Bug 8701

Summary: Incorrect line clipping with very large coordinates
Product: Mesa Reporter: Brian Paul <brian.paul>
Component: Mesa coreAssignee: mesa-dev
Status: RESOLVED MOVED QA Contact:
Severity: normal    
Priority: high    
Version: 6.5   
Hardware: x86 (IA32)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: demo program

Description Brian Paul 2006-10-18 14:40:22 UTC
Mesa's line clipping code fails when a vertex coordinate is of very large magnitude.
Comment 1 Brian Paul 2006-10-18 14:41:06 UTC
Created attachment 7460 [details]
demo program
Comment 2 Brian Paul 2006-10-18 14:43:26 UTC
The problem boils down to computing t = -2.e8 / (-2.e8 - 3.5)

We wind up with t=1, but t should instead be some value very close to, but less
than 1.0.  Tried double precision with no change.  Will have to study this
further someday.
Comment 3 chemtech 2013-03-15 14:22:15 UTC
Brian Paul
Do you still experience this issue with newer soft ?
Please check the status of your issue.
Comment 4 Brian Paul 2013-03-15 15:18:27 UTC
Unfortunately, swrast, softpipe and llvmpipe all still suffer from this.
Comment 5 GitLab Migration User 2019-09-18 20:21:54 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/mesa/mesa/issues/956.

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