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How to control the framerate
FacundoARG - Aug 11, 2009
    FacundoARG Aug 11, 2009 
Hi I'm a video game developer, but not yet professional on Sega Saturn. I need to coordinate the framerate on this machine. Anyone know, how can do this?. For example I need to reproduce a function like SDL_GetTicks() from SDL.


Thanks.


PD: sorry for my english

   ExCyber Aug 11, 2009 
In terms of hardware, you could use an SH-2 timer, or maybe even the H-position register in VDP2. I don't know how it would be done in SGL/SBL.

    mic Aug 12, 2009 
If you just want to do frame rate limiting then you could poll bit 3 of TVSTAT, which is set during VBlank (see the VDP2 maunal).

    FacundoARG Aug 16, 2009 
Thanks for your advice, now I am studing the sega_tim.h .


I hope this will solve my problems.

    vbt Aug 26, 2009 
Maybe something like this for getticks :

Code: 
  
Uint16 previouscount=0; int SDL_InitSubSystem(Uint32 flags) { if(flags &= SDL_INIT_AUDIO) { char sound_map[] = {0xff,0xff};//,0xff,0xff,0xff,0xff,0xff,0xff,0xff}; #ifdef ACTION_REPLAY slInitSound(sddrvstsk , sizeof(sddrvstsk) , (Uint8 *)sound_map , sizeof(sound_map)) ; #else #define SDDRV_NAME "SDDRVS.TSK" #define SDDRV_SIZE 26610 #define SDDRV_ADDR 0x00202000//0x6080000 unsigned char *drv; //slPrint("driver loaded",slLocate(1,1)); drv = (unsigned char *)malloc(SDDRV_SIZE); GFS_Load(GFS_NameToId((Sint8*)SDDRV_NAME),0,(void *) tutu,SDDRV_SIZE); slInitSound(drv , SDDRV_SIZE , (Uint8 *)sound_map , sizeof(sound_map)) ; free(drv); #endif } if(flags &= SDL_INIT_TIMER) { TIM_FRT_INIT(TIM_CKS_32); TIM_FRT_SET_16(0); } return 0; } Uint32 SDL_GetTicks(void) { previouscount += TIM_FRT_CNT_TO_MCR(TIM_FRT_GET_16()) / 1000; TIM_FRT_SET_16(0); return previouscount; }

about waiting for vblank (from Charles Mac Donald samples) :

Code: 
  
#define TVSTAT (*(Uint16 *)0x25F80004) void wait_vblank(void) { while((TVSTAT & 8) == 0); while((TVSTAT & 8) == 8); }