Prevent DoF effect disappearing at small focus_distances
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Breakdown-Dog
changed the title
max(focus - f, EPSILON) to ensure the denominator is alwaysfocus_distances
JMS55
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Nov 12, 2025
JMS55
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C-Bug
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Seems the CI failed because the heapless crate update caused Bevy to use a deprecated method. May need another PR to fix this issue. |
IceSentry
reviewed
Nov 12, 2025
| @group(1) @binding(1) var color_texture_sampler: sampler; | ||
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| // used to ensure `depth * (focus - f)` is always a positive number, | ||
| const EPSILON: f32 = 1.19209290e-07; |
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You can use f32::EPSILON, no need to define a custom constant.
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I tried using f32::EPSILON in WGSL, but it seems this constant isn't provided by the language. So I just copied the value from Rust's standard library and defined a custom constant in my WGSL code.
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I completely forgot this was wgsl and not rust. Ignore that 😅
IceSentry
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Nov 12, 2025
| // | ||
| // [1]: https://en.wikipedia.org/wiki/Circle_of_confusion#Determining_a_circle_of_confusion_diameter_from_the_object_field | ||
| let candidate_coc = scale * abs(depth - focus) / (depth * (focus - f)); | ||
| let candidate_coc = scale * abs(depth - focus) / (depth * max(focus - f, EPSILON)); |
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Suggested change
| let candidate_coc = scale * abs(depth - focus) / (depth * max(focus - f, EPSILON)); | |
| let candidate_coc = scale * abs(depth - focus) / (depth * max(focus - f, f32::EPSILON)); |
IceSentry
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Nov 12, 2025
mockersf
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Nov 12, 2025
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Objective
depth_of_fieldexample, settingfocal_distanceto a small value (<= 0.02) causes the DoF effect to disappear unexpectedly.I believe that a small focal_distance makes
(focus - f)zero or negative. This leads to a non-positive candidate_coc, which is then clamped to 0.0, effectively disabling the DoF effect.Although the formula is physically accurate, we cannot assume users have a deep understanding of the depth of field effect. This will make them confused.
Solution
Use
max(focus - f, EPSILON)to ensure the denominator is always positive.Now, the effect looks correct.
Testing