mirror of
https://github.com/zenorogue/hyperrogue.git
synced 2024-12-05 01:29:54 +00:00
172 lines
4.4 KiB
C++
172 lines
4.4 KiB
C++
/*
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* SDL_SavePNG -- libpng-based SDL_Surface writer.
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*
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* This code is free software, available under zlib/libpng license.
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* http://www.libpng.org/pub/png/src/libpng-LICENSE.txt
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*/
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#ifdef CAP_SDL2
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#if CAP_SDL2
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#define USE_SDL2
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#endif
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#endif
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#ifdef USE_SDL2
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#include <SDL2/SDL.h>
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#else
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#include <SDL/SDL.h>
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#endif
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#include <png.h>
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#define SUCCESS 0
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#define ERROR -1
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#define USE_ROW_POINTERS
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#if SDL_BYTEORDER == SDL_BIG_ENDIAN
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#define rmask 0xFF000000
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#define gmask 0x00FF0000
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#define bmask 0x0000FF00
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#define amask 0x000000FF
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#else
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#define rmask 0x000000FF
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#define gmask 0x0000FF00
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#define bmask 0x00FF0000
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#define amask 0xFF000000
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#endif
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/* libpng callbacks */
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static void png_error_SDL(png_structp ctx, png_const_charp str)
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{
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SDL_SetError("libpng: %s\n", str);
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}
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static void png_write_SDL(png_structp png_ptr, png_bytep data, png_size_t length)
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{
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SDL_RWops *rw = (SDL_RWops*)png_get_io_ptr(png_ptr);
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SDL_RWwrite(rw, data, sizeof(png_byte), length);
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}
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#ifdef __cplusplus
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extern "C"
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#endif
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SDL_Surface *SDL_PNGFormatAlpha(SDL_Surface *src)
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{
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SDL_Surface *surf;
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SDL_Rect rect = { 0, 0, 0, 0 };
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/* NO-OP for images < 32bpp and 32bpp images that already have Alpha channel */
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if (src->format->BitsPerPixel <= 24 || src->format->Amask) {
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src->refcount++;
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return src;
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}
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/* Convert 32bpp alpha-less image to 24bpp alpha-less image */
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rect.w = src->w;
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rect.h = src->h;
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surf = SDL_CreateRGBSurface(src->flags, src->w, src->h, 24,
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src->format->Rmask, src->format->Gmask, src->format->Bmask, 0);
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SDL_LowerBlit(src, &rect, surf, &rect);
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return surf;
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}
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#ifdef __cplusplus
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extern "C"
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#endif
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int SDL_SavePNG_RW(SDL_Surface *surface, SDL_RWops *dst, int freedst)
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{
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png_structp png_ptr;
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png_infop info_ptr;
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png_colorp pal_ptr;
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SDL_Palette *pal;
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int i, colortype;
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#ifdef USE_ROW_POINTERS
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png_bytep *row_pointers;
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#endif
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/* Initialize and do basic error checking */
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if (!dst)
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{
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SDL_SetError("Argument 2 to SDL_SavePNG_RW can't be NULL, expecting SDL_RWops*\n");
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return (ERROR);
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}
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if (!surface)
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{
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SDL_SetError("Argument 1 to SDL_SavePNG_RW can't be NULL, expecting SDL_Surface*\n");
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if (freedst) SDL_RWclose(dst);
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return (ERROR);
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}
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png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, png_error_SDL, NULL); /* err_ptr, err_fn, warn_fn */
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if (!png_ptr)
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{
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SDL_SetError("Unable to png_create_write_struct on %s\n", PNG_LIBPNG_VER_STRING);
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if (freedst) SDL_RWclose(dst);
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return (ERROR);
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}
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info_ptr = png_create_info_struct(png_ptr);
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if (!info_ptr)
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{
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SDL_SetError("Unable to png_create_info_struct\n");
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png_destroy_write_struct(&png_ptr, NULL);
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if (freedst) SDL_RWclose(dst);
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return (ERROR);
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}
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if (setjmp(png_jmpbuf(png_ptr))) /* All other errors, see also "png_error_SDL" */
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{
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png_destroy_write_struct(&png_ptr, &info_ptr);
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if (freedst) SDL_RWclose(dst);
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return (ERROR);
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}
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/* Setup our RWops writer */
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png_set_write_fn(png_ptr, dst, png_write_SDL, NULL); /* w_ptr, write_fn, flush_fn */
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/* Prepare chunks */
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colortype = PNG_COLOR_MASK_COLOR;
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if (surface->format->BytesPerPixel > 0
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&& surface->format->BytesPerPixel <= 8
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&& (pal = surface->format->palette))
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{
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colortype |= PNG_COLOR_MASK_PALETTE;
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pal_ptr = (png_colorp)malloc(pal->ncolors * sizeof(png_color));
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for (i = 0; i < pal->ncolors; i++) {
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pal_ptr[i].red = pal->colors[i].r;
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pal_ptr[i].green = pal->colors[i].g;
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pal_ptr[i].blue = pal->colors[i].b;
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}
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png_set_PLTE(png_ptr, info_ptr, pal_ptr, pal->ncolors);
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free(pal_ptr);
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}
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else if (surface->format->BytesPerPixel > 3 || surface->format->Amask)
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colortype |= PNG_COLOR_MASK_ALPHA;
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png_set_IHDR(png_ptr, info_ptr, surface->w, surface->h, 8, colortype,
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PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
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// png_set_packing(png_ptr);
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/* Allow BGR surfaces */
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if (surface->format->Rmask == bmask
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&& surface->format->Gmask == gmask
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&& surface->format->Bmask == rmask)
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png_set_bgr(png_ptr);
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/* Write everything */
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png_write_info(png_ptr, info_ptr);
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#ifdef USE_ROW_POINTERS
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row_pointers = (png_bytep*) malloc(sizeof(png_bytep)*surface->h);
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for (i = 0; i < surface->h; i++)
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row_pointers[i] = (png_bytep)(Uint8*)surface->pixels + i * surface->pitch;
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png_write_image(png_ptr, row_pointers);
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free(row_pointers);
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#else
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for (i = 0; i < surface->h; i++)
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png_write_row(png_ptr, (png_bytep)(Uint8*)surface->pixels + i * surface->pitch);
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#endif
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png_write_end(png_ptr, info_ptr);
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/* Done */
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png_destroy_write_struct(&png_ptr, &info_ptr);
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if (freedst) SDL_RWclose(dst);
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return (SUCCESS);
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}
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