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|
use crate::{
Binding, BuiltIn, Expression, GlobalVariable, Handle, ScalarKind, ShaderStage, StorageAccess,
StorageClass, Type, TypeInner, VectorSize,
};
use super::ast::*;
use super::error::ErrorKind;
use super::token::TokenMetadata;
impl Program {
pub fn lookup_variable(&mut self, name: &str) -> Result<Option<Handle<Expression>>, ErrorKind> {
let mut expression: Option<Handle<Expression>> = None;
match name {
"gl_Position" => {
#[cfg(feature = "glsl-validate")]
match self.shader_stage {
ShaderStage::Vertex | ShaderStage::Fragment { .. } => {}
_ => {
return Err(ErrorKind::VariableNotAvailable(name.into()));
}
};
let h = self
.module
.global_variables
.fetch_or_append(GlobalVariable {
name: Some(name.into()),
class: if self.shader_stage == ShaderStage::Vertex {
StorageClass::Output
} else {
StorageClass::Input
},
binding: Some(Binding::BuiltIn(BuiltIn::Position)),
ty: self.module.types.fetch_or_append(Type {
name: None,
inner: TypeInner::Vector {
size: VectorSize::Quad,
kind: ScalarKind::Float,
width: 4,
},
}),
init: None,
interpolation: None,
storage_access: StorageAccess::empty(),
});
self.lookup_global_variables.insert(name.into(), h);
let exp = self
.context
.expressions
.append(Expression::GlobalVariable(h));
self.context.lookup_global_var_exps.insert(name.into(), exp);
expression = Some(exp);
}
"gl_VertexIndex" => {
#[cfg(feature = "glsl-validate")]
match self.shader_stage {
ShaderStage::Vertex => {}
_ => {
return Err(ErrorKind::VariableNotAvailable(name.into()));
}
};
let h = self
.module
.global_variables
.fetch_or_append(GlobalVariable {
name: Some(name.into()),
class: StorageClass::Input,
binding: Some(Binding::BuiltIn(BuiltIn::VertexIndex)),
ty: self.module.types.fetch_or_append(Type {
name: None,
inner: TypeInner::Scalar {
kind: ScalarKind::Uint,
width: 4,
},
}),
init: None,
interpolation: None,
storage_access: StorageAccess::empty(),
});
self.lookup_global_variables.insert(name.into(), h);
let exp = self
.context
.expressions
.append(Expression::GlobalVariable(h));
self.context.lookup_global_var_exps.insert(name.into(), exp);
expression = Some(exp);
}
_ => {}
}
if let Some(expression) = expression {
Ok(Some(expression))
} else if let Some(local_var) = self.context.lookup_local_var(name) {
Ok(Some(local_var))
} else if let Some(global_var) = self.context.lookup_global_var_exps.get(name) {
Ok(Some(*global_var))
} else {
Ok(None)
}
}
pub fn field_selection(
&mut self,
expression: Handle<Expression>,
name: &str,
meta: TokenMetadata,
) -> Result<Handle<Expression>, ErrorKind> {
match *self.resolve_type(expression)? {
TypeInner::Struct { ref members } => {
let index = members
.iter()
.position(|m| m.name == Some(name.into()))
.ok_or_else(|| ErrorKind::UnknownField(meta, name.into()))?;
Ok(self.context.expressions.append(Expression::AccessIndex {
base: expression,
index: index as u32,
}))
}
// swizzles (xyzw, rgba, stpq)
TypeInner::Vector { size, kind, width } => {
let check_swizzle_components = |comps: &str| {
name.chars()
.map(|c| {
comps
.find(c)
.and_then(|i| if i < size as usize { Some(i) } else { None })
})
.fold(Some(Vec::<usize>::new()), |acc, cur| {
cur.and_then(|i| {
acc.map(|mut v| {
v.push(i);
v
})
})
})
};
let indices = check_swizzle_components("xyzw")
.or_else(|| check_swizzle_components("rgba"))
.or_else(|| check_swizzle_components("stpq"));
if let Some(v) = indices {
let components: Vec<Handle<Expression>> = v
.iter()
.map(|idx| {
self.context.expressions.append(Expression::AccessIndex {
base: expression,
index: *idx as u32,
})
})
.collect();
if components.len() == 1 {
// only single element swizzle, like pos.y, just return that component
Ok(components[0])
} else {
Ok(self.context.expressions.append(Expression::Compose {
ty: self.module.types.fetch_or_append(Type {
name: None,
inner: TypeInner::Vector {
kind,
width,
size: match components.len() {
2 => VectorSize::Bi,
3 => VectorSize::Tri,
4 => VectorSize::Quad,
_ => {
return Err(ErrorKind::SemanticError(
"Bad swizzle size",
));
}
},
},
}),
components,
}))
}
} else {
Err(ErrorKind::SemanticError("Invalid swizzle for vector"))
}
}
_ => Err(ErrorKind::SemanticError("Can't lookup field on this type")),
}
}
}
|
