Two serious stencil texture bugs #26184

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Miika Hamalainen · 2011-02-22T15:54:14+01:00

Miika Hamalainen commented

2011-02-22 15:54:14 +01:00

%%%While I was looking through stencil handling code I found two quite serious bugs in stencil system.

Stencil mask affects the texture it is assigned from:

If you set a stencil mask from a texture that affects for example both stencil and color -> color from that texture gets affected by that stencil mask as well.

See attachments: stencil_bug_1.png and stencil_bug_1.blend

Stencil normal effect is multiplied by every texture

If you have a stencil mask, it's effect on normal increases for every texture processed in texture stack. (No matter whether texture does something or not.)

See attachments: stencil_bug_normal.png and stencil_bug_normal.blend

Ton said that these bugs have been in Blender for ages, and thus fixing them would "break" old renders that use stencil masks. However, I don't agree we should wait for material system rewrite with these since these bugs are very easy to fix.

At least we should change "Stencil" checkbox description to define it affects current texture as well. (Which doesn't make any sense. :)
For normal bug: It's very serious, and something should be done about it anyway.%%%

%%%While I was looking through stencil handling code I found two quite serious bugs in stencil system. 1. Stencil mask affects the texture it is assigned from: If you set a stencil mask from a texture that affects for example both stencil and color -> color from that texture gets affected by that stencil mask as well. See attachments: stencil_bug_1.png and stencil_bug_1.blend 2. Stencil normal effect is multiplied by every texture If you have a stencil mask, it's effect on normal increases for every texture processed in texture stack. (No matter whether texture does something or not.) See attachments: stencil_bug_normal.png and stencil_bug_normal.blend Ton said that these bugs have been in Blender for ages, and thus fixing them would "break" old renders that use stencil masks. However, I don't agree we should wait for material system rewrite with these since these bugs are very easy to fix. At least we should change "Stencil" checkbox description to define it affects current texture as well. (Which doesn't make any sense. :) For normal bug: It's very serious, and something should be done about it anyway.%%%

Miika Hamalainen commented

2011-02-22 15:54:14 +01:00

Changed status to: 'Open'

M.G. Kishalmi commented

2011-02-22 16:25:12 +01:00

%%%r35072 @ linux64

attached a screenshot showing the same (mis)behaviour in blender 2.49a
because of Tnor *= stencilTin for every non-stencil texture, the stencil effect multiplies with every slot.

attached a patch with a fix too, but didn't commit.

kaito: if it's there > 5 years, it becomes a feature automatically :)
%%%

%%%r35072 @ linux64 attached a screenshot showing the same (mis)behaviour in blender 2.49a because of Tnor *= stencilTin for every non-stencil texture, the stencil effect multiplies with every slot. attached a patch with a fix too, but didn't commit. - kaito: if it's there > 5 years, it becomes a feature automatically :) %%%

M.G. Kishalmi commented

2011-02-22 16:34:31 +01:00

%%%fixed small error in the patch.%%%

Ton Roosendaal commented

2011-02-24 16:57:30 +01:00

%%%Tested the current status of texture stencil.
I agree the implementation is messed up here, but the fix isn't worth breaking renders that were created this way. It does work now, even with its limits.

The status of our material/texture/light system is really beyond repair in many ways, I really prefer to move on start a proper design project a.s.a.p.

Added note in wiki, and link to this report here:
http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Rendering

Thanks for the efforts to make this patch!%%%

%%%Tested the current status of texture stencil. I agree the implementation is messed up here, but the fix isn't worth breaking renders that were created this way. It does work now, even with its limits. The status of our material/texture/light system is really beyond repair in many ways, I really prefer to move on start a proper design project a.s.a.p. Added note in wiki, and link to this report here: http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Tools#Rendering Thanks for the efforts to make this patch!%%%

Ton Roosendaal commented

2011-02-24 16:57:30 +01:00

Changed status from 'Open' to: 'Archived'

Ton Roosendaal closed this issue

2011-02-24 16:57:30 +01:00

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Two serious stencil texture bugs #26184