GLSL Backend

Generate OpenGL Shading Language code from dew expressions.

Enable

dew-scalar = { version = "0.1", features = ["glsl"] }
dew-linalg = { version = "0.1", features = ["glsl"] }

dew-scalar

Generate Expression

use dew_core::Expr;
use dew_scalar::glsl::emit_glsl;

let expr = Expr::parse("sin(x) + cos(y)").unwrap();
let glsl = emit_glsl(expr.ast()).unwrap();

println!("{}", glsl.code);
// Output: sin(x) + cos(y)

Generate Function

use dew_scalar::glsl::emit_glsl_fn;

let expr = Expr::parse("x * x + y * y").unwrap();
let glsl = emit_glsl_fn("distance_squared", expr.ast(), &["x", "y"]).unwrap();

println!("{}", glsl);
// Output:
// float distance_squared(float x, float y) {
//     return x * x + y * y;
// }

dew-linalg

Generate with Types

use dew_core::Expr;
use dew_linalg::glsl::emit_glsl;
use dew_linalg::Type;
use std::collections::HashMap;

let expr = Expr::parse("normalize(v) * 2.0").unwrap();

// Declare variable types
let mut var_types: HashMap<String, Type> = HashMap::new();
var_types.insert("v".to_string(), Type::Vec3);

let result = emit_glsl(expr.ast(), &var_types).unwrap();

println!("{}", result.code);
// Output: (normalize(v) * 2.0000000000)

println!("Result type: {:?}", result.typ);
// Output: Result type: Vec3

Function Mapping

dew	GLSL
lerp(a, b, t)	mix(a, b, t)
ln(x)	log(x)
log10(x)	(log(x) / log(10.0))
inversesqrt(x)	inversesqrt(x)
x ^ y	pow(x, y)
fract(x)	fract(x)

Most functions map directly (sin, cos, exp, etc.).

GLSL Versions

The generated code is compatible with:

• GLSL 4.50+ (OpenGL 4.5+)
• GLSL ES 3.00+ (OpenGL ES 3.0+, WebGL 2.0)

Comparison with WGSL

Feature	GLSL	WGSL
Target	OpenGL, Vulkan, WebGL 2	WebGPU
Type syntax	vec3, mat4	vec3<f32>, mat4x4<f32>
Function prefix	None	None
Naming	inversesqrt	inverseSqrt

Both backends generate functionally equivalent code with minor syntax differences.