bugfix(fps): Decouple camera shaker time step from render update (#1451)

Author: xezon

GeneralsMD/Code/GameEngineDevice/Source/W3DDevice/GameClient/W3DView.cpp

@@ -409,7 +409,9 @@ void W3DView::buildCameraTransform( Matrix3D *transform )
 	transform->Look_At( sourcePos, targetPos, 0 );
 
 	//WST 11/12/2002 New camera shaker system
-	CameraShakerSystem.Timestep(1.0f/30.0f);
+	// TheSuperHackers @tweak The camera shaker is now decoupled from the render update.
+	const Real logicTimeScaleOverFpsRatio = TheGameEngine->getActualLogicTimeScaleOverFpsRatio();
+	CameraShakerSystem.Timestep(TheW3DFrameLengthInMsec * logicTimeScaleOverFpsRatio);
 	CameraShakerSystem.Update_Camera_Shaker(sourcePos, &m_shakerAngles);
 	transform->Rotate_X(m_shakerAngles.X);
 	transform->Rotate_Y(m_shakerAngles.Y);
@@ -1084,8 +1086,34 @@ void W3DView::updateView(void)
 // render update, but it advanced separately for every fixed time step. This ensures that
 // things like vehicle wheels no longer spin too fast on high frame rates or keep spinning
 // on game pause.
+// The camera shaker is also no longer tied to the render update. The shake does sharp shakes
+// on every fixed time step, and is not intended to have linear interpolation during the
+// render update.
 void W3DView::stepView()
 {
+	//
+	// Process camera shake
+	//
+	if (m_shakeIntensity > 0.01f)
+	{
+		m_shakeOffset.x = m_shakeIntensity * m_shakeAngleCos;
+		m_shakeOffset.y = m_shakeIntensity * m_shakeAngleSin;
+
+		// fake a stiff spring/damper
+		const Real dampingCoeff = 0.75f;
+		m_shakeIntensity *= dampingCoeff;
+
+		// spring is so "stiff", it pulls 180 degrees opposite each frame
+		m_shakeAngleCos = -m_shakeAngleCos;
+		m_shakeAngleSin = -m_shakeAngleSin;
+	}
+	else
+	{
+		m_shakeIntensity = 0.0f;
+		m_shakeOffset.x = 0.0f;
+		m_shakeOffset.y = 0.0f;
+	}
+
 	if (TheScriptEngine->isTimeFast()) {
 		return; // don't draw - makes it faster :) jba.
 	}
@@ -1310,29 +1338,11 @@ void W3DView::update(void)
 	}
 	//
 	// Process camera shake
-	/// @todo Make this framerate-independent
 	//
 	if (m_shakeIntensity > 0.01f)
 	{
-		m_shakeOffset.x = m_shakeIntensity * m_shakeAngleCos;
-		m_shakeOffset.y = m_shakeIntensity * m_shakeAngleSin;
-
-		// fake a stiff spring/damper
-		const Real dampingCoeff = 0.75f;
-		m_shakeIntensity *= dampingCoeff;
-
-		// spring is so "stiff", it pulls 180 degrees opposite each frame
-		m_shakeAngleCos = -m_shakeAngleCos;
-		m_shakeAngleSin = -m_shakeAngleSin;
-
 		recalcCamera = true;
 	}
-	else
-	{
-		m_shakeIntensity = 0.0f;
-		m_shakeOffset.x = 0.0f;
-		m_shakeOffset.y = 0.0f;
-	}
 
 	//Process New C3 Camera Shaker system
 	if (CameraShakerSystem.IsCameraShaking())