/* ---------------------------------------------------------------------------
* Return a pointer to a given pixel. Accounts for image orientation (T_TO_B,
* R_TO_L, etc). Returns NULL if the pixel is out of range.
*/
uint8_t *tga_find_pixel(const tga_image *img, uint16_t x, uint16_t y)
{
if (x >= img->width || y >= img->height)
return NULL;
if (!tga_is_top_to_bottom(img)) y = img->height - 1 - y;
if (tga_is_right_to_left(img)) x = img->width - 1 - x;
return img->image_data + (x + y * img->width) * img->pixel_depth/8;
}
void load_tga(tga_image *tga, const char *fn)
{
DONTFAIL( tga_read(tga, fn) );
printf("Loaded %dx%dx%dbpp targa (\"%s\").\n",
tga->width, tga->height, tga->pixel_depth, fn);
if (!tga_is_mono(tga)) DONTFAIL( tga_desaturate_rec_601_1(tga) );
if (!tga_is_top_to_bottom(tga)) DONTFAIL( tga_flip_vert(tga) );
if (tga_is_right_to_left(tga)) DONTFAIL( tga_flip_horiz(tga) );
if ((tga->width % 8 != 0) || (tga->height % 8 != 0))
{
printf("Width and height must be multiples of 8\n");
exit(EXIT_FAILURE);
}
}
static RGBSpectrum *ReadImageTGA(const std::string &name, int *width,
int *height) {
tga_image img;
tga_result result;
if ((result = tga_read(&img, name.c_str())) != TGA_NOERR) {
Error("Unable to read from TGA file \"%s\" (%s)", name.c_str(),
tga_error(result));
return nullptr;
}
if (tga_is_right_to_left(&img)) tga_flip_horiz(&img);
if (!tga_is_top_to_bottom(&img)) tga_flip_vert(&img);
if (tga_is_colormapped(&img)) tga_color_unmap(&img);
*width = img.width;
*height = img.height;
// "Unpack" the pixels (origin in the lower left corner).
// TGA pixels are in BGRA format.
RGBSpectrum *ret = new RGBSpectrum[*width * *height];
RGBSpectrum *dst = ret;
for (int y = *height - 1; y >= 0; y--)
for (int x = 0; x < *width; x++) {
uint8_t *src = tga_find_pixel(&img, x, y);
if (tga_is_mono(&img))
*dst++ = RGBSpectrum(*src / 255.f);
else {
Float c[3];
c[2] = src[0] / 255.f;
c[1] = src[1] / 255.f;
c[0] = src[2] / 255.f;
*dst++ = RGBSpectrum::FromRGB(c);
}
}
tga_free_buffers(&img);
Info("Read TGA image %s (%d x %d)", name.c_str(), *width, *height);
return ret;
}
/* ---------------------------------------------------------------------------
* Horizontally flip the image in place. Reverses the right-to-left bit in
* the image descriptor.
*/
tga_result tga_flip_horiz(tga_image *img)
{
uint16_t row;
size_t bpp;
uint8_t *left, *right;
int r_to_l;
if (!SANE_DEPTH(img->pixel_depth)) return TGAERR_PIXEL_DEPTH;
bpp = (size_t)(img->pixel_depth / 8); /* bytes per pixel */
for (row=0; row<img->height; row++)
{
left = img->image_data + row * img->width * bpp;
right = left + (img->width - 1) * bpp;
/* reverse from left to right */
while (left < right)
{
uint8_t buffer[4];
/* swap */
memcpy(buffer, left, bpp);
memcpy(left, right, bpp);
memcpy(right, buffer, bpp);
left += bpp;
right -= bpp;
}
}
/* Correct image_descriptor's left-to-right-ness. */
r_to_l = tga_is_right_to_left(img);
img->image_descriptor &= ~TGA_R_TO_L_BIT; /* mask out r-to-l bit */
if (!r_to_l)
/* was l-to-r, need to set r_to_l */
img->image_descriptor |= TGA_R_TO_L_BIT;
/* else bit is already rubbed out */
return TGA_NOERR;
}
