glsl-in: Allow nested accesses in lhs positions

src/front/glsl/ast.rs

@@ -97,7 +97,9 @@ pub struct EntryArg {
 #[derive(Debug, Clone)]
 pub struct VariableReference {
  pub expr: Handle<Expression>,
+ /// Wether the variable is of a pointer type (and needs loading) or not
  pub load: bool,
+ /// Wether the value of the variable can be changed or not
  pub mutable: bool,
  pub constant: Option<(Handle<Constant>, Handle<Type>)>,
  pub entry_arg: Option<usize>,

src/front/glsl/context.rs

@@ -16,26 +16,26 @@ use crate::{
 use std::{convert::TryFrom, ops::Index};
 
 /// The position at which an expression is, used while lowering
-#[derive(Clone, Copy, PartialEq, Eq)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub enum ExprPos {
  /// The expression is in the left hand side of an assignment
  Lhs,
  /// The expression is in the right hand side of an assignment
  Rhs,
  /// The expression is an array being indexed, needed to allow constant
  /// arrays to be dinamically indexed
- ArrayBase {
+ AccessBase {
  /// The index is a constant
  constant_index: bool,
  },
 }
 
 impl ExprPos {
- /// Returns an lhs position if the current position is lhs otherwise ArrayBase
- fn maybe_array_base(&self, constant_index: bool) -> Self {
+ /// Returns an lhs position if the current position is lhs otherwise AccessBase
+ fn maybe_access_base(&self, constant_index: bool) -> Self {
  match *self {
  ExprPos::Lhs => *self,
- _ => ExprPos::ArrayBase { constant_index },
+ _ => ExprPos::AccessBase { constant_index },
  }
  }
 }
@@ -492,6 +492,8 @@ impl Context {
  ) -> Result<(Option<Handle<Expression>>, Span)> {
  let HirExpr { ref kind, meta } = stmt.hir_exprs[expr];
 
+ log::debug!("Lowering {:?}", expr);
+
  let handle = match *kind {
  HirExprKind::Access { base, index } => {
  let (index, index_meta) =
@@ -508,7 +510,7 @@ impl Context {
  stmt,
  parser,
  base,
- pos.maybe_array_base(maybe_constant_index.is_some()),
+ pos.maybe_access_base(maybe_constant_index.is_some()),
  body,
  )?
  .0;
@@ -551,18 +553,20 @@ impl Context {
  pointer
  }
  HirExprKind::Select { base, ref field } => {
- let base = self.lower_expect_inner(stmt, parser, base, pos, body)?.0;
+ let base = self
+ .lower_expect_inner(stmt, parser, base, pos.maybe_access_base(true), body)?
+ .0;
 
- parser.field_selection(self, ExprPos::Lhs == pos, body, base, field, meta)?
+ parser.field_selection(self, pos, body, base, field, meta)?
  }
  HirExprKind::Constant(constant) if pos != ExprPos::Lhs => {
  self.add_expression(Expression::Constant(constant), meta, body)
  }
  HirExprKind::Binary { left, op, right } if pos != ExprPos::Lhs => {
  let (mut left, left_meta) =
- self.lower_expect_inner(stmt, parser, left, pos, body)?;
+ self.lower_expect_inner(stmt, parser, left, ExprPos::Rhs, body)?;
  let (mut right, right_meta) =
- self.lower_expect_inner(stmt, parser, right, pos, body)?;
+ self.lower_expect_inner(stmt, parser, right, ExprPos::Rhs, body)?;
 
  match op {
  BinaryOperator::ShiftLeft | BinaryOperator::ShiftRight => self
@@ -1003,7 +1007,9 @@ impl Context {
  }
  }
  HirExprKind::Unary { op, expr } if pos != ExprPos::Lhs => {
- let expr = self.lower_expect_inner(stmt, parser, expr, pos, body)?.0;
+ let expr = self
+ .lower_expect_inner(stmt, parser, expr, ExprPos::Rhs, body)?
+ .0;
 
  self.add_expression(Expression::Unary { op, expr }, meta, body)
  }
@@ -1020,20 +1026,29 @@ impl Context {
 
  var.expr
  }
- ExprPos::ArrayBase {
- constant_index: false,
- } => {
- if let Some((constant, ty)) = var.constant {
- let local = self.locals.append(
- LocalVariable {
- name: None,
- ty,
- init: Some(constant),
- },
- Span::default(),
- );
+ ExprPos::AccessBase { constant_index } => {
+ // If the index isn't constant all accesses backed by a constant base need
+ // to be done trough a proxy local variable, since constants have a non
+ // pointer type which is required for dynamic indexing
+ if !constant_index {
+ if let Some((constant, ty)) = var.constant {
+ let local = self.locals.append(
+ LocalVariable {
+ name: None,
+ ty,
+ init: Some(constant),
+ },
+ Span::default(),
+ );
 
- self.add_expression(Expression::LocalVariable(local), Span::default(), body)
+ self.add_expression(
+ Expression::LocalVariable(local),
+ Span::default(),
+ body,
+ )
+ } else {
+ var.expr
+ }
  } else {
  var.expr
  }
@@ -1091,9 +1106,12 @@ impl Context {
  let (mut value, value_meta) =
  self.lower_expect_inner(stmt, parser, value, ExprPos::Rhs, body)?;
 
- let scalar_components = self.expr_scalar_components(parser, pointer, ptr_meta)?;
+ let ty = match *parser.resolve_type(self, pointer, ptr_meta)? {
+ TypeInner::Pointer { base, .. } => &parser.module.types[base].inner,
+ ref ty => ty,
+ };
 
- if let Some((kind, width)) = scalar_components {
+ if let Some((kind, width)) = scalar_components(ty) {
  self.implicit_conversion(parser, &mut value, value_meta, kind, width)?;
  }
 
@@ -1216,6 +1234,14 @@ impl Context {
  }
  };
 
+ log::trace!(
+ "Lowered {:?}\n\tKind = {:?}\n\tPos = {:?}\n\tResult = {:?}",
+ expr,
+ kind,
+ pos,
+ handle
+ );
+
  Ok((Some(handle), meta))
  }
 

src/front/glsl/variables.rs

@@ -1,6 +1,6 @@
 use super::{
  ast::*,
- context::Context,
+ context::{Context, ExprPos},
  error::{Error, ErrorKind},
  Parser, Result, Span,
 };
@@ -231,7 +231,7 @@ impl Parser {
  pub(crate) fn field_selection(
  &mut self,
  ctx: &mut Context,
- lhs: bool,
+ pos: ExprPos,
  body: &mut Block,
  expression: Handle<Expression>,
  name: &str,
@@ -250,14 +250,21 @@ impl Parser {
  kind: ErrorKind::UnknownField(name.into()),
  meta,
  })?;
- Ok(ctx.add_expression(
+ let pointer = ctx.add_expression(
  Expression::AccessIndex {
  base: expression,
  index: index as u32,
  },
  meta,
  body,
- ))
+ );
+
+ Ok(match pos {
+ ExprPos::Rhs if is_pointer => {
+ ctx.add_expression(Expression::Load { pointer }, meta, body)
+ }
+ _ => pointer,
+ })
  }
  // swizzles (xyzw, rgba, stpq)
  TypeInner::Vector { size, .. } => {
@@ -277,7 +284,7 @@ impl Parser {
  .or_else(|| check_swizzle_components("stpq"));
 
  if let Some(components) = components {
- if lhs {
+ if let ExprPos::Lhs = pos {
  let not_unique = (1..components.len())
  .any(|i| components[i..].contains(&components[i - 1]));
  if not_unique {
@@ -315,14 +322,23 @@ impl Parser {
  }
 
  let size = match components.len() {
+ // Swizzles with just one component are accesses and not swizzles
  1 => {
- // only single element swizzle, like pos.y, just return that component.
- if lhs {
- // Because of possible nested swizzles, like pos.xy.x, we have to unwrap the potential load expr.
- if let Expression::Load { ref pointer } = ctx[expression] {
- expression = *pointer;
+ match pos {
+ // If the position is in the right hand side and the base
+ // vector is a pointer, load it, otherwise the swizzle would
+ // produce a pointer
+ ExprPos::Rhs if is_pointer => {
+ expression = ctx.add_expression(
+ Expression::Load {
+ pointer: expression,
+ },
+ meta,
+ body,
+ );
  }
- }
+ _ => {}
+ };
  return Ok(ctx.add_expression(
  Expression::AccessIndex {
  base: expression,

tests/in/glsl/buffer.frag

@@ -0,0 +1,22 @@
+#version 450
+
+layout(set = 0, binding = 0) buffer testBufferBlock {
+ uint[] data;
+} testBuffer;
+
+layout(set = 0, binding = 1) writeonly buffer testBufferWriteOnlyBlock {
+ uint[] data;
+} testBufferWriteOnly;
+
+layout(set = 0, binding = 2) readonly buffer testBufferReadOnlyBlock {
+ uint[] data;
+} testBufferReadOnly;
+
+void main() {
+ uint a = testBuffer.data[0];
+ testBuffer.data[1] = 2;
+
+ testBufferWriteOnly.data[1] = 2;
+
+ uint b = testBufferReadOnly.data[0];
+}

tests/out/wgsl/bevy-pbr-frag.wgsl

@@ -498,21 +498,21 @@ fn point_light(light: PointLight, roughness_8: f32, NdotV: f32, N: vec3<f32>, V_
  R_1 = R;
  F0_1 = F0_;
  diffuseColor_1 = diffuseColor;
- let _e56 = light_1;
+ let _e57 = light_1.pos;
  let _e59 = v_WorldPosition_1;
- light_to_frag = (_e56.pos.xyz - _e59.xyz);
+ light_to_frag = (_e57.xyz - _e59.xyz);
  let _e65 = light_to_frag;
  let _e66 = light_to_frag;
  distance_square = dot(_e65, _e66);
- let _e70 = light_1;
+ let _e71 = light_1.lightParams;
  let _e73 = distance_square;
- let _e74 = light_1;
- let _e77 = getDistanceAttenuation(_e73, _e74.lightParams.x);
+ let _e75 = light_1.lightParams;
+ let _e77 = getDistanceAttenuation(_e73, _e75.x);
  rangeAttenuation = _e77;
  let _e79 = roughness_9;
  a_1 = _e79;
- let _e81 = light_1;
- radius = _e81.lightParams.y;
+ let _e82 = light_1.lightParams;
+ radius = _e82.y;
  let _e87 = light_to_frag;
  let _e88 = R_1;
  let _e90 = R_1;
@@ -611,10 +611,10 @@ fn point_light(light: PointLight, roughness_8: f32, NdotV: f32, N: vec3<f32>, V_
  diffuse = (_e302 * _e311);
  let _e314 = diffuse;
  let _e315 = specular_1;
- let _e317 = light_1;
+ let _e318 = light_1.color;
  let _e321 = rangeAttenuation;
  let _e322 = NoL_6;
- return (((_e314 + _e315) * _e317.color.xyz) * (_e321 * _e322));
+ return (((_e314 + _e315) * _e318.xyz) * (_e321 * _e322));
 }
 
 fn dir_light(light_2: DirectionalLight, roughness_10: f32, NdotV_2: f32, normal: vec3<f32>, view: vec3<f32>, R_2: vec3<f32>, F0_2: vec3<f32>, diffuseColor_2: vec3<f32>) -> vec3<f32> {
@@ -643,8 +643,8 @@ fn dir_light(light_2: DirectionalLight, roughness_10: f32, NdotV_2: f32, normal:
  R_3 = R_2;
  F0_3 = F0_2;
  diffuseColor_3 = diffuseColor_2;
- let _e56 = light_3;
- incident_light = _e56.direction.xyz;
+ let _e57 = light_3.direction;
+ incident_light = _e57.xyz;
  let _e60 = incident_light;
  let _e61 = view_1;
  let _e63 = incident_light;
@@ -684,9 +684,9 @@ fn dir_light(light_2: DirectionalLight, roughness_10: f32, NdotV_2: f32, normal:
  specular_2 = _e146;
  let _e148 = specular_2;
  let _e149 = diffuse_1;
- let _e151 = light_3;
+ let _e152 = light_3.color;
  let _e155 = NoL_7;
- return (((_e148 + _e149) * _e151.color.xyz) * _e155);
+ return (((_e148 + _e149) * _e152.xyz) * _e155);
 }
 
 fn main_1() {

tests/out/wgsl/buffer-frag.wgsl

@@ -0,0 +1,37 @@
+struct testBufferBlock {
+ data: array<u32>,
+}
+
+struct testBufferWriteOnlyBlock {
+ data: array<u32>,
+}
+
+struct testBufferReadOnlyBlock {
+ data: array<u32>,
+}
+
+@group(0) @binding(0) 
+var<storage, read_write> testBuffer: testBufferBlock;
+@group(0) @binding(1) 
+var<storage, read_write> testBufferWriteOnly: testBufferWriteOnlyBlock;
+@group(0) @binding(2) 
+var<storage> testBufferReadOnly: testBufferReadOnlyBlock;
+
+fn main_1() {
+ var a: u32;
+ var b: u32;
+
+ let _e12 = testBuffer.data[0];
+ a = _e12;
+ testBuffer.data[1] = u32(2);
+ testBufferWriteOnly.data[1] = u32(2);
+ let _e27 = testBufferReadOnly.data[0];
+ b = _e27;
+ return;
+}
+
+@stage(fragment) 
+fn main() {
+ main_1();
+ return;
+}

tests/out/wgsl/declarations-vert.wgsl

@@ -34,12 +34,12 @@ fn main_1() {
  var a_1: f32;
  var b: f32;
 
- let _e34 = in_array_2;
- from_input_array = _e34[1];
- let _e39 = array_2d;
- a_1 = _e39[0][0];
- let _e50 = array_toomanyd;
- b = _e50[0][0][0][0][0][0][0];
+ let _e35 = in_array_2[1];
+ from_input_array = _e35;
+ let _e41 = array_2d[0][0];
+ a_1 = _e41;
+ let _e57 = array_toomanyd[0][0][0][0][0][0][0];
+ b = _e57;
  out_array[0] = vec4<f32>(2.0);
  return;
 }