- FILE *file=fopen(fn.c_str(), "r");
- if(!file) throw Exception("Couldn't open "+fn);
-
- char sig[8];
- fread(sig, 8, 1, file);
- if(png_sig_cmp((png_byte *)sig, 0, 8))
- throw Exception("Not a PNG image");
-
- png_struct *pngs=png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
- png_info *pngi=png_create_info_struct(pngs);
-
- if(setjmp(png_jmpbuf(pngs)))
- {
- png_destroy_read_struct(&pngs, &pngi, 0);
- fclose(file);
- throw Exception("PNG error");
- }
- png_init_io(pngs, file);
- png_set_sig_bytes(pngs, 8);
-
- png_read_info(pngs, pngi);
-
- unsigned width=png_get_image_width(pngs, pngi);
- unsigned height=png_get_image_height(pngs, pngi);
- unsigned depth=png_get_bit_depth(pngs, pngi);
- unsigned ctype=png_get_color_type(pngs, pngi);
-
- if(ctype==PNG_COLOR_TYPE_PALETTE || depth<8)
- {
- png_destroy_read_struct(&pngs, &pngi, 0);
- fclose(file);
- throw Exception("Invalid color type or bit depth");
- }
-
- if(depth==16)
- png_set_strip_16(pngs);
-
- TextureFormat fmt;
- unsigned planes;
-
- switch(ctype)
- {
- case PNG_COLOR_TYPE_GRAY: fmt=LUMINANCE8; planes=1; break;
- case PNG_COLOR_TYPE_GRAY_ALPHA: fmt=LUMINANCE8_ALPHA8; planes=2; break;
- case PNG_COLOR_TYPE_RGB: fmt=RGB8; planes=3; break;
- case PNG_COLOR_TYPE_RGB_ALPHA: fmt=RGBA8; planes=4; break;
- }
-
- png_byte *data=(png_byte *)malloc(width*height*planes);
- png_byte *row_ptrs[height];
- for(unsigned i=0; i<height; ++i)
- row_ptrs[i]=data+(height-1-i)*width*planes;
-
- png_read_image(pngs, row_ptrs);
-
- image(0, width, height, fmt, data);
- free(data);
-
- png_destroy_read_struct(&pngs, &pngi, 0);
- fclose(file);