[homebrew] Cheril Perils GB/GBC

Discussion of programming and development for the original Game Boy and Game Boy Color.
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tonma
Posts: 23
Joined: Tue Mar 28, 2017 6:26 am
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[homebrew] Cheril Perils GB/GBC

Post by tonma » Tue May 22, 2018 2:12 am

Hi,

I'm working on my first ever GameBoy game. It's a version of the MegaDrive game by Mojon Twins.

I've added tilemap, sprite with animations, basic collision, bank switching (seems to work) and GameBoy / GameBoyColor compatibility.
I'ts works on real hardware.

I'll certainly have questions when I'll attack the sound/music part.

Image

Image

calima
Posts: 1021
Joined: Tue Oct 06, 2015 10:16 am

Re: [homebrew] Cheril Perils GB/GBC

Post by calima » Tue May 22, 2018 10:53 am

The green-and-black text's lowest, darkest color makes it hard to read.

tonma
Posts: 23
Joined: Tue Mar 28, 2017 6:26 am
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Re: [homebrew] Cheril Perils GB/GBC

Post by tonma » Wed May 23, 2018 5:22 am

calima wrote:The green-and-black text's lowest, darkest color makes it hard to read.
Yep, I'll change that to a 2 colors fonts to be more readable.

tonma
Posts: 23
Joined: Tue Mar 28, 2017 6:26 am
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Re: [homebrew] Cheril Perils GB/GBC

Post by tonma » Sat Jun 02, 2018 11:48 pm

News : room transition, ennemies with collision, lethal weapon and modified gameplay.

Video of the gameplay :
https://youtu.be/UMzqGtDpL-A

Image

I also hard coded a music for the title of the game (I used @DavidBonus 's score) :
https://soundcloud.com/user-218371570/gb-title

tonma
Posts: 23
Joined: Tue Mar 28, 2017 6:26 am
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Re: [homebrew] Cheril Perils GB/GBC

Post by tonma » Wed Jun 06, 2018 9:09 am

I have a problem with the bank switching. I read different documents on the forums and tested different solutions.

I use gbdk 2.95 with windows.

Code: Select all

REM		Link banks
REM       ROM+MBC1 : -Wl-yt1
REM       ROM+MBC1+RAM : -Wl-yt2
REM       4 ROM banks  : -Wl-yo4
REM       4 RAM banks  : -Wl-ya4

..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-ba0 -c -o -c -o banks.o banks.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo0 -c -o -c -o bank_0.o bank_0.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo1 -c -o -c -o bank_1.o bank_1.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo2 -c -o -c -o bank_2.o bank_2.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo3 -c -o -c -o bank_3.o bank_3.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j -Wl-yt2 -Wl-yo4 -Wl-ya1 -o banks.gb banks.o bank_0.o bank_1.o bank_2.o bank_3.o
I put my bank fixed code in banks.0 but I have an error at the compilation :
ERROR: address overflow (addr a002 >= 8000)

I use the same syntax for all my bank.

bank0:

Code: Select all

int var_0;  /* In external RAM bank 0 */
extern int var_internal;
void bank_0() ;

void bank_0()  {

}
bank 1 to 3 with a same size const array cut1_tileset, cut2_tileset, cut3_tileset

Code: Select all

#include <gb/gb.h>
#include <stdio.h>

#pragma bank=1

int var_1;  /* In external RAM bank 1 */
extern var_internal;

const unsigned char cut1_tileset[] =
{
  
  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
  0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
  0xFF,0xFF,0xFF,......
};


void bank_1()  /* In ROM bank 1 */
{
 
DISPLAY_ON; 
SPRITES_8x16;
SHOW_BKG;

}
In the external file from compilation :

Code: Select all

AREA _CODE_0
	RADIX HEX
	BASE A002
	SIZE 0016
	ATTRIB REL CON
	GLOBALS
		_bank_fixed	A002
		_bank_0	A017
AREA _CODE_1
	RADIX HEX
	BASE 4000
	SIZE 36C6
	ATTRIB REL CON
	GLOBALS
		_bank_1	4000
		_cut1_tileset	4001
		_bank_1_test	76A1
AREA _CODE_2
	RADIX HEX
	BASE 4000
	SIZE 36BC
	ATTRIB REL CON
	GLOBALS
		_bank_2	4000
		_cut2_tileset	400A
AREA _CODE_3
	RADIX HEX
	BASE 4000
	SIZE 36A1
	ATTRIB REL CON
	GLOBALS
		_bank_3	4000
		_cut3_tileset	4001

tonma
Posts: 23
Joined: Tue Mar 28, 2017 6:26 am
Contact:

Re: [homebrew] Cheril Perils GB/GBC

Post by tonma » Thu Jun 07, 2018 2:33 am

After a lot of tests, I've find how bank switching works with my version of gbdk.

I've tried with 7 banks switchables using ROM+MBC1+RAM :

Code: Select all

..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-ba0 -c -o -c -o banks.o banks.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo0 -c -o -c -o bank_0.o bank_0.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo1 -c -o -c -o bank_1.o bank_1.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo2 -c -o -c -o bank_2.o bank_2.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo3 -c -o -c -o bank_3.o bank_3.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo4 -c -o -c -o bank_4.o bank_4.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo5 -c -o -c -o bank_5.o bank_5.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo6 -c -o -c -o bank_6.o bank_6.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo7 -c -o -c -o bank_7.o bank_7.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j -Wl-yt2 -Wl-yo8 -Wl-ya1 -o banks.gb banks.o bank_0.o bank_1.o bank_2.o bank_3.o bank_4.o bank_5.o bank_6.o bank_7.o
Image

I used "banked" and pragma for each bank (1->7) :

Code: Select all

#include <gb/gb.h>
#include <stdio.h>
#pragma bank=1
extern var_internal;

const unsigned char title_map[] = { 0,0,0,0, ....};

void bank_1() banked /* In ROM bank 1 */
{
puts("I'm in ROM bank 1");
}
So I have in my map file 7 banks with more of $3000 of rom used :

Code: Select all

AREA _CODE_1
	RADIX HEX
	BASE 4000
	SIZE 3521
	ATTRIB REL CON
	GLOBALS
		_bank_1	4000
		_title_map	400A
		_title_tileset	6BA2
		_title_tiledata	72A2
		_title_map_pal	7322
		_title_start_map	748A
		_bank_1_test	74E4
But now I have a problem with the bank 0, the "fixed bank".
Normaly with the memory map, banks switchable go to $4000 and it's ok : Base 4000

-Wf-ba0 banks.c
-Wf-bo0 bank_0.c
The fixed bank may go to $0150-$3FFF and the internal ram bank $C000-$CFFF. So my rom code/data of bank_0 must begin at $0150.

In my map file, my code begin at A000 in the cartrige RAM :

Code: Select all

AREA _CODE_0
	RADIX HEX
	BASE A006
	SIZE 001C
	ATTRIB REL CON
	GLOBALS
		_bank0	A006
I certainly doing something wrong in the declaration of my compilation file. The tests continue.

tonma
Posts: 23
Joined: Tue Mar 28, 2017 6:26 am
Contact:

Re: [homebrew] Cheril Perils GB/GBC

Post by tonma » Thu Jun 07, 2018 4:33 am

Seems to works now. :mrgreen:
My code in bank 0 has the good address value :

Code: Select all

AREA _CODE
	RADIX HEX
	BASE 0200
	SIZE 2822
	ATTRIB REL CON
I just changed my compilation file.
I'm not using anymore -Wf-bo0 for the fixed bank and using the External RAM in A000.

Code: Select all

REM ..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-ba0 -c -o banks.o banks.c
REM ..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-bo0 -c -o bank_0.o bank_0.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j -c -o banks.o banks.c
..\..\bin\lcc -Wa-l -Wl-m -Wl-j  -Wf-ba0 -c -o bank_0.o bank_0.c

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