alice-teacher Screen flickers when moving accellerating camera

[Eric Brown]

James,

They may have actually gotten it from this how to I created:

http://www.alice.org/resources/how-tos/vr-locomotion-direct-control/

I have intended for a while to translate some of the VR how-tos back to just normal Alice animation and interactivity how tos as much of the programming is the same.  

This flicker issue is something we have had in our back log for a while and this has brought it back to the top of our list to see if we have more insight into how to fix it or if other things we are working on may alleviate it.  Some of our dodge on addressing this was because we knew our player was going to handle some of this rendering better.  This is a good example of something that may run a little rougher in the play window of the IDE but exporting it and running it in the player could have better results.  So you may want to have your students give that a go.  

Don’t forget we also have a slight end around process that would allow them to take whatever they are building and make a standalone app with it:

http://www.alice.org/resources/how-tos/making-an-alice-app/

I recently published an interactive narrative example that runs better in the player and has been wrapped as an example of a standalone Alice executable:

http://www.alice.org/featured-projects/interactive-narrative-example-evergarden/

Sincerely,

Eric


> On Apr 20, 2021, at 6:49 AM, Vanderhyde, James <vanderhyde at sxu.edu> wrote:
> 
> Don, thanks. Decreasing the duration does cause less flicker. But it also changes the nice feel of acceleration and deceleration caused by the stacking up of the key events. The duration is the amount of time it takes to reach top speed, so setting the the duration to 0 causes instantaneous acceleration. It feels very different.
> 
> I know Alice 3 is not a game engine, and using stacking up of key events to achieve acceleration is kind of a hack. I don’t know how the students came up with it. I will share this solution with them to see if it is acceptable.
> 
> James
> —
> James Vanderhyde
> Associate Professor and Department Chair
> Computer Science
> Saint Xavier University
> 3700 W. 103rd St.
> Chicago, IL 60655
> 773-298-3454
> 
> On Apr 20, 2021, at 7:51 AM, Donald Slater via alice-teachers <alice-teachers at lists.andrew.cmu.edu> wrote:
> 
> James,
> From the development Team…
> 
>> The key repeat speed of 30 per second (per key) combined with the default 1 second animation can stack up a few too many transformations.
>> They should get less flicker by lowering the duration of each animation to 0.25 or 0.1 second, or even 0. The effective motion won't be much changed.
> 
> We are looking at some of the assumptions regarding our defaults. Thank you for bringing this to our attention…
> 
> Take care and be well,
> 
> Don Slater
> 
> Alice Project
> 
>> On Apr 17, 2021, at 12:27 PM, Vanderhyde, James <vanderhyde at sxu.edu> wrote:
>> 
>> Some of my students are making car race games. They came up with a way to do player control or the car using the COMBINE option on the keyboard event with a move forward duration 1. It actually has a very nice feel of acceleration, because the combined movement instructions stack up until a max speed is hit due to the fixed frame rate.
>> 
>> However, something weird happens when you set the camera’s vehicle property to the car. The screen flickers as the camera accelerates. I’m attaching an Alice program that exhibits the behavior. Use up arrow to move forward and right arrow to turn. The flicker occurs sporadically, but more frequently if you try turning. The flicker also happens just moving the camera, so it does not seem to be connected to the vehicle. But the vehicle makes it worse, it seems.
>> 
>> Alice 3.6.0.1 +build .500
>> MacOS Mojave 10.14.6
>> Intel Core i7
>> Intel Iris Pro graphics
>> 
>> James
>> —
>> James Vanderhyde
>> Associate Professor and Department Chair
>> Computer Science
>> Saint Xavier University
>> 3700 W. 103rd St.
>> Chicago, IL 60655
>> 773-298-3454
>> <camera flicker bug.a3p>_______________________________________________
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