added underdeveloped but working image support (no freeing or samplers)

src/layout/texture.rs

@@ -0,0 +1,48 @@
+use image::DynamicImage;
+
+use crate::render::TexturePrimitive;
+
+/// TODO: proper resource management
+pub struct TextureHandle {
+    pub inner: TexturePrimitive,
+}
+
+/// a texture manager for a ui
+/// note that this is heavily oriented towards wgpu's renderer so the primitives don't need mapped
+#[derive(Default)]
+pub struct Textures {
+    /// TODO: these are images, not views rn
+    views: Vec<DynamicImage>,
+    changed: bool,
+}
+
+pub struct TextureUpdates<'a> {
+    pub images: Option<&'a [DynamicImage]>,
+}
+
+impl Textures {
+    pub fn add(&mut self, image: DynamicImage) -> TextureHandle {
+        let view_idx = self.views.len() as u32;
+        self.views.push(image);
+        // 0 == default in renderer; TODO: actually create samplers here
+        let sampler_idx = 0;
+        self.changed = true;
+        TextureHandle {
+            inner: TexturePrimitive {
+                view_idx,
+                sampler_idx,
+            },
+        }
+    }
+
+    pub fn updates(&mut self) -> TextureUpdates<'_> {
+        if self.changed {
+            self.changed = false;
+            TextureUpdates {
+                images: Some(&self.views),
+            }
+        } else {
+            TextureUpdates { images: None }
+        }
+    }
+}