Particle properties
Here we can adjust and alter the actual
appearance of each particle over the course of its lifetime. This is the
meat of the engine.
Each particle has a texture or sprite that is
applied to it, as we have already discussed, but we can also set the
color, opacity, speed, and size of the particle throughout its
lifetime.
Color/Opacity Gradient
The first control deals with the color and the
opacity of the particles.
Click on the Color/Opacity bar to open its
editing widget. In this window you have two bars. The top bar is a
gradient from white to black and the bottom bar is solid red.
The left end of each bar represents the
beginning of the particle's lifetime. The right end is when its lifetime
ends.
Look below the bottom left corner of the red Color Gradient and you will see a small red handle. This
is a control point on the gradient. Click the handle to select it, then
click the box labeled Color: to open the Color
Picker.
Here you can select any color you want to give
your particles. Pick a color, and click OK to close the color picker. You
can click anywhere within the red bar to create a new control point. Each
control point can be assigned any color you like, and can be placed
anywhere on the color bar.
The Location readout at the
bottom of the widget will tell you where your current Control Point is, in
a percentage of the particle’s lifetime.
The Opacity Gradient works
similarly to control the opacity (transparency) of each particle over the
course of its life. Above the Opacity Gradient you will see two control
points; a white one on the left, and a black one on the right. Clicking on
one of them will enable the Opacity Slider at the top of
the widget.
The value readout will tell you how opaque you
are at the current setting. 0% means that the particles are completely
transparent, and 100% means they are completely opaque. Notice that in the
opacity gradient, full opacity is represented by white, and full
transparency by black.
In each gradient, you can have up to 20 control
points.
The color and opacity gradients are critical to the quality of our
finished fire effect. If you want to be adventurous, try to get your
gradients to match this picture.
If you prefer to be exact, use these settings for your control
points.
OPACITY GRADIENT: 3 CONTROL
POINTS
1: Value 100%, Location
0%
2: Value 16%, Location 89%
3: Value 4%, Location 100%
COLOR GRADIENT: 4 CONTROL POINTS
Getting the colors close should be enough, if you can’t get
them exact.
1: Location 0%, Red 240, Green 164, Blue
104
2: Location 38%, Red 240, Green 124, Blue
18
3: Location 89%, Red 240, Green 94, Blue
2
4: Location 100% Red 255, Green 0, Blue
0
