sdmc/source/main.c

///////////////////////////////////////
// SDMC example //
///////////////////////////////////////
 
//this example shows you how to load a binary image file from the SD card and display it on the lower screen
//for this to work you should copy test.bin to same folder as your .3dsx
//this file was generated with GIMP by saving a 240x320 image to raw RGB
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
 
#include <3ds.h>
#include "costable.h"
 
//this will contain the data read from SDMC
u8* buffer;
 
//3DS has VFPs so we could just use cos
//but we're old school so LUT4life
s32 pcCos(u16 v)
{
 return costable[v&0x1FF];
}
 
void renderEffect()
{
 static int cnt;
 u8* bufAdr=gfxGetFramebuffer(GFX_TOP, GFX_LEFT, NULL, NULL);
 
 int i, j;
 for(i=1;i<400;i++)
 {
 for(j=1;j<240;j++)
 {
 u32 v=(j+i*240)*3;
 bufAdr[v]=(pcCos(i+cnt)+4096)/32;
 bufAdr[v+1]=(pcCos(j-256+cnt)+4096)/64;
 bufAdr[v+2]=(pcCos(i+128-cnt)+4096)/32;
 }
 }
 
 cnt++;
}
 
int main(int argc, char** argv)
{
 
 gfxInitDefault(); //makes displaying to screen easier
 
 FILE *file = fopen("test.bin","rb");
 if (file == NULL) goto exit;
 
 // seek to end of file
 fseek(file,0,SEEK_END);
 
 // file pointer tells us the size
 off_t size = ftell(file);
 
 // seek back to start
 fseek(file,0,SEEK_SET);
 
 //allocate a buffer
 buffer=malloc(size);
 if(!buffer)goto exit;
 
 //read contents !
 off_t bytesRead = fread(buffer,1,size,file);
 
 //close the file because we like being nice and tidy
 fclose(file);
 
 if(size!=bytesRead)goto exit;
 
 while(aptMainLoop())
 {
 //exit when user hits B
 hidScanInput();
 if(keysHeld()&KEY_B)break;
 
 //render rainbow
 renderEffect();
 
 //copy buffer to lower screen (don't have to do it every frame)
 memcpy(gfxGetFramebuffer(GFX_BOTTOM, GFX_BOTTOM, NULL, NULL), buffer, size);
 
 //wait & swap
 gfxSwapBuffersGpu();
 gspWaitForEvent(GSPGPU_EVENT_VBlank0, false);
 }
 
 //cleanup and return
 //returning from main() returns to hbmenu when run under ninjhax
 exit:
 
 //closing all services even more so
 gfxExit();
 return 0;
}