skeleton: tracked input state, analog pad api, camera manipulator, file paths

EventHandler now keeps keys/mouse/pad state so apps don't have to;
sk::Camera is an orbit/dolly/pan manipulator over an rw::Camera;
GetFilePath mangles paths for cdrom0:/host:/host0: on ps2.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

skeleton/camera.h

@@ -0,0 +1,75 @@
+#ifndef SKELCAMERA_H
+#define SKELCAMERA_H
+
+namespace sk {
+
+// Manipulator around an rw::Camera. Keeps position/target/up and
+// drives the rw camera's frame from them in update().
+struct Camera
+{
+	rw::Camera *m_rwcam;
+	rw::V3d m_position;
+	rw::V3d m_target;
+	rw::V3d m_up;
+	rw::V3d m_localup;
+
+	float m_fov, m_aspectRatio;
+	float m_near, m_far;
+
+	void init(void);
+	void attach(rw::Camera *cam);
+
+	void setTarget(rw::V3d target);
+	float getHeading(void);
+
+	void turn(float yaw, float pitch);
+	void orbit(float yaw, float pitch);
+	void dolly(float dist);
+	void zoom(float dist);
+	void pan(float x, float y);
+
+	void update(void);
+	float distanceTo(rw::V3d v);
+	float distanceToTarget(void);
+	rw::bool32 isSphereVisible(rw::Sphere *sph, rw::Matrix *xform);
+};
+
+/*
+ * Controls.
+ *
+ * Two kinds of input, and they must not be treated alike:
+ *
+ *  displacement - mouse motion, wheel. Already frame rate independent,
+ *                 a given hand movement gives the same delta at any fps.
+ *                 Scale by a constant gain, never by dt.
+ *  rate         - held keys, stick deflection. A speed, so scale by dt.
+ *
+ * Mouse deltas are normalized by the viewport, so sensitivity does not
+ * change with resolution.
+ */
+struct CameraControls
+{
+	float mouseSens;	// gain for mouse displacement
+	float wheelSens;	// gain for wheel displacement
+	float stickSens;	// radians/sec for stick look
+	float moveSpeed;	// units/sec
+	float speedUpMult;	// while shift/R1 held
+};
+extern CameraControls cameraControls;
+
+void CameraControlsInit(void);
+
+// Editor style: orbit/pan/zoom about the target.
+// mouse: left orbit, middle pan, right zoom, wheel zoom
+// pad:   left stick orbit, right stick pan, L1/R1 zoom
+void CameraEditorControls(Camera *cam, float dt);
+
+// First person style: look with the mouse/right stick, fly with the keys.
+// mouse: left drag look
+// keys:  WASD move, Q/E down/up, shift faster
+// pad:   right stick look, left stick move, L2/R2 down/up, R1 faster
+void CameraFlyControls(Camera *cam, float dt);
+
+}
+
+#endif