I initially implemented frexp() as an IR opcode with a lowering pass,
but since it returns a value and has an out-parameter, it would break
assumptions our optimization passes make about ir_expressions being pure
(i.e., having no side effects).
For example, if opt_tree_grafting encounters this code:
uniform float u;
void main()
{
int exp;
float f = frexp(u, out exp);
float g = float(exp)/256.0;
float h = float(exp) + 1.0;
gl_FragColor = vec4(f, g, h, g + h);
}
it may try to optimize it to this:
uniform float u;
void main()
{
int exp;
float g = float(exp)/256.0;
float h = float(exp) + 1.0;
gl_FragColor = vec4(frexp(u, out exp), g, h, g + h);
}
Some hardware has an instruction which performs frexp(), but we would
need some other compiler infrastructure to be able to generate it, such
as an intrinsics system that would allow backends to emit specific code
for particular bits of IR.
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Note the parameter name change in the int version of ir_constant, to
avoid the conflict with the loop iterator.
v2: Make analogous change to builtin_builder::imm().
Reviewed-by: Paul Berry <stereotype441@gmail.com>
These functions are defined in EXT_texture_array, which makes no
mention of what shader types they should be allowed in. At the time
EXT_texture_array was introduced, functions ending in "Lod" were
available only in vertex shaders, however this restriction was lifted
in later spec versions and extensions.
We already have the function lod_exists_in_stage() for figuring out
whether functions ending in "Lod" should be available, so just re-use
that.
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Everyone at the Khronos meeting was as surprised that GLSL didn't
already support this as we were. Several vendors said they'd ship it,
but there didn't seem to be enough interest to put in the effort to make
it ARB or KHR.
v2: Fix a couple typos and rename the spec file to
EXT_shader_integer_mix.spec. Suggested by Roland.
Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
We used to pass the number of components actually used for the
coordinate (rather than padding, shadow comparitors, and projectors) by
hand, specifying it on every _texture() call.
The new helper function can just compute this, eliminating a lot of
potential mistakes.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Because why doesn't GLSL allow you to do this already?
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
This creates a new replacement for the existing built-in function code.
The new module lives in builtin_functions.cpp (not builtin_function.cpp)
and exists in parallel with the existing system. It isn't used yet.
The new built-in function code takes a significantly different approach:
Instead of implementing built-ins via printed IR, build time scripts,
and run time parsing, we now implement them directly in C++, using
ir_builder. This translates to faster load times, and a much less
complex build system.
It also takes a different approach to built-in availability: each
signature now stores a boolean predicate, which makes it easy to
construct arbitrary expressions based on _mesa_glsl_parse_state's
fields. This is much more flexible than the old system, and also
easier to use.
Built-ins are also now stored in a single gl_shader object, rather
than being spread out across a number of shaders that need to be linked.
When searching for a matching prototype, we simply consult the
availability predicate. This also simplifies the code.
v2: Incorporate Matt Turner's feedback: use the new fma() function rather
than expr(). Don't expose textureQueryLOD() in GLSL 4.00 (since it
was renamed to textureQueryLod()). Also correct some #undefs.
v3: Incorporate Paul Berry's feedback: rename legacy to compatibility;
add comments to explain a few things; fix uvec availability; include
shaderobj.h instead of repeating the _mesa_new_shader prototype.
v4: Fix lack of TEX_PROJECT on textureProjGrad[Offset] (caught by oglc).
Add an out_var convenience function (more feedback by Matt Turner).
v5: Rework availability predicates for Lod functions. They were broken.
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Enthusiastically-acked-by: Paul Berry <stereotype441@gmail.com>
