(svn r10143) -Add: store the filename of the grfs opened and allow easy access to the name
-Codechange: store the SpriteID in the spritecache too -Add: add a PNG loader for graphical files -Documentation: added a document to explain the PNG formatreplace/41b28d7194a279bdc17475d4fbe2ea6ec885a466
truelight
17 years ago
parent
4185c4afcd
commit
b7443d800b
@ -0,0 +1,36 @@
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32bpp and OpenTTD
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=================
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OpenTTD has 32bpp support. This means: OpenTTD still is 8bpp, but it has the
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posibility to override the graphics with 32bpp. This means that it isn't a
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replacement of grf or newgrf, but simply an addition. If you want to use 32bpp
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graphics of a newgrf, you do need the newgrf itself too (with 8bpp graphics).
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The Format
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----------
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32bpp images are stored in PNG. They should go in:
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data/sprites/<grfname>/<SpriteID>.png
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For example, a grfname would be 'openttd' (without .grf, lowercase), and the
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SpriteID 3, to override the 3rd sprite in openttd.grf with a 32bpp version.
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The format of this PNG can be almost anything, but we advise to use RGBA
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format. Alpha-channel is fully supported.
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As the core of OpenTTD is 8bpp, and because you of course want company colours
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in your images, you will need to add a mask for every sprite that needs colour
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remapping. The name is simular as above, only you have to put a 'm' behind the
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SpriteID. This image should be a 8bpp palette image, where the palette is the
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OpenTTD palette. Upon load of the PNG, the mask is loaded too, and overrides
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the RGB (not the Alpha) of the original PNG image, and replacing it with a
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8bpp color remapped and converted to 32bpp.
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An other thing that OpenTTD needs in your png, is 2 tEXt chunks: x_offs and
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y_offs. This to define the x- and y-offset, of course. Use the tool we supply
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to add this information. Sadly enough most graphical editors trashes those
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chunks upon save, so you have to readd it every time you save your image.
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Your images should be the same as the grf, in size.
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@ -0,0 +1,180 @@
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/* $Id$ */
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/** @file grf.cpp */
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#include "../stdafx.h"
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#include "../gfx.h"
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#include "../fileio.h"
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#include "../variables.h"
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#include "../debug.h"
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#include "png.hpp"
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#include <png.h>
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#define PNG_SLOT 62
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static void PNGAPI png_my_read(png_structp png_ptr, png_bytep data, png_size_t length)
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{
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FioReadBlock(data, length);
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}
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static void PNGAPI png_my_error(png_structp png_ptr, png_const_charp message)
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{
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DEBUG(sprite, 0, "ERROR (libpng): %s - %s", message, (char *)png_get_error_ptr(png_ptr));
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longjmp(png_ptr->jmpbuf, 1);
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}
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static void PNGAPI png_my_warning(png_structp png_ptr, png_const_charp message)
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{
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DEBUG(sprite, 0, "WARNING (libpng): %s - %s", message, (char *)png_get_error_ptr(png_ptr));
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}
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static bool OpenPNGFile(const char *filename, uint32 id, bool mask)
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{
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char png_file[MAX_PATH];
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snprintf(png_file, sizeof(png_file), "sprites" PATHSEP "%s" PATHSEP "%d%s.png", filename, id, mask ? "m" : "");
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if (FioCheckFileExists(png_file)) {
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FioOpenFile(PNG_SLOT, png_file);
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return true;
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}
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/* TODO -- Add TAR support */
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return false;
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}
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static bool LoadPNG(SpriteLoader::Sprite *sprite, const char *filename, uint32 id, bool mask)
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{
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png_byte header[8];
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png_structp png_ptr;
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png_infop info_ptr, end_info;
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uint bit_depth, color_type;
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uint i, pixelsize;
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png_bytep row_pointer;
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SpriteLoader::CommonPixel *dst;
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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
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/* Check the header */
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FioReadBlock(header, 8);
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if (png_sig_cmp(header, 0, 8) != 0) return false;
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/* Create the reader */
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png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (png_voidp)NULL, png_my_error, png_my_warning);
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if (png_ptr == NULL) return false;
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/* Create initial stuff */
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info_ptr = png_create_info_struct(png_ptr);
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if (info_ptr == NULL) {
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png_destroy_read_struct(&png_ptr, (png_infopp)NULL, (png_infopp)NULL);
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return false;
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}
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end_info = png_create_info_struct(png_ptr);
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if (end_info == NULL) {
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png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
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return false;
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}
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/* Make sure that upon error, we can clean up graceful */
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if (setjmp(png_jmpbuf(png_ptr))) {
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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return false;
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}
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/* Read the file */
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png_set_read_fn(png_ptr, NULL, png_my_read);
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png_set_sig_bytes(png_ptr, 8);
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png_read_info(png_ptr, info_ptr);
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if (!mask) {
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/* Read the text chunks */
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png_textp text_ptr;
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int num_text = 0;
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png_get_text(png_ptr, info_ptr, &text_ptr, &num_text);
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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);
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for (int i = 0; i < num_text; i++) {
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/* x_offs and y_offs are in the text-chunk of PNG */
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if (strcmp("x_offs", text_ptr[i].key) == 0) sprite->x_offs = strtol(text_ptr[i].text, NULL, 0);
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if (strcmp("y_offs", text_ptr[i].key) == 0) sprite->y_offs = strtol(text_ptr[i].text, NULL, 0);
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}
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sprite->height = info_ptr->height;
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sprite->width = info_ptr->width;
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sprite->data = CallocT<SpriteLoader::CommonPixel>(sprite->width * sprite->height);
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}
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bit_depth = png_get_bit_depth(png_ptr, info_ptr);
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color_type = png_get_color_type(png_ptr, info_ptr);
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if (mask && (bit_depth != 8 || color_type != PNG_COLOR_TYPE_PALETTE)) {
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DEBUG(misc, 0, "Ignoring mask for SpriteID %d as it isn't a 8 bit palette image", id);
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return true;
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}
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if (!mask) {
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if (bit_depth == 16) png_set_strip_16(png_ptr);
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if (color_type == PNG_COLOR_TYPE_PALETTE) png_set_palette_to_rgb(png_ptr);
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/* TODO 32bpp: Convert grayscale to rgb */
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#ifdef TTD_LITTLE_ENDIAN
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png_set_bgr(png_ptr);
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#else
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if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) png_set_swap_alpha(png_ptr);
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#endif
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if (color_type == PNG_COLOR_TYPE_RGB) {
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#ifdef TTD_LITTLE_ENDIAN
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png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
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#else
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png_set_filler(png_ptr, 0xff, PNG_FILLER_BEFORE);
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#endif
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}
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pixelsize = sizeof(uint32);
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} else {
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pixelsize = sizeof(uint8);
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}
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row_pointer = (png_byte *)malloc(info_ptr->width * pixelsize);
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if (row_pointer == NULL) {
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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return false;
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}
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for (i = 0; i < info_ptr->height; i++) {
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png_read_row(png_ptr, row_pointer, NULL);
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dst = sprite->data + i * info_ptr->width;
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for (uint x = 0; x < info_ptr->width; x++) {
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if (mask) {
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if (row_pointer[x * sizeof(uint8)] != 0) {
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dst[x].b = 0;
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dst[x].g = 0;
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dst[x].r = 0;
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/* Alpha channel is used from the original image (to allow transparency in remap colors) */
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dst[x].m = row_pointer[x * sizeof(uint8)];
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}
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} else {
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dst[x].b = row_pointer[x * sizeof(uint32) + 0];
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dst[x].g = row_pointer[x * sizeof(uint32) + 1];
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dst[x].r = row_pointer[x * sizeof(uint32) + 2];
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dst[x].a = row_pointer[x * sizeof(uint32) + 3];
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dst[x].m = 0;
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}
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}
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}
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free(row_pointer);
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png_destroy_read_struct(&png_ptr, &info_ptr, &end_info);
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return true;
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}
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bool SpriteLoaderPNG::LoadSprite(SpriteLoader::Sprite *sprite, const char *filename, uint32 file_pos)
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{
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if (!LoadPNG(sprite, filename, file_pos, false)) return false;
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if (!LoadPNG(sprite, filename, file_pos, true)) return false;
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return true;
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}
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@ -0,0 +1,18 @@
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/* $Id$ */
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/** @file png.hpp */
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#ifndef SPRITELOADER_PNG_HPP
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#define SPRITELOADER_PNG_HPP
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#include "spriteloader.hpp"
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class SpriteLoaderPNG : public SpriteLoader {
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public:
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/**
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* Load a sprite from the disk and return a sprite struct which is the same for all loaders.
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*/
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bool LoadSprite(SpriteLoader::Sprite *sprite, const char *filename, uint32 file_pos);
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};
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#endif /* SPRITELOADER_PNG_HPP */
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