QRhiColorAttachment Class

Member Function Documentation

[constexpr noexcept] QRhiColorAttachment::QRhiColorAttachment()

Constructs an empty color attachment description.

QRhiColorAttachment::QRhiColorAttachment(QRhiRenderBuffer *renderBuffer)

Constructs a color attachment description that specifies renderBuffer as the associated color buffer.

QRhiColorAttachment::QRhiColorAttachment(QRhiTexture *texture)

Constructs a color attachment description that specifies texture as the associated color buffer.

int QRhiColorAttachment::layer() const

Returns the layer index (cubemap face or array layer). 0 by default.

See also setLayer().

int QRhiColorAttachment::level() const

Returns the mip level. 0 by default.

See also setLevel().

[since 6.7] int QRhiColorAttachment::multiViewCount() const

Returns the currently set number of views. Defaults to 0 which indicates the render target with this color attachment is not going to be used with multiview rendering.

This function was introduced in Qt 6.7.

See also setMultiViewCount().

QRhiRenderBuffer *QRhiColorAttachment::renderBuffer() const

Returns the renderbuffer this attachment description references, or nullptr if there is none.

In practice associating a QRhiRenderBuffer with a QRhiColorAttachment makes the most sense when setting up multisample rendering via a multisample color renderbuffer that is then resolved into a non-multisample texture at the end of the render pass.

See also setRenderBuffer().

int QRhiColorAttachment::resolveLayer() const

Returns the currently set resolve texture layer. Defaults to 0.

See also setResolveLayer().

int QRhiColorAttachment::resolveLevel() const

Returns the currently set resolve texture mip level. Defaults to 0.

See also setResolveLevel().

QRhiTexture *QRhiColorAttachment::resolveTexture() const

Returns the resolve texture this attachment description references, or nullptr if there is none.

Setting a non-null resolve texture is applicable when the attachment references a multisample texture or renderbuffer. The QRhiTexture in the resolveTexture() is then a non-multisample 2D texture (or texture array) with the same size (but a sample count of 1). The multisample content is automatically resolved into this texture at the end of each render pass.

See also setResolveTexture().

void QRhiColorAttachment::setLayer(int layer)

Sets the layer index.

See also layer().

void QRhiColorAttachment::setLevel(int level)

Sets the mip level.

See also level().

[since 6.7] void QRhiColorAttachment::setMultiViewCount(int count)

Sets the view count. Setting a value larger than 1 indicates that the render target with this color attachment is going to be used with multiview rendering. The default value is 0. Values smaller than 2 indicate no multiview rendering.

When count is set to 2 or greater, the color attachment must be associated with a 2D texture array. layer() and multiViewCount() together define the range of texture array elements that are targeted during multiview rendering.

For example, if layer is 0 and multiViewCount is 2, the texture array must have 2 (or more) elements, and the multiview rendering will target elements 0 and 1. The gl_ViewIndex variable in the shaders has a value of 0 or 1 then, where view 0 corresponds to the texture array element 0, and view 1 to the array element 1.

See GL_OVR_multiview for more details regarding multiview rendering. Do note that Qt requires GL_OVR_multiview2 as well, when running on OpenGL (ES).

Multiview rendering is available only when the MultiView feature is reported as supported from isFeatureSupported().

This function was introduced in Qt 6.7.

See also multiViewCount().

void QRhiColorAttachment::setRenderBuffer(QRhiRenderBuffer *rb)

Sets the renderbuffer rb.

See also renderBuffer().

void QRhiColorAttachment::setResolveLayer(int layer)

Sets the resolve texture layer to use.

See also resolveLayer().

void QRhiColorAttachment::setResolveLevel(int level)

Sets the resolve texture mip level to use.

See also resolveLevel().

void QRhiColorAttachment::setResolveTexture(QRhiTexture *tex)

Sets the resolve texture tex.

tex is expected to be a 2D texture or a 2D texture array. In either case, resolving targets a single mip level of a single layer (array element) of tex. The mip level and array layer are specified by resolveLevel() and resolveLayer().

An exception is multiview: when the color attachment is associated with a texture array and multiview is enabled, the resolve texture must also be a texture array with sufficient elements for all views. In this case all elements that correspond to views are resolved automatically; the behavior is similar to the following pseudo-code:

for (i = 0; i < multiViewCount(); ++i)
    resolve texture's layer() + i into resolveTexture's resolveLayer() + i

Setting a non-multisample texture to resolve a multisample texture or renderbuffer automatically at the end of the render pass is often preferable to working with multisample textures (and not setting a resolve texture), because it avoids the need for writing dedicated fragment shaders that work exclusively with multisample textures (sampler2DMS, texelFetch, etc.), and rather allows using the same shader as one would if the attachment's texture was not multisampled to begin with. This comes at the expense of an additional resource (the non-multisample tex).

See also resolveTexture().

void QRhiColorAttachment::setTexture(QRhiTexture *tex)

Sets the texture tex.

See also texture().

QRhiTexture *QRhiColorAttachment::texture() const

Returns the texture this attachment description references, or nullptr if there is none.

See also setTexture().