Re: OType
Posted: Tue Jun 26, 2018 10:33 pm
So awesome...
Twilighte we miss you.
Twilighte we miss you.
Oki, so the scroll step is two lines because AIC uses one paper/color combination for the even lines and another for the odd ones.
The problem is that the scroll is far from 50fps, so there's a large probability that copying the line and attribute will not happen atomically, so you can get bright flashes caused by having some of the graphics displayed with the wrong set of colors.NekoNoNiaow wrote: ↑Sat Apr 20, 2019 3:25 am Oki, so the scroll step is two lines because AIC uses one paper/color combination for the even lines and another for the odd ones.
This said, if one is willing to also copy the color attributes at the left side of the play field, then it becomes possible to only scroll by one line.
Damn, you are right, I completely forgot about the absence of vsync.
Yes, which is why I suggested to copy the attributes, not just the pixel data. This way the colors are preserved.
I seem to be interpreting what DBug says differently than you do. To me (I may be wrong obviously), it seems that he is saying that since the copy cannot be aligned to vsync, there are bound to be lines where the attributes and pixel data will not be in sync, which will lead to color artifact.
The O-Type video seems to show that the copy is already not VSYNC aligned: there is ample tearing as the screen scrolls along so copy time is not the issue.
I understood. What I mean is that the player's ships (enemies too?) also use AIC, so if they are still at, say, the bottom of the play area and you scroll attributes one row up, their colors will change.NekoNoNiaow wrote: ↑Mon Apr 22, 2019 9:10 pmYes, which is why I suggested to copy the attributes, not just the pixel data. This way the colors are preserved.
Hum... ok, I now understand what you mean. Nothing better than a good example! Thanks.
Do not be sorry!Chema wrote: ↑Tue Apr 23, 2019 1:12 pm About the vsync thing, I am sorry if I misunderstood. In any case, it is possible to get an interrupt in sync with the vertical retrace, as was proposed here viewtopic.php?f=8&t=78&hilit=vsync&start=15#p15173
Synopsis
Its world war 2, the conflict is at its height. Two alien scout ships come to investigate and are shot down accidentally in the cross fire over Berlin. They emergency land in the outskirts and are transported to a secret base in the heart of Bavaria.
Captured Scientists from a research base in Poland are brought in to discover there origin, the generals believing its of American or British origin. The scientists are led by Dr Piotr Puschev.
Dr Alsven and his team discover the dead aliens within and realise the true identity. Further investigations discover hand weapons and in one experiment the explosion is enough to clear an escape passage for some of the scientists including Dr Puschev.
Dr Puschev reaches Britain with just one of his colleagues, Aleksander Potangsky. The rest of his team are shot or captured. One of the pursuing Nazi generals manages to remain undercover on entering Britain and pursues Dr Puschev and his comrade.
However the duo manage to reach British intelligence who immediately setup a covert operation to send in their best team (led by Sam Rushdon) to investigate and attempt to substantiate his claims. Dr Puschev draws a rough map of the location of the base and volunteers to join the team. Aleksander Potangsky volunteers to remain at HQ to support in the research program, providing valuable intel.
Meanwhile more alien ships start to descend on planet earth this time with greater shielding and armoury. They bombard all the major cities and as the team head for Berlin it becomes clear the gravity of the situation.
If they are not defeated by the Nazi onslaught their fate will still be at the hands of an alien nation who seem dedicated to mass slaughter of the human kind.
Level 1 - The flight of discovery
Scene 1
Dr Piotr Puschev and Sam Rushdon(with his team) head for the airfield in there trucks while being pursued by the Nazi general.
Spyhunter style race with guns, road spurs and road works.
Scene 2
Piotr, Sam and his team board the airship bound for Bavaria. The Nazi general manages to secretly board
Slowly the Nazi general manages to pick off each member of Sam's team leaving just him and Piotr to play a game of wits against the agressor.
Meanwhile Dr Puschev(Piotr) gives as much intel on the alien crafts as he can recall to Sam.
Ideas for gameplay please
Scene 3
On landing somewhere in Bavaria, both Piotr and Sam head for the secret base on foot guided by the map drawn by Piotr. However the Nazi general has notified local authorities and there whereabouts and possible intentions.
007 Licence ot Kill/Rambo style scrolling shooter heading away from aerodrome, through local town and up into the hills.
Scene 4
The duo reach the secret bavarian base which is mostly underground and camouflaged as a Hydro-electric generating plant.
Keeping with the previous gameplay the duo must reach the ships.
Level 2 - Flight into the unknown
Scene 1
Sam and Piotr manage to lock themselves inside the secure hanger holding the two alien crafts. They find them relatively unscathed. They decide to attempt to fly them back to British soil.
Gameplay trainer for flying alien craft.
Scene 2
In their absence the alien invasion has taken a sinister turn defeating the German onslaught and devastating British and US defences.
The alien craft must now face ground to air fire from German gunners, Air to air combat from the remaining airbourne planes in an attempt to head back to UK soil.
Vertical shmup
Scene 3
Sam and Piotr reach britain but face an increasing barrage of fighter planes and ground based weaponry from the British defences since they see no difference between their craft and the alien onslaught.
Wishing not to kill his own countrymen, Sam decides to head out to sea and Piotr follows. They land on a remote island in the scottish isles to discuss the situation. They realise these craft are not mere air based flying craft but vehicles capable of space travel. They realise the only way to stop this madness is to head out to the oncoming storm and attempt to destroy the alien menace.
Vertical Shmup in upper atmosphere starting with weather balloons, bombers, fighter planes and alien craft.
Level 3 - The final frontier
Scene 1
The ships now face the onslaught of the oncoming alien hoards which they must defeat. However Aleksander is still providing intel and working with British cypher experts at Bletchley park have been able to decipher the Alien language. It is revealed that it is possible to fool the onslaught into believing the two alien craft contain their own. Experiments run the previous day on transmitting the carrier wave cipher appear to show the same technology can be adapted to fool alien craft into thinking that british airplanes are also their own. This major breakthrough suddenly emphasises the importance both of Aleksander's work and of the duo heading into space.
Meanwhile Sam has worked out how to use the onboard communications and is able to speak directly to British HQ. He passes on the intel to Piotr.
Gameplay continues as Shmup in space.
Scene 2
Sam and Piotr discover a massive wormhole that appears to have been opened by the aliens. It is being sustained by 8 sentinels around its curcumference.
So they decide to collapse it but must destroy all sentinels. But each one is heavily guarded by shields and battlements.
Scene 3
In the mayhem of destroying the last sentinel, the collapse of the wormhole pulls all craft local to it back into itself, dragging Sam and Piotr screaming into the oblivion of space. However they appear on the other side, whereupon communication is immediately lost to Earth. The cipher was broken in the wormhole collapse and now an alien homeworld and 1001 alien dreadnoughts and ships turn their heads towards two lonely craft drifting in space and so the final battle begins.
Vertical Shmup facing battle cruisers, dreadnoughts, alien fighter craft, carriers, etc.
Level 4 - Worlds apart
Scene 1
Whilst Sam and Piotr have somehow managed it through the alien defences they now face the alien planets. There are a total of 5 planets that coexist almnost against physics since they rotate only miles apart, their atmospheres constantly blending with one another. But this has happened for eons. And the craft now attempt to seek passage through the gap.
Shmup
Scene 2
Next worlds (depending on motivation)
Level 5 - To weild so much power
At the very centre of the alien solar system lies a single sun. around the sun are sentinels similar to those found around the artificial wormhole. Both Piotr and Sam realise that these sentinels are capturing the immensity of the suns energy and somehow transforming it into a usable energy by the ships for interstella transport and creating the wormholes.
Sam and Piotr realise that in order to hold any hope of Earths survival (if it still exists) they must destroy the sentinels.
End game
They die saving earth and most of its inhabitants