View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0028177 | Community | OCCT:Visualization | public | 2016-11-30 14:07 | 2023-08-01 15:09 |
| Reporter | Markus | Assigned To | |||
| Priority | normal | Severity | minor | ||
| Status | new | Resolution | open | ||
| Product Version | 7.1.0 | ||||
| Target Version | Unscheduled | ||||
| Summary | 0028177: Visualization - MSAA has no effect on clipping planes when using built-in GLSL programs | ||||
| Description | If MSAA is activated and a clipping plane used in the Samples, the edges at the clipping plane are not anti-aliased. However, in Draw they are anti-aliased. What is the difference? Or what can be the reason why it isn't working in the samples. | ||||
| Steps To Reproduce | - Open the Viewer3d sample - Click on the button for "overlapped boxes" - Switch on and adjust model clipping so that the box is clipped - Switch on antialiasing => the edges at the clipping plane are not anti-aliased. The others are. See appended images. However, in Draw it works: pload ALL vinit vclipplane create pln1 vclipplane change pln1 equation 1 0 0 -0.1 vclipplane set pln1 view Driver1/Viewer1/View1 box b 100 100 100 vdisplay b vsetdispmode 1 vfit vrotate 10 10 10 vclipplane change pln1 equation 1 0 0 -0.5 vrenderparams -msaa 4 | ||||
| Tags | No tags attached. | ||||
| Test case number | |||||
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without MSAA.png (10,320 bytes) |
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with MSAA.png (11,377 bytes) |
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> However, in Draw it works There is no visual difference in Draw - the aliasing is same. |
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Sorry, it worked in OCCT 7.0. It doesn't work anymore in OCCT 7.1. |
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Draw 7.0 without MSAA.png (4,814 bytes) |
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Draw 7.0 with MSAA.png (5,085 bytes) |
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The difference is that fixed-function pipeline is not used by default anymore since OCCT 7.1.0. You can enable it temporarily as a workaround if this issue is critical for you. |
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Thanks, it is not critical but it would be good to fix it. |
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It is in TODO list (0027748): > 1) Hardware supporting gl_ClipDistance > (GLSL1.3 on desktop; APPLE_clip_distance > or GL_EXT_clip_cull_distance on OpenGL ES) > might show better performance since it allows > skipping Fragment Shader if entire primitive (e.g. triangle) > is behind the clipping plane(s). Although there might be some another workaround for it, which is not clear for now. Technically the problem is caused by *discard* command called to apply clipping plane within Fragment Shader. So that entire pixel is either clipped or not, making MSAA buffer samples equal from clipping planes point of view. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2016-11-30 14:07 | Timo | New Issue | |
| 2016-11-30 14:07 | Timo | Assigned To | => kgv |
| 2016-11-30 14:07 | Timo | File Added: without MSAA.png | |
| 2016-11-30 14:08 | Timo | File Added: with MSAA.png | |
| 2016-11-30 14:12 | kgv | Note Added: 0060918 | |
| 2016-11-30 14:52 | Timo | Note Added: 0060920 | |
| 2016-11-30 14:52 | Timo | File Added: Draw 7.0 without MSAA.png | |
| 2016-11-30 14:52 | Timo | File Added: Draw 7.0 with MSAA.png | |
| 2016-11-30 15:14 | kgv | Note Added: 0060924 | |
| 2016-11-30 15:14 | kgv | Note Edited: 0060924 | |
| 2016-11-30 15:15 | kgv | Summary | MSAA does not work at clipping plane in samples but it works in Draw => Visualization - MSAA has no effect on clipping planes when using built-in GLSL programs |
| 2016-11-30 15:20 | kgv | Relationship added | child of 0027748 |
| 2016-11-30 15:21 | Timo | Note Added: 0060925 | |
| 2016-11-30 15:28 | kgv | Note Added: 0060927 | |
| 2016-11-30 15:29 | kgv | Note Edited: 0060927 | |
| 2016-11-30 15:29 | kgv | Note Edited: 0060927 | |
| 2017-05-31 15:37 | Timo | Reporter | Timo => Markus |
| 2017-07-20 11:32 | kgv | Target Version | 7.2.0 => 7.3.0 |
| 2018-03-13 14:37 | kgv | Target Version | 7.3.0 => 7.4.0 |
| 2018-03-25 12:01 | kgv | Relationship added | related to 0028487 |
| 2019-09-04 15:36 |
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Target Version | 7.4.0 => 7.5.0 |
| 2020-08-28 14:32 | kgv | Target Version | 7.5.0 => 7.6.0 |
| 2021-08-24 14:13 | kgv | Target Version | 7.6.0 => 7.7.0 |
| 2022-08-17 11:59 | kgv | Target Version | 7.7.0 => 7.8.0 |
| 2022-10-19 15:47 |
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Assigned To | kgv => vpozdyayev |
| 2023-08-01 15:09 | dpasukhi | Target Version | 7.8.0 => Unscheduled |
