8 bit jpeg support from Thilo Schulz

https://bugzilla.icculus.org/show_bug.cgi?id=2373
This commit is contained in:
Zachary Slater 2005-09-07 20:42:43 +00:00
parent 62678a0215
commit cda15d093a

View file

@ -1378,7 +1378,8 @@ static void LoadJPG( const char *filename, unsigned char **pic, int *width, int
/* More stuff */
JSAMPARRAY buffer; /* Output row buffer */
int row_stride; /* physical row width in output buffer */
unsigned char *out;
int pixelcount;
unsigned char *out, *out_converted;
byte *fbuffer;
byte *bbuf;
@ -1439,14 +1440,10 @@ static void LoadJPG( const char *filename, unsigned char **pic, int *width, int
*/
/* JSAMPLEs per row in output buffer */
// This row_stride from libjpeg's example code doesn't work, since we
// want to fill in an alpha channel ourselves and jpegs might be 8-bit.
//row_stride = cinfo.output_width * cinfo.output_components;
row_stride = cinfo.output_width * 4;
out = ri.Malloc(row_stride*cinfo.output_height);
pixelcount = cinfo.output_width * cinfo.output_height;
row_stride = cinfo.output_width * cinfo.output_components;
out = ri.Malloc(pixelcount * 4);
*pic = out;
*width = cinfo.output_width;
*height = cinfo.output_height;
@ -1465,13 +1462,36 @@ static void LoadJPG( const char *filename, unsigned char **pic, int *width, int
buffer = &bbuf;
(void) jpeg_read_scanlines(&cinfo, buffer, 1);
}
// clear all the alphas to 255
// If we are processing an 8-bit JPEG (greyscale), we'll have to convert
// the greyscale values to RGBA.
if(cinfo.output_components == 1)
{
int sindex, dindex = 0;
unsigned char greyshade;
// allocate a new buffer for the transformed image
out_converted = ri.Malloc(pixelcount*4);
for(sindex = 0; sindex < pixelcount; sindex++)
{
greyshade = out[sindex];
out_converted[dindex++] = greyshade;
out_converted[dindex++] = greyshade;
out_converted[dindex++] = greyshade;
out_converted[dindex++] = 255;
}
ri.Free(out);
out = out_converted;
}
else
{
// clear all the alphas to 255
int i, j;
byte *buf;
buf = *pic;
buf = out;
j = cinfo.output_width * cinfo.output_height * 4;
for ( i = 3 ; i < j ; i+=4 ) {
@ -1479,6 +1499,8 @@ static void LoadJPG( const char *filename, unsigned char **pic, int *width, int
}
}
*pic = out;
/* Step 7: Finish decompression */
(void) jpeg_finish_decompress(&cinfo);