update

frontend/src/camera.rs

@@ -0,0 +1,52 @@
+//! Camera and input state management
+
+/// GPU-compatible camera uniform data
+#[repr(C)]
+#[derive(Copy, Clone, Debug, bytemuck::Pod, bytemuck::Zeroable)]
+pub struct CameraUniform {
+    /// x: scale_x, y: scale_y, z: translate_x, w: translate_y
+    pub params: [f32; 4],
+    /// x: is_dark (1.0 for dark, 0.0 for light), y,z,w: padding
+    pub theme: [f32; 4],
+}
+
+/// Camera state for 2D map view
+pub struct Camera {
+    pub x: f32,
+    pub y: f32,
+    pub zoom: f32,
+    pub aspect: f32,
+}
+
+impl Camera {
+    pub fn to_uniform(&self, is_dark: bool) -> CameraUniform {
+        // Simple 2D orthographic projection-like transform
+        // We want to map world coordinates to clip space [-1, 1]
+        // zoom controls how much of the world we see.
+        // aspect ratio correction is needed for non-square windows.
+        
+        // Scale:
+        // If zoom is 1.0, we see 2.0 units of world height (from -1 to 1).
+        // scale_y = zoom
+        // scale_x = zoom / aspect
+        
+        CameraUniform {
+            params: [
+                self.zoom / self.aspect, // scale_x
+                -self.zoom,              // scale_y (flipped for North-Up)
+                -self.x * (self.zoom / self.aspect), // translate_x
+                self.y * self.zoom,      // translate_y (flipped sign)
+            ],
+            theme: [
+                if is_dark { 1.0 } else { 0.0 },
+                0.0, 0.0, 0.0
+            ],
+        }
+    }
+}
+
+/// Mouse/touch input state for drag operations
+pub struct InputState {
+    pub is_dragging: bool,
+    pub last_cursor: Option<(f64, f64)>,
+}