Add monitor events, limit fps to monitor the window is in, reduce latency (glFinish, fps limit)

1 files changed, 360 insertions, 16 deletions

diff --git a/src/window/window.c b/src/window/window.c
index 980e811..8035239 100644
--- a/src/window/window.c
+++ b/src/window/window.c
@@ -6,6 +6,7 @@
 #include <X11/cursorfont.h>
 #include <X11/Xatom.h>
 #include <X11/extensions/Xrender.h>
+#include <X11/extensions/Xrandr.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
@@ -14,6 +15,7 @@
 #include <unistd.h>
 
 /* TODO: Handle XIM better. Set XIM position to text position on screen (for text input) and reset input when selecting a new text input, etc */
+/* TODO: Separate events from windows. Especially when it comes to monitor events */
 
 /* Should be in range [2,] */
 #define MAX_STACKED_EVENTS 32
@@ -51,6 +53,8 @@ static bool x11_events_circular_buffer_pop(x11_events_circular_buffer *self, mgl
     return true;
 }
 
+#define MAX_MONITORS 12
+
 typedef struct {
     GLXContext glx_context;
     XIM xim;
@@ -74,6 +78,11 @@ typedef struct {
     GLXFBConfig *fbconfigs;
     GLXFBConfig fbconfig;
     XVisualInfo *visual_info;
+
+    /* This only contains connected and active monitors */
+    mgl_monitor monitors[MAX_MONITORS];
+    int num_monitors;
+
     /*
         Used to stack text event on top of key press/release events and other text events.
         For example pressing a key should give the user both key press and text events
@@ -163,6 +172,9 @@ static int x11_context_init(x11_context *self, bool alpha) {
     self->fbconfig = NULL;
     self->visual_info = NULL;
 
+    memset(self->monitors, 0, sizeof(self->monitors));
+    self->num_monitors = 0;
+
     if(!glx_context_choose(context, &self->fbconfigs, &self->fbconfig, &self->visual_info, alpha)) {
         x11_context_deinit(self);
         return -1;
@@ -176,8 +188,10 @@ static int x11_context_init(x11_context *self, bool alpha) {
 
     const char data[1] = {0};
     Pixmap blank_bitmap = XCreateBitmapFromData(context->connection, DefaultRootWindow(context->connection), data, 1, 1);
-    if(!blank_bitmap)
+    if(!blank_bitmap) {
+        x11_context_deinit(self);
         return -1;
+    }
 
     XColor dummy;
     self->invisible_cursor = XCreatePixmapCursor(context->connection, blank_bitmap, blank_bitmap, &dummy, &dummy, 0, 0);
@@ -195,6 +209,15 @@ static int x11_context_init(x11_context *self, bool alpha) {
 void x11_context_deinit(x11_context *self) {
     mgl_context *context = mgl_get_context();
 
+    for(int i = 0; i < self->num_monitors; ++i) {
+        mgl_monitor *monitor = &self->monitors[i];
+        if(monitor->name) {
+            free((char*)monitor->name);
+            monitor->name = NULL;
+        }
+    }
+    self->num_monitors = 0;
+
     if(self->color_map) {
         XFreeColormap(context->connection, self->color_map);
         self->color_map = None;
@@ -246,6 +269,140 @@ static bool x11_context_pop_event(x11_context *self, mgl_event *event) {
     return x11_events_circular_buffer_pop(&self->events, event);
 }
 
+static mgl_monitor* x11_context_add_monitor(x11_context *self, RROutput output_id, RRCrtc crtc_id, const char *name, mgl_vec2i pos, mgl_vec2i size, int refresh_rate) {
+    if(self->num_monitors == MAX_MONITORS)
+        return NULL;
+
+    mgl_monitor *monitor = &self->monitors[self->num_monitors];
+    monitor->id = output_id;
+    monitor->crtc_id = crtc_id;
+    monitor->name = strdup(name);
+    if(!monitor->name)
+        return NULL;
+    monitor->pos = pos;
+    monitor->size = size;
+    monitor->refresh_rate = refresh_rate;
+    self->num_monitors++;
+
+    return monitor;
+}
+
+static mgl_monitor* x11_context_get_monitor_by_id(x11_context *self, RROutput output_id) {
+    for(int i = 0; i < self->num_monitors; ++i) {
+        mgl_monitor *monitor = &self->monitors[i];
+        if(monitor->id == (int)output_id)
+            return monitor;
+    }
+    return NULL;
+}
+
+static mgl_monitor* x11_context_get_monitor_by_crtc_id(x11_context *self, RRCrtc crtc_id) {
+    for(int i = 0; i < self->num_monitors; ++i) {
+        mgl_monitor *monitor = &self->monitors[i];
+        if(monitor->crtc_id == (int)crtc_id)
+            return monitor;
+    }
+    return NULL;
+}
+
+static bool x11_context_remove_monitor(x11_context *self, RROutput output_id, mgl_event *event) {
+    int index_to_remove = -1;
+    for(int i = 0; i < self->num_monitors; ++i) {
+        mgl_monitor *monitor = &self->monitors[i];
+        if(monitor->id == (int)output_id) {
+            index_to_remove = i;
+            break;
+        }
+    }
+
+    if(index_to_remove == -1)
+        return false;
+
+    mgl_monitor *monitor = &self->monitors[index_to_remove];
+    free((char*)monitor->name);
+    monitor->name = NULL;
+
+    for(int i = index_to_remove + 1; i < self->num_monitors; ++i) {
+        self->monitors[i - 1] = self->monitors[i];
+    }
+    self->num_monitors--;
+
+    event->monitor_disconnected.id = output_id;
+    return true;
+}
+
+static int round_int(double value) {
+    return value + 0.5;
+}
+
+static int monitor_info_get_framerate(const XRRModeInfo *mode_info) {
+    double v_total = mode_info->vTotal;
+    if(mode_info->modeFlags & RR_DoubleScan) {
+        v_total *= 2;
+    }
+
+    if(mode_info->modeFlags & RR_Interlace) {
+        v_total /= 2;
+    }
+
+    if(mode_info->hTotal > 0 && v_total > 0.0001) {
+        return round_int((double)mode_info->dotClock / ((double)mode_info->hTotal * v_total));
+    } else {
+        return 0;
+    }
+}
+
+static const XRRModeInfo* get_mode_info(const XRRScreenResources *sr, RRMode id) {
+    for(int i = 0; i < sr->nmode; ++i) {
+        if(sr->modes[i].id == id)
+            return &sr->modes[i];
+    }    
+    return NULL;
+}
+
+typedef void (*active_monitor_callback)(const mgl_monitor *monitor, void *userdata);
+static void for_each_active_monitor_output(Display *display, active_monitor_callback callback, void *userdata) {
+    XRRScreenResources *screen_res = XRRGetScreenResources(display, DefaultRootWindow(display));
+    if(!screen_res)
+        return;
+
+    char display_name[256];
+    for(int i = 0; i < screen_res->noutput; ++i) {
+        XRROutputInfo *out_info = XRRGetOutputInfo(display, screen_res, screen_res->outputs[i]);
+        if(out_info && out_info->crtc && out_info->connection == RR_Connected) {
+            XRRCrtcInfo *crt_info = XRRGetCrtcInfo(display, screen_res, out_info->crtc);
+            if(crt_info && crt_info->mode) {
+                const XRRModeInfo *mode_info = get_mode_info(screen_res, crt_info->mode);
+                if(mode_info && out_info->nameLen < (int)sizeof(display_name)) {
+                    memcpy(display_name, out_info->name, out_info->nameLen);
+                    display_name[out_info->nameLen] = '\0';
+
+                    mgl_monitor monitor = {
+                        .id = screen_res->outputs[i],
+                        .crtc_id = out_info->crtc,
+                        .name = display_name,
+                        .pos = { .x = crt_info->x, .y = crt_info->y },
+                        .size = { .x = (int)crt_info->width, .y = (int)crt_info->height },
+                        .refresh_rate = monitor_info_get_framerate(mode_info),
+                    };
+                    callback(&monitor, userdata);
+                }
+            }
+            if(crt_info)
+                XRRFreeCrtcInfo(crt_info);
+        }
+        if(out_info)
+            XRRFreeOutputInfo(out_info);
+    }
+
+    XRRFreeScreenResources(screen_res);
+}
+
+static void monitor_callback_add_to_x11_context(const mgl_monitor *monitor, void *userdata) {
+    x11_context *x11_context = userdata;
+    x11_context_add_monitor(x11_context, monitor->id, monitor->crtc_id, monitor->name, monitor->pos, monitor->size, monitor->refresh_rate);
+}
+
 /* TODO: Use gl OML present for other platforms than nvidia? nvidia doesn't support present yet */
 
 /* TODO: check for glx swap control extension string (GLX_EXT_swap_control, etc) */
@@ -271,6 +428,34 @@ static void set_vertical_sync_enabled(Window window, int enabled) {
         fprintf(stderr, "mgl warning: setting vertical sync failed\n");
 }
 
+static void mgl_window_set_frame_time_limit_monitor(mgl_window *self) {
+    int monitor_refresh_rate = 0;
+    mgl_vec2i window_center = (mgl_vec2i) { self->pos.x + self->size.x / 2, self->pos.y + self->size.y / 2 };
+    for(int i = 0; i < self->num_monitors; ++i) {
+        mgl_monitor *monitor = &self->monitors[i];
+        if(window_center.x >= monitor->pos.x && window_center.x <= monitor->pos.x + monitor->size.x
+            && window_center.y >= monitor->pos.y && window_center.y <= monitor->pos.y + monitor->size.y)
+        {
+            monitor_refresh_rate = monitor->refresh_rate;
+            break;
+        }
+    }
+
+    if(monitor_refresh_rate == 0 && self->num_monitors > 0)
+        monitor_refresh_rate = self->monitors[0].refresh_rate;
+
+    if(monitor_refresh_rate == 0)
+        monitor_refresh_rate = 60;
+
+    self->frame_time_limit_monitor = 1.0 / (double)monitor_refresh_rate;
+}
+
+static void mgl_window_on_move(mgl_window *self, int x, int y) {
+    self->pos.x = x;
+    self->pos.y = y;
+    mgl_window_set_frame_time_limit_monitor(self);
+}
+
 static void mgl_window_on_resize(mgl_window *self, int width, int height) {
     self->size.x = width;
     self->size.y = height;
@@ -295,9 +480,13 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
     self->focused = false;
     self->key_repeat_enabled = true;
     self->frame_time_limit = 0.0;
+    self->frame_time_limit_monitor = 0.0;
     mgl_clock_init(&self->frame_timer);
     self->clipboard_string = NULL;
     self->clipboard_size = 0;
+    self->monitors = NULL;
+    self->num_monitors = 0;
+    self->pos = (mgl_vec2i){ 0, 0 };
 
     mgl_vec2i window_size = params ? params->size : (mgl_vec2i){ 0, 0 };
     if(window_size.x <= 0 || window_size.y <= 0) {
@@ -306,6 +495,8 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
     }
     self->size = window_size;
 
+    mgl_vec2i window_pos = params ? params->position : (mgl_vec2i){ 0, 0 };
+
     self->context = malloc(sizeof(x11_context));
     if(!self->context) {
         fprintf(stderr, "mgl error: failed to allocate x11 context\n");
@@ -319,6 +510,9 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
         return -1;
     }
 
+    self->monitors = x11_context->monitors;
+    self->num_monitors = 0;
+
     mgl_context *context = mgl_get_context();
 
     Window parent_window = params ? params->parent_window : None;
@@ -360,11 +554,15 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
             return -1;
         }
 
+        if(params && params->size.x > 0 && params->size.y > 0) {
+            XResizeWindow(context->connection, existing_window, params->size.x, params->size.y);
+        }
+
         self->window = existing_window;
         if(hide_window)
             XUnmapWindow(context->connection, existing_window);
     } else {
-        self->window = XCreateWindow(context->connection, parent_window, params->position.x, params->position.y,
+        self->window = XCreateWindow(context->connection, parent_window, window_pos.x, window_pos.y,
             window_size.x, window_size.y, 0,
             x11_context->visual_info->depth, InputOutput, x11_context->visual_info->visual,
             CWColormap | CWEventMask | CWOverrideRedirect | CWBorderPixel | CWBackPixel | CWBitGravity, &window_attr);
@@ -421,8 +619,6 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
     unsigned int dummy_u;
     XQueryPointer(context->connection, self->window, &dummy_w, &dummy_w, &dummy_i, &dummy_i, &self->cursor_position.x, &self->cursor_position.y, &dummy_u);
 
-    mgl_window_on_resize(self, self->size.x, self->size.y);
-
     x11_context->xim = XOpenIM(context->connection, NULL, NULL, NULL);
     if(!x11_context->xim) {
         fprintf(stderr, "mgl error: XOpenIM failed\n");
@@ -437,6 +633,12 @@ static int mgl_window_init(mgl_window *self, const char *title, const mgl_window
         return -1;
     }
 
+    for_each_active_monitor_output(context->connection, monitor_callback_add_to_x11_context, x11_context);
+    self->num_monitors = x11_context->num_monitors;
+
+    mgl_window_on_resize(self, self->size.x, self->size.y);
+    mgl_window_on_move(self, window_pos.x, window_pos.y);
+
     self->open = true;
     self->focused = false; /* TODO: Check if we need to call XGetInputFocus for this, or just wait for focus event */
     return 0;
@@ -590,7 +792,7 @@ static mgl_mouse_button x11_button_to_mgl_button(unsigned int button) {
     return MGL_BUTTON_UNKNOWN;
 }
 
-static void mgl_window_handle_key_event(mgl_window *self, XKeyEvent *xkey, mgl_event *event, mgl_context *context, bool pressed) {
+static void mgl_window_handle_key_event(mgl_window *self, XKeyEvent *xkey, mgl_event *event, mgl_context *context) {
     event->key.code = x11_keysym_to_mgl_key(XKeycodeToKeysym(context->connection, xkey->keycode, 0));
     event->key.alt = ((xkey->state & Mod1Mask) != 0);
     event->key.control = ((xkey->state & ControlMask) != 0);
@@ -638,11 +840,146 @@ static void mgl_window_handle_text_event(mgl_window *self, XEvent *xev) {
     }
 }
 
+static bool mgl_on_monitor_added(Display *display, x11_context *x11_context, XRROutputChangeNotifyEvent *rr_output_change_event, XRRScreenResources *screen_res, RROutput output_id, XRROutputInfo *out_info, mgl_event *event) {
+    char display_name[256];
+    mgl_monitor *monitor = NULL;
+    XRRCrtcInfo *crt_info = NULL;
+    const XRRModeInfo *mode_info = NULL;
+
+    if(!rr_output_change_event->mode)
+        return false;
+
+    if(x11_context_get_monitor_by_id(x11_context, output_id))
+        return false;
+
+    if(out_info->nameLen >= (int)sizeof(display_name))
+        return false;
+
+    crt_info = XRRGetCrtcInfo(display, screen_res, out_info->crtc);
+    if(!crt_info)
+        goto done;
+
+    mode_info = get_mode_info(screen_res, rr_output_change_event->mode);
+    if(!mode_info)
+        goto done;
+
+    memcpy(display_name, out_info->name, out_info->nameLen);
+    display_name[out_info->nameLen] = '\0';
+
+    monitor = x11_context_add_monitor(x11_context, output_id, out_info->crtc, display_name,
+        (mgl_vec2i){ .x = crt_info->x, .y = crt_info->y },
+        (mgl_vec2i){ .x = (int)crt_info->width, .y = (int)crt_info->height },
+        monitor_info_get_framerate(mode_info));
+
+    if(!monitor)
+        goto done;
+
+    event->monitor_connected.id = monitor->id;
+    event->monitor_connected.name = monitor->name;
+    event->monitor_connected.x = monitor->pos.x;
+    event->monitor_connected.y = monitor->pos.y;
+    event->monitor_connected.width = monitor->size.x;
+    event->monitor_connected.height = monitor->size.y;
+    event->monitor_connected.refresh_rate = monitor->refresh_rate;
+
+    done:
+    if(crt_info)
+        XRRFreeCrtcInfo(crt_info);
+    return monitor != NULL;
+}
+
+static bool mgl_on_monitor_state_changed(Display *display, x11_context *x11_context, XRROutputChangeNotifyEvent *rr_output_change_event, mgl_event *event) {
+    bool state_changed = false;
+    XRROutputInfo *out_info = NULL;
+
+    if(!rr_output_change_event->output)
+        return false;
+
+    XRRScreenResources *screen_res = XRRGetScreenResources(display, DefaultRootWindow(display));
+    if(!screen_res)
+        return false;
+
+    out_info = XRRGetOutputInfo(display, screen_res, rr_output_change_event->output);
+    if(out_info && out_info->crtc && out_info->connection == RR_Connected) {
+        state_changed = mgl_on_monitor_added(display, x11_context, rr_output_change_event, screen_res, rr_output_change_event->output, out_info, event);
+    } else {
+        state_changed = x11_context_remove_monitor(x11_context, rr_output_change_event->output, event);
+    }
+
+    if(out_info)
+        XRRFreeOutputInfo(out_info);
+    
+    XRRFreeScreenResources(screen_res);
+    return state_changed;
+}
+
+static bool mgl_on_monitor_property_changed(Display *display, x11_context *x11_context, XRRCrtcChangeNotifyEvent *rr_crtc_change_event, mgl_event *event) {
+    if(!rr_crtc_change_event->crtc)
+        return false;
+
+    mgl_monitor *monitor = x11_context_get_monitor_by_crtc_id(x11_context, rr_crtc_change_event->crtc);
+    if(!monitor)
+        return false;
+
+    XRRScreenResources *screen_res = XRRGetScreenResources(display, DefaultRootWindow(display));
+    if(!screen_res)
+        return false;
+
+    monitor->pos = (mgl_vec2i){ .x = rr_crtc_change_event->x, .y = rr_crtc_change_event->y };
+    monitor->size = (mgl_vec2i){ .x = rr_crtc_change_event->width, .y = rr_crtc_change_event->height };
+    const XRRModeInfo *mode_info = get_mode_info(screen_res, rr_crtc_change_event->mode);
+    if(mode_info)
+        monitor->refresh_rate = monitor_info_get_framerate(mode_info);
+
+    XRRFreeScreenResources(screen_res);
+
+    event->monitor_property_changed.id = monitor->id;
+    event->monitor_property_changed.name = monitor->name;
+    event->monitor_property_changed.x = monitor->pos.x;
+    event->monitor_property_changed.y = monitor->pos.y;
+    event->monitor_property_changed.width = monitor->size.x;
+    event->monitor_property_changed.height = monitor->size.y;
+    event->monitor_property_changed.refresh_rate = monitor->refresh_rate;
+    return true;
+}
+
+/* Returns true if an event was generated */
+static bool mgl_on_rr_notify(mgl_context *context, x11_context *x11_context, XEvent *xev, int subtype, mgl_event *event) {
+    switch(subtype) {
+        case RRNotify_CrtcChange: {
+            XRRCrtcChangeNotifyEvent *rr_crtc_change_event = (XRRCrtcChangeNotifyEvent*)xev;
+            return mgl_on_monitor_property_changed(context->connection, x11_context, rr_crtc_change_event, event);
+        }
+        case RRNotify_OutputChange: {
+            XRROutputChangeNotifyEvent *rr_output_change_event = (XRROutputChangeNotifyEvent*)xev;
+            return mgl_on_monitor_state_changed(context->connection, x11_context, rr_output_change_event, event);
+        }
+    }
+    return false;
+}
+
 static void mgl_window_on_receive_event(mgl_window *self, XEvent *xev, mgl_event *event, mgl_context *context) {
+    x11_context *x11_context = self->context;
+    switch(xev->type - context->randr_event_base) {
+        case RRScreenChangeNotify: {
+            XRRUpdateConfiguration(xev);
+            event->type = MGL_EVENT_UNKNOWN;
+            return;
+        }
+        case RRNotify: {
+            XRRNotifyEvent *rr_event = (XRRNotifyEvent*)xev;
+            if(mgl_on_rr_notify(context, x11_context, xev, rr_event->subtype, event)) {
+                self->num_monitors = x11_context->num_monitors;
+                return;
+            }
+
+            event->type = MGL_EVENT_UNKNOWN;
+            return;
+        }
+    }
+
     switch(xev->type) {
         case KeyPress: {
-            x11_context *x11_context = self->context;
-
             if(!self->key_repeat_enabled && xev->xkey.keycode == x11_context->prev_keycode_pressed && !x11_context->key_was_released) {
                 event->type = MGL_EVENT_UNKNOWN;
                 return;
@@ -652,17 +989,16 @@ static void mgl_window_on_receive_event(mgl_window *self, XEvent *xev, mgl_event
             x11_context->key_was_released = false;
 
             event->type = MGL_EVENT_KEY_PRESSED;
-            mgl_window_handle_key_event(self, &xev->xkey, event, context, true);
+            mgl_window_handle_key_event(self, &xev->xkey, event, context);
             mgl_window_handle_text_event(self, xev);
             return;
         }
         case KeyRelease: {
-            x11_context *x11_context = self->context;
             if(xev->xkey.keycode == x11_context->prev_keycode_pressed)
                 x11_context->key_was_released = true;
 
             event->type = MGL_EVENT_KEY_RELEASED;
-            mgl_window_handle_key_event(self, &xev->xkey, event, context, false);
+            mgl_window_handle_key_event(self, &xev->xkey, event, context);
             return;
         }
         case ButtonPress: {
@@ -694,7 +1030,6 @@ static void mgl_window_on_receive_event(mgl_window *self, XEvent *xev, mgl_event
             return;
         }
         case FocusIn: {
-            x11_context *x11_context = self->context;
             XSetICFocus(x11_context->xic);
 
             XWMHints* hints = XGetWMHints(context->connection, self->window);
@@ -709,7 +1044,6 @@ static void mgl_window_on_receive_event(mgl_window *self, XEvent *xev, mgl_event
             return;
         }
         case FocusOut: {
-            x11_context *x11_context = self->context;
             XUnsetICFocus(x11_context->xic);
             event->type = MGL_EVENT_LOST_FOCUS;
             self->focused = false;
@@ -717,6 +1051,10 @@ static void mgl_window_on_receive_event(mgl_window *self, XEvent *xev, mgl_event
         }
         case ConfigureNotify: {
             while(XCheckTypedWindowEvent(context->connection, self->window, ConfigureNotify, xev)) {}
+            if(xev->xconfigure.x != self->pos.x || xev->xconfigure.y != self->pos.y) {
+                mgl_window_on_move(self, xev->xconfigure.x, xev->xconfigure.y);
+            }
+
             if(xev->xconfigure.width != self->size.x || xev->xconfigure.height != self->size.y) {
                 mgl_window_on_resize(self, xev->xconfigure.width, xev->xconfigure.height);
 
@@ -725,6 +1063,7 @@ static void mgl_window_on_receive_event(mgl_window *self, XEvent *xev, mgl_event
                 event->size.height = self->size.y;
                 return;
             }
+
             event->type = MGL_EVENT_UNKNOWN;
             return;
         }
@@ -743,8 +1082,6 @@ static void mgl_window_on_receive_event(mgl_window *self, XEvent *xev, mgl_event
             return;
         }
         case SelectionRequest: {
-            x11_context *x11_context = self->context;
-
             XSelectionEvent selection_event;
             selection_event.type = SelectionNotify;
             selection_event.requestor = xev->xselectionrequest.requestor;
@@ -840,7 +1177,7 @@ bool mgl_window_poll_event(mgl_window *self, mgl_event *event) {
     if(XPending(display)) {
         XEvent xev; /* TODO: Move to window struct */
         XNextEvent(display, &xev);
-        if(xev.xany.window == self->window || xev.type == ClientMessage)
+        if(xev.xany.window == self->window || xev.type == ClientMessage || xev.type - context->randr_event_base >= 0)
             mgl_window_on_receive_event(self, &xev, event, context);
         else
             event->type = MGL_EVENT_UNKNOWN;
@@ -853,12 +1190,19 @@ bool mgl_window_poll_event(mgl_window *self, mgl_event *event) {
 void mgl_window_display(mgl_window *self) {
     mgl_context *context = mgl_get_context();
     context->gl.glXSwapBuffers(context->connection, self->window);
+    context->gl.glFlush();
+    context->gl.glFinish();
 
     if(self->frame_time_limit > 0.000001) {
         double time_left_to_sleep = self->frame_time_limit - mgl_clock_get_elapsed_time_seconds(&self->frame_timer);
         if(time_left_to_sleep > 0.000001)
             usleep(time_left_to_sleep * 1000000.0);
         mgl_clock_restart(&self->frame_timer);
+    } else if(self->frame_time_limit_monitor >= 0.000001) {
+        double time_left_to_sleep = self->frame_time_limit_monitor - mgl_clock_get_elapsed_time_seconds(&self->frame_timer);
+        if(time_left_to_sleep > 0.000001)
+            usleep(time_left_to_sleep * 1000000.0);
+        mgl_clock_restart(&self->frame_timer);
     }
 }
 
@@ -972,7 +1316,7 @@ void mgl_window_set_framerate_limit(mgl_window *self, int fps) {
     if(fps <= 0)
         self->frame_time_limit = 0.0;
     else
-        self->frame_time_limit = 1.0 / fps;
+        self->frame_time_limit = 1.0 / (double)fps;
 }
 
 void mgl_window_set_vsync_enabled(mgl_window *self, bool enabled) {