Makes the dual source implementation in wgpu WebGPU spec compliant.
Furthermore, makes the dual source blending extension available when targeting WebGPU.
This allows abstract-typed expressions to be used for some or all of
the switch selector and case selectors. If these are all not
convertible to the same concrete scalar integer type we return an
error. If all the selector expressions are abstract then they are
concretized to i32.
The note previously provided by the relevant error message, suggesting
adding or removing the `u` suffix from case values, has been
removed. While useful for simple literal values, it was comically
incorrect for more complex case expressions. The error message should
still be useful enough to allow the user to easily identify the
problem.
Instead allow the const to be converted each time it is const
evaluated as part of another expression. This allows an abstract const
to be used as a different type depending on the context.
As a result, abstract types may now find their way in to the IR, which
we don't want. This occurs because the compact pass treats named
expressions as used, mostly so that our snapshot tests are more
useful, and therefore does not remove them. To prevent this, we avoid
adding abstract-typed local consts to the named expressions list. This
will have no functional effect on any shaders produced by the
backends, but some unused local const declarations will no longer be
present.
When an entry point's return type is anonymous, have
`naga::proc::Namer` assign it a name based on its shader stage.
Remove bespoke logic for this from the WGSL backend.
Fixes#7263.
Parsing currently fails for shaders that attempt to dynamically index
an abstract-typed array (or vector, etc), like so:
var x = array(1, 2, 3)[i];
This is caused by attempting to concretize the Expression::Access
expression, which the ConstantEvaluator fails to do so due to the
presence of a non-constant expression.
To solve this, this patch concretizes the base type *prior* to
indexing it (for non-constant indices), meaning the constant evaluator
never sees any non-constant expressions. This matches the WGSL
specification:
When an abstract array value e is indexed by an expression that is
not a const-expression, then the array is concretized before the
index is applied.
(Similar applies for both vectors and matrices, too.)
This may be somewhat non-optimal in that if there are multiple
accesses of the same abstract expression, we will produce duplicated
concretized versions of that expression. This seems unlikely to be a
major issue in practice, and we can always improve this if and when we
encounter a real issue caused by it.
Instead allow the const to be converted and each time it is const
evaluated as part of another expression. This allows an abstract const
to be used as a different type depending on the context.
A consequence of this is that abstract types may now find their way to
the validation stage, which we don't want. We therefore additionally
now ensure that the compact pass removes global constants of abstract
types. This will have no *functional* effect on shaders generated by
the backends, as the expressions belonging to the abstract consts in
the IR will not actually be used, as any usage in the input shader
will have been const-evaluated away. Certain unused const declarations
will now be removed, however, as can be seen by the effect on the
snapshot outputs.
Adds infrastructure to the MSL backend for emitting helper functions,
based upon the existing HLSL backend equivalent. Emit helper functions
for MathFunction::Abs and UnaryOperator::Negate with a signed integer
scalar or vector operand. And for BinaryOperator::Divide and
BinaryOperator::Modulo with signed or unsigned integer scalar or
vector operands.
Abs and Negate are written to avoid signed integer overflow when the
operand equals INT_MIN. This is achieved by bitcasting the value to
unsigned and using the negation operator, then bitcasting the result
back to signed.
Division and Modulo avoid undefined bevaviour for INT_MIN / -1 and
divide-by-zero by using 1 for the divisor instead. Additionally we
avoid undefined behaviour when using the modulo operator when either
or both operands are negative by using the equation from the WGSL
spec, using division, subtraction and multiplication, rather than
MSL's modulus operator.
Lastly, as the usage of the wrapper function for unary integer
negation makes the negation_avoids_prefix_decrement() testcase less
interesting, we extend it to additionally test negating floats.
When lowering a return statement, call expression_for_abstract()
rather than expression() to avoid concretizing the return value. Then,
if the function has a return type, call try_automatic_conversions() to
attempt to convert our return value to the correct type.
This has the unfortunate side effect that some errors that would have
been caught by the validator are instead encountered as conversion
errors by the parser. This may result in a slightly less descriptive
error message in some cases. (See the change to the invalid_functions()
test, for example.)
Implement WGSL frontend and WGSL, SPIR-V, HLSL, MSL, and GLSL
backends. WGSL and SPIR-V backends natively support the instruction.
MSL and HLSL emulate it by casting to f16 and back to f32. GLSL does
similar but must (mis)use (un)pack2x16 to do so.
Introduce a new module, `naga::back::continue_forward`, containing
shared code for rendering Naga `Continue` statements as backend
`break` statements and assignments to introduced `bool` locals.
See the module's documentation for details.
- [hlsl-out] Transform degenerate single body switches into `do-while`
loops. Properly render `Continue` statements enclosed by
`Switch` statements enclosed by `Loop` statements.
- [glsl-out] Transform degenerate single body switches into `do-while`
loops.
Improve `naga xtask validate spv` error message.
Fixes#4485.
Fixes#4514.
This fixes 2 issues:
- we used to index `adjusted_global_expressions` with the handle index of the constant instead of its initializer
- we used to adjust the initializer multiple times if the arena contained multiple `Expression::Constant`s pointing to the same constant
Allow `LocalVariable::init` to be an override expression.
Note that this is unrelated to WGSL compliance. The WGSL front end
already accepts any sort of expression as an initializer for
`LocalVariable`s, but initialization by an override expression was
handled in the same way as initialization by a runtime expression, via
an explicit `Store` statement.
This commit merely lets us skip the `Store` when the initializer is an
override expression, producing slightly cleaner output in some cases.
* add GL_EXT_texture_shadow_lod feature detection
* allow more cases of cube depth texture sampling in glsl
* add test for sampling a cubemap array depth texture with lod
* add test for chosing GL_EXT_texture_shadow_lod over the grad workaround if instructed
* add changelog entry for GL_EXT_texture_shadow_lod
* fix criteria for requiring and using TEXTURE_SHADOW_LOD
* require gles 320 for textureSampling over cubeArrayShadow
* prevent false positives in TEXTURE_SHADOW_LOD in checks
* make workaround_lod_with_grad usecase selection less context dependant
* move 3d array texture error into the validator
* correct ImageSample logic errors
