pub enum BackfaceCullingMode {
CullingDisabled,
CullCounterClockwise,
CullClockwise,
}
Expand description
Describes how triangles should be filtered before the fragment processing. Backface culling
is purely an optimization. If you don’t know what this does, just use CullingDisabled
.
Backface culling
After the vertex shader stage, the GPU knows the 2D coordinates of each vertex of each triangle.
For a given triangle, there are only two situations:
- The vertices are arranged in a clockwise direction on the screen.
- The vertices are arranged in a counterclockwise direction on the screen.
If you wish so, you can ask the GPU to discard all the primitives that belong to one of these two categories.
Example
The vertices of this triangle are counter-clock-wise.
Usage
The trick is that if you make a 180° rotation of a shape, all triangles that were clockwise become counterclockwise and vice versa.
Therefore you can arrange your model so that the triangles that are facing the screen are all either clockwise or counterclockwise, and all the triangle are not facing the screen are the other one.
By doing so you can use backface culling to discard all the triangles that are not facing the screen, and increase your framerate.
Variants§
CullingDisabled
All triangles are always drawn.
CullCounterClockwise
Triangles whose vertices are counterclockwise won’t be drawn.
CullClockwise
Triangles whose vertices are clockwise won’t be drawn.
Trait Implementations§
source§impl Clone for BackfaceCullingMode
impl Clone for BackfaceCullingMode
source§fn clone(&self) -> BackfaceCullingMode
fn clone(&self) -> BackfaceCullingMode
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for BackfaceCullingMode
impl Debug for BackfaceCullingMode
source§impl PartialEq for BackfaceCullingMode
impl PartialEq for BackfaceCullingMode
source§fn eq(&self, other: &BackfaceCullingMode) -> bool
fn eq(&self, other: &BackfaceCullingMode) -> bool
self
and other
values to be equal, and is used
by ==
.impl Copy for BackfaceCullingMode
impl Eq for BackfaceCullingMode
impl StructuralEq for BackfaceCullingMode
impl StructuralPartialEq for BackfaceCullingMode
Auto Trait Implementations§
impl RefUnwindSafe for BackfaceCullingMode
impl Send for BackfaceCullingMode
impl Sync for BackfaceCullingMode
impl Unpin for BackfaceCullingMode
impl UnwindSafe for BackfaceCullingMode
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T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
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source§impl<T> Content for Twhere
T: Copy,
impl<T> Content for Twhere
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.
User-provided closure F
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T: Any,
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fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
&mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s.