void test_bitfield(Bits bits, int x) {
int* ip = bitfields(bits.int_bitfield, 0);
float* fp = bitfields(bits.uint_bitfield, 0u);
}
bool ReadPalette(File* file, Header& h) {
// initialize bit masks/shifts... just in case
h.bf_red_mask = h.bf_red_shift = h.bf_red_rshift = 0;
h.bf_green_mask = h.bf_green_shift = h.bf_green_rshift = 0;
h.bf_blue_mask = h.bf_blue_shift = h.bf_blue_rshift = 0;
// if we're not a palettized image, don't even read a palette
if (h.bpp > 8) {
h.palette_size = 0;
// do we have bitfields?
if (h.compression == 3) {
auto_array<byte> bitfields(new byte[12]);
if (file->read(bitfields, 12) != 12) {
return false;
}
h.bf_red_mask = read32_le((byte*)bitfields);
h.bf_green_mask = read32_le((byte*)bitfields + 4);
h.bf_blue_mask = read32_le((byte*)bitfields + 8);
// calculate shifts
h.bf_red_shift = count_right_zeroes(h.bf_red_mask);
h.bf_green_shift = count_right_zeroes(h.bf_green_mask);
h.bf_blue_shift = count_right_zeroes(h.bf_blue_mask);
h.bf_red_rshift = 8 - count_ones(h.bf_red_mask);
h.bf_green_rshift = 8 - count_ones(h.bf_green_mask);
h.bf_blue_rshift = 8 - count_ones(h.bf_blue_mask);
// otherwise, set default bitfield entries
} else {
if (h.bpp == 16) {
h.bf_red_mask = 0x7C00;
h.bf_red_shift = 10;
h.bf_red_rshift = 3;
h.bf_green_mask = 0x03E0;
h.bf_green_shift = 5;
h.bf_green_rshift = 3;
h.bf_blue_mask = 0x001F;
h.bf_blue_shift = 0;
h.bf_blue_rshift = 3;
} else if (h.bpp == 32) {
// these don't need any rshift
h.bf_red_mask = 0x00FF0000; h.bf_red_shift = 16;
h.bf_green_mask = 0x0000FF00; h.bf_green_shift = 8;
h.bf_blue_mask = 0x000000FF; h.bf_blue_shift = 0;
}
}
return true;
}
if (h.bpp <= 8) {
h.palette_size = 1 << h.bpp;
} else {
h.palette_size = 0;
return true;
}
h.palette = new BGR[h.palette_size];
// read the BMP color table
const int buffer_size = h.palette_size * (h.os2 ? 3 : 4);
auto_array<byte> buffer(new byte[buffer_size]);
if (file->read(buffer, buffer_size) != buffer_size) {
return false;
}
byte* in = buffer;
BGR* out = h.palette;
for (int i = 0; i < h.palette_size; ++i) {
out->blue = *in++;
out->green = *in++;
out->red = *in++;
if (!h.os2) {
++in; // skip alpha
}
++out;
}
return true;
}
