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/* $Id$ */

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/** @file png.cpp Reading sprites from png files. */

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#ifdef WITH_PNG

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#include "../stdafx.h"

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#include "../gfx_func.h"

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#include "../fileio_func.h"

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#include "../debug.h"

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#include "../core/alloc_func.hpp"

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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, volatile 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) {

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			png_set_palette_to_rgb(png_ptr);

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			color_type = PNG_COLOR_TYPE_RGB;

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		}

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		if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {

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			png_set_gray_to_rgb(png_ptr);

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			color_type = PNG_COLOR_TYPE_RGB;

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		}

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		if (color_type == PNG_COLOR_TYPE_RGB) {

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			png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);

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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 *)MallocT<byte>(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].r = 0;

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					dst[x].g = 0;

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					dst[x].b = 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].r = 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].b = 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, uint8 file_slot, size_t file_pos, SpriteType sprite_type)

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{

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	const char *filename = FioGetFilename(file_slot);

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	if (!LoadPNG(sprite, filename, (uint32)file_pos, false)) return false;

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	if (!LoadPNG(sprite, filename, (uint32)file_pos, true)) return false;

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	return true;

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}

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#endif /* WITH_PNG */