ShaderImage QML Type
Provides Image access to shader programs. More...
| Import Statement: | import Qt3D.Render 2.15 |
| Since: | Qt 5.14 |
| Instantiates: | QShaderImage |
Properties
Detailed Description
To make the content of textures available for read and write operations in a shader, they need to exposed as ShaderImage. Textures can be composed of several mip levels, layers and faces. Additionally declaring a ShaderImage allows specifying which level, layer or face of the texture content we want to access.
ShaderImage has to be assigned as a Parameter's value and reference a valid Qt3D.Render.AbstractTexture 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 ShaderImage 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 | Texture1D |
| image2D | GL_IMAGE_2D | Texture2D |
| image3D | GL_IMAGE_3D | Texture3D |
| image2DRect | GL_IMAGE_2D_RECT | TextureRectangle |
| imageCube | GL_IMAGE_CUBE | TextureCubeMap |
| imageBuffer | GL_IMAGE_BUFFER | TextureBuffer |
| image1DArray | GL_IMAGE_1D_ARRAY | Texture1DArray |
| image2DArray | GL_IMAGE_2D_ARRAY | Texture2DArray |
| imageCubeArray | GL_IMAGE_CUBE_MAP_ARRAY | TextureCubeMapArray |
| image2DMS | GL_IMAGE_2D_MULTISAMPLE | Texture2DMultisample |
| image2DMSArray | GL_IMAGE_2D_MULTISAMPLE_ARRAY | Texture2DMultisampleArray |
| iimage1D | GL_INT_IMAGE_1D | Texture1D |
| iimage2D | GL_INT_IMAGE_2D | Texture2D |
| iimage3D | GL_INT_IMAGE_3D | Texture3D |
| iimage2DRect | GL_INT_IMAGE_2D_RECT | TextureRectangle |
| iimageCube | GL_INT_IMAGE_CUBE | TextureCubeMap |
| iimageBuffer | GL_INT_IMAGE_BUFFER | TextureBuffer |
| iimage1DArray | GL_INT_IMAGE_1D_ARRAY | Texture1DArray |
| iimage2DArray | GL_INT_IMAGE_2D_ARRAY | Texture2DArray |
| iimageCubeArray | GL_INT_IMAGE_CUBE_MAP_ARRAY | TextureCubeMapArray |
| iimage2DMS | GL_INT_IMAGE_2D_MULTISAMPLE | Texture2DMultisample |
| iimage2DMSArray | GL_INT_IMAGE_2D_MULTISAMPLE_ARRAY | Texture2DMultisampleArray |
| uimage1D | GL_UNSIGNED_INT_IMAGE_1D | Texture1D |
| uimage2D | GL_UNSIGNED_INT_IMAGE_2D | Texture2D |
| uimage3D | GL_UNSIGNED_INT_IMAGE_3D | Texture3D |
| uimage2DRect | GL_UNSIGNED_INT_IMAGE_2D_RECT | TextureRectangle |
| uimageCube | GL_UNSIGNED_INT_IMAGE_CUBE | TextureCubeMap |
| uimageBuffer | GL_UNSIGNED_INT_IMAGE_BUFFER | TextureBuffer |
| uimage1DArray | GL_UNSIGNED_INT_IMAGE_1D_ARRAY | Texture1DArray |
| uimage2DArray | GL_UNSIGNED_INT_IMAGE_2D_ARRAY | Texture2DArray |
| uimageCubeArray | GL_UNSIGNED_INT_IMAGE_CUBE_MAP_ARRAY | TextureCubeMapArray |
| uimage2DMS | GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE | Texture2DMultisample |
| uimage2DMSArray | GL_UNSIGNED_INT_IMAGE_2D_MULTISAMPLE_ARRAY | Texture2DMultisampleArray |
OpenGL ES 3.1 supports the following image types:
| GLSL Type | OpenGL Type Enum | Texture Type |
|---|---|---|
| image2D | GL_IMAGE_2D | Texture2D |
| image3D | GL_IMAGE_3D | Texture3D |
| imageCube | GL_IMAGE_CUBE | TextureCubeMap |
| image2DArray | GL_IMAGE_2D_ARRAY | Texture2DArray |
| iimage2D | GL_INT_IMAGE_2D | Texture2D |
| iimage3D | GL_INT_IMAGE_3D | Texture3D |
| iimageCube | GL_INT_IMAGE_CUBE | TextureCubeMap |
| iimage2DArray | GL_INT_IMAGE_2D_ARRAY | Texture2DArray |
| uimage2D | GL_UNSIGNED_INT_IMAGE_2D | Texture2D |
| uimage3D | GL_UNSIGNED_INT_IMAGE_3D | Texture3D |
| uimageCube | GL_UNSIGNED_INT_IMAGE_CUBE | TextureCubeMap |
| uimage2DArray | GL_UNSIGNED_INT_IMAGE_2D_ARRAY | Texture2DArray |
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 | TextureBuffer |
| imageCubeArray | GL_IMAGE_CUBE_MAP_ARRAY | TextureCubeMapArray |
| iimageBuffer | GL_IMAGE_BUFFER | TextureBuffer |
| iimageCubeArray | GL_INT_IMAGE_CUBE_MAP_ARRAY | TextureCubeMapArray |
| uimageBuffer | GL_UNSIGNED_INT_IMAGE_BUFFER | TextureBuffer |
| uimageCubeArray | GL_UNSIGNED_INT_IMAGE_CUBE_MAP_ARRAY | TextureCubeMapArray |
Expected use would look like:
import Qt3D.Render 2.14
Entity {
...
Texture2D {
id: tex2D
...
}
Material {
parameters: Parameter {
name: "imageUniformName"
value: ShaderImage {
texture: tex2D
}
}
...
}
...
}
Property Documentation
access : enumeration |
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.
| Constant | Description |
|---|---|
ShaderImage.ReadOnly | Read-only access. |
ShaderImage.WriteOnly | Write-only access. |
ShaderImage.ReadWrite | Read-write access. |
The default value is ShaderImage.ReadWrite.
format : enumeration |
Specifies the image format, which is essentially important when storing values in the ShaderImage 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 ShaderImage.Automatic.
layer : int |
Holds which layer out of the referenced texture should be used for the ShaderImage. 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.
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.
mipLevel : int |
Holds which mipLevel out of the referenced texture should be used for the ShaderImage.
The default value is 0.