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wolf3d-browser/js/raycaster.js
Brian Harris e0b653888d Wolfenstein 3D browser version 
This is the code for the browser version of Wolfenstein 3D which is
playable on http://www.wolfenstein.com/game_NA.php
2013-05-16 11:34:31 -05:00

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/*
* ===========================================================================
*
* Wolf3D Browser Version GPL Source Code
* Copyright (C) 2012 id Software LLC, a ZeniMax Media company.
*
* This file is part of the Wolf3D Browser Version GPL Source Code ("Wolf3D Browser Source Code").
*
* Wolf3D Browser Source Code 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.
*
* Wolf3D Browser Source Code 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 version 2
* along with Wolf3D Browser Source Code. If not, see <http://www.gnu.org/licenses/>.
*
* If you have questions concerning this license, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
*
* ===========================================================================
*/
Wolf.setConsts({
UPPERZCOORD : 0.6,
LOWERZCOORD : -0.6,
// marks
TRACE_MARK_MAP : 1, // marks traced area in 'AM_AutoMap.vis' array
// obstacle levels
TRACE_SIGHT : 2, // player sight
TRACE_SIGHT_AI : 4, // enemy sight
TRACE_BULLET : 8, // bullet
TRACE_OBJECT : 16, // object
TRACE_HIT_VERT : 32, // vertical wall was hit
TRACE_HIT_DOOR : 64, // door was hit
TRACE_HIT_PWALL : 128 // pushwall was hit
});
Wolf.Raycaster = (function() {
var x_tile_step = [ 1, -1, -1, 1 ],
y_tile_step = [ 1, 1, -1, -1 ];
var TILESHIFT = Wolf.TILESHIFT,
TRACE_HIT_VERT = Wolf.TRACE_HIT_VERT,
TILEGLOBAL = Wolf.TILEGLOBAL,
WALL_TILE = Wolf.WALL_TILE,
DOOR_TILE = Wolf.DOOR_TILE,
TILE2POS = Wolf.TILE2POS,
POS2TILE = Wolf.POS2TILE,
FINE2RAD = Wolf.FINE2RAD,
TRACE_HIT_DOOR = Wolf.TRACE_HIT_DOOR,
PUSHWALL_TILE = Wolf.PUSHWALL_TILE,
TRACE_HIT_PWALL = Wolf.TRACE_HIT_PWALL,
DOOR_FULLOPEN = Wolf.DOOR_FULLOPEN,
XnextTable = Wolf.Math.XnextTable,
YnextTable = Wolf.Math.YnextTable,
getQuadrant = Wolf.Math.getQuadrant,
TanTable = Wolf.Math.TanTable;
function traceCheck(tileMap, doorMap, visibleTiles, x, y, frac, dfrac, vert, flip, tracePoint) {
var door;
if (tileMap[x][y] & WALL_TILE) {
if (vert) {
tracePoint.x = (x << TILESHIFT) + (flip ? TILEGLOBAL : 0);
tracePoint.y = (y << TILESHIFT) + frac;
tracePoint.flags |= TRACE_HIT_VERT;
} else {
tracePoint.x = (x << TILESHIFT) + frac;
tracePoint.y = (y << TILESHIFT) + (flip ? TILEGLOBAL : 0);
tracePoint.flags &= ~TRACE_HIT_VERT;
}
tracePoint.tileX = x;
tracePoint.tileY = y;
tracePoint.frac = frac / TILEGLOBAL;
return true; // wall, stop tracing
}
if (visibleTiles) {
visibleTiles[x][y] = true; // this tile is visible
}
if (tileMap[x][y] & DOOR_TILE && doorMap[x][y].action != Wolf.dr_open) {
door = doorMap[x][y];
frac += dfrac >> 1;
if (POS2TILE(frac)) {
return false;
}
if (vert) {
if (door.action != Wolf.dr_closed && (frac >> 10) > DOOR_FULLOPEN - Wolf.Doors.opened(door)) {
return false; // opened enough
}
tracePoint.x = TILE2POS(x);
tracePoint.y = (y << TILESHIFT) + frac;
tracePoint.flags |= TRACE_HIT_VERT;
tracePoint.frac = frac / TILEGLOBAL;
} else {
if (door.action != Wolf.dr_closed && (frac >> 10) < Wolf.Doors.opened(door)) {
return false; // opened enough
}
tracePoint.y = TILE2POS(y);
tracePoint.x = (x << TILESHIFT) + frac;
tracePoint.flags &= ~TRACE_HIT_VERT;
tracePoint.frac = 1 - frac / TILEGLOBAL;
}
tracePoint.flags |= TRACE_HIT_DOOR;
tracePoint.tileX = x;
tracePoint.tileY = y;
tracePoint.frac += Wolf.Doors.opened(door) / DOOR_FULLOPEN;
return true; // closed door, stop tracing
}
if (tileMap[x][y] & PUSHWALL_TILE) {
var pwall = Wolf.PushWall.get(),
offset = pwall.pointsMoved / 128;
frac += dfrac * offset;
if (POS2TILE(frac)) {
return false;
}
if (vert) {
tracePoint.x = (x << TILESHIFT) + (flip ? TILEGLOBAL : 0) + offset * TILEGLOBAL * (flip ? -1 : 1);
tracePoint.y = (y << TILESHIFT) + frac;
tracePoint.flags |= TRACE_HIT_VERT;
} else {
tracePoint.x = (x << TILESHIFT) + frac;
tracePoint.y = (y << TILESHIFT) + (flip ? TILEGLOBAL : 0) + offset * TILEGLOBAL * (flip ? -1 : 1);
tracePoint.flags &= ~TRACE_HIT_VERT;
}
tracePoint.flags |= TRACE_HIT_PWALL;
tracePoint.tileX = x;
tracePoint.tileY = y;
tracePoint.frac = frac / TILEGLOBAL;
return true;
}
return false; // no intersection, go on!
}
function trace(level, visibleTiles, tracePoint) {
var xtilestep, ytilestep,
xstep, ystep,
xtile, ytile,
xintercept, yintercept,
YmapPos, XmapPos,
tileMap = level.tileMap,
doorMap = level.state.doorMap,
q;
// Setup for ray casting
q = getQuadrant(FINE2RAD(tracePoint.angle));
xtilestep = x_tile_step[q];
ytilestep = y_tile_step[q];
xtile = POS2TILE(tracePoint.x) + xtilestep;
ytile = POS2TILE(tracePoint.y) + ytilestep;
xstep = ytilestep * XnextTable[tracePoint.angle];
ystep = xtilestep * YnextTable[tracePoint.angle];
xintercept = (((((ytilestep == -1 ? ytile+1 : ytile) << TILESHIFT) - tracePoint.y)
/ TanTable[tracePoint.angle])>>0) + tracePoint.x;
yintercept = (((((xtilestep == -1 ? xtile+1 : xtile) << TILESHIFT) - tracePoint.x)
* TanTable[tracePoint.angle])>>0) + tracePoint.y;
YmapPos = yintercept >> TILESHIFT; // toXray
XmapPos = xintercept >> TILESHIFT; // toYray
if (visibleTiles) {
// this tile is visible
visibleTiles[POS2TILE(tracePoint.x)][POS2TILE(tracePoint.y)] = true;
}
var traceCount = 0;
// Start of ray-casting
while (1) {
traceCount++;
// Vertical loop // an analogue for X-Ray
while (!(ytilestep == -1 && YmapPos <= ytile) && !(ytilestep == 1 && YmapPos >= ytile)) {
if (xtile < 0 || xtile >= 64 || YmapPos < 0 || YmapPos >= 64) {
tracePoint.oob = true;
return;
}
if (traceCheck(tileMap, doorMap, visibleTiles, xtile, YmapPos, yintercept % TILEGLOBAL, ystep, true, (xtilestep == -1), tracePoint)) {
if (xstep < 0) {
tracePoint.frac = 1 - tracePoint.frac;
}
return;
}
// prepare for next step
xtile += xtilestep;
yintercept += ystep;
YmapPos = yintercept >> TILESHIFT;
}
// Horizontal loop // an analogue for Y-Ray
while (!(xtilestep == -1 && XmapPos <= xtile) && !(xtilestep == 1 && XmapPos >= xtile)) {
if (ytile < 0 || ytile >= 64 || XmapPos < 0 || XmapPos >= 64) {
tracePoint.oob = true;
return;
}
if (traceCheck(tileMap, doorMap, visibleTiles, XmapPos, ytile, xintercept % TILEGLOBAL, xstep, false, (ytilestep == -1), tracePoint)) {
if (ystep > 0) {
tracePoint.frac = 1 - tracePoint.frac;
}
return;
}
// prepare for next step
ytile += ytilestep;
xintercept += xstep;
XmapPos = xintercept >> TILESHIFT;
}
if (traceCount > 1000) {
return;
}
} // end of while( 1 )
}
function traceRays(viewport, level) {
var n, i, j,
tileMap = level.tileMap,
tracePoint,
visibleTiles = [],
numRays = Wolf.XRES / Wolf.SLICE_WIDTH,
tracers = [];
for (i=0;i<64;i++) {
visibleTiles[i] = [];
for (j=0;j<64;j++) {
visibleTiles[i][j] = 0;
}
}
// Ray casting
for (n = 0 ; n < numRays ; ++n) {
tracePoint = {
x : viewport.x,
y : viewport.y,
angle : Wolf.Math.normalizeAngle(viewport.angle - Wolf.Math.ColumnAngle[n * Wolf.SLICE_WIDTH]),
flags : Wolf.TRACE_SIGHT | Wolf.TRACE_MARK_MAP,
oob : false
};
trace(level, visibleTiles, tracePoint);
tracers[n] = tracePoint;
// Ugly hack to get rid of "blank slice" glitch due to out-of-bounds raycasting.
// We simply re-use the previous slice if possible.
if (tracePoint.oob) {
if (n > 0 && !tracers[n-1].oob) {
tracers[n] = tracers[n-1];
}
}
}
return {
visibleTiles : visibleTiles,
tracers : tracers
};
}
return {
traceRays : traceRays,
trace : trace
};
})();
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