pub enum DepthTest {
    Ignore,
    Overwrite,
    IfEqual,
    IfNotEqual,
    IfMore,
    IfMoreOrEqual,
    IfLess,
    IfLessOrEqual,
}
Expand description

The function that the GPU will use to determine whether to write over an existing pixel on the target.

Depth buffers

After the fragment shader has been run, the GPU maps the output Z coordinates to the depth range (which you can specify in the draw parameters) in order to obtain the depth value in in window coordinates. This depth value is always between 0.0 and 1.0.

In addition to the buffer where pixel colors are stored, you can also have a buffer which contains the depth value of each pixel. Whenever the GPU tries to write a pixel, it will first compare the depth value of the pixel to be written with the depth value that is stored at this location. If depth_write is set to true in the draw parameters, it will then write the depth value in the buffer.

The most common value for depth testing is to set depth_test to IfLess, and depth_write to true.

If you don’t have a depth buffer available, you can only pass Overwrite. Glium detects if you pass any other value and reports an error.

Variants§

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Ignore

Never replace the target pixel.

This option doesn’t really make sense, but is here for completeness.

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Overwrite

Always replace the target pixel.

This is the default mode.

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IfEqual

Replace if the z-value of the source is equal to the destination.

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IfNotEqual

Replace if the z-value of the source is different than the destination.

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IfMore

Replace if the z-value of the source is more than the destination.

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IfMoreOrEqual

Replace if the z-value of the source is more than, or equal to the destination.

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IfLess

Replace if the z-value of the source is less than the destination.

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IfLessOrEqual

Replace if the z-value of the source is less than, or equal to the destination.

Implementations§

Returns true if the function requires a depth buffer to be used.

Trait Implementations§

Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
A type that holds a sized version of the content.
Prepares an output buffer, then turns this buffer into an Owned.
Returns the size of each element.
Produces a pointer to the data.
Builds a pointer to this type from a raw pointer.
Returns true if the size is suitable to store a type like this.

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.