Anonymous | Login | 03-02-2021 01:32 UTC |
Main | My View | View Issues | Change Log | Docs |
Viewing Issue Simple Details [ Jump to Notes ] | [ View Advanced ] [ Issue History ] [ Print ] | |||||||||||
ID | Category | Severity | Reproducibility | Date Submitted | Last Update | |||||||
0005674 | [Squeak] Morphic | minor | sometimes | 12-27-06 06:39 | 11-05-07 03:22 | |||||||
Reporter | wiz | View Status | public | |||||||||
Assigned To | ||||||||||||
Priority | normal | Resolution | open | |||||||||
Status | new | Product Version | 3.9 | |||||||||
Summary | 0005674: Why doesn't heading = forwardDirection + rotationDegrees for all morphs all the time? | |||||||||||
Description |
This is actually a MAJOR bug with a minor urgency. This is an integration issue. The meaning of heading forwardDirection and rotationDegrees varies between morph species morphs (inflexible), transformation (nothing but flex) polygons and circles (self flexing) matrixtransform, flash and truetypefonts ( ??? ) Since many of these interact with each other and all of them should be able to interact. There should be a consistent (non recursing) protocol aided by consistent definitions of these words and the referencePoints they depend upon. |
|||||||||||
Additional Information |
The only way to solve this is to come up with a consistent definition (not hard) Publish it. (Where) Get consensus (Good luck) Repair and refactor and reinforce it in the code. (Ahhh) My proposal for the definitions starts with the invariant heading = forwardDirection + rotationDegrees My understanding of the difference between the three words is: Forward direction is the direction an unrotated object will go in when told forward. You can have a rectangle that looks like a rectange. Set it forward direction to East. It still looks like itself an unrotated rectangle. When tell forward it marches east instead of the default north. Now you can take the blue halo handle and give the rectangle a tilt say 90 degress. When you ask it to go forward in marches south. Now our outside understanding of this is that it marches south because it has a forward direction of 90 degrees and its been tilted another 90 degrees. Which brings me to the other two words. Heading is the direction that it marches. And rotation degrees is the amount of tilt. That is the difference between the direction and the forward direction. There are various way that these notions break down in practice. In particular a tilted rendee does not answer correctly when ask its rotation degrees because it relies on its owner for that data. Polygons and circle don't remember they have been tilted because the always adjust the forward direction. This loses an important distinction. The reason to fix this bug is once it has been tackled a clarity can be achieved that will disolve a great number of sticky bugs. You can find most of them by searching mantis for the word rotation. Yours in service, -- Jerome Peace |
|||||||||||
Attached Files |
![]() ![]() |
|||||||||||
|
![]() |
||||||||||||||||
|
Mantis 1.0.8[^]
Copyright © 2000 - 2007 Mantis Group
51 total queries executed. 35 unique queries executed. |