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Project Rembrandt: Difference between revisions
→Adding lights to a model
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==== Performance and compatibility considerations ==== | |||
Every light on screen is equivalent for the GPU of redrawing the light volume with a shader, without z buffer culling. So each light comes with a cost, that is small taken individually but noticeable when a lot of them are visible. That cost also increase with the size of the light volume. | |||
Beside that, it is wise to allow a model to work with the classical renderer that know nothing about lights and would render light volumes like other geometry. So a good practice is to complement each light animation with a select animation checking : | |||
*if Rembrandt is enabled | |||
*if the user selected quality match with the purpose of the light | |||
*if the light should be on or off according to the other parameters of the simulation (position of the sun, position of switch, presence of power, ...) | |||
A quality property is created to reflect the user preferences about quality vs performance concerning lights, and a proper slider is added to the shader dialog. | |||
[[File:Fgfs-shaders-with-light.jpg|thumb|Light quality slider]] | |||
The propery to use is : | |||
/sim/rendering/shaders/lights | |||
The quality slider sets its range from 0 (no lights) to 4 (all lights on). Simple airport lamp post appears at 1. Few bridge lamps at 2, all simple bridge lamp at 3 and more involved one at 4. | |||
Example: | |||
<syntaxhighlight lang="xml"> | |||
<animation> | |||
<type>light</type> | |||
<light-type>spot</light-type> | |||
<name>LightSource</name> | |||
<object-name>LightVolume</object-name> | |||
... | |||
</animation> | |||
<animation> | |||
<type>select</type> | |||
<!-- Select the named animation --> | |||
<object-name>LightSource</object-name> | |||
<condition> | |||
<and> | |||
<!-- Rembrandt enabled ? --> | |||
<property>/sim/rendering/rembrandt/enabled</property> | |||
<!-- Quality ok ? --> | |||
<greater-than> | |||
<property>/sim/rendering/shaders/lights</property> | |||
<value>3.0</value> | |||
</greater-than> | |||
<!-- Simulation conditions ? --> | |||
<greater-than> | |||
<property>/sim/time/sun-angle-rad</property> | |||
<value>1.57</value> | |||
</greater-than> | |||
</and> | |||
</condition> | |||
</animation> | |||
</syntaxhighlight> | |||
== TODO List == | == TODO List == | ||