EXT-8673: FIXED: UDP texture loading is slower in 2.x viewers than 1.23.5

Improved the following:
1, make sure the texture callback queue is properly handled and cleaned in time;
2, estimate the LLVOTree pixel area more accurately;
3, eliminate the possibility of back and forth stopping/restarting a texture fetching

1 files changed, 23 insertions, 10 deletions

diff --git a/indra/newview/llvotree.cpp b/indra/newview/llvotree.cpp
index 0efe6682be..9c08c0eec1 100644
--- a/indra/newview/llvotree.cpp
+++ b/indra/newview/llvotree.cpp
@@ -448,22 +448,35 @@ void LLVOTree::render(LLAgent &agent)
 
 void LLVOTree::setPixelAreaAndAngle(LLAgent &agent)
 {
-	// First calculate values as for any other object (for mAppAngle)
-	LLViewerObject::setPixelAreaAndAngle(agent);
-
-	// Re-calculate mPixelArea accurately
+	LLVector3 center = getPositionAgent();//center of tree.
+	LLVector3 viewer_pos_agent = gAgentCamera.getCameraPositionAgent();
+	LLVector3 lookAt = center - viewer_pos_agent;
+	F32 dist = lookAt.normVec() ;	
+	F32 cos_angle_to_view_dir = lookAt * LLViewerCamera::getInstance()->getXAxis() ;	
 	
-	// This should be the camera's center, as soon as we move to all region-local.
-	LLVector3 relative_position = getPositionAgent() - gAgentCamera.getCameraPositionAgent();
-	F32 range_squared = relative_position.lengthSquared() ;				
+	F32 range = dist - getMinScale()/2;
+	if (range < F_ALMOST_ZERO || isHUDAttachment())		// range == zero
+	{
+		mAppAngle = 180.f;
+	}
+	else
+	{
+		mAppAngle = (F32) atan2( getMaxScale(), range) * RAD_TO_DEG;		
+	}
 
 	F32 max_scale = mBillboardScale * getMaxScale();
 	F32 area = max_scale * (max_scale*mBillboardRatio);
-
 	// Compute pixels per meter at the given range
-	F32 pixels_per_meter = LLViewerCamera::getInstance()->getViewHeightInPixels() / tan(LLViewerCamera::getInstance()->getView());
+	F32 pixels_per_meter = LLViewerCamera::getInstance()->getViewHeightInPixels() / (tan(LLViewerCamera::getInstance()->getView()) * dist);
+	mPixelArea = pixels_per_meter * pixels_per_meter * area ;	
+
+	F32 importance = LLFace::calcImportanceToCamera(cos_angle_to_view_dir, dist) ;
+	mPixelArea = LLFace::adjustPixelArea(importance, mPixelArea) ;
+	if (mPixelArea > LLViewerCamera::getInstance()->getScreenPixelArea())
+	{
+		mAppAngle = 180.f;
+	}
 
-	mPixelArea = (pixels_per_meter) * (pixels_per_meter) * area / range_squared;
 #if 0
 	// mAppAngle is a bit of voodoo;
 	// use the one calculated LLViewerObject::setPixelAreaAndAngle above