TiMan: Add a sourced SOMA guide with explanations and stock-script examples.

2026-10-02T12:23:32Z

Add a sourced SOMA guide with explanations and stock-script examples.

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This page describes SOMA’s Image Trail effect.

Image trail blends previous frames into the current image. Multiple instances can be active, with the strongest amount used; FadeOut removes an instance and Clear removes all effects.

== Before you start ==
# Open the map script inside your own mod. Keep its generated includes, <code>cScrMap : iScrMap</code> class and callback structure. See [[HPL3/SOMA/Getting Started/Add Your First Script|Add your first script]] if you have not edited a map script yet.
# Add the helper include shown below alongside the script’s other includes.
# Read the stock example before copying its calls: named entities, voice subjects, materials and callbacks must belong to the map or resources you are using.

== Follow the stock example ==
<syntaxhighlight lang="cpp">
#include "helpers/helper_effects.hps"
</syntaxhighlight>

=== Effect_ImageTrail_Start ===
Image trail blends the image of multiple previous frames over time, multiple instances can be active at the same time
The strongest instance of image trail will be used

{| class="wikitable"
! Parameter !! Meaning
|-
| <code>afAmount</code> || how much of the previous frame should be blended, values from 0-inf, 0 = disabled
|-
| <code>afFadeInTime</code> || how long it should take to fade to fade in
|-
| <code>afStayTime</code> || how long it will stay before starting to fade out. If <0, then it stays for ever.
|-
| <code>afFadeOutTime</code> || how long it will take to fade out
|}

In <code>maps/02_06_theta_tunnels_old/02_06_theta_tunnels.hps</code>, SOMA calls <code>Effect_ImageTrail_Start</code> as follows.

<syntaxhighlight lang="cpp">
Effect_ImageTrail_Start(0.5,1,10,8.0);
</syntaxhighlight>

{| class="wikitable"
! Parameter !! Value in this stock call
|-
| <code>afAmount</code> || <code>0.5</code>
|-
| <code>afFadeInTime</code> || <code>1</code>
|-
| <code>afStayTime</code> || <code>10</code>
|-
| <code>afFadeOutTime</code> || <code>8.0</code>
|}

This is an excerpt from that stock script; its referenced names and variables belong to that script.

=== Effect_ImageTrail_FadeOut ===
Fades out an active instance of image trail

{| class="wikitable"
! Parameter !! Meaning
|-
| <code>alID</code> || id of the trail instance, returned by _Start
|-
| <code>afFadeOutTime</code> || how long it will take to fade out
|}

In <code>maps/chapter03/03_01_omicron_outside/03_01_omicron_outside.hps</code>, SOMA calls <code>Effect_ImageTrail_FadeOut</code> as follows.

<syntaxhighlight lang="cpp">
Effect_ImageTrail_FadeOut(mlImageTrailId, 2);
</syntaxhighlight>

{| class="wikitable"
! Parameter !! Value in this stock call
|-
| <code>alID</code> || <code>mlImageTrailId</code>
|-
| <code>afFadeOutTime</code> || <code>2</code>
|}

This is an excerpt from that stock script; its referenced names and variables belong to that script.

=== Effect_ImageTrail_Clear ===
Clears all effects

== Check your change ==
Save the script and restart the map in development mode with <code>F5</code>. If the script fails, open <code>F1</code> and use '''Show Error List''' or '''Show HPL Log'''. See [[HPL3/SOMA/Getting Started/Test Debug and Continue|the development loop]] for the launch and debugging steps.

== See also ==
* [[HPL3/SOMA/Scripting/Effects Helper|SOMA effects helpers]]

[[Category:English]]

HPL3/SOMA/Scripting/Image Trail - Revision history

TiMan: Add a sourced SOMA guide with explanations and stock-script examples.