preprocess: implement stage separator to complete preprocessor

librashader-preprocess/src/error.rs

@@ -15,13 +15,12 @@ pub enum PreprocessError {
     UnexpectedEol(usize),
     #[error("error parsing pragma")]
     PragmaParseError(String),
-    #[error("duplicate parameter but arguments do not match")]
+    #[error("duplicate pragma found")]
-    DuplicateParameterError(String),
+    DuplicatePragmaError(String),
     #[error("shader format is unknown or not found")]
     UnknownShaderFormat,
-    #[error("tried to declare shader format twice")]
+    #[error("stage must be either vertex or fragment")]
-    DuplicateShaderFormat,
+    InvalidStage,
-
 }
 
 impl From<Infallible> for PreprocessError {

librashader-preprocess/src/include.rs

@@ -1,4 +1,4 @@
-use crate::PreprocessError;
+use crate::{PreprocessError, SourceOutput};
 use std::fs::File;
 use std::io::Read;
 use std::path::Path;
@@ -7,20 +7,6 @@ use std::str::Lines;
 const GL_GOOGLE_CPP_STYLE_LINE_DIRECTIVE: &'static str =
     "#extension GL_GOOGLE_CPP_STYLE_LINE_DIRECTIVE : require";
 
-trait SourceOutput {
-    fn push_line(&mut self, str: &str);
-    fn mark_line(&mut self, line_no: usize, comment: &str) {
-        self.push_line(&format!("#line {} \"{}\"", line_no, comment))
-    }
-}
-
-impl SourceOutput for String {
-    fn push_line(&mut self, str: &str) {
-        self.push_str(str);
-        self.push('\n');
-    }
-}
-
 fn read_file(path: impl AsRef<Path>) -> Result<String, PreprocessError> {
     let path = path.as_ref();
     let mut source = String::new();

librashader-preprocess/src/lib.rs

@@ -1,13 +1,54 @@
 mod error;
 mod include;
 mod pragma;
+mod stage;
 
+use std::path::Path;
 pub use error::*;
+use librashader::ShaderSource;
+use crate::include::read_source;
+
+
+pub(crate) trait SourceOutput {
+    fn push_line(&mut self, str: &str);
+    fn mark_line(&mut self, line_no: usize, comment: &str) {
+        self.push_line(&format!("#line {} \"{}\"", line_no, comment))
+    }
+}
+
+impl SourceOutput for String {
+    fn push_line(&mut self, str: &str) {
+        self.push_str(str);
+        self.push('\n');
+    }
+}
+
+pub fn load_shader_source(path: impl AsRef<Path>) -> Result<ShaderSource, PreprocessError> {
+    let source = read_source(path)?;
+    let meta = pragma::parse_pragma_meta(&source)?;
+    let text = stage::process_stages(&source)?;
+
+    Ok(ShaderSource {
+        vertex: text.vertex,
+        fragment: text.fragment,
+        name: meta.name,
+        parameters: meta.parameters,
+        format: meta.format,
+    })
+}
 
 #[cfg(test)]
 mod test {
     use crate::include::read_source;
-    use crate::pragma;
+    use crate::{load_shader_source, pragma};
+
+    #[test]
+    pub fn load_file() {
+        let result =
+            load_shader_source("../test/slang-shaders/blurs/shaders/royale/blur3x3-last-pass.slang")
+                .unwrap();
+        eprintln!("{result:#?}")
+    }
 
     #[test]
     pub fn preprocess_file() {

librashader-preprocess/src/pragma.rs

@@ -7,6 +7,12 @@ use nom::sequence::delimited;
 use librashader::{ShaderFormat, ShaderParameter};
 use crate::PreprocessError;
 
+#[derive(Debug)]
+pub(crate) struct ShaderMeta {
+    pub(crate) format: ShaderFormat,
+    pub(crate) parameters: Vec<ShaderParameter>,
+    pub(crate) name: Option<String>
+}
 
 fn parse_parameter_string(input: &str) -> Result<ShaderParameter, PreprocessError>{
     fn parse_parameter_string_inner(input: &str) -> IResult<&str, ShaderParameter> {
@@ -39,16 +45,17 @@ fn parse_parameter_string(input: &str) -> Result<ShaderParameter, PreprocessErro
     }
 }
 
-pub fn parse_pragma_meta(source: impl AsRef<str>) -> Result<(ShaderFormat, Vec<ShaderParameter>), PreprocessError> {
+pub(crate) fn parse_pragma_meta(source: impl AsRef<str>) -> Result<ShaderMeta, PreprocessError> {
     let source = source.as_ref();
     let mut parameters: Vec<ShaderParameter> = Vec::new();
     let mut format = ShaderFormat::default();
+    let mut name = None;
     for line in source.lines() {
         if line.starts_with("#pragma parameter ") {
             let parameter = parse_parameter_string(line)?;
             if let Some(existing) = parameters.iter().find(|&p| p.id == parameter.id) {
                 if existing != &parameter {
-                    return Err(PreprocessError::DuplicateParameterError(parameter.id))
+                    return Err(PreprocessError::DuplicatePragmaError(parameter.id))
                 }
             } else {
                 parameters.push(parameter);
@@ -57,7 +64,7 @@ pub fn parse_pragma_meta(source: impl AsRef<str>) -> Result<(ShaderFormat, Vec<S
 
         if line.starts_with("#pragma format ") {
             if format != ShaderFormat::Unknown {
-                return Err(PreprocessError::DuplicateShaderFormat)
+                return Err(PreprocessError::DuplicatePragmaError(line.to_string()))
             }
 
             let format_string = line["#pragma format ".len()..].trim();
@@ -67,9 +74,17 @@ pub fn parse_pragma_meta(source: impl AsRef<str>) -> Result<(ShaderFormat, Vec<S
                 return Err(PreprocessError::UnknownShaderFormat)
             }
         }
+
+        if line.starts_with("#pragma name ") {
+            if name.is_some() {
+                return Err(PreprocessError::DuplicatePragmaError(line.to_string()));
+            }
+
+            name = Some(line.trim().to_string())
+        }
     }
 
-    Ok((format, parameters))
+    Ok(ShaderMeta { name, format, parameters })
 }
 
 #[cfg(test)]

librashader-preprocess/src/stage.rs

@@ -0,0 +1,58 @@
+use std::str::FromStr;
+use crate::{PreprocessError, SourceOutput};
+
+enum ActiveStage {
+    Both,
+    Fragment,
+    Vertex
+}
+
+impl FromStr for ActiveStage {
+    type Err = PreprocessError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "vertex" => Ok(ActiveStage::Vertex),
+            "fragment" => Ok(ActiveStage::Fragment),
+            _ => Err(PreprocessError::InvalidStage)
+        }
+    }
+}
+
+#[derive(Default)]
+pub(crate) struct ShaderOutput {
+    pub(crate) fragment: String,
+    pub(crate) vertex: String
+}
+
+pub(crate) fn process_stages(source: &str) -> Result<ShaderOutput, PreprocessError> {
+    let mut active_stage = ActiveStage::Both;
+    let mut output = ShaderOutput::default();
+
+    for line in source.lines() {
+        if line.starts_with("#pragma stage ") {
+            let stage = line["#pragma stage ".len()..].trim();
+            active_stage = ActiveStage::from_str(stage)?;
+            continue;
+        }
+
+        if line.starts_with("#pragma name ") || line.starts_with("#pragma format ") {
+            continue;
+        }
+
+        match active_stage {
+            ActiveStage::Both => {
+                output.fragment.push_line(line);
+                output.vertex.push_line(line);
+            }
+            ActiveStage::Fragment => {
+                output.fragment.push_line(line);
+            }
+            ActiveStage::Vertex => {
+                output.vertex.push_line(line)
+            }
+        }
+    }
+
+    Ok(output)
+}

librashader/src/lib.rs

@@ -1,6 +1,7 @@
 use std::convert::Infallible;
 use std::str::FromStr;
 
+#[derive(Debug, Clone, PartialEq)]
 pub struct ShaderSource {
     pub vertex: String,
     pub fragment: String,