bnes-libretro/nall/bmp.hpp

102 lines
3.3 KiB
C++

#ifndef NALL_BMP_HPP
#define NALL_BMP_HPP
#include <nall/file.hpp>
//BMP reader / writer
//author: byuu
//note: only 24-bit RGB and 32-bit ARGB uncompressed images supported
namespace nall {
struct bmp {
inline static bool read(const string &filename, uint32_t *&data, unsigned &width, unsigned &height);
inline static bool write(const string &filename, const uint32_t *data, unsigned width, unsigned height, unsigned pitch, bool alpha = false);
};
bool bmp::read(const string &filename, uint32_t *&data, unsigned &width, unsigned &height) {
file fp;
if(fp.open(filename, file::mode::read) == false) return false;
if(fp.size() < 0x36) return false;
if(fp.readm(2) != 0x424d) return false;
fp.seek(0x000a);
unsigned offset = fp.readl(4);
unsigned dibsize = fp.readl(4);
if(dibsize != 40) return false;
signed headerWidth = fp.readl(4);
if(headerWidth < 0) return false;
signed headerHeight = fp.readl(4);
fp.readl(2);
unsigned bitsPerPixel = fp.readl(2);
if(bitsPerPixel != 24 && bitsPerPixel != 32) return false;
unsigned compression = fp.readl(4);
if(compression != 0) return false;
fp.seek(offset);
bool noFlip = headerHeight < 0;
width = headerWidth, height = abs(headerHeight);
data = new uint32_t[width * height];
unsigned bytesPerPixel = bitsPerPixel / 8;
unsigned alignedWidth = width * bytesPerPixel;
unsigned paddingLength = 0;
while(alignedWidth % 4) alignedWidth++, paddingLength++;
for(unsigned y = 0; y < height; y++) {
uint32_t *p = noFlip ? data + y * width : data + (height - 1 - y) * width;
for(unsigned x = 0; x < width; x++, p++) {
*p = fp.readl(bytesPerPixel);
if(bytesPerPixel == 3) *p |= 255 << 24;
}
if(paddingLength) fp.readl(paddingLength);
}
fp.close();
return true;
}
bool bmp::write(const string &filename, const uint32_t *data, unsigned width, unsigned height, unsigned pitch, bool alpha) {
file fp;
if(fp.open(filename, file::mode::write) == false) return false;
unsigned bitsPerPixel = alpha ? 32 : 24;
unsigned bytesPerPixel = bitsPerPixel / 8;
unsigned alignedWidth = width * bytesPerPixel;
unsigned paddingLength = 0;
unsigned imageSize = alignedWidth * height;
unsigned fileSize = 0x36 + imageSize;
while(alignedWidth % 4) alignedWidth++, paddingLength++;
fp.writem(0x424d, 2); //signature
fp.writel(fileSize, 4); //file size
fp.writel(0, 2); //reserved
fp.writel(0, 2); //reserved
fp.writel(0x36, 4); //offset
fp.writel(40, 4); //DIB size
fp.writel(width, 4); //width
fp.writel(-height, 4); //height
fp.writel(1, 2); //color planes
fp.writel(bitsPerPixel, 2); //bits per pixel
fp.writel(0, 4); //compression method (BI_RGB)
fp.writel(imageSize, 4); //image data size
fp.writel(3780, 4); //horizontal resolution
fp.writel(3780, 4); //vertical resolution
fp.writel(0, 4); //palette size
fp.writel(0, 4); //important color count
for(unsigned y = 0; y < height; y++) {
const uint32_t *p = (const uint32_t*)((const uint8_t*)data + y * pitch);
for(unsigned x = 0; x < width; x++) fp.writel(*p++, bytesPerPixel);
if(paddingLength) fp.writel(0, paddingLength);
}
fp.close();
return true;
}
}
#endif