png.cpp

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00001 /* $Id: png.cpp 13686 2008-07-09 19:13:21Z rubidium $ */
00002 
00005 #ifdef WITH_PNG
00006 
00007 #include "../stdafx.h"
00008 #include "../gfx_func.h"
00009 #include "../fileio.h"
00010 #include "../debug.h"
00011 #include "../core/alloc_func.hpp"
00012 #include "png.hpp"
00013 #include <png.h>
00014 
00015 #define PNG_SLOT 62
00016 
00017 static void PNGAPI png_my_read(png_structp png_ptr, png_bytep data, png_size_t length)
00018 {
00019   FioReadBlock(data, length);
00020 }
00021 
00022 static void PNGAPI png_my_error(png_structp png_ptr, png_const_charp message)
00023 {
00024   DEBUG(sprite, 0, "ERROR (libpng): %s - %s", message, (char *)png_get_error_ptr(png_ptr));
00025   longjmp(png_ptr->jmpbuf, 1);
00026 }
00027 
00028 static void PNGAPI png_my_warning(png_structp png_ptr, png_const_charp message)
00029 {
00030   DEBUG(sprite, 0, "WARNING (libpng): %s - %s", message, (char *)png_get_error_ptr(png_ptr));
00031 }
00032 
00033 static bool OpenPNGFile(const char *filename, uint32 id, bool mask)
00034 {
00035   char png_file[MAX_PATH];
00036 
00037   snprintf(png_file, sizeof(png_file), "sprites" PATHSEP "%s" PATHSEP "%d%s.png", filename, id, mask ? "m" : "");
00038   if (FioCheckFileExists(png_file)) {
00039     FioOpenFile(PNG_SLOT, png_file);
00040     return true;
00041   }
00042 
00043   /* TODO -- Add TAR support */
00044   return false;
00045 }
00046 
00047 static bool LoadPNG(SpriteLoader::Sprite *sprite, const char *filename, uint32 id, volatile bool mask)
00048 {
00049   png_byte header[8];
00050   png_structp png_ptr;
00051   png_infop info_ptr, end_info;
00052   uint bit_depth, color_type;
00053   uint i, pixelsize;
00054   png_bytep row_pointer;
00055   SpriteLoader::CommonPixel *dst;
00056 
00057   if (!OpenPNGFile(filename, id, mask)) return mask; // If mask is true, and file not found, continue true anyway, as it isn't a show-stopper
00058 
00059   /* Check the header */
00060   FioReadBlock(header, 8);
00061   if (png_sig_cmp(header, 0, 8) != 0) return false;
00062 
00063   /* Create the reader */
00064   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL, png_my_error, png_my_warning);
00065   if (png_ptr == NULL) return false;
00066 
00067   /* Create initial stuff */
00068   info_ptr = png_create_info_struct(png_ptr);
00069   if (info_ptr == NULL) {
00070     png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
00071     return false;
00072   }
00073   end_info = png_create_info_struct(png_ptr);
00074   if (end_info == NULL) {
00075     png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
00076     return false;
00077   }
00078 
00079   /* Make sure that upon error, we can clean up graceful */
00080   if (setjmp(png_jmpbuf(png_ptr))) {
00081     png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
00082     return false;
00083   }
00084 
00085   /* Read the file */
00086   png_set_read_fn(png_ptr, NULL, png_my_read);
00087   png_set_sig_bytes(png_ptr, 8);
00088 
00089   png_read_info(png_ptr, info_ptr);
00090 
00091   if (!mask) {
00092     /* Read the text chunks */
00093     png_textp text_ptr;
00094     int num_text = 0;
00095     png_get_text(png_ptr, info_ptr, &text_ptr, &num_text);
00096     if (num_text == 0) DEBUG(misc, 0, "Warning: PNG Sprite '%s/%d.png' doesn't have x_offs and y_offs; expect graphical problems", filename, id);
00097     for (int i = 0; i < num_text; i++) {
00098       /* x_offs and y_offs are in the text-chunk of PNG */
00099       if (strcmp("x_offs", text_ptr[i].key) == 0) sprite->x_offs = strtol(text_ptr[i].text, NULL, 0);
00100       if (strcmp("y_offs", text_ptr[i].key) == 0) sprite->y_offs = strtol(text_ptr[i].text, NULL, 0);
00101     }
00102 
00103     sprite->height = info_ptr->height;
00104     sprite->width  = info_ptr->width;
00105     sprite->data = CallocT<SpriteLoader::CommonPixel>(sprite->width * sprite->height);
00106   }
00107 
00108   bit_depth  = png_get_bit_depth(png_ptr, info_ptr);
00109   color_type = png_get_color_type(png_ptr, info_ptr);
00110 
00111   if (mask && (bit_depth != 8 || color_type != PNG_COLOR_TYPE_PALETTE)) {
00112     DEBUG(misc, 0, "Ignoring mask for SpriteID %d as it isn't a 8 bit palette image", id);
00113     return true;
00114   }
00115 
00116   if (!mask) {
00117     if (bit_depth == 16) png_set_strip_16(png_ptr);
00118 
00119     if (color_type == PNG_COLOR_TYPE_PALETTE) {
00120       png_set_palette_to_rgb(png_ptr);
00121       color_type = PNG_COLOR_TYPE_RGB;
00122     }
00123     if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
00124       png_set_gray_to_rgb(png_ptr);
00125       color_type = PNG_COLOR_TYPE_RGB;
00126     }
00127 
00128     if (color_type == PNG_COLOR_TYPE_RGB) {
00129       png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
00130     }
00131 
00132     pixelsize = sizeof(uint32);
00133   } else {
00134     pixelsize = sizeof(uint8);
00135   }
00136 
00137   row_pointer = (png_byte *)MallocT<byte>(info_ptr->width * pixelsize);
00138   if (row_pointer == NULL) {
00139     png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
00140     return false;
00141   }
00142 
00143   for (i = 0; i < info_ptr->height; i++) {
00144     png_read_row(png_ptr, row_pointer, NULL);
00145 
00146     dst = sprite->data + i * info_ptr->width;
00147 
00148     for (uint x = 0; x < info_ptr->width; x++) {
00149       if (mask) {
00150         if (row_pointer[x * sizeof(uint8)] != 0) {
00151           dst[x].r = 0;
00152           dst[x].g = 0;
00153           dst[x].b = 0;
00154           /* Alpha channel is used from the original image (to allow transparency in remap colors) */
00155           dst[x].m = row_pointer[x * sizeof(uint8)];
00156         }
00157       } else {
00158         dst[x].r = row_pointer[x * sizeof(uint32) + 0];
00159         dst[x].g = row_pointer[x * sizeof(uint32) + 1];
00160         dst[x].b = row_pointer[x * sizeof(uint32) + 2];
00161         dst[x].a = row_pointer[x * sizeof(uint32) + 3];
00162         dst[x].m = 0;
00163       }
00164     }
00165   }
00166 
00167   free(row_pointer);
00168   png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
00169 
00170   return true;
00171 }
00172 
00173 bool SpriteLoaderPNG::LoadSprite(SpriteLoader::Sprite *sprite, uint8 file_slot, uint32 file_pos)
00174 {
00175   const char *filename = FioGetFilename(file_slot);
00176   if (!LoadPNG(sprite, filename, file_pos, false)) return false;
00177   if (!LoadPNG(sprite, filename, file_pos, true)) return false;
00178   return true;
00179 }
00180 
00181 #endif /* WITH_PNG */

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