Feature/particle speed up

[titison]

With this feature you can speed up particles.
For example with negative speed + spherical shape you can make very nice effects.

Syntax

 <speedUp constant="-0.03" relative="0.03"/>

Both are optional ( so you could do <speedUp constant="-0.03"/> aswell ), but can be combined aswell.

Constant means that each cycle a percentage of the start speed is added
Relative means that each cycle a percentage of the current speed is added

Here are some Examples which you can see here:

Here are the Xmls of the Examples:
The "lines"

<unit-particle-system>
        <texture value="true" path="images/particle.bmp" luminance="true"/>
    <mode value="normal"/>
    <primitive value="quad"/>
    <offset x="-1" y="1" z="0.5"/>
    <direction x="0.03" y="0" z="0"/>
    <color red="1" green="1" blue="1" alpha="1" />
    <color-no-energy red="0" green="0" blue="1" alpha="1" />
        <radius value="0" />
        <size value="0.1" />
        <size-no-energy value="0.4" />
        <speed value="2.0" />
    <speedUp constant="0" relative="0.01"/> / <speedUp constant="0.01" relative="0"/>
    <gravity value="0"/>
        <emission-rate value="0.5" />
        <energy-max value="170" />
        <energy-var value="0" />
    <relative value="true" />
        <fixed value="true" />
        <teamcolorNoEnergy value="false" />
        <teamcolorEnergy value="false" />
</unit-particle-system>

The "ball":

<unit-particle-system>
        <texture value="true" path="images/particle.bmp" luminance="true"/>
    <mode value="normal"/>
    <shape value="spherical">
        <angle value="90"/>
    </shape>
    <primitive value="quad"/>
    <offset x="0" y="0" z="1"/>
    <direction x="1.0" y="0" z="0"/>
    <color red="1" green="1" blue="1" alpha="1" />
    <color-no-energy red="0" green="0" blue="1" alpha="1" />
        <radius value="0.1" />
        <size value="0.1" />
        <size-no-energy value="0.4" />
        <speed value="2.0" />
    <speedUp constant="-0.03" relative="-0.007"/>
    <gravity value="0"/>
        <emission-rate value="0.5" />
        <energy-max value="70" />
        <energy-var value="0" />
    <relative value="true" />
        <fixed value="true" />
        <teamcolorNoEnergy value="false" />
        <teamcolorEnergy value="false" />
    <alternations value="1" />
</unit-particle-system>

The "Ring"

<unit-particle-system>
        <texture value="true" path="images/particle.bmp" luminance="true"/>
    <mode value="normal"/>
    <shape value="conical">
       <angle value="90" />
        </shape>
    <primitive value="quad"/>
    <offset x="0" y="-0.9" z="0"/>
    <direction x="0.0" y="1" z="0"/>
    <color red="1" green="1" blue="1" alpha="1" />
    <color-no-energy red="0" green="0" blue="1" alpha="1" />
        <radius value="0" />
        <size value="0.1" />
        <size-no-energy value="0.4" />
        <speed value="2.0" />
    <speedUp constant="0" relative="-0.05"/>
    <gravity value="0"/>
        <emission-rate value="0.5" />
        <energy-max value="170" />
        <energy-var value="0" />
    <relative value="true" />
        <fixed value="true" />
        <teamcolorNoEnergy value="false" />
        <teamcolorEnergy value="false" />
</unit-particle-system>

The Crown

<unit-particle-system>
        <texture value="true" path="images/particle.bmp" luminance="true"/>
    <mode value="normal"/>
    <shape value="conical">
       <angle value="90" />
        </shape>
    <primitive value="quad"/>
    <offset x="0" y="0.9" z="0"/>
    <direction x="0.0" y="0.1" z="0"/>
    <color red="1" green="1" blue="1" alpha="1" />
    <color-no-energy red="0" green="0" blue="1" alpha="1" />
        <radius value="0" />
        <size value="0.2" />
        <size-no-energy value="1" />
        <speed value="2.0" />
    <speedUp constant="0" relative="-0.05"/>
    <gravity value="-0.05"/>
        <emission-rate value="0.5" />
        <energy-max value="230" />
        <energy-var value="0" />
    <relative value="true" />
        <fixed value="true" />
        <teamcolorNoEnergy value="false" />
        <teamcolorEnergy value="false" />
</unit-particle-system>

[titiger]

Please discribe/discuss this in forum. Maybe others have more ideas on this.