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https://github.com/UberGames/lilium-voyager.git
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142 lines
4.8 KiB
C++
142 lines
4.8 KiB
C++
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#include "jpeglib.h"
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#include <memory.h>
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GLOBAL void LoadJPGBuff(unsigned char *fbuffer, unsigned char **pic, int *width, int *height )
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{
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/* This struct contains the JPEG decompression parameters and pointers to
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* working space (which is allocated as needed by the JPEG library).
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*/
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struct jpeg_decompress_struct cinfo;
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/* We use our private extension JPEG error handler.
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* Note that this struct must live as long as the main JPEG parameter
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* struct, to avoid dangling-pointer problems.
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*/
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/* This struct represents a JPEG error handler. It is declared separately
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* because applications often want to supply a specialized error handler
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* (see the second half of this file for an example). But here we just
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* take the easy way out and use the standard error handler, which will
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* print a message on stderr and call exit() if compression fails.
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* Note that this struct must live as long as the main JPEG parameter
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* struct, to avoid dangling-pointer problems.
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*/
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struct jpeg_error_mgr jerr;
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/* More stuff */
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JSAMPARRAY buffer; /* Output row buffer */
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int row_stride; /* physical row width in output buffer */
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unsigned char *out;
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byte *bbuf;
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int nSize;
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/* Step 1: allocate and initialize JPEG decompression object */
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/* We have to set up the error handler first, in case the initialization
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* step fails. (Unlikely, but it could happen if you are out of memory.)
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* This routine fills in the contents of struct jerr, and returns jerr's
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* address which we place into the link field in cinfo.
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*/
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cinfo.err = jpeg_std_error(&jerr);
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/* Now we can initialize the JPEG decompression object. */
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jpeg_create_decompress(&cinfo);
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/* Step 2: specify data source (eg, a file) */
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jpeg_stdio_src(&cinfo, fbuffer);
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/* Step 3: read file parameters with jpeg_read_header() */
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(void) jpeg_read_header(&cinfo, TRUE);
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/* We can ignore the return value from jpeg_read_header since
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* (a) suspension is not possible with the stdio data source, and
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* (b) we passed TRUE to reject a tables-only JPEG file as an error.
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* See libjpeg.doc for more info.
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*/
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/* Step 4: set parameters for decompression */
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/* In this example, we don't need to change any of the defaults set by
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* jpeg_read_header(), so we do nothing here.
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*/
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/* Step 5: Start decompressor */
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(void) jpeg_start_decompress(&cinfo);
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/* We can ignore the return value since suspension is not possible
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* with the stdio data source.
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*/
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/* We may need to do some setup of our own at this point before reading
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* the data. After jpeg_start_decompress() we have the correct scaled
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* output image dimensions available, as well as the output colormap
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* if we asked for color quantization.
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* In this example, we need to make an output work buffer of the right size.
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*/
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/* JSAMPLEs per row in output buffer */
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row_stride = cinfo.output_width * cinfo.output_components;
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nSize = cinfo.output_width*cinfo.output_height*cinfo.output_components;
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out = reinterpret_cast<unsigned char*>(malloc(nSize+1));
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memset(out, 0, nSize+1);
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*pic = out;
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*width = cinfo.output_width;
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*height = cinfo.output_height;
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/* Step 6: while (scan lines remain to be read) */
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/* jpeg_read_scanlines(...); */
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/* Here we use the library's state variable cinfo.output_scanline as the
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* loop counter, so that we don't have to keep track ourselves.
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*/
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while (cinfo.output_scanline < cinfo.output_height) {
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/* jpeg_read_scanlines expects an array of pointers to scanlines.
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* Here the array is only one element long, but you could ask for
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* more than one scanline at a time if that's more convenient.
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*/
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bbuf = ((out+(row_stride*cinfo.output_scanline)));
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buffer = &bbuf;
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(void) jpeg_read_scanlines(&cinfo, buffer, 1);
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}
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// clear all the alphas to 255
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{
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int i, j;
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byte *buf;
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buf = *pic;
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j = cinfo.output_width * cinfo.output_height * 4;
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for ( i = 3 ; i < j ; i+=4 ) {
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buf[i] = 255;
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}
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}
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/* Step 7: Finish decompression */
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(void) jpeg_finish_decompress(&cinfo);
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/* We can ignore the return value since suspension is not possible
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* with the stdio data source.
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*/
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/* Step 8: Release JPEG decompression object */
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/* This is an important step since it will release a good deal of memory. */
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jpeg_destroy_decompress(&cinfo);
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/* After finish_decompress, we can close the input file.
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* Here we postpone it until after no more JPEG errors are possible,
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* so as to simplify the setjmp error logic above. (Actually, I don't
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* think that jpeg_destroy can do an error exit, but why assume anything...)
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*/
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//free (fbuffer);
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/* At this point you may want to check to see whether any corrupt-data
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* warnings occurred (test whether jerr.pub.num_warnings is nonzero).
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*/
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/* And we're done! */
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}
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