From 7bdcac83e5836241f6d1a603795d0385295fd183 Mon Sep 17 00:00:00 2001
From: Pelle Johnsen <pelle.johnsen@gmail.com>
Date: Mon, 21 Sep 2020 15:10:17 +0000
Subject: [PATCH] [glsl-in] Support anonymous global uniforms

Partly fixes #210
---
 src/front/glsl/ast.rs       |  2 +-
 src/front/glsl/parser.rs    | 19 +++++++++++--------
 src/front/glsl/variables.rs | 37 +++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/src/front/glsl/ast.rs b/src/front/glsl/ast.rs
index bd8f12595e..ce63dee0be 100644
--- a/src/front/glsl/ast.rs
+++ b/src/front/glsl/ast.rs
@@ -159,7 +159,7 @@ pub enum TypeQualifier {
 #[derive(Debug)]
 pub struct VarDeclaration {
     pub type_qualifiers: Vec<TypeQualifier>,
-    pub ids_initializers: Vec<(String, Option<ExpressionRule>)>,
+    pub ids_initializers: Vec<(Option<String>, Option<ExpressionRule>)>,
     pub ty: Handle<Type>,
 }
 
diff --git a/src/front/glsl/parser.rs b/src/front/glsl/parser.rs
index e0dff7325d..f39e1b985a 100644
--- a/src/front/glsl/parser.rs
+++ b/src/front/glsl/parser.rs
@@ -475,7 +475,7 @@ pomelo! {
         struct_declaration_list(sdl) RightBrace Semicolon {
         VarDeclaration{
             type_qualifiers: t,
-            ids_initializers: vec![],
+            ids_initializers: vec![(None, None)],
             ty: extra.module.types.fetch_or_append(Type{
                 name: Some(i.1),
                 inner: TypeInner::Struct {
@@ -489,7 +489,7 @@ pomelo! {
         struct_declaration_list(sdl) RightBrace Identifier(i2) Semicolon {
         VarDeclaration{
             type_qualifiers: t,
-            ids_initializers: vec![(i2.1, None)],
+            ids_initializers: vec![(Some(i2.1), None)],
             ty: extra.module.types.fetch_or_append(Type{
                 name: Some(i1.1),
                 inner: TypeInner::Struct {
@@ -504,13 +504,13 @@ pomelo! {
 
     init_declarator_list ::= single_declaration;
     init_declarator_list ::= init_declarator_list(mut idl) Comma Identifier(i) {
-        idl.ids_initializers.push((i.1, None));
+        idl.ids_initializers.push((Some(i.1), None));
         idl
     }
     // init_declarator_list ::= init_declarator_list Comma Identifier array_specifier;
     // init_declarator_list ::= init_declarator_list Comma Identifier array_specifier Equal initializer;
     init_declarator_list ::= init_declarator_list(mut idl) Comma Identifier(i) Equal initializer(init) {
-        idl.ids_initializers.push((i.1, Some(init)));
+        idl.ids_initializers.push((Some(i.1), Some(init)));
         idl
     }
 
@@ -528,7 +528,7 @@ pomelo! {
 
         VarDeclaration{
             type_qualifiers: t.0,
-            ids_initializers: vec![(i.1, None)],
+            ids_initializers: vec![(Some(i.1), None)],
             ty,
         }
     }
@@ -539,7 +539,7 @@ pomelo! {
 
         VarDeclaration{
             type_qualifiers: t.0,
-            ids_initializers: vec![(i.1, Some(init))],
+            ids_initializers: vec![(Some(i.1), Some(init))],
             ty,
         }
     }
@@ -705,6 +705,7 @@ pomelo! {
         let mut statements = Vec::<Statement>::new();
         // local variables
         for (id, initializer) in d.ids_initializers {
+            let id = id.ok_or(ErrorKind::SemanticError("local var must be named"))?;
             // check if already declared in current scope
             #[cfg(feature = "glsl-validate")]
             {
@@ -871,7 +872,7 @@ pomelo! {
         for (id, initializer) in d.ids_initializers {
             let h = extra.module.global_variables.fetch_or_append(
                 GlobalVariable {
-                    name: Some(id.clone()),
+                    name: id.clone(),
                     class,
                     binding: binding.clone(),
                     ty: d.ty,
@@ -879,7 +880,9 @@ pomelo! {
                     storage_access: StorageAccess::empty(), //TODO
                 },
             );
-            extra.lookup_global_variables.insert(id, h);
+            if let Some(id) = id {
+                extra.lookup_global_variables.insert(id, h);
+            }
         }
     }
 
diff --git a/src/front/glsl/variables.rs b/src/front/glsl/variables.rs
index 834f787651..14d91ca4ca 100644
--- a/src/front/glsl/variables.rs
+++ b/src/front/glsl/variables.rs
@@ -7,6 +7,41 @@ use super::ast::*;
 use super::error::ErrorKind;
 
 impl Program {
+    fn lookup_global_struct_member(&mut self, name: &str) -> Option<Handle<Expression>> {
+        let global_struct_member = self
+            .module
+            .global_variables
+            .iter()
+            // find globals without name
+            .filter(|(_, var)| var.name.is_none())
+            // find those of struct type and map to their members
+            .filter_map(|(h, var)| {
+                let ty = &self.module.types[var.ty];
+                if let TypeInner::Struct { members } = &ty.inner {
+                    Some((h, members))
+                } else {
+                    None
+                }
+            })
+            // find member matching name
+            .find_map(|(h, members)| {
+                members
+                    .iter()
+                    .position(|m| m.name == Some(name.into()))
+                    .map(|idx| (h, idx))
+            });
+        global_struct_member.map(|(h, idx)| {
+            let base = self
+                .context
+                .expressions
+                .append(Expression::GlobalVariable(h));
+            self.context.expressions.append(Expression::AccessIndex {
+                base,
+                index: idx as u32,
+            })
+        })
+    }
+
     pub fn lookup_variable(&mut self, name: &str) -> Result<Option<Handle<Expression>>, ErrorKind> {
         let mut expression: Option<Handle<Expression>> = None;
         match name {
@@ -92,6 +127,8 @@ impl Program {
             Ok(Some(local_var))
         } else if let Some(global_var) = self.context.lookup_global_var_exps.get(name) {
             Ok(Some(*global_var))
+        } else if let Some(global_member) = self.lookup_global_struct_member(name) {
+            Ok(Some(global_member))
         } else {
             Ok(None)
         }