1 files changed, 42 insertions, 0 deletions
diff --git a/engine/src/opengl/texture.rs b/engine/src/opengl/texture.rs
index 4186479..56eb118 100644
--- a/engine/src/opengl/texture.rs
+++ b/engine/src/opengl/texture.rs
@@ -1,6 +1,7 @@
 use std::ptr::null;
 
 use crate::opengl::currently_bound::CurrentlyBound;
+use crate::texture::Id;
 use crate::vector::Vec2;
 
 #[derive(Debug)]
@@ -234,3 +235,44 @@ impl PixelDataFormat
         }
     }
 }
+
+pub fn set_active_texture_unit(texture_unit: TextureUnit)
+{
+    unsafe {
+        gl::ActiveTexture(texture_unit.into_gl());
+    }
+}
+
+macro_rules! texture_unit_enum {
+    (cnt=$cnt: literal) => {
+        seq_macro::seq!(N in 0..$cnt {
+            #[derive(Debug, Clone, Copy)]
+            pub enum TextureUnit {
+                #(
+                    No~N,
+                )*
+            }
+
+            impl TextureUnit {
+                fn into_gl(self) -> gl::types::GLenum {
+                    match self {
+                        #(
+                            Self::No~N => gl::TEXTURE~N,
+                        )*
+                    }
+                }
+
+                pub fn from_texture_id(texture_id: Id) -> Option<Self> {
+                    match texture_id.into_inner() {
+                        #(
+                            N => Some(Self::No~N),
+                        )*
+                        _ => None
+                    }
+                }
+            }
+        });
+    };
+}
+
+texture_unit_enum!(cnt = 31);