From 89e714a07774f1e79548729155d33e6348ce019d Mon Sep 17 00:00:00 2001
From: Eric Wasylishen <ewasylishen@gmail.com>
Date: Tue, 6 Jun 2023 23:30:50 -0600
Subject: [PATCH] lightpreview: don't render frames when not interacting

---
 lightpreview/glview.cpp | 24 +++++++++++++++++++++++-
 lightpreview/glview.h   |  2 ++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/lightpreview/glview.cpp b/lightpreview/glview.cpp
index 7d33bffc..cccd8386 100644
--- a/lightpreview/glview.cpp
+++ b/lightpreview/glview.cpp
@@ -252,6 +252,17 @@ void main() {
 }
 )";
 
+bool GLView::shouldLiveUpdate() const
+{
+    if (m_keysPressed)
+        return true;
+
+    if (QApplication::mouseButtons())
+        return true;
+
+    return false;
+}
+
 void GLView::handleLoggedMessage(const QOpenGLDebugMessage &debugMessage)
 {
     if (debugMessage.type() == QOpenGLDebugMessage::ErrorType)
@@ -453,7 +464,13 @@ void GLView::paintGL()
 
     m_program->release();
 
-    update(); // schedule the next frame
+    if (shouldLiveUpdate()) {
+        update(); // schedule the next frame
+    } else {
+        qDebug() << "pausing anims..";
+        m_lastFrame = std::nullopt;
+        m_lastMouseDownPos = std::nullopt;
+    }
 }
 
 void GLView::setCamera(const qvec3d &origin, const qvec3d &fwd)
@@ -968,6 +985,11 @@ void GLView::wheelEvent(QWheelEvent *event)
     m_moveSpeed = clamp(m_moveSpeed, 10.0f, 5000.0f);
 }
 
+void GLView::mousePressEvent(QMouseEvent *event)
+{
+    update();
+}
+
 void GLView::applyFlyMovement(float duration_seconds)
 {
     // qDebug() << "timer event: duration: " << duration_seconds;
diff --git a/lightpreview/glview.h b/lightpreview/glview.h
index 90870468..31e410c5 100644
--- a/lightpreview/glview.h
+++ b/lightpreview/glview.h
@@ -165,12 +165,14 @@ protected:
     void resizeGL(int width, int height) override;
 
 private:
+    bool shouldLiveUpdate() const;
     void handleLoggedMessage(const QOpenGLDebugMessage &debugMessage);
 
 protected:
     void keyPressEvent(QKeyEvent *event) override;
     void keyReleaseEvent(QKeyEvent *event) override;
     void wheelEvent(QWheelEvent *event) override;
+    void mousePressEvent(QMouseEvent *event) override;
 
 private:
     void applyMouseMotion();