From 51e4ad8512a2b11da8737f345676b03d94e0fa2a Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Wed, 21 Dec 2005 01:45:00 +0000 Subject: [PATCH] Changed menu linking code to avoid breaking the 128 instruction limit and to highlight back-links systematically. --- webdvd.cpp | 196 +++++++++++++++++++++-------------------------------- 1 file changed, 78 insertions(+), 118 deletions(-) diff --git a/webdvd.cpp b/webdvd.cpp index e3c02e9..d0f2e05 100644 --- a/webdvd.cpp +++ b/webdvd.cpp @@ -171,7 +171,7 @@ namespace std::vector menus; std::vector titles; }; - + class webdvd_window : public Gtk::Window { public: @@ -765,9 +765,6 @@ namespace } } - void generate_menu_dispatch(std::ostream &, int indent, - int first_menu, int last_menu); - void webdvd_window::generate_dvd() { temp_file temp("webdvd-dvdauthor-"); @@ -776,10 +773,9 @@ namespace // We generate code that uses registers in the following way: // - // g0: button destination (when jumping to menu 1), then scratch + // g0: scratch // g1: current location - // g2-g11: location history (g2 = most recent) - // g12: location that last linked to a video + // 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 @@ -790,7 +786,6 @@ namespace 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; - static const int location_bias = button_mult + 1; file << "<dvdauthor>\n" @@ -805,93 +800,102 @@ namespace if (menu_num == 0) { - // This is the first (title) menu, which needs to include - // initialisation and dispatch code. - + // This is the first (title) menu, displayed when the + // disc is first played. file << " <pgc entry='title'>\n" " <pre>\n" - // Has the location been set yet? + // Initialise the current location if it is not set + // (all general registers are initially 0). " if (g1 eq 0)\n" - " {\n" - // Initialise the current location to first button on - // this menu. - " g1 = " << location_bias << ";\n" - " }\n" - " else\n" - " {\n" - // Has the user selected a link? - " if (g0 ne 0)\n" - " {\n" - // First update the history. - // Does link go to the last page in the history? - " if (((g0 ^ g2) & " << menu_mask - << ") == 0)\n" - // It does; we treat this as going back and pop the old - // location off the history stack into the current - // location. Clear the free stack slot. - " {\n" - " g1 = g2; g2 = g3; g3 = g4; g4 = g5;\n" - " g5 = g6; g6 = g7; g7 = g8; g8 = g9;\n" - " g9 = g10; g10 = g11; g11 = 0;\n" - " }\n" - " else\n" - // Link goes to some other page, so push current - // location onto the history stack and set the current - // location to be exactly the target location. - " {\n" - " g11 = g10; g10 = g9; g9 = g8; g8 = g7;\n" - " g7 = g6; g6 = g5; g5 = g4; g4 = g3;\n" - " g3 = g2; g2 = g1; g1 = g0;\n" - " }\n" - " }\n" - // Find the target page number. - " g0 = g1 & " << menu_mask << ";\n"; - // There seems to be no way to perform a computed jump, - // so we generate all possible jumps and a binary search - // to select the correct one. - generate_menu_dispatch(file, 12, - 0, contents_.menus.size() - 1); - file << - " }\n"; + " g1 = " << 1 + button_mult << ";\n"; } - else // menu_num != 0 + 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 << - // Clear link indicator and highlight the - // appropriate link/button. - " g0 = 0; s8 = g1 & " << button_mask << ";\n" + // Highlight the appropriate button. + " s8 = g1 & " << button_mask << ";\n" " </pre>\n" - " <vob file='" - << menu.vob_temp->get_name() << "'/>\n"; + " <vob file='" << menu.vob_temp->get_name() << "'/>\n"; for (std::size_t button_num = 0; button_num != menu.entries.size(); ++button_num) { - file << " <button> " - // Update current location. - " g1 = " - << location_bias + button_num * button_mult + menu_num - << ";"; + file << " <button> "; - // Jump to appropriate resource. if (menu.entries[button_num].first == dvd_contents::menu_pgc) { - file << " g0 = " - << location_bias + menu.entries[button_num].second - << "; jump menu 1;"; + int dest_menu_num = menu.entries[button_num].second; + + // 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> & + dest_menu_entries = + contents_.menus[dest_menu_num].entries; + dvd_contents::pgc_ref this_pgc( + dvd_contents::menu_pgc, menu_num); + std::size_t dest_button_num = dest_menu_entries.size(); + while (dest_button_num != 0 + && dest_menu_entries[--dest_button_num] != this_pgc) + ; + + file << "g1 = " + << (1 + dest_menu_num + + (1 + dest_button_num) * button_mult) + << "; jump menu " << 1 + dest_menu_num << ";"; } else { assert(menu.entries[button_num].first == dvd_contents::title_pgc); - file << " jump title " + + file << "g1 = " + << 1 + menu_num + (1 + button_num) * button_mult + << "; jump title " << 1 + menu.entries[button_num].second << ";"; } @@ -923,13 +927,13 @@ namespace " </menus>\n" " <titles>\n" " <pgc>\n" - // Record calling page/menu. + // Record calling location. " <pre> g12 = g1; </pre>\n" << contents_.titles[title_num].vob_list << - // If page/menu location has not been changed during the - // video, change the location to be the following - // link/button when returning to it. In any case, - // return to a page/menu. + // 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" @@ -964,50 +968,6 @@ namespace } } - void generate_menu_dispatch(std::ostream & file, int indent, - int first_menu, int last_menu) - { - if (first_menu == last_menu) - { - if (first_menu == 0) - { - // This dispatch code is generated *on* the first menu - // so don't create an infinite loop. - } - else - { - file << std::setw(indent) << "" - << "jump menu " << 1 + first_menu << ";\n"; - } - } - else // first_menu != last_menu - { - if (first_menu == 0 && last_menu == 1) - { - // dvdauthor doesn't allow empty blocks or null - // statements so when selecting between the first 2 - // menus we don't use an "else" part. We must use - // braces so that a following "else" will match the - // right "if". - file << std::setw(indent) << "" << "{\n" - << std::setw(indent) << "" << "if (g0 eq 2)\n" - << std::setw(indent + 2) << "" << "jump menu 2;\n" - << std::setw(indent) << "" << "}\n"; - } - else - { - int middle = (first_menu + last_menu) / 2; - file << std::setw(indent) << "" << "if (g0 le " << 1 + middle - << ")\n"; - generate_menu_dispatch(file, indent + 2, - first_menu, middle); - file << std::setw(indent) << "" << "else\n"; - generate_menu_dispatch(file, indent + 2, - middle + 1, last_menu); - } - } - } - const video::frame_params & lookup_frame_params(const char * str) { assert(str); -- 2.39.2