https://www.jpct.net/wiki/index.php?title=Nullpointer_during_rendering_and/or_collision_detection&feed=atom&action=historyNullpointer during rendering and/or collision detection - Revision history2024-03-28T13:43:05ZRevision history for this page on the wikiMediaWiki 1.23.15https://www.jpct.net/wiki/index.php?title=Nullpointer_during_rendering_and/or_collision_detection&diff=520&oldid=prevAdmin: /* The problem */2013-05-16T14:16:09Z<p><span dir="auto"><span class="autocomment">The problem</span></span></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 14:16, 16 May 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;"></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>From time to time, your application exits with a null pointer exception in either the rendering thread or while calling one of the collision detection 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>From time to time, your application exits with a null pointer exception in either the rendering thread or while calling one of the collision detection methods.</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;">Other symptoms might be flickering or object distortions in some frames.</ins></div></td></tr>
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</table>Adminhttps://www.jpct.net/wiki/index.php?title=Nullpointer_during_rendering_and/or_collision_detection&diff=519&oldid=prevAdmin: /* Solution */2013-04-26T08:08:10Z<p><span dir="auto"><span class="autocomment">Solution</span></span></p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 08:08, 26 April 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>Don't do this. Let the event listener method set a flag, evaluate this in the render thread and do the work there.</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>Don't do this. Let the event listener method set a flag, evaluate this in the render thread and do the work there.</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;">Another option is to synchronize rendering and event processing, but i don't encourage you to do this. It's error-prone and doesn't have a real advantage.</ins></div></td></tr>
</table>Adminhttps://www.jpct.net/wiki/index.php?title=Nullpointer_during_rendering_and/or_collision_detection&diff=518&oldid=prevAdmin: Created page with '=The problem= From time to time, your application exits with a null pointer exception in either the rendering thread or while calling one of the collision detection methods. =P…'2013-04-26T08:05:49Z<p>Created page with '=The problem= From time to time, your application exits with a null pointer exception in either the rendering thread or while calling one of the collision detection methods. =P…'</p>
<p><b>New page</b></p><div>=The problem=<br />
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From time to time, your application exits with a null pointer exception in either the rendering thread or while calling one of the collision detection methods.<br />
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=Possible reason=<br />
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jPCT (as well as jPCT-AE) isn't thread safe. That means that at runtime, no other thread is allowed to work on jPCT related object than the rendering thread itself. If you are familiar with the way in which Swing works: It's very similar to that.<br />
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If you encounter this problem, the most likely reason is that you are doing work in multiple threads which should be done in the render thread only. This often happens if one works on jPCT related instances in some event listener method.<br />
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=Solution=<br />
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Don't do this. Let the event listener method set a flag, evaluate this in the render thread and do the work there.</div>Admin