openframeworks / openframeworks/openFrameworks

triangle winding order inconsistent between screen and fbo render targets

Open
#3,381 1 comment 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

bug core
Dominant language
C++
Stars
10.4k
Forks
2.6k
Avg merge
1d 21h
Merged PRs (30d)
9

Description

If I draw a backface-culled primitive straight to screen it seems that front-facing triangles are wound clockwise (glFrontFace(GL_CW) has neutral effect).

When i then draw the same scene inside an ofFbo, front faces seems to revert to OpenGL default, glFrontFace(GL_CCW) has neutral effect.

This could be because by default we're either z-flipping the screen or ofFbos, and might be related to #3353.
I'm noting this down as a reminder to investigate further.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

The issue names no files or tests. Start by reproducing backface culling for the same scene rendered directly to the screen and inside an ofFbo, then compare the reported winding and z-flip behavior, including the possible connection to issue #3353. Done means identifying why the winding differs and documenting or correcting the inconsistent behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
computer-graphics
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.