renderer: Tearing implementation (#3441)

CMakeLists.txt

@@ -218,5 +218,6 @@ protocol("stable/xdg-shell/xdg-shell.xml" "xdg-shell" false)
 protocol("unstable/linux-dmabuf/linux-dmabuf-unstable-v1.xml" "linux-dmabuf-unstable-v1" false)
 protocol("unstable/xdg-output/xdg-output-unstable-v1.xml" "xdg-output-unstable-v1" false)
 protocol("staging/fractional-scale/fractional-scale-v1.xml" "fractional-scale-v1" false)
+protocol("staging/tearing-control/tearing-control-v1.xml" "tearing-control-v1" false)
 protocol("unstable/text-input/text-input-unstable-v1.xml" "text-input-unstable-v1" false)
 protocol("staging/cursor-shape/cursor-shape-v1.xml" "cursor-shape-v1" false)

protocols/meson.build

@@ -25,6 +25,7 @@ protocols = [
   [wl_protocol_dir, 'unstable/xdg-output/xdg-output-unstable-v1.xml'],
   [wl_protocol_dir, 'staging/fractional-scale/fractional-scale-v1.xml'],
   [wl_protocol_dir, 'staging/cursor-shape/cursor-shape-v1.xml'],
+  [wl_protocol_dir, 'staging/tearing-control/tearing-control-v1.xml'],
   ['wlr-foreign-toplevel-management-unstable-v1.xml'],
   ['wlr-layer-shell-unstable-v1.xml'],
   ['wlr-output-power-management-unstable-v1.xml'],

src/Compositor.cpp

@@ -257,6 +257,8 @@ void CCompositor::initServer() {
 
     m_sWLRCursorShapeMgr = wlr_cursor_shape_manager_v1_create(m_sWLDisplay, 1);
 
+    m_sWLRTearingControlMgr = wlr_tearing_control_manager_v1_create(m_sWLDisplay, 1);
+
     if (!m_sWLRHeadlessBackend) {
         Debug::log(CRIT, "Couldn't create the headless backend");
         throwError("wlr_headless_backend_create() failed!");
@@ -315,6 +317,7 @@ void CCompositor::initAllSignals() {
     addWLSignal(&m_sWLRSessionLockMgr->events.new_lock, &Events::listen_newSessionLock, m_sWLRSessionLockMgr, "SessionLockMgr");
     addWLSignal(&m_sWLRGammaCtrlMgr->events.set_gamma, &Events::listen_setGamma, m_sWLRGammaCtrlMgr, "GammaCtrlMgr");
     addWLSignal(&m_sWLRCursorShapeMgr->events.request_set_shape, &Events::listen_setCursorShape, m_sWLRCursorShapeMgr, "CursorShapeMgr");
+    addWLSignal(&m_sWLRTearingControlMgr->events.new_object, &Events::listen_newTearingHint, m_sWLRTearingControlMgr, "TearingControlMgr");
 
     if (m_sWRLDRMLeaseMgr)
         addWLSignal(&m_sWRLDRMLeaseMgr->events.request, &Events::listen_leaseRequest, &m_sWRLDRMLeaseMgr, "DRM");
@@ -2475,7 +2478,13 @@ int CCompositor::getNewSpecialID() {
 }
 
 void CCompositor::performUserChecks() {
-    // empty
+    const auto atomicEnv    = getenv("WLR_DRM_NO_ATOMIC");
+    const auto atomicEnvStr = std::string(atomicEnv ? atomicEnv : "");
+    if (g_pConfigManager->getInt("general:allow_tearing") == 1 && atomicEnvStr != "1") {
+        g_pHyprNotificationOverlay->addNotification("You have enabled tearing, but immediate presentations are not available on your configuration. Try adding "
+                                                    "env = WLR_DRM_NO_ATOMIC,1 to your config.",
+                                                    CColor(0), 15000, ICON_WARNING);
+    }
 }
 
 void CCompositor::moveWindowToWorkspaceSafe(CWindow* pWindow, CWorkspace* pWorkspace) {

src/Compositor.hpp

@@ -85,6 +85,7 @@ class CCompositor {
     wlr_session_lock_manager_v1*               m_sWLRSessionLockMgr;
     wlr_gamma_control_manager_v1*              m_sWLRGammaCtrlMgr;
     wlr_cursor_shape_manager_v1*               m_sWLRCursorShapeMgr;
+    wlr_tearing_control_manager_v1*            m_sWLRTearingControlMgr;
     // ------------------------------------------------- //
 
     std::string                               m_szWLDisplaySocket   = "";

src/Window.cpp

@@ -414,6 +414,11 @@ void CWindow::onUnmap() {
         if (PMONITOR && PMONITOR->specialWorkspaceID == m_iWorkspaceID)
             PMONITOR->setSpecialWorkspace(nullptr);
     }
+
+    const auto PMONITOR = g_pCompositor->getMonitorFromID(m_iMonitorID);
+
+    if (PMONITOR && PMONITOR->solitaryClient == this)
+        PMONITOR->solitaryClient = nullptr;
 }
 
 void CWindow::onMap() {
@@ -492,6 +497,8 @@ void CWindow::applyDynamicRule(const SWindowRule& r) {
     } else if (r.szRule == "opaque") {
         if (!m_sAdditionalConfigData.forceOpaqueOverridden)
             m_sAdditionalConfigData.forceOpaque = true;
+    } else if (r.szRule == "immediate") {
+        m_sAdditionalConfigData.forceTearing = true;
     } else if (r.szRule.find("rounding") == 0) {
         try {
             m_sAdditionalConfigData.rounding = std::stoi(r.szRule.substr(r.szRule.find_first_of(' ') + 1));
@@ -580,6 +587,7 @@ void CWindow::updateDynamicRules() {
     m_sAdditionalConfigData.borderSize      = -1;
     m_sAdditionalConfigData.keepAspectRatio = false;
     m_sAdditionalConfigData.xray            = -1;
+    m_sAdditionalConfigData.forceTearing    = false;
 
     const auto WINDOWRULES = g_pConfigManager->getMatchingRules(this);
     for (auto& r : WINDOWRULES) {
@@ -925,3 +933,7 @@ int CWindow::getRealBorderSize() {
 
     return g_pConfigManager->getConfigValuePtr("general:border_size")->intValue;
 }
+
+bool CWindow::canBeTorn() {
+    return (m_sAdditionalConfigData.forceTearing.toUnderlying() || m_bTearingHint) && g_pHyprRenderer->m_bTearingEnvSatisfied;
+}

src/Window.hpp

@@ -11,14 +11,16 @@
 #include "macros.hpp"
 #include "managers/XWaylandManager.hpp"
 
-enum eIdleInhibitMode {
+enum eIdleInhibitMode
+{
     IDLEINHIBIT_NONE = 0,
     IDLEINHIBIT_ALWAYS,
     IDLEINHIBIT_FULLSCREEN,
     IDLEINHIBIT_FOCUS
 };
 
-enum eGroupRules {
+enum eGroupRules
+{
     // effective only during first map, except for _ALWAYS variant
     GROUP_NONE        = 0,
     GROUP_SET         = 1 << 0, // Open as new group or add to focused group
@@ -138,6 +140,7 @@ struct SWindowAdditionalConfigData {
     CWindowOverridableVar<bool> keepAspectRatio       = false;
     CWindowOverridableVar<int>  xray                  = -1; // -1 means unset, takes precedence over the renderdata one
     CWindowOverridableVar<int>  borderSize            = -1; // -1 means unset, takes precedence over the renderdata one
+    CWindowOverridableVar<bool> forceTearing          = false;
 };
 
 struct SWindowRule {
@@ -317,6 +320,8 @@ class CWindow {
     } m_sGroupData;
     uint16_t m_eGroupRules = GROUP_NONE;
 
+    bool     m_bTearingHint = false;
+
     // For the list lookup
     bool operator==(const CWindow& rhs) {
         return m_uSurface.xdg == rhs.m_uSurface.xdg && m_uSurface.xwayland == rhs.m_uSurface.xwayland && m_vPosition == rhs.m_vPosition && m_vSize == rhs.m_vSize &&
@@ -348,6 +353,7 @@ class CWindow {
     Vector2D                 middle();
     bool                     opaque();
     float                    rounding();
+    bool                     canBeTorn();
 
     int                      getRealBorderSize();
     void                     updateSpecialRenderData();

src/config/ConfigManager.cpp

@@ -87,6 +87,7 @@ void CConfigManager::setDefaultVars() {
     configValues["general:extend_border_grab_area"].intValue = 15;
     configValues["general:hover_icon_on_border"].intValue    = 1;
     configValues["general:layout"].strValue                  = "dwindle";
+    configValues["general:allow_tearing"].intValue           = 0;
 
     configValues["misc:disable_hyprland_logo"].intValue        = 0;
     configValues["misc:disable_splash_rendering"].intValue     = 0;
@@ -279,7 +280,7 @@ void CConfigManager::setDeviceDefaultVars(const std::string& dev) {
     cfgValues["scroll_button_lock"].intValue      = 0;
     cfgValues["transform"].intValue               = 0;
     cfgValues["output"].strValue                  = STRVAL_EMPTY;
-    cfgValues["enabled"].intValue                 = 1; // only for mice / touchpads
+    cfgValues["enabled"].intValue                 = 1;          // only for mice / touchpads
     cfgValues["region_position"].vecValue         = Vector2D(); // only for tablets
     cfgValues["region_size"].vecValue             = Vector2D(); // only for tablets
 }
@@ -912,7 +913,7 @@ bool windowRuleValid(const std::string& RULE) {
              RULE != "nomaximizerequest" && RULE != "fakefullscreen" && RULE != "nomaxsize" && RULE != "pin" && RULE != "noanim" && RULE != "dimaround" && RULE != "windowdance" &&
              RULE != "maximize" && RULE != "keepaspectratio" && RULE.find("animation") != 0 && RULE.find("rounding") != 0 && RULE.find("workspace") != 0 &&
              RULE.find("bordercolor") != 0 && RULE != "forcergbx" && RULE != "noinitialfocus" && RULE != "stayfocused" && RULE.find("bordersize") != 0 && RULE.find("xray") != 0 &&
-             RULE.find("center") != 0 && RULE.find("group") != 0);
+             RULE.find("center") != 0 && RULE.find("group") != 0 && RULE != "immediate");
 }
 
 bool layerRuleValid(const std::string& RULE) {
@@ -1244,7 +1245,7 @@ void CConfigManager::handleSource(const std::string& command, const std::string&
         int         linenum = 1;
         if (ifs.is_open()) {
             auto configCurrentPathBackup = configCurrentPath;
-            
+
             while (std::getline(ifs, line)) {
                 // Read line by line.
                 try {
@@ -1265,7 +1266,7 @@ void CConfigManager::handleSource(const std::string& command, const std::string&
             }
 
             ifs.close();
-            
+
             configCurrentPath = configCurrentPathBackup;
         }
     }

src/debug/HyprCtl.cpp

@@ -1009,6 +1009,8 @@ std::string dispatchSetProp(std::string request) {
             PWINDOW->m_sSpecialRenderData.borderSize.forceSetIgnoreLocked(configStringToInt(VAL), lock);
         } else if (PROP == "keepaspectratio") {
             PWINDOW->m_sAdditionalConfigData.keepAspectRatio.forceSetIgnoreLocked(configStringToInt(VAL), lock);
+        } else if (PROP == "immediate") {
+            PWINDOW->m_sAdditionalConfigData.forceTearing.forceSetIgnoreLocked(configStringToInt(VAL), lock);
         } else {
             return "prop not found";
         }

src/events/Events.hpp

@@ -174,4 +174,7 @@ namespace Events {
 
     // Cursor shape
     LISTENER(setCursorShape);
+
+    // Tearing hints
+    LISTENER(newTearingHint);
 };

src/events/Misc.cpp

@@ -237,3 +237,43 @@ void Events::listener_setCursorShape(wl_listener* listener, void* data) {
 
     g_pInputManager->processMouseRequest(E);
 }
+
+void Events::listener_newTearingHint(wl_listener* listener, void* data) {
+    const auto TCTL = (wlr_tearing_control_v1*)data;
+
+    const auto PWINDOW = g_pCompositor->getWindowFromSurface(TCTL->surface);
+
+    if (!PWINDOW) {
+        Debug::log(ERR, "Tearing hint {} was attached to an unknown surface", (uintptr_t)data);
+        return;
+    }
+
+    Debug::log(LOG, "New tearing hint for window {} at {}", PWINDOW, (uintptr_t)data);
+
+    const auto NEWCTRL = g_pHyprRenderer->m_vTearingControllers.emplace_back(std::make_unique<STearingController>()).get();
+    NEWCTRL->pWlrHint  = (wlr_tearing_control_v1*)data;
+
+    NEWCTRL->hyprListener_destroy.initCallback(
+        &NEWCTRL->pWlrHint->events.destroy,
+        [&](void* owner, void* data) {
+            Debug::log(LOG, "Destroyed {} tearing hint", (uintptr_t)((STearingController*)owner)->pWlrHint);
+
+            std::erase_if(g_pHyprRenderer->m_vTearingControllers, [&](const auto& other) { return other.get() == owner; });
+        },
+        NEWCTRL, "TearingController");
+
+    NEWCTRL->hyprListener_set.initCallback(
+        &NEWCTRL->pWlrHint->events.set_hint,
+        [&](void* owner, void* data) {
+            const auto TEARINGHINT = (STearingController*)owner;
+
+            const auto PWINDOW = g_pCompositor->getWindowFromSurface(TEARINGHINT->pWlrHint->surface);
+
+            if (PWINDOW) {
+                PWINDOW->m_bTearingHint = TEARINGHINT->pWlrHint->hint;
+
+                Debug::log(LOG, "Hint {} (window {}) set tearing hint to {}", (uintptr_t)TEARINGHINT->pWlrHint, PWINDOW, (uint32_t)TEARINGHINT->pWlrHint->hint);
+            }
+        },
+        NEWCTRL, "TearingController");
+}

src/events/Monitors.cpp

@@ -149,6 +149,14 @@ void Events::listener_monitorFrame(void* owner, void* data) {
     if (!PMONITOR->m_bEnabled)
         return;
 
+    if (PMONITOR->ignoreNextFlipEvent) {
+        Debug::log(LOG, "Ignore next flip event for {}", PMONITOR->szName);
+        PMONITOR->ignoreNextFlipEvent = false;
+        return;
+    }
+
+    PMONITOR->renderingFromVblankEvent = true;
+
     static auto* const PENABLERAT = &g_pConfigManager->getConfigValuePtr("misc:render_ahead_of_time")->intValue;
     static auto* const PRATSAFE   = &g_pConfigManager->getConfigValuePtr("misc:render_ahead_safezone")->intValue;
 
@@ -181,6 +189,8 @@ void Events::listener_monitorFrame(void* owner, void* data) {
     } else {
         g_pHyprRenderer->renderMonitor(PMONITOR);
     }
+
+    PMONITOR->renderingFromVblankEvent = false;
 }
 
 void Events::listener_monitorDestroy(void* owner, void* data) {

src/helpers/Monitor.cpp

@@ -40,6 +40,8 @@ void CMonitor::onConnect(bool noRule) {
     hyprListener_monitorCommit.initCallback(&output->events.commit, &Events::listener_monitorCommit, this);
     hyprListener_monitorBind.initCallback(&output->events.bind, &Events::listener_monitorBind, this);
 
+    canTear = wlr_backend_is_drm(output->backend); // tearing only works on drm
+
     if (m_bEnabled) {
         wlr_output_enable(output, 1);
         wlr_output_commit(output);

src/helpers/Monitor.hpp

@@ -81,6 +81,13 @@ class CMonitor {
 
     CRegion                lastFrameDamage; // stores last frame damage
 
+    // for tearing
+    CWindow* solitaryClient           = nullptr;
+    bool     canTear                  = false;
+    bool     nextRenderTorn           = false;
+    bool     ignoreNextFlipEvent      = false;
+    bool     renderingFromVblankEvent = false;
+
     // for the special workspace. 0 means not open.
     int                                                        specialWorkspaceID = 0;
 

src/helpers/SubsurfaceTree.cpp

@@ -245,6 +245,15 @@ void Events::listener_commitSubsurface(void* owner, void* data) {
 
     if (pNode->pSurface && pNode->pSurface->exists())
         g_pHyprRenderer->damageSurface(pNode->pSurface->wlr(), lx, ly, SCALE);
+
+    if (pNode->pWindowOwner) {
+        // tearing: if solitary, redraw it. This still might be a single surface window
+        const auto PMONITOR = g_pCompositor->getMonitorFromID(pNode->pWindowOwner->m_iMonitorID);
+        if (PMONITOR->solitaryClient == pNode->pWindowOwner && pNode->pWindowOwner->canBeTorn() && PMONITOR->canTear) {
+            PMONITOR->nextRenderTorn = true;
+            g_pHyprRenderer->renderMonitor(PMONITOR);
+        }
+    }
 }
 
 void Events::listener_destroySubsurface(void* owner, void* data) {

src/helpers/WLClasses.hpp

@@ -180,7 +180,7 @@ struct SConstraint {
     Vector2D getLogicConstraintSize();
 
     bool     operator==(const SConstraint& b) const {
-            return constraint == b.constraint;
+        return constraint == b.constraint;
     }
 };
 
@@ -393,3 +393,14 @@ struct SSwitchDevice {
         return pWlrDevice == other.pWlrDevice;
     }
 };
+
+struct STearingController {
+    wlr_tearing_control_v1* pWlrHint = nullptr;
+
+    DYNLISTENER(set);
+    DYNLISTENER(destroy);
+
+    bool operator==(const STearingController& other) {
+        return pWlrHint == other.pWlrHint;
+    }
+};

src/includes.hpp

@@ -105,6 +105,7 @@ extern "C" {
 #include <wlr/types/wlr_single_pixel_buffer_v1.h>
 #include <wlr/types/wlr_idle_notify_v1.h>
 #include <wlr/types/wlr_cursor_shape_v1.h>
+#include <wlr/types/wlr_tearing_control_v1.h>
 
 #include <libdrm/drm_fourcc.h>
 

src/managers/input/InputManager.cpp

@@ -118,7 +118,8 @@ void CInputManager::mouseMoveUnified(uint32_t time, bool refocus) {
     if (*PZOOMFACTOR != 1.f)
         g_pHyprRenderer->damageMonitor(PMONITOR);
 
-    g_pCompositor->scheduleFrameForMonitor(PMONITOR);
+    if (!PMONITOR->solitaryClient) // if there is a solitary client we can't schedule a frame here, this will completely fuck up drm
+        g_pCompositor->scheduleFrameForMonitor(PMONITOR);
 
     CWindow* forcedFocus = m_pForcedFocus;
 

src/render/Renderer.cpp

@@ -3,6 +3,13 @@
 #include "linux-dmabuf-unstable-v1-protocol.h"
 #include "../helpers/Region.hpp"
 
+CHyprRenderer::CHyprRenderer() {
+    const auto ENV = getenv("WLR_DRM_NO_ATOMIC");
+
+    if (ENV && std::string(ENV) == "1")
+        m_bTearingEnvSatisfied = true;
+}
+
 void renderSurface(struct wlr_surface* surface, int x, int y, void* data) {
     const auto TEXTURE = wlr_surface_get_texture(surface);
     const auto RDATA   = (SRenderData*)data;
@@ -702,51 +709,12 @@ bool CHyprRenderer::attemptDirectScanout(CMonitor* pMonitor) {
     if (!wlr_output_is_direct_scanout_allowed(pMonitor->output))
         return false;
 
-    const auto PWORKSPACE = g_pCompositor->getWorkspaceByID(pMonitor->activeWorkspace);
-
-    if (!PWORKSPACE || !PWORKSPACE->m_bHasFullscreenWindow || g_pInputManager->m_sDrag.drag || g_pCompositor->m_sSeat.exclusiveClient || pMonitor->specialWorkspaceID)
-        return false;
-
-    const auto PCANDIDATE = g_pCompositor->getFullscreenWindowOnWorkspace(PWORKSPACE->m_iID);
+    const auto PCANDIDATE = pMonitor->solitaryClient;
 
     if (!PCANDIDATE)
-        return false; // ????
-
-    if (PCANDIDATE->m_fAlpha.fl() != 1.f || PCANDIDATE->m_fActiveInactiveAlpha.fl() != 1.f || PWORKSPACE->m_fAlpha.fl() != 1.f)
         return false;
 
-    if (PCANDIDATE->m_vRealSize.vec() != pMonitor->vecSize || PCANDIDATE->m_vRealPosition.vec() != pMonitor->vecPosition || PCANDIDATE->m_vRealPosition.isBeingAnimated() ||
-        PCANDIDATE->m_vRealSize.isBeingAnimated())
-        return false;
-
-    if (!pMonitor->m_aLayerSurfaceLayers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY].empty())
-        return false;
-
-    for (auto& topls : pMonitor->m_aLayerSurfaceLayers[ZWLR_LAYER_SHELL_V1_LAYER_TOP]) {
-        if (topls->alpha.fl() != 0.f)
-            return false;
-    }
-
-    // check if it did not open any subsurfaces or shit
-    int surfaceCount = 0;
-    if (PCANDIDATE->m_bIsX11) {
-        surfaceCount = 1;
-
-        // check opaque
-        if (PCANDIDATE->m_uSurface.xwayland->has_alpha)
-            return false;
-    } else {
-        wlr_xdg_surface_for_each_surface(PCANDIDATE->m_uSurface.xdg, countSubsurfacesIter, &surfaceCount);
-        wlr_xdg_surface_for_each_popup_surface(PCANDIDATE->m_uSurface.xdg, countSubsurfacesIter, &surfaceCount);
-
-        if (!PCANDIDATE->m_uSurface.xdg->surface->opaque)
-            return false;
-    }
-
-    if (surfaceCount != 1)
-        return false;
-
-    const auto PSURFACE = PCANDIDATE->m_pWLSurface.wlr();
+    const auto PSURFACE = g_pXWaylandManager->getWindowSurface(PCANDIDATE);
 
     if (!PSURFACE || PSURFACE->current.scale != pMonitor->output->scale || PSURFACE->current.transform != pMonitor->output->transform)
         return false;
@@ -754,9 +722,8 @@ bool CHyprRenderer::attemptDirectScanout(CMonitor* pMonitor) {
     // finally, we should be GTG.
     wlr_output_attach_buffer(pMonitor->output, &PSURFACE->buffer->base);
 
-    if (!wlr_output_test(pMonitor->output)) {
+    if (!wlr_output_test(pMonitor->output))
         return false;
-    }
 
     timespec now;
     clock_gettime(CLOCK_MONOTONIC, &now);
@@ -790,6 +757,7 @@ void CHyprRenderer::renderMonitor(CMonitor* pMonitor) {
     static auto* const                                    PRENDERTEX          = &g_pConfigManager->getConfigValuePtr("misc:disable_hyprland_logo")->intValue;
     static auto* const                                    PBACKGROUNDCOLOR    = &g_pConfigManager->getConfigValuePtr("misc:background_color")->intValue;
     static auto* const                                    PANIMENABLED        = &g_pConfigManager->getConfigValuePtr("animations:enabled")->intValue;
+    static auto* const                                    PTEARINGENABLED     = &g_pConfigManager->getConfigValuePtr("general:allow_tearing")->intValue;
 
     static int                                            damageBlinkCleanup = 0; // because double-buffered
 
@@ -876,8 +844,38 @@ void CHyprRenderer::renderMonitor(CMonitor* pMonitor) {
         }
     }
 
-    // Direct scanout first
-    if (!*PNODIRECTSCANOUT) {
+    // tearing and DS first
+    bool shouldTear = false;
+    bool canTear    = *PTEARINGENABLED && g_pHyprOpenGL->m_RenderData.mouseZoomFactor == 1.0;
+    recheckSolitaryForMonitor(pMonitor);
+    if (pMonitor->nextRenderTorn) {
+        pMonitor->nextRenderTorn = false;
+
+        if (!*PTEARINGENABLED) {
+            Debug::log(WARN, "Tearing commit requested but the master switch general:allow_tearing is off, ignoring");
+            return;
+        }
+
+        if (g_pHyprOpenGL->m_RenderData.mouseZoomFactor != 1.0) {
+            Debug::log(WARN, "Tearing commit requested but scale factor is not 1, ignoring");
+            return;
+        }
+
+        if (!pMonitor->canTear) {
+            Debug::log(WARN, "Tearing commit requested but monitor doesn't support it, ignoring");
+            return;
+        }
+
+        if (pMonitor->solitaryClient)
+            shouldTear = true;
+    } else {
+        // if this is a non-tearing commit, and we are in a state where we should tear
+        // then this is a vblank commit that we should ignore
+        if (canTear && pMonitor->solitaryClient && pMonitor->canTear && pMonitor->solitaryClient->canBeTorn() && pMonitor->renderingFromVblankEvent)
+            return;
+    }
+
+    if (!*PNODIRECTSCANOUT && !shouldTear) {
         if (attemptDirectScanout(pMonitor)) {
             return;
         } else if (m_pLastScanout) {
@@ -1061,6 +1059,8 @@ void CHyprRenderer::renderMonitor(CMonitor* pMonitor) {
 
     EMIT_HOOK_EVENT("render", RENDER_POST);
 
+    pMonitor->output->pending.tearing_page_flip = shouldTear;
+
     if (!wlr_output_commit(pMonitor->output)) {
         if (UNLOCK_SC)
             wlr_output_lock_software_cursors(pMonitor->output, false);
@@ -1068,6 +1068,9 @@ void CHyprRenderer::renderMonitor(CMonitor* pMonitor) {
         return;
     }
 
+    if (shouldTear)
+        pMonitor->ignoreNextFlipEvent = true;
+
     wlr_damage_ring_rotate(&pMonitor->damage);
 
     if (UNLOCK_SC)
@@ -1986,3 +1989,47 @@ bool CHyprRenderer::canSkipBackBufferClear(CMonitor* pMonitor) {
 
     return false;
 }
+
+void CHyprRenderer::recheckSolitaryForMonitor(CMonitor* pMonitor) {
+    pMonitor->solitaryClient = nullptr; // reset it, if we find one it will be set.
+
+    const auto PWORKSPACE = g_pCompositor->getWorkspaceByID(pMonitor->activeWorkspace);
+
+    if (!PWORKSPACE || !PWORKSPACE->m_bHasFullscreenWindow || g_pInputManager->m_sDrag.drag || g_pCompositor->m_sSeat.exclusiveClient || pMonitor->specialWorkspaceID)
+        return;
+
+    const auto PCANDIDATE = g_pCompositor->getFullscreenWindowOnWorkspace(PWORKSPACE->m_iID);
+
+    if (!PCANDIDATE)
+        return; // ????
+
+    if (!PCANDIDATE->opaque())
+        return;
+
+    if (PCANDIDATE->m_vRealSize.vec() != pMonitor->vecSize || PCANDIDATE->m_vRealPosition.vec() != pMonitor->vecPosition || PCANDIDATE->m_vRealPosition.isBeingAnimated() ||
+        PCANDIDATE->m_vRealSize.isBeingAnimated())
+        return;
+
+    if (!pMonitor->m_aLayerSurfaceLayers[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY].empty())
+        return;
+
+    for (auto& topls : pMonitor->m_aLayerSurfaceLayers[ZWLR_LAYER_SHELL_V1_LAYER_TOP]) {
+        if (topls->alpha.fl() != 0.f)
+            return;
+    }
+
+    // check if it did not open any subsurfaces or shit
+    int surfaceCount = 0;
+    if (PCANDIDATE->m_bIsX11) {
+        surfaceCount = 1;
+    } else {
+        wlr_xdg_surface_for_each_surface(PCANDIDATE->m_uSurface.xdg, countSubsurfacesIter, &surfaceCount);
+        wlr_xdg_surface_for_each_popup_surface(PCANDIDATE->m_uSurface.xdg, countSubsurfacesIter, &surfaceCount);
+    }
+
+    if (surfaceCount != 1)
+        Debug::log(LOG, "fuf: >1 surf");
+
+    // found one!
+    pMonitor->solitaryClient = PCANDIDATE;
+}

src/render/Renderer.hpp

@@ -33,6 +33,8 @@ struct SSessionLockSurface;
 
 class CHyprRenderer {
   public:
+    CHyprRenderer();
+
     void                            renderMonitor(CMonitor* pMonitor);
     void                            outputMgrApplyTest(wlr_output_configuration_v1*, bool);
     void                            arrangeLayersForMonitor(const int&);
@@ -53,6 +55,7 @@ class CHyprRenderer {
     void                            renderLockscreen(CMonitor* pMonitor, timespec* now);
     void                            setOccludedForBackLayers(CRegion& region, CWorkspace* pWorkspace);
     bool                            canSkipBackBufferClear(CMonitor* pMonitor);
+    void                            recheckSolitaryForMonitor(CMonitor* pMonitor);
 
     bool                            m_bWindowRequestedCursorHide = false;
     bool                            m_bBlockSurfaceFeedback      = false;
@@ -61,19 +64,22 @@ class CHyprRenderer {
     CMonitor*                       m_pMostHzMonitor             = nullptr;
     bool                            m_bDirectScanoutBlocked      = false;
     bool                            m_bSoftwareCursorsLocked     = false;
+    bool                            m_bTearingEnvSatisfied       = false;
 
     DAMAGETRACKINGMODES
     damageTrackingModeFromStr(const std::string&);
 
-    bool             attemptDirectScanout(CMonitor*);
-    void             setWindowScanoutMode(CWindow*);
-    void             initiateManualCrash();
+    bool                                             attemptDirectScanout(CMonitor*);
+    void                                             setWindowScanoutMode(CWindow*);
+    void                                             initiateManualCrash();
 
-    bool             m_bCrashingInProgress = false;
-    float            m_fCrashingDistort    = 0.5f;
-    wl_event_source* m_pCrashingLoop       = nullptr;
+    bool                                             m_bCrashingInProgress = false;
+    float                                            m_fCrashingDistort    = 0.5f;
+    wl_event_source*                                 m_pCrashingLoop       = nullptr;
 
-    CTimer           m_tRenderTimer;
+    std::vector<std::unique_ptr<STearingController>> m_vTearingControllers;
+
+    CTimer                                           m_tRenderTimer;
 
   private:
     void arrangeLayerArray(CMonitor*, const std::vector<std::unique_ptr<SLayerSurface>>&, bool, wlr_box*);