diff --git a/Cargo.lock b/Cargo.lock
index 72bf388f..8343dee2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -390,6 +390,7 @@ version = "0.1.0"
 dependencies = [
  "bumpalo 2.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "dreammaker 0.1.0",
+ "gfx_core 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "inflate 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "linked-hash-map 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lodepng 2.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/src/editor/Cargo.toml b/src/editor/Cargo.toml
index eaf40ce4..3a9d37fc 100644
--- a/src/editor/Cargo.toml
+++ b/src/editor/Cargo.toml
@@ -9,7 +9,7 @@ path = "main.rs"
 
 [dependencies]
 dreammaker = { path = "../dreammaker" }
-dmm-tools = { path = "../tools" }
+dmm-tools = { path = "../tools", features = ["gfx_core"] }
 glutin = "0.21.1"
 gfx_gl = "0.6.0"
 gfx = "0.18"
diff --git a/src/editor/map_renderer.rs b/src/editor/map_renderer.rs
index 67cb522b..ff82ae6b 100644
--- a/src/editor/map_renderer.rs
+++ b/src/editor/map_renderer.rs
@@ -10,7 +10,7 @@ use slice_of_array::prelude::*;
 
 use dm::objtree::ObjectTree;
 use dmm_tools::dmm::Prefab;
-use dmm_tools::minimap::Sprite;
+use dmm_tools::minimap::{Sprite, Category, Layer};
 
 use dmi::*;
 use map_repr::AtomMap;
@@ -30,9 +30,9 @@ gfx_defines! {
         transform: [[f32; 4]; 4] = "transform",
     }
 
-    #[derive(PartialOrd, Default)]
+    #[derive(Default)]
     constant RenderPop {
-        category: u32 = "category",
+        category: Category = "category",
         texture: u32 = "texture",  // icon
         size: [f32; 2] = "size",  // icon
 
@@ -43,7 +43,7 @@ gfx_defines! {
         ofs_y: i32 = "ofs_y",  // pixel_y + pixel_z + step_y
 
         plane: i32 = "plane",
-        layer: i32 = "layer",
+        layer: Layer = "layer",
     }
 
     pipeline pipe {
@@ -78,7 +78,7 @@ pub struct RenderedMap {
 
 #[derive(Debug, Clone)]
 pub struct DrawCall {
-    pub category: u32,
+    pub category: Category,
     pub texture: u32,
     pub len: u32,
 }
@@ -205,7 +205,7 @@ impl RenderedMap {
 
         let mut start = 0;
         for call in map.levels[z as usize].draw_calls.iter() {
-            if !parent.layers[call.category as usize] {
+            if !call.category.matches_basic_layers(&parent.layers) {
                 start += call.len;
                 continue;
             }
@@ -271,12 +271,6 @@ impl RenderedMap {
 // forgive me
 impl ::std::cmp::Eq for RenderPop {}
 
-impl ::std::cmp::Ord for RenderPop {
-    fn cmp(&self, other: &Self) -> ::std::cmp::Ordering {
-        self.partial_cmp(other).expect("in RenderPop::cmp, a field was NaN")
-    }
-}
-
 impl ::std::hash::Hash for RenderPop {
     fn hash<H: ::std::hash::Hasher>(&self, state: &mut H) {
         self.category.hash(state);
@@ -327,7 +321,7 @@ impl RenderPop {
         ];
 
         Some(RenderPop {
-            category: sprite.category.encode(),
+            category: sprite.category,
             texture: texture_id as u32,
             uv,
             color,
@@ -335,7 +329,7 @@ impl RenderPop {
             ofs_x: sprite.ofs_x,
             ofs_y: sprite.ofs_y,
             plane: sprite.plane,
-            layer: sprite.layer.encode(),
+            layer: sprite.layer,
         })
     }
 
diff --git a/src/tools/Cargo.toml b/src/tools/Cargo.toml
index 20c95302..6417c5aa 100644
--- a/src/tools/Cargo.toml
+++ b/src/tools/Cargo.toml
@@ -19,5 +19,9 @@ bumpalo = "2.6.0"
 version = "0.15.0"
 optional = true
 
+[dependencies.gfx_core]
+version = "0.9.2"
+optional = true
+
 [dev-dependencies]
 walkdir = "2.0.1"
diff --git a/src/tools/lib.rs b/src/tools/lib.rs
index ce2a35c0..87abc8fe 100644
--- a/src/tools/lib.rs
+++ b/src/tools/lib.rs
@@ -12,6 +12,8 @@ extern crate linked_hash_map;
 extern crate rand;
 extern crate bumpalo;
 
+#[cfg(feature="gfx_core")] extern crate gfx_core;
+
 pub mod dmm;
 mod icon_cache;
 pub mod minimap;
diff --git a/src/tools/minimap.rs b/src/tools/minimap.rs
index ae778380..4b0e66c9 100644
--- a/src/tools/minimap.rs
+++ b/src/tools/minimap.rs
@@ -403,7 +403,7 @@ impl<'a> GetVar<'a> for TypeRef<'a> {
 // Renderer-agnostic sprite structure
 
 /// Information about when a sprite should be shown or hidden.
-#[derive(Default, Debug, Clone, Copy, Eq, PartialEq)]
+#[derive(Default, Debug, Clone, Copy, Eq, PartialEq, Hash)]
 pub struct Category {
     raw: u32,
 }
@@ -430,8 +430,15 @@ impl Category {
     }
 
     /// Encode this category for FFI representation.
-    pub fn encode(self) -> u32 {
-        self.raw
+    pub fn matches_basic_layers(self, visible: &[bool]) -> bool {
+        visible.get(self.raw as usize).copied().unwrap_or(false)
+    }
+}
+
+#[cfg(feature="gfx_core")]
+impl gfx_core::shade::BaseTyped for Category {
+    fn get_base_type() -> gfx_core::shade::BaseType {
+        u32::get_base_type()
     }
 }
 
@@ -442,13 +449,6 @@ pub struct Layer {
     frac: u16,
 }
 
-impl Layer {
-    /// Encode this layer as an `i32` for FFI representation.
-    pub fn encode(self) -> i32 {
-        ((self.whole as i32) << 16) | (self.frac as i32)
-    }
-}
-
 impl From<i16> for Layer {
     fn from(whole: i16) -> Layer {
         Layer { whole, frac: 0 }
@@ -468,6 +468,13 @@ impl From<f32> for Layer {
     }
 }
 
+#[cfg(feature="gfx_core")]
+impl gfx_core::shade::BaseTyped for Layer {
+    fn get_base_type() -> gfx_core::shade::BaseType {
+        i32::get_base_type()
+    }
+}
+
 /// A Sprite is a fragment of an atom's appearance.
 ///
 /// Every atom has a default sprite, which may be disabled, and a list of