_B_MAIN_BG);

   vramSetMainBanks(
            VRAM_A_MAIN_BG_0x06000000,
            VRAM_B_MAIN_BG_0x06020000,
            VRAM_C_MAIN_BG_0x06040000,
            VRAM_D_MAIN_BG_0x06060000);

   consoleDemoInit();

   // Taken from one of the examples
   iprintf("\n\n\tHello DS devers\n");
   iprintf("\twww.drunkencoders.com\n");
   iprintf("\t256 color bitmap demo");

   // Initialize our background and place it in memory
   int bg1 = bgInit( 3, BgType_Bmp8, BgSize_B8_512x512, 0, 0 );
   dmaCopy( rahBitmap, bgGetGfxPtr(bg1), rahBitmapLen );
   dmaCopy( rahPal, BG_PALETTE, rahPalLen );

   while(1)
   {
      swiWaitForVBlank();
   }

   return 0;
}

[Sylus101]

If you've updated to the latest libnds...

You don't need powerOn ( POWER_ALL_2D );

videoSetMode ( MODE_5_2D ); is fine, the bg will be made active inside the bgInit function.

Instead of using bgGetGfxPtr(bg1) when coping the bitmap data, try just BG_GFX. I think bgGetGfxPtr(bg1) should work, but just for sake of argument...

Everything else looked fine as far as I can tell.

[awesomejuice]

Nevermind. Using memcopy instead of dmacopy seems to have worked for us.

[mido]

Nevermind. Using memcopy instead of dmacopy seems to have worked for us.

I believe that you can't DMA Copy onto the stack (which your bg1 variable is).
I could be wrong but that's my understanding. I've had issues with DMA Copy before and it had to do with moving memory to/from the stack. Has to be global I think.

[Sylus101]

Nevermind. Using memcopy instead of dmacopy seems to have worked for us.

I believe that you can't DMA Copy onto the stack (which your bg1 variable is).
I could be wrong but that's my understanding. I've had issues with DMA Copy before and it had to do with moving memory to/from the stack. Has to be global I think.

The dmaCopy wouldn't have been writing to bg1, it would have been writing to the location that bgGetGfxPtr(bg1) returns which is a pointer to a VRAM memory address. I should have worked...