use super::{BackendResult, Error, Version, Writer};
use crate::{
back::glsl::{Options, WriterFlags},
AddressSpace, Binding, Expression, Handle, ImageClass, ImageDimension, Interpolation,
SampleLevel, Sampling, Scalar, ScalarKind, ShaderStage, StorageFormat, Type, TypeInner,
};
use std::fmt::Write;
bitflags::bitflags! {
/// Structure used to encode additions to GLSL that aren't supported by all versions.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct Features: u32 {
/// Buffer address space support.
const BUFFER_STORAGE = 1;
const ARRAY_OF_ARRAYS = 1 << 1;
/// 8 byte floats.
const DOUBLE_TYPE = 1 << 2;
/// More image formats.
const FULL_IMAGE_FORMATS = 1 << 3;
const MULTISAMPLED_TEXTURES = 1 << 4;
const MULTISAMPLED_TEXTURE_ARRAYS = 1 << 5;
const CUBE_TEXTURES_ARRAY = 1 << 6;
const COMPUTE_SHADER = 1 << 7;
/// Image load and early depth tests.
const IMAGE_LOAD_STORE = 1 << 8;
const CONSERVATIVE_DEPTH = 1 << 9;
/// Interpolation and auxiliary qualifiers.
///
/// Perspective, Flat, and Centroid are available in all GLSL versions we support.
const NOPERSPECTIVE_QUALIFIER = 1 << 11;
const SAMPLE_QUALIFIER = 1 << 12;
const CLIP_DISTANCE = 1 << 13;
const CULL_DISTANCE = 1 << 14;
/// Sample ID.
const SAMPLE_VARIABLES = 1 << 15;
/// Arrays with a dynamic length.
const DYNAMIC_ARRAY_SIZE = 1 << 16;
const MULTI_VIEW = 1 << 17;
/// Texture samples query
const TEXTURE_SAMPLES = 1 << 18;
/// Texture levels query
const TEXTURE_LEVELS = 1 << 19;
/// Image size query
const IMAGE_SIZE = 1 << 20;
/// Dual source blending
const DUAL_SOURCE_BLENDING = 1 << 21;
/// Instance index
///
/// We can always support this, either through the language or a polyfill
const INSTANCE_INDEX = 1 << 22;
/// Sample specific LODs of cube / array shadow textures
const TEXTURE_SHADOW_LOD = 1 << 23;
/// Subgroup operations
const SUBGROUP_OPERATIONS = 1 << 24;
/// Image atomics
const TEXTURE_ATOMICS = 1 << 25;
}
}
/// Helper structure used to store the required [`Features`] needed to output a
/// [`Module`](crate::Module)
///
/// Provides helper methods to check for availability and writing required extensions
pub struct FeaturesManager(Features);
impl FeaturesManager {
/// Creates a new [`FeaturesManager`] instance
pub const fn new() -> Self {
Self(Features::empty())
}
/// Adds to the list of required [`Features`]
pub fn request(&mut self, features: Features) {
self.0 |= features
}
/// Checks if the list of features [`Features`] contains the specified [`Features`]
pub fn contains(&mut self, features: Features) -> bool {
self.0.contains(features)
}
/// Checks that all required [`Features`] are available for the specified
/// [`Version`] otherwise returns an [`Error::MissingFeatures`].
pub fn check_availability(&self, version: Version) -> BackendResult {
// Will store all the features that are unavailable
let mut missing = Features::empty();
// Helper macro to check for feature availability
macro_rules! check_feature {
// Used when only core glsl supports the feature
($feature:ident, $core:literal) => {
if self.0.contains(Features::$feature)
&& (version < Version::Desktop($core) || version.is_es())
{
missing |= Features::$feature;
}
};
// Used when both core and es support the feature
($feature:ident, $core:literal, $es:literal) => {
if self.0.contains(Features::$feature)
&& (version < Version::Desktop($core) || version < Version::new_gles($es))
{
missing |= Features::$feature;
}
};
}
check_feature!(COMPUTE_SHADER, 420, 310);
check_feature!(BUFFER_STORAGE, 400, 310);
check_feature!(DOUBLE_TYPE, 150);
check_feature!(CUBE_TEXTURES_ARRAY, 130, 310);
check_feature!(MULTISAMPLED_TEXTURES, 150, 300);
check_feature!(MULTISAMPLED_TEXTURE_ARRAYS, 150, 310);
check_feature!(ARRAY_OF_ARRAYS, 120, 310);
check_feature!(IMAGE_LOAD_STORE, 130, 310);
check_feature!(CONSERVATIVE_DEPTH, 130, 300);
check_feature!(NOPERSPECTIVE_QUALIFIER, 130);
check_feature!(SAMPLE_QUALIFIER, 400, 320);
check_feature!(CLIP_DISTANCE, 130, 300 /* with extension */);
check_feature!(CULL_DISTANCE, 450, 300 /* with extension */);
check_feature!(SAMPLE_VARIABLES, 400, 300);
check_feature!(DYNAMIC_ARRAY_SIZE, 430, 310);
check_feature!(DUAL_SOURCE_BLENDING, 330, 300 /* with extension */);
check_feature!(SUBGROUP_OPERATIONS, 430, 310);
check_feature!(TEXTURE_ATOMICS, 420, 310);
match version {
Version::Embedded { is_webgl: true, .. } => check_feature!(MULTI_VIEW, 140, 300),
_ => check_feature!(MULTI_VIEW, 140, 310),
};
// Only available on glsl core, this means that opengl es can't query the number
// of samples nor levels in a image and neither do bound checks on the sample nor
// the level argument of texelFecth
check_feature!(TEXTURE_SAMPLES, 150);
check_feature!(TEXTURE_LEVELS, 130);
check_feature!(IMAGE_SIZE, 430, 310);
check_feature!(TEXTURE_SHADOW_LOD, 200, 300);
// Return an error if there are missing features
if missing.is_empty() {
Ok(())
} else {
Err(Error::MissingFeatures(missing))
}
}
/// Helper method used to write all needed extensions
///
/// # Notes
/// This won't check for feature availability so it might output extensions that aren't even
/// supported.[`check_availability`](Self::check_availability) will check feature ava
ilability
pub fn write(&self, options: &Options, mut out: impl Write) -> BackendResult {
if self.0.contains(Features::COMPUTE_SHADER) && !options.version.is_es() {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_compute_shader.txt
writeln!(out, "#extension GL_ARB_compute_shader : require")?;
}
if self.0.contains(Features::BUFFER_STORAGE) && !options.version.is_es() {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_shader_storage_buffer_object.txt
writeln!(
out,
"#extension GL_ARB_shader_storage_buffer_object : require"
)?;
}
if self.0.contains(Features::DOUBLE_TYPE) && options.version < Version::Desktop(400) {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_gpu_shader_fp64.txt
writeln!(out, "#extension GL_ARB_gpu_shader_fp64 : require")?;
}
if self.0.contains(Features::CUBE_TEXTURES_ARRAY) {
if options.version.is_es() {
// https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_texture_cube_map_array.txt
writeln!(out, "#extension GL_EXT_texture_cube_map_array : require")?;
} else if options.version < Version::Desktop(400) {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_texture_cube_map_array.txt
writeln!(out, "#extension GL_ARB_texture_cube_map_array : require")?;
}
}
if self.0.contains(Features::MULTISAMPLED_TEXTURE_ARRAYS) && options.version.is_es() {
// https://www.khronos.org/registry/OpenGL/extensions/OES/OES_texture_storage_multisample_2d_array.txt
writeln!(
out,
"#extension GL_OES_texture_storage_multisample_2d_array : require"
)?;
}
if self.0.contains(Features::ARRAY_OF_ARRAYS) && options.version < Version::Desktop(430) {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_arrays_of_arrays.txt
writeln!(out, "#extension ARB_arrays_of_arrays : require")?;
}
if self.0.contains(Features::IMAGE_LOAD_STORE) {
if self.0.contains(Features::FULL_IMAGE_FORMATS) && options.version.is_es() {
// https://www.khronos.org/registry/OpenGL/extensions/NV/NV_image_formats.txt
writeln!(out, "#extension GL_NV_image_formats : require")?;
}
if options.version < Version::Desktop(420) {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_shader_image_load_store.txt
writeln!(out, "#extension GL_ARB_shader_image_load_store : require")?;
}
}
if self.0.contains(Features::CONSERVATIVE_DEPTH) {
if options.version.is_es() {
// https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_conservative_depth.txt
writeln!(out, "#extension GL_EXT_conservative_depth : require")?;
}
if options.version < Version::Desktop(420) {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_conservative_depth.txt
writeln!(out, "#extension GL_ARB_conservative_depth : require")?;
}
}
if (self.0.contains(Features::CLIP_DISTANCE) || self.0.contains(Features::CULL_DISTANCE))
&& options.version.is_es()
{
// https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_clip_cull_distance.txt
writeln!(out, "#extension GL_EXT_clip_cull_distance : require")?;
}
if self.0.contains(Features::SAMPLE_VARIABLES) && options.version.is_es() {
// https://www.khronos.org/registry/OpenGL/extensions/OES/OES_sample_variables.txt
writeln!(out, "#extension GL_OES_sample_variables : require")?;
}
if self.0.contains(Features::MULTI_VIEW) {
if let Version::Embedded { is_webgl: true, .. } = options.version {
// https://www.khronos.org/registry/OpenGL/extensions/OVR/OVR_multiview2.txt
writeln!(out, "#extension GL_OVR_multiview2 : require")?;
} else {
// https://github.com/KhronosGroup/GLSL/blob/master/extensions/ext/GL_EXT_multiview.txt
writeln!(out, "#extension GL_EXT_multiview : require")?;
}
}
if self.0.contains(Features::TEXTURE_SAMPLES) {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_shader_texture_image_samples.txt
writeln!(
out,
"#extension GL_ARB_shader_texture_image_samples : require"
)?;
}
if self.0.contains(Features::TEXTURE_LEVELS) && options.version < Version::Desktop(430) {
// https://www.khronos.org/registry/OpenGL/extensions/ARB/ARB_texture_query_levels.txt
writeln!(out, "#extension GL_ARB_texture_query_levels : require")?;
}
if self.0.contains(Features::DUAL_SOURCE_BLENDING) && options.version.is_es() {
// https://registry.khronos.org/OpenGL/extensions/EXT/EXT_blend_func_extended.txt
writeln!(out, "#extension GL_EXT_blend_func_extended : require")?;
}
if self.0.contains(Features::INSTANCE_INDEX) {
if options.writer_flags.contains(WriterFlags::DRAW_PARAMETERS) {
// https://registry.khronos.org/OpenGL/extensions/ARB/ARB_shader_draw_parameters.txt
writeln!(out, "#extension GL_ARB_shader_draw_parameters : require")?;
}
}
if self.0.contains(Features::TEXTURE_SHADOW_LOD) {
// https://registry.khronos.org/OpenGL/extensions/EXT/EXT_texture_shadow_lod.txt
writeln!(out, "#extension GL_EXT_texture_shadow_lod : require")?;
}
if self.0.contains(Features::SUBGROUP_OPERATIONS) {
// https://registry.khronos.org/OpenGL/extensions/KHR/KHR_shader_subgroup.txt
writeln!(out, "#extension GL_KHR_shader_subgroup_basic : require")?;
writeln!(out, "#extension GL_KHR_shader_subgroup_vote : require")?;
writeln!(
out,
"#extension GL_KHR_shader_subgroup_arithmetic : require"
)?;
writeln!(out, "#extension GL_KHR_shader_subgroup_ballot : require")?;
writeln!(out, "#extension GL_KHR_shader_subgroup_shuffle : require")?;
writeln!(
out,
"#extension GL_KHR_shader_subgroup_shuffle_relative : require"
)?;
}
if self.0.contains(Features::TEXTURE_ATOMICS) {
// https://www.khronos.org/registry/OpenGL/extensions/OES/OES_shader_image_atomic.txt
writeln!(out, "#extension GL_OES_shader_image_atomic : require")?;
}
Ok(())
}
}
impl<W> Writer<'_, W> {
/// Helper method that searches the module for all the needed [`Features`]
///
/// # Errors
/// If the version doesn't support any of the needed [`Features`] a
/// [`Error::MissingFeatures`] will be returned
pub(super) fn collect_required_features(&mut self) -> BackendResult {
let ep_info = self.info.get_entry_point(self.entry_point_idx as usize);
if let Some(depth_test) = self.entry_point.early_depth_test {
// If IMAGE_LOAD_STORE is supported for this version of GLSL
if self.options.version.supports_early_depth_test() {
self.features.request(Features::IMAGE_LOAD_STORE);
}
if depth_test.conservative.is_some() {
self.features.request(Features::CONSERVATIVE_DEPTH);
}
}
for arg in self.entry_point.function.arguments.iter() {
self.varying_required_features(arg.binding.as_ref(), arg.ty);
}
if let Some(ref result) = self.entry_point.function.result {
self.varying_required_features(result.binding.as_ref(), result.ty);
}
if let ShaderStage::Compute = self.entry_point.stage {
self.features.request(Features::COMPUTE_SHADER)
}
if self.multiview.is_some() {
self.features.request(Features::MULTI_VIEW);
}
for (ty_handle, ty) in self.module.types.iter() {
match ty.inner {
TypeInner::Scalar(scalar)
| TypeInner::Vector { scalar, .. }
| TypeInner::Matrix { scalar, .. } => self.scalar_required_features(scalar),
TypeInner::Array { base, size, .. } => {
if let TypeInner::Array { .. } = self.module.types[base].inner {
self.features.request(Features::ARRAY_OF_ARRAYS)
}
// If the array is dynamically sized
if size == crate::ArraySize::Dynamic {
let mut is_used = false;
// Check if this type is used in a global that is needed by the current entrypoint
for (global_handle, global) in self.module.global_variables.iter() {
// Skip unused globals
if ep_info[global_handle].is_empty() {
continue;
}
// If this array is the type of a global, then this array is used
if global.ty == ty_handle {
is_used = true;
break;
}
// If the type of this global is a struct
if let TypeInner::Struct { ref members, .. } =
self.module.types[global.ty].inner
{
// Check the last element of the struct to see if it's type uses
// this array
if let Some(last) = members.last() {
if last.ty == ty_handle {
is_used = true;
break;
}
}
}
}
// If this dynamically size array is used, we need dynamic array size support
if is_used {
self.features.request(Features::DYNAMIC_ARRAY_SIZE);
}
}
}
TypeInner::Image {
dim,
arrayed,
class,
} => {
if arrayed && dim == ImageDimension::Cube {
self.features.request(Features::CUBE_TEXTURES_ARRAY)
}
match class {
ImageClass::Sampled { multi: true, .. }
| ImageClass::Depth { multi: true } => {
self.features.request(Features::MULTISAMPLED_TEXTURES);
if arrayed {
self.features.request(Features::MULTISAMPLED_TEXTURE_ARRAYS);
}
}
ImageClass::Storage { format, .. } => match format {
StorageFormat::R8Unorm
| StorageFormat::R8Snorm
| StorageFormat::R8Uint
| StorageFormat::R8Sint
| StorageFormat::R16Uint
| StorageFormat::R16Sint
| StorageFormat::R16Float
| StorageFormat::Rg8Unorm
| StorageFormat::Rg8Snorm
| StorageFormat::Rg8Uint
| StorageFormat::Rg8Sint
| StorageFormat::Rg16Uint
| StorageFormat::Rg16Sint
| StorageFormat::Rg16Float
| StorageFormat::Rgb10a2Uint
| StorageFormat::Rgb10a2Unorm
| StorageFormat::Rg11b10Ufloat
| StorageFormat::Rg32Uint
| StorageFormat::Rg32Sint
| StorageFormat::Rg32Float => {
self.features.request(Features::FULL_IMAGE_FORMATS)
}
_ => {}
},
ImageClass::Sampled { multi: false, .. }
| ImageClass::Depth { multi: false } => {}
}
}
_ => {}
}
}
let mut push_constant_used = false;
for (handle, global) in self.module.global_variables.iter() {
if ep_info[handle].is_empty() {
continue;
}
match global.space {
AddressSpace::WorkGroup => self.features.request(Features::COMPUTE_SHADER),
AddressSpace::Storage { .. } => self.features.request(Features::BUFFER_STORAGE),
AddressSpace::PushConstant => {
if push_constant_used {
return Err(Error::MultiplePushConstants);
}
push_constant_used = true;
}
_ => {}
}
}
// We will need to pass some of the members to a closure, so we need
// to separate them otherwise the borrow checker will complain, this
// shouldn't be needed in rust 2021
let &mut Self {
module,
info,
ref mut features,
entry_point,
entry_point_idx,
ref policies,
..
} = self;
// Loop through all expressions in both functions and the entry point
// to check for needed features
for (expressions, info) in module
.functions
.iter()
.map(|(h, f)| (&f.expressions, &info[h]))
.chain(std::iter::once((
&entry_point.function.expressions,
info.get_entry_point(entry_point_idx as usize),
)))
{
for (_, expr) in expressions.iter() {
match *expr {
// Check for queries that need aditonal features
Expression::ImageQuery {
image,
query,
..
} => match query {
// Storage images use `imageSize` which is only available
// in glsl > 420
//
// layers queries are also implemented as size queries
crate::ImageQuery::Size { .. } | crate::ImageQuery::NumLayers => {
if let TypeInner::Image {
class: ImageClass::Storage { .. }, ..
} = *info[image].ty.inner_with(&module.types) {
features.request(Features::IMAGE_SIZE)
}
},
crate::ImageQuery::NumLevels => features.request(Features::TEXTURE_LEVELS),
crate::ImageQuery::NumSamples => features.request(Features::TEXTURE_SAMPLES),
}
,
// Check for image loads that needs bound checking on the sample
// or level argument since this requires a feature
Expression::ImageLoad {
sample, level, ..
} => {
if policies.image_load != crate::proc::BoundsCheckPolicy::Unchecked {
if sample.is_some() {
features.request(Features::TEXTURE_SAMPLES)
}
if level.is_some() {
features.request(Features::TEXTURE_LEVELS)
}
}
}
Expression::ImageSample { image, level, offset, .. } => {
if let TypeInner::Image {
dim,
arrayed,
class: ImageClass::Depth { .. },
} = *info[image].ty.inner_with(&module.types) {
let lod = matches!(level, SampleLevel::Zero | SampleLevel::Exact(_));
let bias = matches!(level, SampleLevel::Bias(_));
let auto = matches!(level, SampleLevel::Auto);
let cube = dim == ImageDimension::Cube;
let array2d = dim == ImageDimension::D2 && arrayed;
let gles = self.options.version.is_es();
// We have a workaround of using `textureGrad` instead of `textureLod` if the LOD is zero,
// so we don't *need* this extension for those cases.
// But if we're explicitly allowed to use the extension (`WriterFlags::TEXTURE_SHADOW_LOD`),
// we always use it instead of the workaround.
let grad_workaround_applicable = (array2d || (cube && !arrayed)) && level == SampleLevel::Zero;
let prefer_grad_workaround = grad_workaround_applicable && !self.options.writer_flags.contains(WriterFlags::TEXTURE_SHADOW_LOD);
let mut ext_used = false;
// float texture(sampler2DArrayShadow sampler, vec4 P [, float bias])
// float texture(samplerCubeArrayShadow sampler, vec4 P, float compare [, float bias])
ext_used |= (array2d || cube && arrayed) && bias;
// The non `bias` version of this was standardized in GL 4.3, but never in GLES.
// float textureOffset(sampler2DArrayShadow sampler, vec4 P, ivec2 offset [, float bias])
ext_used |= array2d && (bias || (gles && auto)) && offset.is_some();
// float textureLod(sampler2DArrayShadow sampler, vec4 P, float lod)
// float textureLodOffset(sampler2DArrayShadow sampler, vec4 P, float lod, ivec2 offset)
// float textureLod(samplerCubeShadow sampler, vec4 P, float lod)
// float textureLod(samplerCubeArrayShadow sampler, vec4 P, float compare, float lod)
ext_used |= (cube || array2d) && lod && !prefer_grad_workaround;
if ext_used {
features.request(Features::TEXTURE_SHADOW_LOD);
}
}
}
Expression::SubgroupBallotResult |
Expression::SubgroupOperationResult { .. } => {
features.request(Features::SUBGROUP_OPERATIONS)
}
_ => {}
}
}
}
for blocks in module
.functions
.iter()
.map(|(_, f)| &f.body)
.chain(std::iter::once(&entry_point.function.body))
{
for (stmt, _) in blocks.span_iter() {
match *stmt {
crate::Statement::ImageAtomic { .. } => {
features.request(Features::TEXTURE_ATOMICS)
}
_ => {}
}
}
}
self.features.check_availability(self.options.version)
}
/// Helper method that checks the [`Features`] needed by a scalar
fn scalar_required_features(&mut self, scalar: Scalar) {
if scalar.kind == ScalarKind::Float && scalar.width == 8 {
self.features.request(Features::DOUBLE_TYPE);
}
}
fn varying_required_features(&mut self, binding: Option<&Binding>, ty: Handle<Type>) {
if let TypeInner::Struct { ref members, .. } = self.module.types[ty].inner {
for member in members {
self.varying_required_features(member.binding.as_ref(), member.ty);
}
} else if let Some(binding) = binding {
match *binding {
Binding::BuiltIn(built_in) => match built_in {
crate::BuiltIn::ClipDistance => self.features.request(Features::CLIP_DISTANCE),
crate::BuiltIn::CullDistance => self.features.request(Features::CULL_DISTANCE),
crate::BuiltIn::SampleIndex => {
self.features.request(Features::SAMPLE_VARIABLES)
}
crate::BuiltIn::ViewIndex => self.features.request(Features::MULTI_VIEW),
crate::BuiltIn::InstanceIndex | crate::BuiltIn::DrawID => {
self.features.request(Features::INSTANCE_INDEX)
}
_ => {}
},
Binding::Location {
location: _,
interpolation,
sampling,
second_blend_source,
} => {
if interpolation == Some(Interpolation::Linear) {
self.features.request(Features::NOPERSPECTIVE_QUALIFIER);
}
if sampling == Some(Sampling::Sample) {
self.features.request(Features::SAMPLE_QUALIFIER);
}
if second_blend_source {
self.features.request(Features::DUAL_SOURCE_BLENDING);
}
}
}
}
}
}
