Spiral / Swirl Effect This example draws a sort of spiral / swirling effect.
This short demo shows off some simple visual effects using Alpha blending. The effect works by drawing a blended shape (in this case a circle) over the backdrop from the previous update.
When we display the backdrop; we apply some alpha blending onto it to reduce the colour levels. This Make it appear as if the moving object is leaving a trail..
Requires PB V1.64K2
[pbcode]
#include "blitimage"
Screen=NewFxIMage(GetScreenWidth(),GetSCreenHeight())
Colour=RndRGB()
Do
RendertoImage Screen
Baseangle#=wrapangle(Baseangle#,1)
scx=GetScreenWidth()/2
scy=GetScreenHeight()/2
inkmode 1+32
Offset=0
for lp=0 to 360 step 5
a#=Baseangle#+lp
x#=scx+cosradius(a#,100+lp)
y#=scy+sinradius(a#,100-lp)
circlec x#,y#,32+Offset,true,Colour
Offset++
next
inkmode 1
rendertoscreen
BlitImageAlphaPostMultColour(Screen,0,0,$ffffff)
if spacekey()
ink $ffffff
setcursor 0,0
print Fps()
endif
Sync
loop
[/pbcode]
Video: