New HLSL syntax is required to support tiled resources in
Shader Model 5.0 (allowed only on devices with Tiled Resources support).
Each relevant HLSL intrinsic method for tiled resources (see the table below)
accepts either one (feedback) or two (clamp
and feedback in this order) additional
optional parameters. For example, the Sample method is:
Sample(sampler, location
[, offset [, clamp [, feedback] ] ]).
The offset,
clamp and
feedback parameters are optional.
Programmers have to specify all optional parameters up to the one they need,
which is consistent with the C++ rules for default function arguments. For
example, if the feedback status is
needed, both offset and
clamp parameters need to be explicitly
supplied to Sample, even though they may not be logically needed.
The clamp
parameter is a scalar float value. The literal value of
clamp=0.0f indicates that clamp
operation is not performed.
The feedback
parameter is a uint variable that can
be supplied to memory-access querying intrinsic: CheckAccessFullyMapped. Programmers must not modify or interpret the value of the
feedback parameter; however, the
compiler does not provide any advanced analysis and diagnostics to detect this.
There is one HLSL intrinsic to query the feedback status:
bool CheckAccessFullyMapped(in
uint FeedbackVar);
CheckAccessFullyMapped
interprets the value of FeedbackVar
and returns true if all data being
accessed was mapped in the resource; otherwise,
CheckAccessFullyMapped returns
false.
If either clamp
or feedback parameter is present, the
compiler emits a variant of the basic instruction. For example, Sample of a
tiled resource generates sample_cl_s instruction. If neither
clamp nor
feedback is specified, the compiler
emits the basic instruction, so that there is no change from the current
behavior. The clamp value of 0.0f
indicates that no clamp is performed; thus, the driver compiler can further
tailor the instruction to the target hardware. If
feedback is a NULL register in an
instruction, the feedback is unused;
thus, the driver compiler can further tailor the instruction to the target
architecture.
If the HLSL compiler infers that
clamp is 0.0f and feedback
is unused, the compiler emits the corresponding basic instruction (e.g., sample
rather than sample_cl_s).
If a tiled resource access consists of several constituent
byte code instructions, e.g., for structured resources, the compiler aggregates
individual feedback values via the OR operation to produce the final feedback
value. Therefore, programmers see a single feedback value for such a complex
access.
This is the summary table of HLSL intrinsic methods changed
to support feedback and/or clamp. These all work on tiled and non-tiled resources of all dimensions.
Non-tiled resources always appear to be fully mapped.
| HLSL Objects | Intrinsic methods with feedback
option (*) - also has clamp option |
|
[RW]Texture2D [RW]Texture2DArray TextureCUBE TextureCUBEArray |
Gather GatherRed GatherGreen GatherBlue GatherAlpha GatherCmp GatherCmpRed GatherCmpGreen GatherCmpBlue GatherCmpAlpha |
|
[RW]Texture1D [RW]Texture1DArray [RW]Texture2D [RW]Texture2DArray [RW]Texture3D TextureCUBE TextureCUBEArray |
Sample* SampleBias* SampleCmp* SampleCmpLevelZero SampleGrad* SampleLevel |
|
[RW]Texture1D [RW]Texture1DArray [RW]Texture2D Texture2DMS [RW]Texture2DArray Texture2DArrayMS [RW]Texture3D [RW]Buffer [RW]ByteAddressBuffer [RW]StructuredBuffer |
Load |
New HLSL syntax is required to support tiled resources in
Shader Model 5.0 (allowed only on devices with Tiled Resources support).
Each relevant HLSL intrinsic method for tiled resources (see the table below)
accepts either one (feedback) or two (clamp
and feedback in this order) additional
optional parameters. For example, the Sample method is:
Sample(sampler, location
[, offset [, clamp [, feedback] ] ]).
The offset,
clamp and
feedback parameters are optional.
Programmers have to specify all optional parameters up to the one they need,
which is consistent with the C++ rules for default function arguments. For
example, if the feedback status is
needed, both offset and
clamp parameters need to be explicitly
supplied to Sample, even though they may not be logically needed.
The clamp
parameter is a scalar float value. The literal value of
clamp=0.0f indicates that clamp
operation is not performed.
The feedback
parameter is a uint variable that can
be supplied to memory-access querying intrinsic: CheckAccessFullyMapped. Programmers must not modify or interpret the value of the
feedback parameter; however, the
compiler does not provide any advanced analysis and diagnostics to detect this.
There is one HLSL intrinsic to query the feedback status:
bool CheckAccessFullyMapped(in
uint FeedbackVar);
CheckAccessFullyMapped
interprets the value of FeedbackVar
and returns true if all data being
accessed was mapped in the resource; otherwise,
CheckAccessFullyMapped returns
false.
If either clamp
or feedback parameter is present, the
compiler emits a variant of the basic instruction. For example, Sample of a
tiled resource generates sample_cl_s instruction. If neither
clamp nor
feedback is specified, the compiler
emits the basic instruction, so that there is no change from the current
behavior. The clamp value of 0.0f
indicates that no clamp is performed; thus, the driver compiler can further
tailor the instruction to the target hardware. If
feedback is a NULL register in an
instruction, the feedback is unused;
thus, the driver compiler can further tailor the instruction to the target
architecture.
If the HLSL compiler infers that
clamp is 0.0f and feedback
is unused, the compiler emits the corresponding basic instruction (e.g., sample
rather than sample_cl_s).
If a tiled resource access consists of several constituent
byte code instructions, e.g., for structured resources, the compiler aggregates
individual feedback values via the OR operation to produce the final feedback
value. Therefore, programmers see a single feedback value for such a complex
access.
This is the summary table of HLSL intrinsic methods changed
to support feedback and/or clamp. These all work on tiled and non-tiled resources of all dimensions.
Non-tiled resources always appear to be fully mapped.
| HLSL Objects | Intrinsic methods with feedback
option (*) - also has clamp option |
|
[RW]Texture2D [RW]Texture2DArray TextureCUBE TextureCUBEArray |
Gather GatherRed GatherGreen GatherBlue GatherAlpha GatherCmp GatherCmpRed GatherCmpGreen GatherCmpBlue GatherCmpAlpha |
|
[RW]Texture1D [RW]Texture1DArray [RW]Texture2D [RW]Texture2DArray [RW]Texture3D TextureCUBE TextureCUBEArray |
Sample* SampleBias* SampleCmp* SampleCmpLevelZero SampleGrad* SampleLevel |
|
[RW]Texture1D [RW]Texture1DArray [RW]Texture2D Texture2DMS [RW]Texture2DArray Texture2DArrayMS [RW]Texture3D [RW]Buffer [RW]ByteAddressBuffer [RW]StructuredBuffer |
Load |