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author | Max Horn | 2006-02-11 22:45:04 +0000 |
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committer | Max Horn | 2006-02-11 22:45:04 +0000 |
commit | 26ee630756ebdd7c96bccede0881a8c8b98e8f2b (patch) | |
tree | 26e378d5cf990a2b81c2c96e9e683a7f333b62e8 /engines/sword2/scroll.cpp | |
parent | 2a9a0d4211b1ea5723f1409d91cb95de8984429e (diff) | |
download | scummvm-rg350-26ee630756ebdd7c96bccede0881a8c8b98e8f2b.tar.gz scummvm-rg350-26ee630756ebdd7c96bccede0881a8c8b98e8f2b.tar.bz2 scummvm-rg350-26ee630756ebdd7c96bccede0881a8c8b98e8f2b.zip |
Moved engines to the new engines/ directory
svn-id: r20582
Diffstat (limited to 'engines/sword2/scroll.cpp')
-rw-r--r-- | engines/sword2/scroll.cpp | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/engines/sword2/scroll.cpp b/engines/sword2/scroll.cpp new file mode 100644 index 0000000000..3d0a263bc6 --- /dev/null +++ b/engines/sword2/scroll.cpp @@ -0,0 +1,151 @@ +/* Copyright (C) 1994-1998 Revolution Software Ltd. + * Copyright (C) 2003-2006 The ScummVM project + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * $URL$ + * $Id$ + */ + +#include "common/stdafx.h" +#include "sword2/sword2.h" +#include "sword2/defs.h" +#include "sword2/logic.h" + +namespace Sword2 { + +// Max no of pixel allowed to scroll per cycle +#define MAX_SCROLL_DISTANCE 8 + +/** + * Sets the scroll target position for the end of the game cycle. The driver + * will then automatically scroll as many times as it can to reach this + * position in the allotted time. + */ + +void Screen::setScrollTarget(int16 sx, int16 sy) { + _scrollXTarget = sx; + _scrollYTarget = sy; +} + +/** + * If the room is larger than the physical screen, this function is called + * every game cycle to update the scroll offsets. + */ + +void Screen::setScrolling() { + // Normally we aim to get George's feet at (320,250) from top left + // of screen window + // feet_x = 128 + 320 + // feet_y = 128 + 250 + + // Set scroll offsets according to the player's coords + + // If the scroll offsets are being forced in script, ensure that they + // are neither too far to the right nor too far down. + uint32 scrollX = _vm->_logic->readVar(SCROLL_X); + uint32 scrollY = _vm->_logic->readVar(SCROLL_Y); + + if (scrollX || scrollY) { + _thisScreen.scroll_offset_x = MIN((uint16)scrollX, _thisScreen.max_scroll_offset_x); + _thisScreen.scroll_offset_y = MIN((uint16)scrollY, _thisScreen.max_scroll_offset_y); + return; + } + + // George's offset from the centre - the desired position for him + + int16 offset_x = _thisScreen.player_feet_x - _thisScreen.feet_x; + int16 offset_y = _thisScreen.player_feet_y - _thisScreen.feet_y; + + // Prevent scrolling too far left/right/up/down + + if (offset_x < 0) + offset_x = 0; + else if (offset_x > _thisScreen.max_scroll_offset_x) + offset_x = _thisScreen.max_scroll_offset_x; + + if (offset_y < 0) + offset_y = 0; + else if (offset_y > _thisScreen.max_scroll_offset_y) + offset_y = _thisScreen.max_scroll_offset_y; + + // First time on this screen - need absolute scroll immediately! + + if (_thisScreen.scroll_flag == 2) { + debug(5, "init scroll"); + _thisScreen.scroll_offset_x = offset_x; + _thisScreen.scroll_offset_y = offset_y; + _thisScreen.scroll_flag = 1; + return; + } + + // Catch up with required scroll offsets - speed depending on distance + // to catch up (dx and dy) and _scrollFraction used, but limit to + // certain number of pixels per cycle (MAX_SCROLL_DISTANCE) + + int16 dx = _thisScreen.scroll_offset_x - offset_x; + int16 dy = _thisScreen.scroll_offset_y - offset_y; + + uint16 scroll_distance_x; // how much we want to scroll + uint16 scroll_distance_y; + + if (dx < 0) { + // Current scroll_offset_x is less than the required value + + // NB. I'm adding 1 to the result of dx / SCROLL_FRACTION, + // because it would otherwise not scroll at all when + // dx < SCROLL_FRACTION + + // => inc by (fraction of the differnce) NB. dx is -ve, so we + // subtract dx / SCROLL_FRACTION + + scroll_distance_x = 1 - dx / _scrollFraction; + + if (scroll_distance_x > MAX_SCROLL_DISTANCE) + scroll_distance_x = MAX_SCROLL_DISTANCE; + + _thisScreen.scroll_offset_x += scroll_distance_x; + } else if (dx > 0) { + // Current scroll_offset_x is greater than + // the required value + + // => dec by (fraction of the differnce) + + scroll_distance_x = 1 + dx / _scrollFraction; + + if (scroll_distance_x > MAX_SCROLL_DISTANCE) + scroll_distance_x = MAX_SCROLL_DISTANCE; + + _thisScreen.scroll_offset_x -= scroll_distance_x; + } + + if (dy < 0) { + scroll_distance_y = 1 - dy / _scrollFraction; + + if (scroll_distance_y > MAX_SCROLL_DISTANCE) + scroll_distance_y = MAX_SCROLL_DISTANCE; + + _thisScreen.scroll_offset_y += scroll_distance_y; + } else if (dy > 0) { + scroll_distance_y = 1 + dy / _scrollFraction; + + if (scroll_distance_y > MAX_SCROLL_DISTANCE) + scroll_distance_y = MAX_SCROLL_DISTANCE; + + _thisScreen.scroll_offset_y -= scroll_distance_y; + } +} + +} // End of namespace Sword2 |