Frictional Game Wiki

<h1>HPL3 Reference Guide</h1> <div class="level1"> <p> This is a guide for anyone coming from HPL2 to help describe common actions done in Amnesia modding. In this guide, I will show you how to accomplish how to achieve the same effect (or at least as similar as you can get) in HPL3. </p> </div> <h2>Key Pick-Up</h2> <div class="level2"> <p> In HPL3, keys, puzzle objects, or any other item that can be picked up is all grouped together under the term "Tool". When an entity with the type "Tool" is placed in the level, the player can pick it up just by interacting with it - no scripting required. </p> <p> [Image Placeholder - Player Picks Up Chip] </p> <p> Of course, there are times when you want to know if the player has picked up a tool. In this case, you can add a function to the tool's "OnPlayerPickup" callback. This callback gets fired when the player (appropriately enough) picks up the tool. </p> <p> [Image Placeholder - Editor Screenshot of Callback] </p> <p> [Image Placeholder - Codelite Screenshot of Callback] </p> </div> <h2>Forces and Impulses</h2> <div class="level2"> </div> <h3>Force vs Impulse</h3> <div class="level3"> <p> Force changes the speed of an object over time. It is used for things that have a cumulative effect, like gravity or acceleration. </p> <p> Impulse changes the speed of an object instantaneously. It is used for things like jumps and explosions. </p> </div> <h3>Simple Way</h3> <div class="level3"> <p> There are four convenience functions that will quickly allow you to add force or impulse to an entity: </p> <ul> <li class="level1"> <a href="/doku.php?id=hpl3:game:scripting:function_reference:hps_api#entity_addforce" class="wikilink1" title="hpl3:game:scripting:function_reference:hps_api">Entity_AddForce</a></li> <li class="level1"> <a href="/doku.php?id=hpl3:game:scripting:function_reference:hps_api#entity_addforcefromentity" class="wikilink1" title="hpl3:game:scripting:function_reference:hps_api">Entity_AddForceFromEntity</a></li> <li class="level1"> <a href="/doku.php?id=hpl3:game:scripting:function_reference:hps_api#entity_addimpulse" class="wikilink1" title="hpl3:game:scripting:function_reference:hps_api">Entity_AddImpulse</a></li> <li class="level1"> <a href="/doku.php?id=hpl3:game:scripting:function_reference:hps_api#entity_addimpulsefromentity" class="wikilink1" title="hpl3:game:scripting:function_reference:hps_api">Entity_AddImpulseFromEntity</a></li> </ul> <p> The names of the functions offer a straightforward explanation of what the functions do. The Entity_AddForce and Entity_AddImpulse functions enable you to apply force/impulse on an entity with a direction and magnitude specified by a given cVector3f parameter. The Entity_AddForceFromEntity and Entity_AddImpulseFromEntity functions enable you to add force/impulse on an entity originating from the position of another entity with a magnitude specified by a given float parameter. All four functions support wildsards (*) for affecting multiple entities with a single function call. </p> <p> Usage example: </p> <pre class="code =c++">Entity_AddForce<span class="br0">(</span> "entity_name"<span class="sy0">,</span> <span class="co1">// The name of the entity</span> cVector3f<span class="br0">(</span><span class="nu16">0.0</span><span class="sy0">,</span> <span class="nu16">5.0</span><span class="sy0">,</span> <span class="nu16">0.0</span><span class="br0">)</span><span class="sy0">,</span> <span class="co1">// The direction and magnitude of the force (in this case, straight upward)</span> <span class="kw2">false</span><span class="sy0">,</span> <span class="co1">// If true, the force is applied relative to the entity's local rotation</span> <span class="kw2">false</span><span class="br0">)</span><span class="sy0">;</span> <span class="co1">// If true, the force is applied to the entity's main physics body only </span> </pre><p> </p> </div> <h3>Advanced Way</h3> <div class="level3"> <p> Physics in HPL3 is a bit more complicated than in HPL2. Every physics-enabled entity in HPL3 has attached to it an <a href="/doku.php?id=hpl3:community:scripting:classes:iphysicsbody" class="wikilink1" title="hpl3:community:scripting:classes:iphysicsbody">iPhysicsBody</a> which can be retrieved in script. (In order for an entity to be physics-enabled, it must have body objects attached to it in the ModelViewer.) </p> <p> To get the iPhysicsBody object of an entity, you do the following: </p> <pre class="code =c++"><span class="co1">// Retrieve the entity object from the map</span> iLuxEntity @entity <span class="sy0">=</span> Map_GetEntity<span class="br0">(</span>"entity_name"<span class="br0">)</span><span class="sy0">;</span>   <span class="co1">// Retrieve the iPhysicsBody from the entity object</span> iPhysicsBody @body <span class="sy0">=</span> entity.<span class="me1">GetMainBody</span><span class="br0">(</span><span class="br0">)</span><span class="sy0">;</span> </pre><p> </p> <p> From here, the functions related to force and impulse are: </p> <ul> <li class="level1"> <b>AddForce</b> (const cVector3f &in avForce)</li> <li class="level1"> <b>AddForceAtPosition</b> (const cVector3f &in avForce, const cVector3f &in avPos)</li> <li class="level1"> <b>AddImpulse</b> (const cVector3f &in avImpulse)</li> <li class="level1"> <b>AddImpulseAtPosition</b> (const cVector3f &in avImpulse, const cVector3f &in avPos)</li> </ul> <p> These functions behave similarly to their convenience function counterparts, with AddForceAtPosition and AddImpulseAtPosition applying their effects from an arbitrary point in the world rather than the position of another entity. </p> <p> Usage example: </p> <pre class="code =c++"><span class="co1">// Add a vertical force to the entity with a magnitude of 5.0</span> body.<span class="me1">AddForce</span><span class="br0">(</span>cVector3f<span class="br0">(</span><span class="nu16">0.0</span><span class="sy0">,</span> <span class="nu16">5.0</span><span class="sy0">,</span> <span class="nu16">0.0</span><span class="br0">)</span><span class="br0">)</span><span class="sy0">;</span> </pre><p> </p> </div> <h2>To-Do List</h2> <div class="level2"> <ul> <li class="level1"> Monster Spawn</li> <li class="level1"> Wake-Up Sequence</li> </ul> </div>