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doxygen="_cgi:http://www.nevrax.org/cgi-bin/nel-search.cgi" href="http://www.nevrax.org/cgi-bin/nel-search.cgi">Search</a> </center> +<hr><h1>edge_collide.cpp</h1><a href="edge__collide_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><pre>00001 +00007 <font class="comment">/* Copyright, 2001 Nevrax Ltd.</font> +00008 <font class="comment"> *</font> +00009 <font class="comment"> * This file is part of NEVRAX NEL.</font> +00010 <font class="comment"> * NEVRAX NEL is free software; you can redistribute it and/or modify</font> +00011 <font class="comment"> * it under the terms of the GNU General Public License as published by</font> +00012 <font class="comment"> * the Free Software Foundation; either version 2, or (at your option)</font> +00013 <font class="comment"> * any later version.</font> +00014 <font class="comment"></font> +00015 <font class="comment"> * NEVRAX NEL is distributed in the hope that it will be useful, but</font> +00016 <font class="comment"> * WITHOUT ANY WARRANTY; without even the implied warranty of</font> +00017 <font class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</font> +00018 <font class="comment"> * General Public License for more details.</font> +00019 <font class="comment"></font> +00020 <font class="comment"> * You should have received a copy of the GNU General Public License</font> +00021 <font class="comment"> * along with NEVRAX NEL; see the file COPYING. If not, write to the</font> +00022 <font class="comment"> * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,</font> +00023 <font class="comment"> * MA 02111-1307, USA.</font> +00024 <font class="comment"> */</font> +00025 +00026 <font class="preprocessor">#include "<a class="code" href="stdpacs_8h.html">stdpacs.h</a>"</font> +00027 +00028 <font class="preprocessor">#include "<a class="code" href="edge__collide_8h.html">pacs/edge_collide.h</a>"</font> +00029 +00030 <font class="keyword">using</font> <font class="keyword">namespace </font>NLMISC; +00031 <font class="keyword">using</font> <font class="keyword">namespace </font>std; +00032 +00033 +00034 +00035 <font class="keyword">namespace </font>NLPACS +00036 { +00037 +00038 +00039 <font class="keyword">static</font> <font class="keyword">const</font> <font class="keywordtype">float</font> <a class="code" href="namespaceNLPACS.html#a6">EdgeCollideEpsilon</a>= 1e-5f; +00040 +00041 +00042 <font class="comment">// ***************************************************************************</font> +<a name="l00043"></a><a class="code" href="classNLPACS_1_1CEdgeCollide.html#a0">00043</a> <font class="keywordtype">void</font> CEdgeCollide::make(<font class="keyword">const</font> CVector2f &p0, <font class="keyword">const</font> CVector2f &p1) +00044 { +00045 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>= p0; +00046 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>= p1; +00047 <font class="comment">// translation axis of the edge.</font> +00048 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m2">Dir</a>= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>-<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>; +00049 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m2">Dir</a>.normalize(); +00050 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m4">A0</a>= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m2">Dir</a>; +00051 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m5">A1</a>= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m2">Dir</a>; +00052 <font class="comment">// line equation.</font> +00053 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>.x= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m2">Dir</a>.y; +00054 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>.y= -<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m2">Dir</a>.x; +00055 <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m6">C</a>= - <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>; +00056 } +00057 +00058 +00059 <font class="comment">// ***************************************************************************</font> +<a name="l00060"></a><a class="code" href="classNLPACS_1_1CEdgeCollide.html#a1">00060</a> CRational64 CEdgeCollide::testPointMove(<font class="keyword">const</font> CVector2f &start, <font class="keyword">const</font> CVector2f &end, TPointMoveProblem &moveBug) +00061 { +00062 <font class="comment">/*</font> +00063 <font class="comment"> To have a correct test (with no float precision problem):</font> +00064 <font class="comment"> - test first if there is collision beetween the 2 edges:</font> +00065 <font class="comment"> - test if first edge collide the other line.</font> +00066 <font class="comment"> - test if second edge collide the other line.</font> +00067 <font class="comment"> - if both true, yes, there is a collision.</font> +00068 <font class="comment"> - compute time of collision.</font> +00069 <font class="comment"> */</font> +00070 +00071 +00072 <font class="comment">// *this must be a correct edge.</font> +00073 <font class="keywordflow">if</font>(<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>==<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>) +00074 { +00075 moveBug= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#s6s4">EdgeNull</a>; +00076 <font class="keywordflow">return</font> -1; +00077 } +00078 +00079 <font class="comment">// if no movement, no collision.</font> +00080 <font class="keywordflow">if</font>(start==end) +00081 <font class="keywordflow">return</font> 1; +00082 +00083 <font class="comment">// NB those edges are snapped (1/256 for edgeCollide, and 1/1024 for start/end), so no float problem here.</font> +00084 <font class="comment">// precision is 20 bits.</font> +00085 CVector2f normEdge; +00086 CVector2f normMove; +00087 CVector2f deltaEdge; +00088 CVector2f deltaMove; +00089 +00090 <font class="comment">// compute normal of the edge (not normalized, because no need, and for precision problem).</font> +00091 deltaEdge= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>-<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>; +00092 normEdge.x= -deltaEdge.y; +00093 normEdge.y= deltaEdge.x; +00094 +00095 <font class="comment">// compute normal of the movement (not normalized, because no need, and for precision problem).</font> +00096 deltaMove= end-start; +00097 normMove.x= -deltaMove.y; +00098 normMove.y= deltaMove.x; +00099 +00100 <font class="comment">// distance from points of movment against edge line. Use double, because of multiplication.</font> +00101 <font class="comment">// precision is now 43 bits.</font> +00102 <font class="keywordtype">double</font> moveD0= (double)normEdge.x*(double)(start.x-<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.x) + (double)normEdge.y*(double)(start.y-<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.y); +00103 <font class="keywordtype">double</font> moveD1= (double)normEdge.x*(double)(end.x -<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.x) + (double)normEdge.y*(double)(end.y -<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.y); +00104 +00105 <font class="comment">// distance from points of edge against movement line. Use double, because of multiplication.</font> +00106 <font class="comment">// precision is now 43 bits.</font> +00107 <font class="keywordtype">double</font> edgeD0= (double)normMove.x*(double)(<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.x-start.x) + (double)normMove.y*(double)(<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.y-start.y); +00108 <font class="keywordtype">double</font> edgeD1= (double)normMove.x*(double)(<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>.x-start.x) + (double)normMove.y*(double)(<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>.y-start.y); +00109 +00110 +00111 <font class="comment">// If both edges intersect lines (including endpoints), there is a collision, else none.</font> +00112 sint sgnMove0, sgnMove1; +00113 sgnMove0= <a class="code" href="namespaceNLMISC.html#a213">fsgn</a>(moveD0); +00114 sgnMove1= <a class="code" href="namespaceNLMISC.html#a213">fsgn</a>(moveD1); +00115 +00116 <font class="comment">// special case if the 2 edges lies on the same line.</font> +00117 <font class="keywordflow">if</font>(sgnMove0==0 && sgnMove1==0) +00118 { +00119 <font class="comment">// must test if there is a collision. if yes, problem.</font> +00120 <font class="comment">// project all the points on the line of the edge.</font> +00121 <font class="comment">// Use double because of multiplication. precision is now 43 bits.</font> +00122 <font class="keywordtype">double</font> moveA0= (double)deltaEdge.x*(double)(start.x-<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.x) + (double)deltaEdge.y*(double)(start.y-<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.y); +00123 <font class="keywordtype">double</font> moveA1= (double)deltaEdge.x*(double)(end.x -<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.x) + (double)deltaEdge.y*(double)(end.y -<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>.y); +00124 <font class="keywordtype">double</font> edgeA0= 0; +00125 <font class="keywordtype">double</font> edgeA1= (double)deltaEdge.x*(double)deltaEdge.x + (double)deltaEdge.y*(double)deltaEdge.y; +00126 +00127 <font class="comment">// Test is there is intersection (endpoints included). if yes, return -1. else return 1 (no collision at all).</font> +00128 <font class="keywordflow">if</font>(moveA1>=edgeA0 && edgeA1>=moveA0) +00129 { +00130 moveBug= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#s6s0">ParallelEdges</a>; +00131 <font class="keywordflow">return</font> -1; +00132 } +00133 <font class="keywordflow">else</font> +00134 <font class="keywordflow">return</font> 1; +00135 } +00136 +00137 <font class="comment">// if on same side of the line=> there is no collision.</font> +00138 <font class="keywordflow">if</font>( sgnMove0==sgnMove1) +00139 <font class="keywordflow">return</font> 1; +00140 +00141 <font class="comment">// test edge against move line.</font> +00142 sint sgnEdge0, sgnEdge1; +00143 sgnEdge0= <a class="code" href="namespaceNLMISC.html#a213">fsgn</a>(edgeD0); +00144 sgnEdge1= <a class="code" href="namespaceNLMISC.html#a213">fsgn</a>(edgeD1); +00145 +00146 <font class="comment">// should not have this case, because tested before with (sgnMove==0 && sgnMove1==0).</font> +00147 <a class="code" href="debug_8h.html#a6">nlassert</a>(sgnEdge0!=0 || sgnEdge1!=0); +00148 +00149 +00150 <font class="comment">// if on same side of the line, no collision against this edge.</font> +00151 <font class="keywordflow">if</font>( sgnEdge0==sgnEdge1 ) +00152 <font class="keywordflow">return</font> 1; +00153 +00154 <font class="comment">// Here the edges intersect, but ensure that there is no limit problem.</font> +00155 <font class="keywordflow">if</font>(sgnEdge0==0 || sgnEdge1==0) +00156 { +00157 moveBug= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#s6s3">TraverseEndPoint</a>; +00158 <font class="keywordflow">return</font> -1; +00159 } +00160 <font class="keywordflow">else</font> <font class="keywordflow">if</font>(sgnMove1==0) +00161 { +00162 moveBug= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#s6s2">StopOnEdge</a>; +00163 <font class="keywordflow">return</font> -1; +00164 } +00165 <font class="keywordflow">else</font> <font class="keywordflow">if</font>(sgnMove0==0) +00166 { +00167 <font class="comment">// this should not arrive.</font> +00168 moveBug= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#s6s1">StartOnEdge</a>; +00169 <font class="keywordflow">return</font> -1; +00170 } +00171 +00172 +00173 <font class="comment">// Here, there is a normal collision, just compute it.</font> +00174 <font class="comment">// Because of Division, there is a precision lost in double. So compute a CRational64.</font> +00175 <font class="comment">// First, compute numerator and denominator in the highest precision. this is 1024*1024 because of prec multiplication.</font> +00176 <font class="keywordtype">double</font> numerator= (0-moveD0)*1024*1024; +00177 <font class="keywordtype">double</font> denominator= (moveD1-moveD0)*1024*1024; +00178 sint64 numeratorInt= (sint64)numerator; +00179 sint64 denominatorInt= (sint64)denominator; +00180 <font class="comment">/*</font> +00181 <font class="comment"> nlassert(numerator == numeratorInt);</font> +00182 <font class="comment"> nlassert(denominator == denominatorInt);</font> +00183 <font class="comment">*/</font> +00184 <font class="keywordflow">if</font> (numerator != numeratorInt) +00185 <a class="code" href="debug_8h.html#a2">nlwarning</a>(<font class="stringliteral">"numerator(%f) != numeratorInt(%"</font>NL_I64<font class="stringliteral">"d)"</font>, numerator, numeratorInt); +00186 <font class="keywordflow">if</font> (denominator != denominatorInt) +00187 <a class="code" href="debug_8h.html#a2">nlwarning</a>(<font class="stringliteral">"denominator(%f) != denominatorInt(%"</font>NL_I64<font class="stringliteral">"d)"</font>, denominator, denominatorInt); +00188 +00189 <font class="keywordflow">return</font> CRational64(numeratorInt, denominatorInt); +00190 } +00191 +00192 +00193 <font class="comment">// ***************************************************************************</font> +00194 <font class="keyword">static</font> <font class="keyword">inline</font> <font class="keywordtype">float</font> <a class="code" href="namespaceNLPACS.html#a26">testCirclePoint</a>(<font class="keyword">const</font> CVector2f &start, <font class="keyword">const</font> CVector2f &delta, <font class="keywordtype">float</font> radius, <font class="keyword">const</font> CVector2f &point) +00195 { +00196 <font class="comment">// factors of the qaudratic: at² + bt + c=0</font> +00197 <font class="keywordtype">float</font> a,b,c; +00198 <font class="keywordtype">float</font> dta; +00199 <font class="keywordtype">float</font> r0, r1, <a class="code" href="driver__opengl__extension__def_8h.html#a400">res</a>; +00200 CVector2f relC, relV; +00201 +00202 <font class="comment">// compute quadratic..</font> +00203 relC= start-point; +00204 relV= delta; +00205 a= relV.x*relV.x + relV.y*relV.y; <font class="comment">// a>=0.</font> +00206 b= 2* (relC.x*relV.x + relC.y*relV.y); +00207 c= relC.x*relC.x + relC.y*relC.y - radius*radius; +00208 <font class="comment">// compute delta of the quadratic.</font> +00209 dta= b*b - 4*a*c; <font class="comment">// b²-4ac</font> +00210 <font class="keywordflow">if</font>(dta>=0) +00211 { +00212 dta= (float)sqrt(dta); +00213 r0= (-b -dta)/(2*a); +00214 r1= (-b +dta)/(2*a); +00215 <font class="comment">// since a>0, r0<=r1.</font> +00216 <font class="keywordflow">if</font>(r0>r1) +00217 swap(r0,r1); +00218 <font class="comment">// if r1 is negative, then we are out and go away from this point. OK.</font> +00219 <font class="keywordflow">if</font>(r1<=0) +00220 { +00221 <a class="code" href="driver__opengl__extension__def_8h.html#a400">res</a>= 1; +00222 } +00223 <font class="comment">// if r0 is positive, then we may collide this point.</font> +00224 <font class="keywordflow">else</font> <font class="keywordflow">if</font>(r0>=0) +00225 { +00226 <a class="code" href="driver__opengl__extension__def_8h.html#a400">res</a>= <a class="code" href="bit__set_8cpp.html#a0">min</a>(1.f, r0); +00227 } +00228 <font class="keywordflow">else</font> <font class="comment">// r0<0 && r1>0. the point is already in the sphere!!</font> +00229 { +00230 <font class="comment">//nlinfo("COL: Point problem: %.2f, %.2f. b=%.2f", r0, r1, b);</font> +00231 <font class="comment">// we allow the movement only if we go away from this point.</font> +00232 <font class="comment">// this is true if the derivative at t=0 is >=0 (because a>0).</font> +00233 <font class="keywordflow">if</font>(b>0) +00234 <a class="code" href="driver__opengl__extension__def_8h.html#a400">res</a>= 1; <font class="comment">// go out.</font> +00235 <font class="keywordflow">else</font> +00236 <a class="code" href="driver__opengl__extension__def_8h.html#a400">res</a>=0; +00237 } +00238 } +00239 <font class="keywordflow">else</font> +00240 { +00241 <font class="comment">// never hit this point along this movement.</font> +00242 <a class="code" href="driver__opengl__extension__def_8h.html#a400">res</a>= 1; +00243 } +00244 +00245 <font class="keywordflow">return</font> <a class="code" href="driver__opengl__extension__def_8h.html#a400">res</a>; +00246 } +00247 +00248 +00249 <font class="comment">// ***************************************************************************</font> +<a name="l00250"></a><a class="code" href="classNLPACS_1_1CEdgeCollide.html#a2">00250</a> <font class="keywordtype">float</font> CEdgeCollide::testCircleMove(<font class="keyword">const</font> CVector2f &start, <font class="keyword">const</font> CVector2f &delta, <font class="keywordtype">float</font> radius, CVector2f &normal) +00251 { +00252 <font class="comment">// distance from point to line.</font> +00253 <font class="keywordtype">double</font> dist= start*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a> + <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m6">C</a>; +00254 <font class="comment">// projection of speed on normal.</font> +00255 <font class="keywordtype">double</font> speed= delta*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>; +00256 +00257 <font class="comment">// test if the movement is against the line or not.</font> +00258 <font class="keywordtype">bool</font> sensPos= dist>0; +00259 <font class="keywordtype">bool</font> sensSpeed= speed>0; +00260 +00261 <font class="comment">// Does the point intersect the line?</font> +00262 dist= fabs(dist) - radius; +00263 speed= fabs(speed); +00264 <font class="keywordflow">if</font>( dist > speed ) +00265 <font class="keywordflow">return</font> 1; +00266 +00267 <font class="comment">// if not already in collision with the line, test when it collides.</font> +00268 <font class="comment">// ===============================</font> +00269 <font class="keywordflow">if</font>(dist>=0) +00270 { +00271 <font class="comment">// if signs are equals, same side of the line, so we allow the circle to leave the line.</font> +00272 <font class="keywordflow">if</font>(sensPos==sensSpeed ) +00273 <font class="keywordflow">return</font> 1; +00274 +00275 <font class="comment">// collide the line, at what time.</font> +00276 <font class="keywordtype">double</font> <a class="code" href="driver__opengl__extension__def_8h.html#a384">t</a>= dist/speed; +00277 +00278 +00279 <font class="comment">// compute the collision position of the Circle on the edge.</font> +00280 <font class="comment">// this gives the center of the sphere at the collision point.</font> +00281 CVector2d proj= CVector2d(start) + CVector2d(delta)*<a class="code" href="driver__opengl__extension__def_8h.html#a384">t</a>; +00282 <font class="comment">// must add radius vector.</font> +00283 proj+= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a> * (sensSpeed?radius:-radius); +00284 <font class="comment">// compute projection on edge.</font> +00285 <font class="keywordtype">double</font> aProj= proj*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m2">Dir</a>; +00286 +00287 <font class="comment">// if on the interval of the edge.</font> +00288 <font class="keywordflow">if</font>( aProj>=<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m4">A0</a> && aProj<=<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m5">A1</a>) +00289 { +00290 <font class="comment">// collision occurs on interior of the edge. the normal to return is +- Norm.</font> +00291 <font class="keywordflow">if</font>(sensPos) <font class="comment">// if algebric distance of start position was >0.</font> +00292 normal= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>; +00293 <font class="keywordflow">else</font> +00294 normal= -<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>; +00295 +00296 <font class="comment">// return time of collision.</font> +00297 <font class="keywordflow">return</font> (float)<a class="code" href="driver__opengl__extension__def_8h.html#a384">t</a>; +00298 } +00299 } +00300 <font class="comment">// else, must test if circle collide segment at t=0. if yes, return 0.</font> +00301 <font class="comment">// ===============================</font> +00302 <font class="keywordflow">else</font> +00303 { +00304 <font class="comment">// There is just need to test if projection of circle's center onto the line hit the segment.</font> +00305 <font class="comment">// This is not a good test to know if a circle intersect a segment, but other cases are</font> +00306 <font class="comment">// managed with test of endPoints of the segment after.</font> +00307 <font class="keywordtype">float</font> aProj= start*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m2">Dir</a>; +00308 +00309 <font class="comment">// if on the interval of the edge.</font> +00310 <font class="keywordflow">if</font>( aProj>=<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m4">A0</a> && aProj<=<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m5">A1</a>) +00311 { +00312 <font class="comment">// if signs are equals, same side of the line, so we allow the circle to leave the edge.</font> +00313 <font class="comment">/* Special case: do not allow to leave the edge if we are too much in the edge.</font> +00314 <font class="comment"> It is important for CGlobalRetriever::testCollisionWithCollisionChains() because of the</font> +00315 <font class="comment"> "SURFACEMOVE NOT DETECTED" Problem.</font> +00316 <font class="comment"> Suppose we can walk on this chain SA/SB (separate Surface A/SurfaceB). Suppose we are near this edge, </font> +00317 <font class="comment"> and on Surface SA, and suppose there is an other chain SB/SC the circle collide with. If we </font> +00318 <font class="comment"> return 1 (no collision), SB/SC won't be detected (because only SA/?? chains will be tested) and </font> +00319 <font class="comment"> so the cylinder will penetrate SB/SC...</font> +00320 <font class="comment"> This case arise at best if chains SA/SB and chain SB/SC do an angle of 45°</font> +00321 <font class="comment"></font> +00322 <font class="comment"> \todo yoyo: this is a Hack.</font> +00323 <font class="comment"> */</font> +00324 <font class="keywordflow">if</font>(sensPos==sensSpeed && (-dist)<0.5*radius) +00325 { +00326 <font class="keywordflow">return</font> 1; +00327 } +00328 <font class="keywordflow">else</font> +00329 { +00330 <font class="comment">// hit the interior of the edge, and sensPos!=sensSpeed. So must stop now!!</font> +00331 <font class="comment">// collision occurs on interior of the edge. the normal to return is +- Norm.</font> +00332 <font class="keywordflow">if</font>(sensPos) <font class="comment">// if algebric distance of start position was >0.</font> +00333 normal= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>; +00334 <font class="keywordflow">else</font> +00335 normal= -<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>; +00336 +00337 <font class="keywordflow">return</font> 0; +00338 } +00339 } +00340 } +00341 +00342 <font class="comment">// In this case, the Circle do not hit the edge on the interior, but may hit on borders.</font> +00343 <font class="comment">// ===============================</font> +00344 <font class="comment">// Then, we must compute collision sphere-points.</font> +00345 <font class="keywordtype">float</font> tmin, ttmp; +00346 <font class="comment">// first point.</font> +00347 tmin= <a class="code" href="namespaceNLPACS.html#a26">testCirclePoint</a>(start, delta, radius, <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>); +00348 <font class="comment">// second point.</font> +00349 ttmp= <a class="code" href="namespaceNLPACS.html#a26">testCirclePoint</a>(start, delta, radius, <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>); +00350 tmin= <a class="code" href="bit__set_8cpp.html#a0">min</a>(tmin, ttmp); +00351 +00352 <font class="comment">// if collision occurs, compute normal of collision.</font> +00353 <font class="keywordflow">if</font>(tmin<1) +00354 { +00355 <font class="comment">// to which point we collide?</font> +00356 CVector2f colPoint= tmin==ttmp? <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a> : <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>; +00357 <font class="comment">// compute position of the entity at collision.</font> +00358 CVector2f colPos= start + delta*tmin; +00359 +00360 <font class="comment">// and so we have this normal (the perpendicular of the tangent at this point).</font> +00361 normal= colPos - colPoint; +00362 normal.normalize(); +00363 } +00364 +00365 <font class="keywordflow">return</font> tmin; +00366 } +00367 +00368 +00369 +00370 <font class="comment">// ***************************************************************************</font> +<a name="l00371"></a><a class="code" href="classNLPACS_1_1CEdgeCollide.html#c0">00371</a> <font class="keywordtype">bool</font> CEdgeCollide::testEdgeMove(<font class="keyword">const</font> CVector2f &q0, <font class="keyword">const</font> CVector2f &q1, <font class="keyword">const</font> CVector2f &delta, <font class="keywordtype">float</font> &tMin, <font class="keywordtype">float</font> &tMax, <font class="keywordtype">bool</font> &normalOnBox) +00372 { +00373 <font class="keywordtype">double</font> a,b,cv,cc, d,e,f; +00374 CVector2d tmp; +00375 +00376 <font class="comment">// compute D1 line equation of q0q1. bx - ay + c(t)=0, where c is function of time [0,1].</font> +00377 <font class="comment">// ===========================</font> +00378 tmp= q1 - q0; <font class="comment">// NB: along time, the direction doesn't change.</font> +00379 <font class="comment">// Divide by norm()², so that a projection on this edge is true if the proj is in interval [0,1].</font> +00380 tmp/= tmp.sqrnorm(); +00381 a= tmp.x; +00382 b= tmp.y; +00383 <font class="comment">// c= - q0(t)*CVector2d(b,-a). but since q0(t) is a function of time t (q0+delta*t), compute cv, and cc.</font> +00384 <font class="comment">// so c= cv*t + cc.</font> +00385 cv= - CVector2d(b,-a)*delta; +00386 cc= - CVector2d(b,-a)*q0; +00387 +00388 <font class="comment">// compute D2 line equation of P0P1. ex - dy + f=0.</font> +00389 <font class="comment">// ===========================</font> +00390 tmp= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a> - <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>; +00391 <font class="comment">// Divide by norm()², so that a projection on this edge is true if the proj is in interval [0,1].</font> +00392 tmp/= tmp.sqrnorm(); +00393 d= tmp.x; +00394 e= tmp.y; +00395 f= - CVector2d(e,-d)*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>; +00396 +00397 +00398 <font class="comment">// Solve system.</font> +00399 <font class="comment">// ===========================</font> +00400 <font class="comment">/*</font> +00401 <font class="comment"> Compute the intersection I of 2 lines across time.</font> +00402 <font class="comment"> We have the system:</font> +00403 <font class="comment"> bx - ay + c(t)=0</font> +00404 <font class="comment"> ex - dy + f=0</font> +00405 <font class="comment"></font> +00406 <font class="comment"> which solve for:</font> +00407 <font class="comment"> det= ae-bd (0 <=> // lines)</font> +00408 <font class="comment"> x(t)= (d*c(t) - fa) / det</font> +00409 <font class="comment"> y(t)= (e*c(t) - fb) / det</font> +00410 <font class="comment"> */</font> +00411 +00412 <font class="comment">// determinant of matrix2x2.</font> +00413 <font class="keywordtype">double</font> det= a*e - b*d; +00414 <font class="comment">// if to near of 0. (take delta for reference of test).</font> +00415 <font class="keywordflow">if</font>(det==0 || fabs(det)<delta.norm()*<a class="code" href="namespaceNLPACS.html#a6">EdgeCollideEpsilon</a>) +00416 <font class="keywordflow">return</font> <font class="keyword">false</font>; +00417 +00418 <font class="comment">// intersection I(t)= pInt + vInt*t.</font> +00419 CVector2d pInt, vInt; +00420 pInt.x= ( d*cc - f*a ) / det; +00421 pInt.y= ( e*cc - f*b ) / det; +00422 vInt.x= ( d*cv ) / det; +00423 vInt.y= ( e*cv ) / det; +00424 +00425 +00426 <font class="comment">// Project Intersection.</font> +00427 <font class="comment">// ===========================</font> +00428 <font class="comment">/*</font> +00429 <font class="comment"> Now, we project x,y onto each line D1 and D2, which gives u(t) and v(t), each one giving the parameter of </font> +00430 <font class="comment"> the parametric line function. When it is in [0,1], we are on the edge.</font> +00431 <font class="comment"></font> +00432 <font class="comment"> u(t)= (I(t)-q0(t)) * CVector2d(a,b) = uc + uv*t</font> +00433 <font class="comment"> v(t)= (I(t)-P0) * CVector2d(d,e) = vc + vv*t</font> +00434 <font class="comment"> */</font> +00435 <font class="keywordtype">double</font> uc, uv; +00436 <font class="keywordtype">double</font> vc, vv; +00437 <font class="comment">// NB: q0(t)= q0+delta*t</font> +00438 uc= (pInt-q0) * CVector2d(a,b); +00439 uv= (vInt-delta) * CVector2d(a,b); +00440 vc= (pInt-<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>) * CVector2d(d,e); +00441 vv= (vInt) * CVector2d(d,e); +00442 +00443 +00444 <font class="comment">// Compute intervals.</font> +00445 <font class="comment">// ===========================</font> +00446 <font class="comment">/*</font> +00447 <font class="comment"> Now, for each edge, compute time interval where parameter is in [0,1]. If intervals overlap, there is a collision.</font> +00448 <font class="comment"> */</font> +00449 <font class="keywordtype">double</font> tu0, tu1, tv0, tv1; +00450 <font class="comment">// infinite interval.</font> +00451 <font class="keywordtype">bool</font> allU=<font class="keyword">false</font>, allV=<font class="keyword">false</font>; +00452 +00453 <font class="comment">// compute time interval for u(t).</font> +00454 <font class="keywordflow">if</font>(uv==0 || fabs(uv)<<a class="code" href="namespaceNLPACS.html#a6">EdgeCollideEpsilon</a>) +00455 { +00456 <font class="comment">// The intersection does not move along D1. Always projected on u(t)=uc. so if in [0,1], OK, else never collide.</font> +00457 <font class="keywordflow">if</font>(uc<0 || uc>1) +00458 <font class="keywordflow">return</font> <font class="keyword">false</font>; +00459 <font class="comment">// else suppose "always valid".</font> +00460 tu0 =tu1= 0; +00461 allU= <font class="keyword">true</font>; +00462 } +00463 <font class="keywordflow">else</font> +00464 { +00465 tu0= (0-uc)/uv; <font class="comment">// t for u(t)=0</font> +00466 tu1= (1-uc)/uv; <font class="comment">// t for u(t)=1</font> +00467 } +00468 +00469 <font class="comment">// compute time interval for v(t).</font> +00470 <font class="keywordflow">if</font>(vv==0 || fabs(vv)<<a class="code" href="namespaceNLPACS.html#a6">EdgeCollideEpsilon</a>) +00471 { +00472 <font class="comment">// The intersection does not move along D2. Always projected on v(t)=vc. so if in [0,1], OK, else never collide.</font> +00473 <font class="keywordflow">if</font>(vc<0 || vc>1) +00474 <font class="keywordflow">return</font> <font class="keyword">false</font>; +00475 <font class="comment">// else suppose "always valid".</font> +00476 tv0 =tv1= 0; +00477 allV= <font class="keyword">true</font>; +00478 } +00479 <font class="keywordflow">else</font> +00480 { +00481 tv0= (0-vc)/vv; <font class="comment">// t for v(t)=0</font> +00482 tv1= (1-vc)/vv; <font class="comment">// t for v(t)=1</font> +00483 } +00484 +00485 +00486 <font class="comment">// clip intervals.</font> +00487 <font class="comment">// ===========================</font> +00488 <font class="comment">// order time interval.</font> +00489 <font class="keywordflow">if</font>(tu0>tu1) +00490 swap(tu0, tu1); <font class="comment">// now, [tu0, tu1] represent the time interval where line D2 hit the edge D1.</font> +00491 <font class="keywordflow">if</font>(tv0>tv1) +00492 swap(tv0, tv1); <font class="comment">// now, [tv0, tv1] represent the time interval where line D1 hit the edge D2.</font> +00493 +00494 normalOnBox= <font class="keyword">false</font>; +00495 <font class="keywordflow">if</font>(!allU && !allV) +00496 { +00497 <font class="comment">// if intervals do not overlap, no collision.</font> +00498 <font class="keywordflow">if</font>(tu0>tv1 || tv0>tu1) +00499 <font class="keywordflow">return</font> <font class="keyword">false</font>; +00500 <font class="keywordflow">else</font> +00501 { +00502 <font class="comment">// compute intersection of intervals.</font> +00503 tMin= (float)max(tu0, tv0); +00504 tMax= (float)<a class="code" href="bit__set_8cpp.html#a0">min</a>(tu1, tv1); +00505 <font class="comment">// if collision of edgeCollide against the bbox.</font> +00506 <font class="keywordflow">if</font>(tv0>tu0) +00507 normalOnBox= <font class="keyword">true</font>; +00508 } +00509 } +00510 <font class="keywordflow">else</font> <font class="keywordflow">if</font>(allU) +00511 { +00512 <font class="comment">// intersection of Infinite and V interval.</font> +00513 tMin= (float)tv0; +00514 tMax= (float)tv1; +00515 <font class="comment">// if collision of edgeCollide against the bbox.</font> +00516 normalOnBox= <font class="keyword">true</font>; +00517 } +00518 <font class="keywordflow">else</font> <font class="keywordflow">if</font>(allV) +00519 { +00520 <font class="comment">// intersection of Infinite and U interval.</font> +00521 tMin= (float)tu0; +00522 tMax= (float)tu1; +00523 } +00524 <font class="keywordflow">else</font> +00525 { +00526 <font class="comment">// if allU && allV, this means delta is near 0, and so there is always collision.</font> +00527 tMin= -1000; +00528 tMax= 1000; +00529 } +00530 +00531 <font class="keywordflow">return</font> <font class="keyword">true</font>; +00532 } +00533 +00534 +00535 <font class="comment">// ***************************************************************************</font> +<a name="l00536"></a><a class="code" href="classNLPACS_1_1CEdgeCollide.html#a3">00536</a> <font class="keywordtype">float</font> CEdgeCollide::testBBoxMove(<font class="keyword">const</font> CVector2f &start, <font class="keyword">const</font> CVector2f &delta, <font class="keyword">const</font> CVector2f bbox[4], CVector2f &normal) +00537 { +00538 <font class="comment">// distance from center to line.</font> +00539 <font class="keywordtype">float</font> dist= start*<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a> + <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m6">C</a>; +00540 +00541 <font class="comment">// test if the movement is against the line or not.</font> +00542 <font class="keywordtype">bool</font> sensPos= dist>0; +00543 <font class="comment">// if signs are equals, same side of the line, so we allow the circle to leave the line.</font> +00544 <font class="comment">/*if(sensPos==sensSpeed)</font> +00545 <font class="comment"> return 1;*/</font> +00546 +00547 +00548 <font class="comment">// Else, do 4 test edge/edge, and return Tmin.</font> +00549 <font class="keywordtype">float</font> tMin, tMax; +00550 <font class="keywordtype">bool</font> edgeCollided= <font class="keyword">false</font>; +00551 <font class="keywordtype">bool</font> normalOnBox= <font class="keyword">false</font>; +00552 CVector2f boxNormal; +00553 <font class="keywordflow">for</font>(sint i=0;i<4;i++) +00554 { +00555 <font class="keywordtype">float</font> t0, t1; +00556 <font class="keywordtype">bool</font> nob; +00557 CVector2f a= bbox[i]; +00558 CVector2f b= bbox[(i+1)&3]; +00559 +00560 <font class="comment">// test move against this edge.</font> +00561 <font class="keywordflow">if</font>(<a class="code" href="classNLPACS_1_1CEdgeCollide.html#c0">testEdgeMove</a>(a, b, delta, t0, t1, nob)) +00562 { +00563 <font class="keywordflow">if</font>(edgeCollided) +00564 { +00565 tMin= <a class="code" href="bit__set_8cpp.html#a0">min</a>(t0, tMin); +00566 tMax= max(t1, tMax); +00567 } +00568 <font class="keywordflow">else</font> +00569 { +00570 edgeCollided= <font class="keyword">true</font>; +00571 tMin= t0; +00572 tMax= t1; +00573 } +00574 +00575 <font class="comment">// get normal of box against we collide.</font> +00576 <font class="keywordflow">if</font>(tMin==t0) +00577 { +00578 normalOnBox= nob; +00579 <font class="keywordflow">if</font>(nob) +00580 { +00581 CVector2f dab; +00582 <font class="comment">// bbox must be CCW.</font> +00583 dab= b-a; +00584 <font class="comment">// the normal is computed so that the vector goes In the bbox.</font> +00585 boxNormal.x= -dab.y; +00586 boxNormal.y= dab.x; +00587 } +00588 } +00589 } +00590 } +00591 +00592 <font class="comment">// if collision occurs,and int the [0,1] interval...</font> +00593 <font class="keywordflow">if</font>(edgeCollided && tMin<1 && tMax>0) +00594 { +00595 <font class="comment">// compute normal of collision.</font> +00596 <font class="keywordflow">if</font>(normalOnBox) +00597 { +00598 <font class="comment">// assume collsion is an endpoint of the edge against the bbox.</font> +00599 normal= boxNormal; +00600 } +00601 <font class="keywordflow">else</font> +00602 { +00603 <font class="comment">// assume collision occurs on interior of the edge. the normal to return is +- Norm.</font> +00604 <font class="keywordflow">if</font>(sensPos) <font class="comment">// if algebric distance of start position was >0.</font> +00605 normal= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>; +00606 <font class="keywordflow">else</font> +00607 normal= -<a class="code" href="classNLPACS_1_1CEdgeCollide.html#m3">Norm</a>; +00608 } +00609 +00610 <font class="comment">// compute time of collison.</font> +00611 <font class="keywordflow">if</font>(tMin>0) +00612 <font class="comment">// return time of collision.</font> +00613 <font class="keywordflow">return</font> tMin; +00614 <font class="keywordflow">else</font> +00615 { +00616 <font class="comment">// The bbox is inside the edge, at t==0. test if it goes out or not.</font> +00617 <font class="comment">// accept only if we are much near the exit than the enter.</font> +00618 <font class="comment">/* NB: 0.2 is an empirical value "which works well". Normally, 1 is the good value, but because of the</font> +00619 <font class="comment"> "SURFACEMOVE NOT DETECTED" Problem (see testCircleMove()), we must be more restrictive.</font> +00620 <font class="comment"> */</font> +00621 <font class="keywordflow">if</font>( tMax<0.2*(-tMin) ) +00622 <font class="keywordflow">return</font> 1; +00623 <font class="keywordflow">else</font> +00624 <font class="keywordflow">return</font> 0; +00625 } +00626 } +00627 <font class="keywordflow">else</font> +00628 <font class="keywordflow">return</font> 1; +00629 +00630 } +00631 +00632 +00633 <font class="comment">// ***************************************************************************</font> +<a name="l00634"></a><a class="code" href="classNLPACS_1_1CEdgeCollide.html#a4">00634</a> <font class="keywordtype">bool</font> CEdgeCollide::testBBoxCollide(<font class="keyword">const</font> CVector2f bbox[4]) +00635 { +00636 <font class="comment">// clip the edge against the edge of the bbox.</font> +00637 CVector2f p0= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m0">P0</a>, p1= <a class="code" href="classNLPACS_1_1CEdgeCollide.html#m1">P1</a>; +00638 +00639 <font class="keywordflow">for</font>(sint i=0; i<4; i++) +00640 { +00641 CVector2f a= bbox[i]; +00642 CVector2f b= bbox[(i+1)&3]; +00643 CVector2f delta= b-a, norm; +00644 <font class="comment">// sign is important. bbox is CCW. normal goes OUT the bbox.</font> +00645 norm.x= delta.y; +00646 norm.y= -delta.x; +00647 +00648 <font class="keywordtype">float</font> d0= (p0-a)*norm; +00649 <font class="keywordtype">float</font> d1= (p1-a)*norm; +00650 +00651 <font class="comment">// if boths points are out this plane, no collision.</font> +00652 <font class="keywordflow">if</font>( d0>0 && d1>0) +00653 <font class="keywordflow">return</font> <font class="keyword">false</font>; +00654 <font class="comment">// if difference, must clip.</font> +00655 <font class="keywordflow">if</font>( d0>0 || d1>0) +00656 { +00657 CVector2f intersect= p0 + (p1-p0)* ((0-d0)/(d1-d0)); +00658 <font class="keywordflow">if</font>(d1>0) +00659 p1= intersect; +00660 <font class="keywordflow">else</font> +00661 p0= intersect; +00662 } +00663 } +00664 +00665 <font class="comment">// if a segment is still in the bbox, collision occurs.</font> +00666 <font class="keywordflow">return</font> <font class="keyword">true</font>; +00667 } +00668 +00669 +00670 +00671 } <font class="comment">// NLPACS</font> +</pre></div> + +<!-- footer --> +<BR><FONT Size=+5> </FONT> +</TD> +<TD WIDTH=15><IMG SRC=http://www.nevrax.org/inc/img/pixel.gif WIDTH=15 HEIGHT=15 BORDER=0 ALT=""></TD> +</TR> +</TABLE> +</BODY> +</HTML> |