Displaying 16-bit bitmaps
Posted: Wed Mar 11, 2009 5:09 am
Hey all,
I'm completley new at developing for the ds (and anything else thats not a pc 4 that matter). Was having trouble getting a 16-bit bitmap to display. I can get the same image to display in 8-bit depth with little change to the code. I created a class to overlay on the file structure for the bitmap. Because this overlay is for 8-bit i guess thats the problem. But i dont know what to change.
This is the code used to create the overlay object.
This is the code to display the bitmap
Last of all this is the main function which sets everything up and calls DisplayBmp().
Extremely sorry fo the long post...very new at this so i'm having trouble narrowing down the problem. Would apreciate any suggestions.
ty
I'm completley new at developing for the ds (and anything else thats not a pc 4 that matter). Was having trouble getting a 16-bit bitmap to display. I can get the same image to display in 8-bit depth with little change to the code. I created a class to overlay on the file structure for the bitmap. Because this overlay is for 8-bit i guess thats the problem. But i dont know what to change.
This is the code used to create the overlay object.
Code: Select all
typedef struct
{
char signature[2];
unsigned int fileSize;
unsigned int reserved;
unsigned int offset;
}__attribute__ ((packed)) BmpHeader;
typedef struct
{
unsigned int headerSize;
unsigned int width;
unsigned int height;
unsigned short planeCount;
unsigned short bitDepth;
unsigned int compression;
unsigned int compressedImageSize;
unsigned int horizontalResolution;
unsigned int verticalResolution;
unsigned int numColors;
unsigned int importantColors;
}__attribute__ ((packed)) BmpImageInfo;
typedef struct
{
unsigned char blue;
unsigned char green;
unsigned char red;
unsigned char reserved;
}__attribute__ ((packed)) Rgb;
typedef struct
{
BmpHeader header;
BmpImageInfo info;
Rgb colors[256];
unsigned short image[1];
}__attribute__ ((packed)) BmpFile;
extern void DisplayBmp(u16* video_buffer, u16* backgroundPalette, BmpFile* bmp);Code: Select all
void DisplayBmp(u16* video_buffer, u16* backgroundPalette, BmpFile* bmp)
{
int i, ix, iy;
//copy the palette
for(i = 0; i < 256; i++)
{
backgroundPalette[i] = RGB15(bmp->colors[i].red >> 11, bmp->colors[i].green >> 11, bmp->colors[i].blue >> 11);
}
//copy the image
for(iy = 0; iy < bmp->info.height; iy++)
{
for(ix = 0; ix < bmp->info.width / 2; ix++)
video_buffer[iy * 128 + ix] = bmp->image[(bmp->info.height - 1 - iy) * ((bmp->info.width + 3) & ~3) / 2 + ix];
}
}Code: Select all
#include <nds.h>
#include <stdio.h>
#include <bitmap.h>
#include <myPic_bmp.h>
int main(void) {
//point our video buffer to the start of bitmap background video
u16* video_buffer = (u16*)BG_BMP_RAM(0);
//set video mode to mode 5 with background 3 enabled
videoSetMode(MODE_5_2D | DISPLAY_BG3_ACTIVE);
//map vram to start of main background graphics memory
vramSetBankA(VRAM_A_MAIN_BG_0x06000000);
//initialize the background
BACKGROUND.control[3] = BG_BMP16_256x256 | BG_BMP_BASE(0);
BACKGROUND.bg3_rotation.xdy = 0;
BACKGROUND.bg3_rotation.xdx = 1 << 8;
BACKGROUND.bg3_rotation.ydx = 0;
BACKGROUND.bg3_rotation.ydy = 1 << 8;
BmpFile* bmp = (BmpFile*)myPic_bmp;
consoleDemoInit();
printf("%c%c\n", bmp->header.signature[0], bmp->header.signature[1]);
printf("bit depth: %i\n", bmp->info.bitDepth);
printf("width: %i\n", bmp->info.width);
printf("height: %i\n", bmp->info.height);
DisplayBmp(video_buffer, BG_PALETTE, bmp);
return 0;
}ty