Texel output instructions are SPIR-V image instructions that write to an image. Texel output operations are a set of steps that are performed on state, coordinates, and texel values while processing a texel output instruction, and which are common to some or all texel output instructions. They include the following steps, which are performed in the listed order:
Texel output validation operations inspect instruction/image state or coordinates, and in certain circumstances cause the write to have no effect. There are a series of validations that the texel undergoes.
The integer texel coordinates are validated according to the same rules as for texel input coordinate validation.
If the texel fails integer texel coordinate validation, then the write has no effect.
If the texel attempts to write to an unbound region of a sparse image, the
texel is a sparse unbound texel.
In such a case, if the VkPhysicalDeviceSparseProperties
property
residencyNonResidentStrict
is VK_TRUE
, the sparse unbound texel
write has no effect.
If residencyNonResidentStrict
is VK_FALSE
, the effect of the
write is undefined but must be safe.
In addition, the write may have a side effect that is visible to other
image instructions, but must not be written to any device memory
allocation.
Texels undergo a format conversion from the floating point, signed, or
unsigned integer type of the texel data to the VkFormat
of the image
view.
Any unused components are ignored.
Each component is converted based on its type and size (as defined in the
Format Definition section for each
VkFormat
), using the appropriate equations in
16-Bit Floating-Point Numbers and
Fixed-Point Data Conversion.