Struct web_glitz::pipeline::graphics::DepthTest

pub struct DepthTest {
    pub test: TestFunction,
    pub write: bool,
    pub depth_range: DepthRange,
    pub polygon_offset: Option<PolygonOffset>,
}

Provides instructions on how depth testing should be performed.

In order to do a depth test, the [RenderTarget] that is being rendered to must include a depth buffer. A depth buffer stores a depth value between 0.0 (close) and 1.0 (far) for each fragment. Initially the depth value for each fragment is set to 1.0. When rendering to a [RenderTarget] with no depth buffer attached, the depth test behaves as though depth testing is disabled.

The depth test is performed for each fragment. The fragment's depth output will be mapped onto the range defined by [depth_range]:

• Values smaller than the lower bound will be mapped to 0.0.
• Values greater than the upper bound will be mapped to 1.0.
• Values contained on the range will be mapped to the range 0.0..1.0.

The lower bound of the [depth_range] must not be smaller than 0.0, the upper bound of the [depth_range] must not be greater than 1.0, and the lower bound must be strictly smaller than the upper bound.

The resulting depth value may then be compared to the depth buffer's current depth value for this fragment using the test. The test can be one of the following functions:

• TestFunction::Equal: the test passes if the fragment's depth value is equal to the depth buffer's current depth value for this fragment.
• TestFunction::NotEqual: the test passes if the fragment's depth value is not equal to the depth buffer's current depth value for this fragment.
• TestFunction::Less: the test passes if the fragment's depth value is smaller than the depth buffer's current depth value for this fragment.
• TestFunction::Greater: the test passes if the fragment's depth value is greater than the depth buffer's current depth value for this fragment.
• TestFunction::LessOrEqual: the test passes if the fragment's depth value is smaller than or equal to the depth buffer's current depth value for this fragment.
• TestFunction::GreaterOrEqual: the test passes if the fragment's depth value is greater than or equal to the depth buffer's current depth value for this fragment.
• TestFunction::NeverPass: the test never passes, regardless of how the fragment's depth value compares to the depth buffer's current depth value for this fragment.
• TestFunction::AlwaysPass: the test always passes, regardless of how the fragment's depth value compares to depth buffer's current depth value for this fragment.

If the test fails, the fragment will be discarded: none of the [RenderTarget]'s output buffers will be updated. If the test passes and write is true, then the depth buffer's depth value for this fragment will be replaced with the new depth value; if write is false, then the depth buffer will not be updated. If the test passes, the fragment will not be discarded by the depth test, but note that other stages of the pipeline (such as front/back-face culling, stencil testing, the fragment shader) may still discard the fragment.

An instance of for the default depth test options may be obtained via Default:

use web_glitz::pipeline::graphics::{DepthTest, TestFunction, DepthRange};

assert_eq!(DepthTest::default(), DepthTest {
    test: TestFunction::Less,
    write: true,
    depth_range: DepthRange::default(),
    polygon_offset: None
});

Fields

test: TestFunction

The TestFunction used to decide if the DepthTest passes or fails.

Defaults to TestFunction::Less.

write: bool

Whether or not the depth buffer will be updated when the depth test passes.

When set to false, the depth buffer will not be updated when the depth test passes.

Defaults to true.

depth_range: DepthRange

Defines how a fragment's depth output will be mapped onto the range 0.0..1.0 from the near plane at 0.0 to the far plane at 1.0.

See DepthRange for details.

polygon_offset: Option<PolygonOffset>

Defines an optional polygon-offset to be applied to depth fragments optioned from polygonal primitives (triangles).

See PolygonOffset for details.

Defaults to None, in which case no polygon offset will be applied.

Trait Implementations

impl Clone for DepthTest

fn clone(&self) -> DepthTest

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DepthTest

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for DepthTest

fn default() -> Self

Returns the "default value" for a type.

impl PartialEq<DepthTest> for DepthTest

fn eq(&self, other: &DepthTest) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &DepthTest) -> bool

This method tests for !=.

impl StructuralPartialEq for DepthTest