♻️ Extract get_attribute_locations

src/main.rs

@@ -247,28 +247,11 @@ fn main () {
 		"texture",
 	].into_iter ());
 	
-	let attrs: HashMap <_, Option <u32>> = vec! [
+	let attrs = shader_program.get_attribute_locations (vec! [
 		"pos",
 		"uv",
 		"normal",
-	].iter ()
-	.map (|name| {
-		let mut s = String::from ("attr_");
-		s.push_str (name);
-		
-		let c_str = CString::new (s.as_bytes ()).unwrap ();
-		let loc = shader_program.get_attribute_location (&c_str);
-		let loc = match loc.try_into () {
-			Ok (i) => Some (i),
-			_ => {
-				println! ("Attribute {} not found - Optimized out?", name);
-				None
-			},
-		};
-		
-		(String::from (*name), loc)
-	})
-	.collect ();
+	].into_iter ());
 	
 	let texture = Texture::from_file ("sky.png");
 	texture.bind ();

src/shader.rs

@@ -146,6 +146,33 @@ impl ShaderProgram {
 			gl::GetAttribLocation (self.id, name.as_ptr ())
 		}
 	}
+	
+	pub fn get_attribute_locations <'a, I> (&self, names: I)
+	-> HashMap <String, Option <u32>>
+	where I: Iterator <Item = &'a str>
+	{
+		unsafe {
+			gl::UseProgram (self.id);
+		}
+		
+		names
+		.map (|name| {
+			let mut s = String::from ("attr_");
+			s.push_str (name);
+			
+			let c_str = CString::new (s.as_bytes ()).unwrap ();
+			let loc = unsafe {
+				gl::GetAttribLocation (self.id, c_str.as_ptr ())
+			};
+			let loc = match loc.try_into () {
+				Ok (loc) => Some (loc),
+				_ => None,
+			};
+			
+			(String::from (name), loc)
+		})
+		.collect ()
+	}
 }
 
 impl Drop for ShaderProgram {