diff --git a/src/gl/renderer/gl_renderstate.cpp b/src/gl/renderer/gl_renderstate.cpp
index fe4af882f8..c37ccbb992 100644
--- a/src/gl/renderer/gl_renderstate.cpp
+++ b/src/gl/renderer/gl_renderstate.cpp
@@ -122,7 +122,7 @@ bool FRenderState::ApplyShader()
 	static uint64_t firstFrame = 0;
 	// if firstFrame is not yet initialized, initialize it to current time
 	// if we're going to overflow a float (after ~4.6 hours, or 24 bits), re-init to regain precision
-	if ((firstFrame == 0) || (screen->FrameTime - firstFrame >= 1<<24) || level.ShaderStartTime > firstFrame)
+	if ((firstFrame == 0) || (screen->FrameTime - firstFrame >= 1<<24) || level.ShaderStartTime >= firstFrame)
 		firstFrame = screen->FrameTime;
 
 	static const float nulvec[] = { 0.f, 0.f, 0.f, 0.f };