Tech:Asteroids..

Ok, this silly asteroids is driving me nuts (still)

Basically, any vector that is not at being drawn at max intensity, is being
eliminated from the xy output, right out of the dac (This is all on the
scope, no z-axis in effect here).

Game plays ok, customer reported vector traces, like the brightness was too
high, but he did try to adjust that out. No Good. In test mode on a scope,
its missing the complete cross hatch and screen frame. The dacs are not even
trying to output that, just a flat line inbetween the dip switch settings
draw.. On a scope it appears to play fine, (But I imagine on a real monitor,
it would have trace lines, if the Z axis is truely messed up) Test reports
nothing wrong, naturally.

What I've done. Scale0-3 looked ok, but replaced 273-K7 anyway based upon
the fact that this drives the Z axis as well.

I think I've ruled out the position counters. (Some said they were having a
problem where only the right hand of the box vert line was out, I would
suspect that the X was counting beyond 1024 causing that..)

Replaced M7 175, in the vector timer, but as I though about it, I didn't
think that would have helped...

Basically, everything 'seems' to be working... but... not.. I've got to have
a counter or latch being stupid..

So... Does anyone familur with the code understand how to releate brightness
with beam generation/movement ? I would think at the drawing stage it would
not mean anything, since its
controlled by Z, but the line data is completely missing on any low
intensity draw ? So the intensity is being used, looking at the schematics,
it would seem the vec timer is the area where its used, but I don't
understand really why would intensity be needed at that point, why not just
let it draw, and seperate the intensity to the Z at the point where the
state machine executes the draw command... Or am I completly confused...

 I've messed around with the Scale, but only made things bigger (kinda cool)
so, Scale, depending on when its being latched is used for scale and
intensity... yes ??

 Ideas ??? Help

TomW
Received on Mon Feb 15 23:46:18 1999