persitent interaction with buttons

src/gui.rs

@@ -3,63 +3,58 @@ use crate::types::*;
 // TODO: implement Gui on this so we can add children to a widget
 // pub struct Widget {}
 
-pub struct Gui {
-    commands: Vec<GuiCmd>,
-    input: GuiInput,
+type Id = u64;
 
-    cursor: Vec2,
+#[derive(Clone, Copy, Debug, Default)]
+pub struct GuiState {
+    /// The widget being interacted with (e.g. dragged, in case of a slider).
+    pub active_id: Option<Id>,
+}
+
+pub struct Gui {
+    pub commands: Vec<GuiCmd>,
+    pub cursor: Vec2,
+    pub input: GuiInput,
+    pub state: GuiState,
 }
 
 impl Gui {
-    pub fn new(input: GuiInput) -> Self {
-        Gui {
-            commands: vec![],
-            input,
-            cursor: Vec2 { x: 32.0, y: 32.0 },
-        }
-    }
-
     pub fn input(&self) -> &GuiInput {
         &self.input
     }
 
-    pub fn into_commands(self) -> Vec<GuiCmd> {
-        self.commands
-    }
-
-    pub fn paint_commands(&self) -> &[GuiCmd] {
+    pub fn gui_commands(&self) -> &[GuiCmd] {
         &self.commands
     }
 
-    fn rect(&mut self, rect: Rect, style: RectStyle) -> InteractInfo {
-        let hovered = rect.contains(self.input.mouse_pos);
-        let clicked = hovered && self.input.mouse_clicked;
-        let interact = InteractInfo { hovered, clicked };
-        self.commands.push(GuiCmd::Rect {
-            interact,
-            rect,
-            style,
-        });
-        interact
-    }
-
-    fn text<S: Into<String>>(&mut self, pos: Vec2, style: TextStyle, text: S) {
-        self.commands.push(GuiCmd::Text {
-            pos,
-            style,
-            text: text.into(),
-            text_align: TextAlign::Start,
-        });
-    }
-
     // ------------------------------------------------------------------------
 
     pub fn button<S: Into<String>>(&mut self, text: S) -> InteractInfo {
+        let text: String = text.into();
+        let id = self.get_id(&text);
         let rect = Rect {
             pos: self.cursor,
             size: Vec2 { x: 200.0, y: 32.0 }, // TODO: get from some settings
         };
-        let interact = self.rect(rect, RectStyle::Button);
+
+        let hovered = rect.contains(self.input.mouse_pos);
+        let clicked = hovered && self.input.mouse_clicked;
+        if clicked {
+            self.state.active_id = Some(id);
+        }
+        let active = self.state.active_id == Some(id);
+
+        let interact = InteractInfo {
+            hovered,
+            clicked,
+            active,
+        };
+
+        self.commands.push(GuiCmd::Rect {
+            interact,
+            rect,
+            style: RectStyle::Button,
+        });
 
         // TODO: clip-rect of text
         self.text(
@@ -75,7 +70,8 @@ impl Gui {
     }
 
     pub fn label<S: Into<String>>(&mut self, text: S) {
-        for line in text.into().split("\n") {
+        let text: String = text.into();
+        for line in text.split('\n') {
             self.text(self.cursor, TextStyle::Label, line);
             self.cursor.y += 16.0;
         }
@@ -83,4 +79,20 @@ impl Gui {
     }
 
     // ------------------------------------------------------------------------
+
+    fn get_id(&self, id_str: &str) -> Id {
+        use std::hash::Hasher;
+        let mut hasher = std::collections::hash_map::DefaultHasher::new();
+        hasher.write(id_str.as_bytes());
+        hasher.finish()
+    }
+
+    fn text<S: Into<String>>(&mut self, pos: Vec2, style: TextStyle, text: S) {
+        self.commands.push(GuiCmd::Text {
+            pos,
+            style,
+            text: text.into(),
+            text_align: TextAlign::Start,
+        });
+    }
 }