Re: A round shaped LCD screen

On 20 Apr 2005 18:22:04 -0700, Eric Smith <eric@xxxxxxxxxxxx> wrote:

>Steve Calfee <stevexcalfee@xxxxxxxxxxx> writes:
>> Back in the early days of coin-op video games, when we first had x-y
>> monitors (remember Asteroids?), we dreamed of having new display
>> hardware based on r-theta displays. So you could rotate the screen
>> (change theta) and then scale it by changing r.
>>
>> Those whining hardware guys said they could not do it (circa 1978)
>
>Though that's exactly what early radar systems did.
>
>They uses a round tube, with deflection on one axis, the deflection
>assembly was motorized to spin around the tube. Thus the motor
>position gives theta, and the electromagnetic deflection gives r.
>
>Still, for most arcade games, having a polar coordinate display
>would have caused more trouble than it solved. Even in games
>where the majority of the action takes place in a polar coordinate
>space, lots of things would have to be transformed since you often
>need to be able to rotate objects around an origin independent of
>the center of the global coordinate system. Also, displaying
>the score and other text messages would have similar problems,
>unless you actually wanted them displayed "wrapped around a
>circle".
>
>Eric
Yes, that would have been confusing.

What we were talking about was being able to have multiple nested
objects r-theta transformed. This could not have been done with just
display hardware.

This is like having a 3d object that is transformed relative to a
parent object. So the universe (the display) would probably not be
rotated or scaled, but individual items would be. So for example you
could rotate and scale a car and its wheels would also rotate (and be
scaled to match the car size) within the new frame of reference. This
was speculated on way before a semi-true semi-real-time 3d
transformation was possible.

Regards ~Steve
There is no "x" in my email address.
.

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