- Qt 6.4
- Qt 3D
- C++ Classes
- Qt3DRender
- QShaderImage
- Qt 6.4.3 Reference Documentation

# QShaderImage Class

class Qt3DRender::QShaderImage

Provides Image access to shader programs. More...

Header: | #include <QShaderImage>
CMake: | find_package(Qt6 REQUIRED COMPONENTS 3drender) target_link_libraries(mytarget PRIVATE Qt6::3drender)
qmake: | QT += 3drender
Since: | Qt 5.14
Instantiated By: | ShaderImage
Inherits: | Qt3DCore::QNode

- List of all members, including inherited members

## Public Types

enum | Access { ReadOnly, WriteOnly, ReadWrite }
enum | ImageFormat { NoFormat, Automatic, R8_UNorm, RG8_UNorm, RGBA8_UNorm, …, RGB10A2U }

## Properties

access : Access format : ImageFormat layer : int | layered : bool mipLevel : int

## Public Functions

Qt3DRender::QShaderImage::Access | access() const
Qt3DRender::QShaderImage::ImageFormat | format() const
int | layer() const
bool | layered() const
int | mipLevel() const
Qt3DRender::QAbstractTexture * | texture() const

## Public Slots

void | setAccess(Qt3DRender::QShaderImage::Access access)
void | setFormat(Qt3DRender::QShaderImage::ImageFormat format)
void | setLayer(int layer)
void | setLayered(bool layered)
void | setMipLevel(int mipLevel)
void | setTexture(Qt3DRender::QAbstractTexture *texture)

## Signals

void | accessChanged(Qt3DRender::QShaderImage::Access access)
void | formatChanged(Qt3DRender::QShaderImage::ImageFormat format)
void | layerChanged(int layer)
void | layeredChanged(bool layered)
void | mipLevelChanged(int mipLevel)
void | textureChanged(Qt3DRender::QAbstractTexture *texture)

## Detailed Description

To make the content of textures available for read and write operations in a shader, they need to exposed as QShaderImage. Textures can be composed of several mip levels, layers and faces. Additionally declaring a QShaderImage allows specifying which level, layer or face of the texture content we want to access.

QShaderImage has to be assigned as a QParameter's value and reference a valid Qt3DRender::QAbstractTexture to work properly.

If the referenced texture is a one-dimensional array, two-dimensional array, three-dimensional, cube map, cube map array, or two-dimensional multisample array texture, it is possible to bind either the entire texture level or a single layer or face of the texture level. This can be controlled with the layered property.

Support for QShaderImage is only supported with OpenGL 4 and partially with OpenGL ES 3.1 and 3.2.

OpenGL 4 supports the following image types:

GLSL Type | OpenGL Type Enum | Texture Type
--- | --- | ---
image1D | GL_IMAGE_1D | QTexture1D
image2D | GL_IMAGE_2D | QTexture2D
image3D | GL_IMAGE_3D | QTexture3D
image2DRect | GL_IMAGE_2D_RECT | QTextureRectangle
imageCube | GL_IMAGE_CUBE | QTextureCubeMap
imageBuffer | GL_IMAGE_BUFFER | QTextureBuffer
image1DArray | GL_IMAGE_1D_ARRAY | QTexture1DArray
image2DArray | GL_IMAGE_2D_ARRAY | QTexture2DArray
imageCubeArray | GL_IMAGE_CUBE_MAP_ARRAY | QTextureCubeMapArray
image2DMS | GL_IMAGE_2D_MULTISAMPLE | QTexture2DMultisample
image2DMSArray | GL_IMAGE_2D_MULTISAMPLE_ARRAY | QTexture2DMultisampleArray
iimage1D | GL_INT_IMAGE_1D | QTexture1D
iimage2D | GL_INT_IMAGE_2D | QTexture2D
iimage3D | GL_INT_IMAGE_3D | QTexture3D
iimage2DRect | GL_INT_IMAGE_2D_RECT | QTextureRectangle
iimageCube | GL_INT_IMAGE_CUBE | QTextureCubeMap
iimageBuffer | GL_INT_IMAGE_BUFFER | QTextureBuffer
iimage1DArray | GL_INT_IMAGE_1D_ARRAY | QTexture1DArray
iimage2DArray | GL_INT_IMAGE_2D_ARRAY | QTexture2DArray
iimageCubeArray | GL_INT_IMAGE_CUBE_MAP_ARRAY | QTextureCubeMapArray
iimage2DMS | GL_INT_IMAGE_2D_MULTISAMPLE | QTexture2DMultisample
iimage2DMSArray | GL_INT_IMAGE_2D_MULTISAMPLE_ARRAY | QTexture2DMultisampleArray
uimage1D | GL_UNSIGNED_INT_IMAGE_1D | QTexture1D
uimage2D | GL_UNSIGNED_INT_IMAGE_2D | QTexture2D
uimage3D | GL_UNSIGNED_INT_IMAGE_3D | QTexture3D
uimage2DRect | GL_UNSIGNED_INT_IMAGE_2D_RECT | QTextureRectangle
uimageCube | GL_UNSIGNED_INT_IMAGE_CUBE | QTextureCubeMap
uimageBuffer | GL_UNSIGNED_INT_IMAGE_BUFFER | QTextureBuffer
uimage1DArray | GL_UNSIGNED_INT_IMAGE_1D_ARRAY | QTexture1DArray
uimage2DArray | GL_UNSIGNED_INT_IMAGE_2D_ARRAY | QTexture2DArray
uimageCubeArray | GL_UNSIGNED_INT_IMAGE_CUBE_MAP_ARRAY | QTextureCubeMapArray
uimage2DMS | GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE | QTexture2DMultisample
uimage2DMSArray | GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE_ARRAY | QTexture2DMultisampleArray

OpenGL ES 3.1 supports the following image types:

GLSL Type | OpenGL Type Enum | Texture Type
--- | --- | ---
image2D | GL_IMAGE_2D | QTexture2D
image3D | GL_IMAGE_3D | QTexture3D
imageCube | GL_IMAGE_CUBE | QTextureCubeMap
image2DArray | GL_IMAGE_2D_ARRAY | QTexture2DArray
iimage2D | GL_INT_IMAGE_2D | QTexture2D
iimage3D | GL_INT_IMAGE_3D | QTexture3D
iimageCube | GL_INT_IMAGE_CUBE | QTextureCubeMap
iimage2DArray | GL_INT_IMAGE_2D_ARRAY | QTexture2DArray
uimage2D | GL_UNSIGNED_INT_IMAGE_2D | QTexture2D
uimage3D | GL_UNSIGNED_INT_IMAGE_3D | QTexture3D
uimageCube | GL_UNSIGNED_INT_IMAGE_CUBE | QTextureCubeMap
uimage2DArray | GL_UNSIGNED_INT_IMAGE_2D_ARRAY | QTexture2DArray

OpenGL ES 3.2 supports all of the OpenGL ES 3.1 image types as well as the following:

GLSL Type | OpenGL Type Enum | Texture Type
--- | --- | ---
imageBuffer | GL_IMAGE_BUFFER | QTextureBuffer
imageCubeArray | GL_IMAGE_CUBE_MAP_ARRAY | QTextureCubeMapArray
iimageBuffer | GL_IMAGE_BUFFER | QTextureBuffer
iimageCubeArray | GL_INT_IMAGE_CUBE_MAP_ARRAY | QTextureCubeMapArray
uimageBuffer | GL_UNSIGNED_INT_IMAGE_BUFFER | QTextureBuffer
uimageCubeArray | GL_UNSIGNED_INT_IMAGE_CUBE_MAP_ARRAY | QTextureCubeMapArray

Expected use would look like:

     Qt3DRender::QTexture2D *tex2D = new Qt3DRender::QTexture2D();
     ...
     Qt3DRender::QMaterial *material = new Qt3DRender::QMaterial();
     ...
     Qt3DRender::QParameter *imageParameter = new Qt3DRender::QParameter();
     Qt3DRender::QShaderImage *shaderImage = new Qt3DRender::QShaderImage();

     shaderImage->setTexture(tex2D);

     imageParameter->setName("imageUniformName");
     imageParameter->setValue(QVariant::fromValue(shaderImage));

     material->addParameter(imageParamenter);

## Member Type Documentation

### enum QShaderImage::Access

Constant | Value | Description
--- | --- | ---
`Qt3DRender::QShaderImage::ReadOnly` | `0` | Image will only be read from in shaders
`Qt3DRender::QShaderImage::WriteOnly` | `1` | Image will only be written into from shaders
`Qt3DRender::QShaderImage::ReadWrite` | `2` | Image will only be read and written into from shaders

### enum QShaderImage::ImageFormat

This list describes all possible image formats

Constant | Value | Description
--- | --- | ---
`Qt3DRender::QShaderImage::NoFormat` | `0` | GL_NONE
`Qt3DRender::QShaderImage::Automatic` | `1` | Qt 3D will try to determine the format automatically based on the referenced texture.
`Qt3DRender::QShaderImage::R8_UNorm` | `0x8229` | GL_R8 (GLSL type r8, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG8_UNorm` | `0x822B` | GL_RG8 (GLSL type rg8, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA8_UNorm` | `0x8058` | GL_RGBA8 (GLSL type rgba8, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::R16_UNorm` | `0x822A` | GL_R16 (GLSL type r16, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG16_UNorm` | `0x822C` | GL_RG16 (GLSL type rg16, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA16_UNorm` | `0x805B` | GL_RGBA16 (GLSL type rgba16, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::R8_SNorm` | `0x8F94` | GL_R8_SNORM (GLSL type r8_snorm, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG8_SNorm` | `0x8F95` | GL_RG8_SNORM (GLSL type rg8_snorm, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA8_SNorm` | `0x8F97` | GL_RGBA8_SNORM (GLSL type rgba8_snorm, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::R16_SNorm` | `0x8F98` | GL_R16_SNORM (GLSL type r16_snorm, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG16_SNorm` | `0x8F99` | GL_RG16_SNORM (GLSL type rg16_snorm, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA16_SNorm` | `0x8F9B` | GL_RGBA16_SNORM (GLSL type rgba16_snorm, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::R8U` | `0x8232` | GL_R8UI (GLSL type r8ui, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG8U` | `0x8238` | GL_RG8UI (GLSL type rg8ui, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA8U` | `0x8D7C` | GL_RGBA8UI (GLSL type rgba8ui, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::R16U` | `0x8234` | GL_R16UI (GLSL type r16ui, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG16U` | `0x823A` | GL_RG16UI (GLSL type rg16ui, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA16U` | `0x8D76` | GL_RGBA16UI (GLSL type rgba16ui, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::R32U` | `0x8236` | GL_R32UI (GLSL type r32ui, supported by OpenGL 4.2+, OpenGL ES 3.1)
`Qt3DRender::QShaderImage::RG32U` | `0x823C` | GL_RG32UI (GLSL type rg32ui, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA32U` | `0x8D70` | GL_RGBA32UI (GLSL type rgba32ui, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::R8I` | `0x8231` | GL_R8I (GLSL type r8i, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG8I` | `0x8237` | GL_RG8I (GLSL type rg8i, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA8I` | `0x8D8E` | GL_RGBA8I (GLSL type rgba8i, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::R16I` | `0x8233` | GL_R16I (GLSL type r16i, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG16I` | `0x8239` | GL_RG16I (GLSL type rg16i, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA16I` | `0x8D88` | GL_RGBA16I (GLSL type rgba16i, supported by OpenGL 4.2+, OpenGL ES 3.1)
`Qt3DRender::QShaderImage::R32I` | `0x8235` | GL_R32I (GLSL type r32i, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::RG32I` | `0x823B` | GL_RG32I (GLSL type rg32i, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA32I` | `0x8D82` | GL_RGBA32I (GLSL type rgba32i, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::R16F` | `0x822D` | GL_R16F (GLSL type r16f, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RG16F` | `0x822F` | GL_RG16F (GLSL type rg16f, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA16F` | `0x881A` | GL_RGBA16F (GLSL type rgba16f, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::R32F` | `0x822E` | GL_R32F (GLSL type r32f, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::RG32F` | `0x8230` | GL_RG32F (GLSL type rg32f, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGBA32F` | `0x8814` | GL_RGBA32F (GLSL type rgba32f, supported by OpenGL 4.2+, OpenGL ES 3.1+)
`Qt3DRender::QShaderImage::RG11B10F` | `0x8C3A` | GL_R11F_G11F_B10F (GLSL type r11f_g11f_b10f, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGB10A2` | `0x8059` | GL_RGB10_A2 (GLSL type rgb10_a2, supported by OpenGL 4.2+)
`Qt3DRender::QShaderImage::RGB10A2U` | `0x906F` | GL_RGB10_A2UI (GLSL type rgb10_a2ui, supported by OpenGL 4.2+)

## Property Documentation

### access : Access

Specifies the type of access we want to allow from our shader instances to the image. If a shader tries to write or read from an image that has incompatible access, the behavior is undefined.

The default value is QShaderImage::ReadWrite.

Access functions:

Qt3DRender::QShaderImage::Access | access() const
void | setAccess(Qt3DRender::QShaderImage::Access access)

Notifier signal:

void | accessChanged(Qt3DRender::QShaderImage::Access access)

### format : ImageFormat

Specifies the image format, which is essentially important when storing values in the Image from a shader.

The format doesn't have to be the same as the referenced texture's format. It however has to be compatible (matching in size but not necessarily by class type). For instance a texture of format R32F (size 32bits, class 1x32) could be used with an image of format RGBA8I (size 32bits, class 4x8). Table 8.27 of the OpenGL specifications shows the size and class for all supported Image formats.

By default Qt3D will try to set the image format to match that of the referenced texture.

The default value is QShaderImage::Automatic.

Access functions:

Qt3DRender::QShaderImage::ImageFormat | format() const
void | setFormat(Qt3DRender::QShaderImage::ImageFormat format)

Notifier signal:

void | formatChanged(Qt3DRender::QShaderImage::ImageFormat format)

### layer : int

Holds which layer out of the referenced texture should be used for the QShaderImage. This property does nothing if layered is set to true or if the reference texture's type isn't compatible with layers.

Note: When the referenced texture is of type cube map or cube map array and ĺayered is set to false, the face and layer are retrieved in the following manner:

     cubeMapLayer = layer / 6
     cubeMapFace = layer - (cubeMapLayer * 6)

The default value is 0.

Access functions:

int | layer() const
void | setLayer(int layer)

Notifier signal:

void | layerChanged(int layer)

### layered : bool

*

If set to true, if the referenced texture is a one-dimensional array, two-dimensional array, three-dimensional, cube map, cube map array, or two-dimensional multisample array texture, the entire level will be bound for all layers. If set to false, only the single layer specified by the layer property will be bound.

The default value is `false`.

Access functions:

bool | layered() const
void | setLayered(bool layered)

Notifier signal:

void | layeredChanged(bool layered)

### mipLevel : int

Holds which mipLevel out of the referenced texture should be used for the QShaderImage.

The default value is 0.

Access functions:

int | mipLevel() const
void | setMipLevel(int mipLevel)

Notifier signal:

void | mipLevelChanged(int mipLevel)