Mail Archives: djgpp/1998/04/29/06:09:43
root AT delorie DOT com (Demandred) writes:
Really? That seems rather an unlikely email address :-)
> Instead of putting lens flares along a light vector (which would look
> supremely cool - hehe) I was actually thinking of blitting a single
> flare centered over the light source. Actually, I hadn't heard of the
> term 'light vector' until you mentioned it - I'm assuming (from the
> lens flare filters in my graphics package) that it's just a vector
> from the light source that passes through the center of the screen?
Exactly. Each flare should be positioned some fixed percentage of the
distance along this vector. For a light source at position lx, ly, the
flare should be located at:
x = lx*n + SCREEN_W/2*(1-n)
y = ly*n + SCREEN_H/2*(1-n)
If you draw four or five flares at different sizes and with various
values of n (use odd fractions, including some negative values
and/or greater than one), you can get some really nice effects as the
flares move around to follow the lightsource.
For the light itself, I would be inclined to use some other sort of
graphic than the regular lensflares, but this is a matter of artistic
preference. Another cool trick with sun-type lights is to flash the
entire screen to white (palette fade) when the light is very close to
the centre of the display.
Shawn Hargreaves.
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