From 6ce281aa019bef35c81261e328e33948907472c6 Mon Sep 17 00:00:00 2001
From: 3gg <3gg@shellblade.net>
Date: Sun, 29 Jun 2025 09:30:38 -0700
Subject: Tidy camera control

---
 src/plugins/viewer.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/src/plugins/viewer.c b/src/plugins/viewer.c
index 1a27f8f..84fcca4 100644
--- a/src/plugins/viewer.c
+++ b/src/plugins/viewer.c
@@ -51,6 +51,8 @@ typedef struct CameraCommand {
   bool CameraMoveRight    : 1;
   bool CameraMoveForward  : 1;
   bool CameraMoveBackward : 1;
+  bool CameraIsRotating : 1; // When true, subsequent mouse movements cause the
+                             // camera to rotate.
 } CameraCommand;
 
 typedef struct CameraController {
@@ -58,8 +60,6 @@ typedef struct CameraController {
   R mouse_sensitivity;      // Controls the degree with which mouse movements
                             // rotate the camera.
   vec2 prev_mouse_position; // Mouse position in the previous frame.
-  bool rotating;            // When true, subsequent mouse movements cause the
-                            // camera to rotate.
 } CameraController;
 
 typedef struct State {
@@ -197,6 +197,16 @@ void shutdown(Game* game, State* state) {
   }
 }
 
+static CameraCommand make_camera_command_from_input() {
+  return (CameraCommand){
+      .CameraMoveLeft     = gfx_app_is_key_pressed(KeyA),
+      .CameraMoveRight    = gfx_app_is_key_pressed(KeyD),
+      .CameraMoveForward  = gfx_app_is_key_pressed(KeyW),
+      .CameraMoveBackward = gfx_app_is_key_pressed(KeyS),
+      .CameraIsRotating   = gfx_app_is_mouse_button_pressed(LMB),
+  };
+}
+
 static void update_camera(
     CameraController* controller, R dt, vec2 mouse_position,
     CameraCommand command, Spatial3* camera) {
@@ -214,7 +224,7 @@ static void update_camera(
   spatial3_move_forwards(camera, translation.y);
 
   // Rotation.
-  if (controller->rotating) {
+  if (command.CameraIsRotating) {
     const vec2 mouse_delta =
         vec2_sub(mouse_position, controller->prev_mouse_position);
 
@@ -239,15 +249,7 @@ void update(Game* game, State* state, double t, double dt) {
   gfx_app_get_mouse_position(&mouse_x, &mouse_y);
   const vec2 mouse_position = {(R)mouse_x, (R)mouse_y};
 
-  const CameraCommand camera_command = (CameraCommand){
-      .CameraMoveLeft     = gfx_app_is_key_pressed(KeyA),
-      .CameraMoveRight    = gfx_app_is_key_pressed(KeyD),
-      .CameraMoveForward  = gfx_app_is_key_pressed(KeyW),
-      .CameraMoveBackward = gfx_app_is_key_pressed(KeyS),
-  };
-
-  state->camera_controller.rotating = gfx_app_is_mouse_button_pressed(LMB);
-
+  const CameraCommand camera_command = make_camera_command_from_input();
   update_camera(
       &state->camera_controller, (R)dt, mouse_position, camera_command,
       &gfx_get_camera_camera(state->camera)->spatial);
-- 
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