+// Copyright 2005-6 Ben Hutchings <ben@decadentplace.org.uk>.
+// See the file "COPYING" for licence details.
+
+#include <fstream>
+#include <stdexcept>
+
+#include <glibmm/spawn.h>
+
+#include "dvd.hpp"
+#include "generate_dvd.hpp"
+
+dvd_contents::menu::menu()
+ : vob_temp(new temp_file("webdvd-vob-"))
+{
+ vob_temp->close();
+}
+
+void generate_dvd(const dvd_contents & contents,
+ const std::string & output_dir)
+{
+ temp_file temp("webdvd-dvdauthor-");
+ temp.close();
+ std::ofstream file(temp.get_name().c_str());
+
+ // We generate code that uses registers in the following way:
+ //
+ // g0: scratch
+ // g1: current location
+ // g12: location that last jumped to a video
+ //
+ // All locations are divided into two bitfields: the least
+ // significant 10 bits are a page/menu number and the most
+ // significant 6 bits are a link/button number, and numbering
+ // starts at 1, not 0. This is done for compatibility with
+ // the encoding of the s8 (button) register.
+ //
+ static const int button_mult = dvd::reg_s8_button_mult;
+ static const int menu_mask = button_mult - 1;
+ static const int button_mask = (1 << dvd::reg_bits) - button_mult;
+
+ file <<
+ "<dvdauthor>\n"
+ " <vmgm>\n"
+ " <menus>\n";
+
+ for (unsigned menu_num = 0;
+ menu_num != contents.menus.size();
+ ++menu_num)
+ {
+ const dvd_contents::menu & menu = contents.menus[menu_num];
+
+ if (menu_num == 0)
+ {
+ // This is the first (title) menu, displayed when the
+ // disc is first played.
+ file <<
+ " <pgc entry='title'>\n"
+ " <pre>\n"
+ // Initialise the current location if it is not set
+ // (all general registers are initially 0).
+ " if (g1 eq 0)\n"
+ " g1 = " << 1 + button_mult << ";\n";
+ }
+ else
+ {
+ file <<
+ " <pgc>\n"
+ " <pre>\n";
+ }
+
+ // When a title finishes or the user presses the menu
+ // button, this always jumps to the titleset's root menu.
+ // We want to return the user to the last menu they used.
+ // So we arrange for each titleset's root menu to return
+ // to the vmgm title menu and then dispatch from there to
+ // whatever the correct menu is. We determine the correct
+ // menu by looking at the menu part of g1.
+
+ file << " g0 = g1 & " << menu_mask << ";\n";
+
+ // There is a limit of 128 VM instructions in each PGC.
+ // Therefore in each menu's <pre> section we generate
+ // jumps to menus with numbers greater by 512, 256, 128,
+ // ..., 1 where (a) such a menu exists, (b) this menu
+ // number is divisible by twice that increment and (c) the
+ // correct menu is that or a later menu. Thus each menu
+ // has at most 10 such conditional jumps and is reachable
+ // by at most 10 jumps from the title menu. This chain of
+ // jumps might take too long on some players; this has yet
+ // to be investigated.
+
+ for (std::size_t menu_incr = (menu_mask + 1) / 2;
+ menu_incr != 0;
+ menu_incr /= 2)
+ {
+ if (menu_num + menu_incr < contents.menus.size()
+ && (menu_num & (menu_incr * 2 - 1)) == 0)
+ {
+ file <<
+ " if (g0 ge " << 1 + menu_num + menu_incr
+ << ")\n"
+ " jump menu " << 1 + menu_num + menu_incr
+ << ";\n";
+ }
+ }
+
+ file <<
+ // Highlight the appropriate button.
+ " s8 = g1 & " << button_mask << ";\n"
+ " </pre>\n"
+ " <vob file='" << menu.vob_temp->get_name() << "'/>\n";
+
+ for (unsigned button_num = 0;
+ button_num != menu.entries.size();
+ ++button_num)
+ {
+ const dvd_contents::pgc_ref & target =
+ menu.entries[button_num];
+
+ file << " <button> ";
+
+ if (target.type == dvd_contents::menu_pgc)
+ {
+ unsigned target_button_num;
+
+ if (target.sub_index)
+ {
+ target_button_num = target.sub_index;
+ }
+ else
+ {
+ // Look for a button on the new menu that links
+ // back to this one. If there is one, set that to
+ // be the highlighted button; otherwise, use the
+ // first button.
+ const std::vector<dvd_contents::pgc_ref> &
+ target_menu_entries =
+ contents.menus[target.index].entries;
+ dvd_contents::pgc_ref this_pgc(dvd_contents::menu_pgc,
+ menu_num);
+ target_button_num = target_menu_entries.size();
+ while (target_button_num != 0
+ && (target_menu_entries[--target_button_num]
+ != this_pgc))
+ ;
+ target_button_num += 1;
+ }
+
+ file << "g1 = "
+ << (1 + target.index
+ + target_button_num * button_mult)
+ << "; jump menu " << 1 + target.index << ";";
+ }
+ else
+ {
+ assert(target.type == dvd_contents::title_pgc);
+
+ file << "g1 = "
+ << 1 + menu_num + (1 + button_num) * button_mult
+ << "; jump title "
+ << 1 + target.index;
+ if (target.sub_index)
+ file << " chapter " << target.sub_index;
+ file << ";";
+ }
+
+ file << " </button>\n";
+ }
+
+ file << " </pgc>\n";
+ }
+
+ file <<
+ " </menus>\n"
+ " </vmgm>\n";
+
+ // Generate a titleset for each title. This appears to make
+ // jumping to titles a whole lot simpler (but limits us to 99
+ // titles).
+ for (unsigned title_num = 0;
+ title_num != contents.titles.size();
+ ++title_num)
+ {
+ file <<
+ " <titleset>\n"
+ // Generate a dummy menu so that the menu button on the
+ // remote control will work.
+ " <menus>\n"
+ " <pgc entry='root'>\n"
+ " <pre> jump vmgm menu; </pre>\n"
+ " </pgc>\n"
+ " </menus>\n"
+ " <titles>\n"
+ " <pgc>\n"
+ // Record calling location.
+ " <pre> g12 = g1; </pre>\n"
+ << contents.titles[title_num].vob_list <<
+ // If the menu location has not been changed during
+ // the title, set the location to be the following
+ // button in the menu. In any case, return to some
+ // menu.
+ " <post> if (g1 eq g12) g1 = g1 + " << button_mult
+ << "; call menu; </post>\n"
+ " </pgc>\n"
+ " </titles>\n"
+ " </titleset>\n";
+ }
+
+ file <<
+ "</dvdauthor>\n";
+
+ file.close();
+
+ {
+ const char * argv[] = {
+ "dvdauthor",
+ "-o", output_dir.c_str(),
+ "-x", temp.get_name().c_str(),
+ 0
+ };
+ int command_result;
+ Glib::spawn_sync(".",
+ Glib::ArrayHandle<std::string>(
+ argv, sizeof(argv)/sizeof(argv[0]),
+ Glib::OWNERSHIP_NONE),
+ Glib::SPAWN_SEARCH_PATH
+ | Glib::SPAWN_STDOUT_TO_DEV_NULL,
+ SigC::Slot0<void>(),
+ 0, 0,
+ &command_result);
+ if (command_result != 0)
+ throw std::runtime_error("dvdauthor failed");
+ }
+}