set_fov: Add support for time-based transitions (#9705)

[oweals/minetest.git] / src / client / camera.cpp

diff --git a/src/client/camera.cpp b/src/client/camera.cpp
index 69bd82a4797f88a68d1d0180a003dba6a772338b..1a5253db426b61e59b1249445532eb056286be07 100644 (file)
--- a/src/client/camera.cpp
+++ b/src/client/camera.cpp
@@ -86,6 +86,51 @@ Camera::~Camera()
        m_wieldmgr->drop();
 }
 
+void Camera::notifyFovChange()
+{
+       LocalPlayer *player = m_client->getEnv().getLocalPlayer();
+       assert(player);
+
+       PlayerFovSpec spec = player->getFov();
+
+       /*
+        * Update m_old_fov_degrees first - it serves as the starting point of the
+        * upcoming transition.
+        *
+        * If an FOV transition is already active, mark current FOV as the start of
+        * the new transition. If not, set it to the previous transition's target FOV.
+        */
+       if (m_fov_transition_active)
+               m_old_fov_degrees = m_curr_fov_degrees;
+       else
+               m_old_fov_degrees = m_server_sent_fov ? m_target_fov_degrees : m_cache_fov;
+
+       /*
+        * Update m_server_sent_fov next - it corresponds to the target FOV of the
+        * upcoming transition.
+        *
+        * Set it to m_cache_fov, if server-sent FOV is 0. Otherwise check if
+        * server-sent FOV is a multiplier, and multiply it with m_cache_fov instead
+        * of overriding.
+        */
+       if (spec.fov == 0.0f) {
+               m_server_sent_fov = false;
+               m_target_fov_degrees = m_cache_fov;
+       } else {
+               m_server_sent_fov = true;
+               m_target_fov_degrees = spec.is_multiplier ? m_cache_fov * spec.fov : spec.fov;
+       }
+
+       if (spec.transition_time > 0.0f)
+               m_fov_transition_active = true;
+
+       // If FOV smooth transition is active, initialize required variables
+       if (m_fov_transition_active) {
+               m_transition_time = spec.transition_time;
+               m_fov_diff = m_target_fov_degrees - m_old_fov_degrees;
+       }
+}
+
 bool Camera::successfullyCreated(std::string &error_message)
 {
        if (!m_playernode) {
@@ -462,33 +507,38 @@ void Camera::update(LocalPlayer* player, f32 frametime, f32 busytime, f32 tool_r
                m_camera_position = my_cp;
 
        /*
-        * Apply server-sent FOV. If server doesn't enforce FOV,
-        * check for zoom and set to zoom FOV.
-        * Otherwise, default to m_cache_fov
+        * Apply server-sent FOV, instantaneous or smooth transition.
+        * If not, check for zoom and set to zoom FOV.
+        * Otherwise, default to m_cache_fov.
         */
-
-       f32 fov_degrees;
-       PlayerFovSpec fov_spec = player->getFov();
-       if (fov_spec.fov > 0.0f) {
-               // If server-sent FOV is a multiplier, multiply
-               // it with m_cache_fov instead of overriding
-               if (fov_spec.is_multiplier)
-                       fov_degrees = m_cache_fov * fov_spec.fov;
-               else
-                       fov_degrees = fov_spec.fov;
+       if (m_fov_transition_active) {
+               // Smooth FOV transition
+               // Dynamically calculate FOV delta based on frametimes
+               f32 delta = (frametime / m_transition_time) * m_fov_diff;
+               m_curr_fov_degrees += delta;
+
+               // Mark transition as complete if target FOV has been reached
+               if ((m_fov_diff > 0.0f && m_curr_fov_degrees >= m_target_fov_degrees) ||
+                               (m_fov_diff < 0.0f && m_curr_fov_degrees <= m_target_fov_degrees)) {
+                       m_fov_transition_active = false;
+                       m_curr_fov_degrees = m_target_fov_degrees;
+               }
+       } else if (m_server_sent_fov) {
+               // Instantaneous FOV change
+               m_curr_fov_degrees = m_target_fov_degrees;
        } else if (player->getPlayerControl().zoom && player->getZoomFOV() > 0.001f) {
                // Player requests zoom, apply zoom FOV
-               fov_degrees = player->getZoomFOV();
+               m_curr_fov_degrees = player->getZoomFOV();
        } else {
                // Set to client's selected FOV
-               fov_degrees = m_cache_fov;
+               m_curr_fov_degrees = m_cache_fov;
        }
-       fov_degrees = rangelim(fov_degrees, 1.0f, 160.0f);
+       m_curr_fov_degrees = rangelim(m_curr_fov_degrees, 1.0f, 160.0f);
 
        // FOV and aspect ratio
        const v2u32 &window_size = RenderingEngine::get_instance()->getWindowSize();
        m_aspect = (f32) window_size.X / (f32) window_size.Y;
-       m_fov_y = fov_degrees * M_PI / 180.0;
+       m_fov_y = m_curr_fov_degrees * M_PI / 180.0;
        // Increase vertical FOV on lower aspect ratios (<16:10)
        m_fov_y *= MYMAX(1.0, MYMIN(1.4, sqrt(16./10. / m_aspect)));
        m_fov_x = 2 * atan(m_aspect * tan(0.5 * m_fov_y));