https://www.jpct.net/wiki/index.php?title=Collision_detection&feed=atom&action=historyCollision detection - Revision history2024-03-28T16:39:09ZRevision history for this page on the wikiMediaWiki 1.23.15https://www.jpct.net/wiki/index.php?title=Collision_detection&diff=405&oldid=prevAdmin at 22:31, 1 February 20132013-02-01T22:31:19Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 22:31, 1 February 2013</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>=== A simple example ===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>=== A simple example ===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>This is a (pretty hacky) example code that uses the software renderer to render some primitives plus a kind of player (a simple cube) that you can move around with the arrow keys. Watch out for the borders of the plane, nothing prevents you from falling into the abyss.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>This is a (pretty hacky) example code that uses the software renderer <ins class="diffchange diffchange-inline">of desktop jPCT </ins>to render some primitives plus a kind of player (a simple cube) that you can move around with the arrow keys. Watch out for the borders of the plane, nothing prevents you from falling into the abyss.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This code also shows the use of multi-threading for the software renderer.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This code also shows the use of multi-threading for the software renderer.</div></td></tr>
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</table>Adminhttps://www.jpct.net/wiki/index.php?title=Collision_detection&diff=249&oldid=prevAdmin at 18:51, 27 October 20102010-10-27T18:51:19Z<p></p>
<a href="https://www.jpct.net/wiki/index.php?title=Collision_detection&diff=249&oldid=139">Show changes</a>Adminhttps://www.jpct.net/wiki/index.php?title=Collision_detection&diff=139&oldid=prevAdmin at 20:23, 26 June 20092009-06-26T20:23:26Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 20:23, 26 June 2009</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* Collision detection fails: Try to adjust the [http://www.jpct.net/doc/com/threed/jpct/Config.html#collideOffset collideOffset]. If your scene uses larger polygons than i had in mind when setting this value to a default of 40, collision detection will fails on such polygons. Keep in mind that lower values are usually faster, so don't increase it to 1000000something with no need.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* Collision detection fails: Try to adjust the [http://www.jpct.net/doc/com/threed/jpct/Config.html#collideOffset collideOffset]. If your scene uses larger polygons than i had in mind when setting this value to a default of 40, collision detection will fails on such polygons. Keep in mind that lower values are usually faster, so don't increase it to 1000000something with no need.</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* Source and/or target collisions are not working: Make sure that the collision mode has been set correctly ([http://www.jpct.net/doc/com/threed/jpct/Object3D.html#COLLISION_CHECK_OTHERS]/[http://www.jpct.net/doc/com/threed/jpct/Object3D.html#COLLISION_CHECK_SELF]). If an object should be both, don't call the [http://www.jpct.net/doc/com/threed/jpct/Object3D.html#setCollisionMode(int) setCollisionMode-method] twice, but combine the constants with |.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* Collision detection works somehow, but the object in question doesn't move smooth. It looks like as if it collides with something but nothing can be seen: If an object is both, target and source of a collision, it may collide with itself. Adjust the collision mode before checking for collisions of that object and reset it afterwards. Another problem can be caused by the collision [http://www.jpct.net/doc/com/threed/jpct/Config.html#collideEllipsoidThreshold threshold] being set to a pretty low value. Play around with this value.</ins></div></td></tr>
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</table>Adminhttps://www.jpct.net/wiki/index.php?title=Collision_detection&diff=138&oldid=prevAdmin at 20:18, 26 June 20092009-06-26T20:18:13Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 20:18, 26 June 2009</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Second, it's a swept algorithm, i.e. all collisions along the translation will be detected and the translation will be adjusted while this happens. Compared to the spherical approach, the corrected translation isn't really capable of resolving an existing intersection, but it's very good in avoiding it. With this collision detection method, it's pretty easy to let your character climb stairs, rocks etc...</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Second, it's a swept algorithm, i.e. all collisions along the translation will be detected and the translation will be adjusted while this happens. Compared to the spherical approach, the corrected translation isn't really capable of resolving an existing intersection, but it's very good in avoiding it. With this collision detection method, it's pretty easy to let your character climb stairs, rocks etc...</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>One drawback: This is the slowest approach of all three.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>One drawback: This is the slowest approach of all three.</div></td></tr>
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<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==== Trouble shooting ====</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Some common problems explained in short:</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* Collision detection fails: Try to adjust the [http://www.jpct.net/doc/com/threed/jpct/Config.html#collideOffset collideOffset]. If your scene uses larger polygons than i had in mind when setting this value to a default of 40, collision detection will fails on such polygons. Keep in mind that lower values are usually faster, so don't increase it to 1000000something with no need.</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
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</table>Adminhttps://www.jpct.net/wiki/index.php?title=Collision_detection&diff=115&oldid=prevAdmin at 21:10, 6 June 20092009-06-06T21:10:20Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 21:10, 6 June 2009</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Methods using this approach usually are named checkXXXCollisionSpherical(...). Here, a sphere is queried if some other object intersects with it. If this is the case, the translation vector will be adjusted, so that the collision won't happen (if you actually apply the corrected vector, of course you don't have to). This isn't a swept approach, i.e. for a given translation vector, two tests happen: One at the start of the translation and one at the end. If the translation is too large for and/or the sphere's radius too small to make these tests cover the whole translation, any collision in between won't be recognized.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Methods using this approach usually are named checkXXXCollisionSpherical(...). Here, a sphere is queried if some other object intersects with it. If this is the case, the translation vector will be adjusted, so that the collision won't happen (if you actually apply the corrected vector, of course you don't have to). This isn't a swept approach, i.e. for a given translation vector, two tests happen: One at the start of the translation and one at the end. If the translation is too large for and/or the sphere's radius too small to make these tests cover the whole translation, any collision in between won't be recognized.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This method is great for resolving collisions, i.e. if some object already is in a collision, this method can help to pull it out of it. Personally, i'm using this method to compensate for accuracy problems of the other methods, i.e. if they cause an intersection where they should actually avoid it, i'm using method to resolve it.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This method is great for resolving collisions, i.e. if some object already is in a collision, this method can help to pull it out of it. Personally, i'm using this method to compensate for accuracy problems of the other methods, i.e. if they cause an intersection where they should actually avoid it, i'm using method to resolve it.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>I don't <del class="diffchange diffchange-inline">recomment </del>to use this method for a FPS game or similar.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>I don't <ins class="diffchange diffchange-inline">recommend </ins>to use this method for a FPS game or similar.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
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</table>Adminhttps://www.jpct.net/wiki/index.php?title=Collision_detection&diff=104&oldid=prevAdmin at 20:42, 6 June 20092009-06-06T20:42:06Z<p></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">← Older revision</td>
<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 20:42, 6 June 2009</td>
</tr><tr><td colspan="2" class="diff-lineno">Line 24:</td>
<td colspan="2" class="diff-lineno">Line 24:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Second, it's a swept algorithm, i.e. all collisions along the translation will be detected and the translation will be adjusted while this happens. Compared to the spherical approach, the corrected translation isn't really capable of resolving an existing intersection, but it's very good in avoiding it. With this collision detection method, it's pretty easy to let your character climb stairs, rocks etc...</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Second, it's a swept algorithm, i.e. all collisions along the translation will be detected and the translation will be adjusted while this happens. Compared to the spherical approach, the corrected translation isn't really capable of resolving an existing intersection, but it's very good in avoiding it. With this collision detection method, it's pretty easy to let your character climb stairs, rocks etc...</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>One drawback: This is the slowest approach of all three.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>One drawback: This is the slowest approach of all three.</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Other methods ====</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Other methods ====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>There are no other methods build into jPCT, but you can always use a [[ Physics ]] engine of your choice instead of the build in methods.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>There are no other methods build into jPCT, but you can always use a [[ Physics ]] engine of your choice instead of the build in methods.</div></td></tr>
</table>Adminhttps://www.jpct.net/wiki/index.php?title=Collision_detection&diff=103&oldid=prevAdmin: /* Ellipsoid-Polyong */2009-06-06T20:41:38Z<p><span dir="auto"><span class="autocomment">Ellipsoid-Polyong</span></span></p>
<table class='diff diff-contentalign-left'>
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<col class='diff-marker' />
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<td colspan='2' style="background-color: white; color:black; text-align: center;">← Older revision</td>
<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 20:41, 6 June 2009</td>
</tr><tr><td colspan="2" class="diff-lineno">Line 19:</td>
<td colspan="2" class="diff-lineno">Line 19:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>==== Ellipsoid-<del class="diffchange diffchange-inline">Polyong </del>====</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>==== Ellipsoid-<ins class="diffchange diffchange-inline">Polygon </ins>====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This is the most powerful collision detection approach in jPCT. Methods using it are usually named checkXXXCollisionEllipsoid(...). It's similar to the spherical approach, but it has some advantages. At first, it's using an ellipsoid, not a sphere. That means, that it's easier to approximate human-like objects for example with it than it would be with sphere. However, you can always use a sphere as your ellipsoid.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>This is the most powerful collision detection approach in jPCT. Methods using it are usually named checkXXXCollisionEllipsoid(...). It's similar to the spherical approach, but it has some advantages. At first, it's using an ellipsoid, not a sphere. That means, that it's easier to approximate human-like objects for example with it than it would be with sphere. However, you can always use a sphere as your ellipsoid.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Second, it's a swept algorithm, i.e. all collisions along the translation will be detected and the translation will be adjusted while this happens. Compared to the spherical approach, the corrected translation isn't really capable of resolving an existing intersection, but it's very good in avoiding it. With this collision detection method, it's pretty easy to let your character climb stairs, rocks etc...</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Second, it's a swept algorithm, i.e. all collisions along the translation will be detected and the translation will be adjusted while this happens. Compared to the spherical approach, the corrected translation isn't really capable of resolving an existing intersection, but it's very good in avoiding it. With this collision detection method, it's pretty easy to let your character climb stairs, rocks etc...</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>One drawback: This is the slowest approach of all three.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>One drawback: This is the slowest approach of all three.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Other methods ====</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==== Other methods ====</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>There are no other methods build into jPCT, but you can always use a [[ Physics ]] engine of your choice instead of the build in methods.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>There are no other methods build into jPCT, but you can always use a [[ Physics ]] engine of your choice instead of the build in methods.</div></td></tr>
</table>Adminhttps://www.jpct.net/wiki/index.php?title=Collision_detection&diff=102&oldid=prevAdmin: Created page with '=== Collision detection === jPCT has basically three different methods for collision detection. Depending on the application and its requirements, one may be more suitable than ...'2009-06-06T20:41:23Z<p>Created page with '=== Collision detection === jPCT has basically three different methods for collision detection. Depending on the application and its requirements, one may be more suitable than ...'</p>
<p><b>New page</b></p><div>=== Collision detection ===<br />
<br />
jPCT has basically three different methods for collision detection. Depending on the application and its requirements, one may be more suitable than the other. This section provides a brief overview.<br />
To use any kind of collision detection, the collision mode has to be set correctly. An Object3D can either receive collisions from other objects/entities, cause collisions or both (or nothing).<br />
Collision detection on complex models largely benefits from using octrees.<br />
<br />
<br />
==== Ray-Polygon ====<br />
<br />
Methods using this approach usually are named checkXXXCollision(...). The idea of this collision test is simple: A ray will be casted into the scene and the closest polygon in its way will block it. There another method that works very similar to this in World: calcMinDistance. Its basically the same stuff, but it returns the actual distance to the hit polygon which the other checkXXXCollision-methods won't.<br />
This method is fine for detecting bullet hits, for placing a car's wheel on the ground (the car-example is using it for example) and similar.<br />
<br />
<br />
==== Sphere-Polygon ====<br />
<br />
Methods using this approach usually are named checkXXXCollisionSpherical(...). Here, a sphere is queried if some other object intersects with it. If this is the case, the translation vector will be adjusted, so that the collision won't happen (if you actually apply the corrected vector, of course you don't have to). This isn't a swept approach, i.e. for a given translation vector, two tests happen: One at the start of the translation and one at the end. If the translation is too large for and/or the sphere's radius too small to make these tests cover the whole translation, any collision in between won't be recognized.<br />
This method is great for resolving collisions, i.e. if some object already is in a collision, this method can help to pull it out of it. Personally, i'm using this method to compensate for accuracy problems of the other methods, i.e. if they cause an intersection where they should actually avoid it, i'm using method to resolve it.<br />
I don't recomment to use this method for a FPS game or similar.<br />
<br />
<br />
==== Ellipsoid-Polyong ====<br />
<br />
This is the most powerful collision detection approach in jPCT. Methods using it are usually named checkXXXCollisionEllipsoid(...). It's similar to the spherical approach, but it has some advantages. At first, it's using an ellipsoid, not a sphere. That means, that it's easier to approximate human-like objects for example with it than it would be with sphere. However, you can always use a sphere as your ellipsoid.<br />
Second, it's a swept algorithm, i.e. all collisions along the translation will be detected and the translation will be adjusted while this happens. Compared to the spherical approach, the corrected translation isn't really capable of resolving an existing intersection, but it's very good in avoiding it. With this collision detection method, it's pretty easy to let your character climb stairs, rocks etc...<br />
One drawback: This is the slowest approach of all three.<br />
<br />
<br />
==== Other methods ====<br />
<br />
There are no other methods build into jPCT, but you can always use a [[ Physics ]] engine of your choice instead of the build in methods.</div>Admin