From cf4a0a35031f1cc931d112f4375f5ab4f89b49a8 Mon Sep 17 00:00:00 2001
From: yunfeibai <byf1658@gmail.com>
Date: Thu, 15 Feb 2018 13:19:41 -0800
Subject: [PATCH] Add improvement/fix in SortableTransparentInstance back.

---
 .../OpenGLWindow/GLInstancingRenderer.cpp     | 46 +++++++++++--------
 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/examples/OpenGLWindow/GLInstancingRenderer.cpp b/examples/OpenGLWindow/GLInstancingRenderer.cpp
index edbe0ee7d..6edb4a69f 100644
--- a/examples/OpenGLWindow/GLInstancingRenderer.cpp
+++ b/examples/OpenGLWindow/GLInstancingRenderer.cpp
@@ -1989,22 +1989,21 @@ void GLInstancingRenderer::drawLine(const float from[4], const float to[4], cons
 	glUseProgram(0);
 }
 
-struct SortableTransparentInstance
+B3_ATTRIBUTE_ALIGNED16(struct) SortableTransparentInstance
 {
+	b3Scalar m_projection;
+	
 	int m_shapeIndex;
 	int m_instanceId;
-	b3Vector3 m_centerPosition;
 };
 
-struct TransparentDistanceSortPredicate
+B3_ATTRIBUTE_ALIGNED16(struct) TransparentDistanceSortPredicate
 {
-	b3Vector3 m_camForwardVec;
-
-	inline bool operator() (const SortableTransparentInstance& a, const SortableTransparentInstance& b) const 
+	
+	inline bool operator() (const SortableTransparentInstance& a, const SortableTransparentInstance& b) const
 	{
-		b3Scalar projA = a.m_centerPosition.dot(m_camForwardVec);
-		b3Scalar projB = b.m_centerPosition.dot(m_camForwardVec);
-		return (projA > projB);
+		
+		return (a.m_projection > b.m_projection);
 	}
 };
 
@@ -2225,6 +2224,11 @@ b3Assert(glGetError() ==GL_NO_ERROR);
 		//GLuint lastBindTexture = 0;
 
 		transparentInstances.reserve(totalNumInstances);
+		
+		float fwd[3];
+		m_data->m_activeCamera->getCameraForwardVector(fwd);
+		b3Vector3 camForwardVec;
+		camForwardVec.setValue(fwd[0],fwd[1],fwd[2]);
 
 		for (int obj=0;obj<m_graphicsInstances.size();obj++)
 		{
@@ -2239,19 +2243,24 @@ b3Assert(glGetError() ==GL_NO_ERROR);
 				if ((gfxObj->m_flags&eGfxTransparency)==0)
 				{
 					inst.m_instanceId = curOffset;
-					inst.m_centerPosition.setValue(m_data->m_instance_positions_ptr[inst.m_instanceId*4+0],
-								m_data->m_instance_positions_ptr[inst.m_instanceId*4+1],
-								m_data->m_instance_positions_ptr[inst.m_instanceId*4+2]);
-					inst.m_centerPosition *= -1;//reverse sort opaque instances
+					b3Vector3 centerPosition;
+					centerPosition.setValue(m_data->m_instance_positions_ptr[inst.m_instanceId*4+0],
+											m_data->m_instance_positions_ptr[inst.m_instanceId*4+1],
+											m_data->m_instance_positions_ptr[inst.m_instanceId*4+2]);
+					centerPosition *= -1;//reverse sort opaque instances
+					inst.m_projection = centerPosition.dot(camForwardVec);
 					transparentInstances.push_back(inst);
 				} else
 				{
 					for (int i=0;i<gfxObj->m_numGraphicsInstances;i++)
 					{
 						inst.m_instanceId = curOffset+i;
-						inst.m_centerPosition.setValue(m_data->m_instance_positions_ptr[inst.m_instanceId*4+0],
-										m_data->m_instance_positions_ptr[inst.m_instanceId*4+1],
-										m_data->m_instance_positions_ptr[inst.m_instanceId*4+2]);
+						b3Vector3 centerPosition;
+						
+						centerPosition.setValue(m_data->m_instance_positions_ptr[inst.m_instanceId*4+0],
+												m_data->m_instance_positions_ptr[inst.m_instanceId*4+1],
+												m_data->m_instance_positions_ptr[inst.m_instanceId*4+2]);
+						inst.m_projection = centerPosition.dot(camForwardVec);
 						transparentInstances.push_back(inst);
 					}
 				}
@@ -2259,9 +2268,7 @@ b3Assert(glGetError() ==GL_NO_ERROR);
 			}
 		}
 		TransparentDistanceSortPredicate sorter;
-		float fwd[3];
-		m_data->m_activeCamera->getCameraForwardVector(fwd);
-		sorter.m_camForwardVec.setValue(fwd[0],fwd[1],fwd[2]);
+		
 		transparentInstances.quickSort(sorter);
 	}
 
@@ -2532,7 +2539,6 @@ b3Assert(glGetError() ==GL_NO_ERROR);
 							}
 							case B3_USE_PROJECTIVE_TEXTURE_RENDERMODE:
 							{
-								printf("PROJECTIVE TEXTURE!!\n");
 								if ( gfxObj->m_flags&eGfxTransparency)
 								{
 									glDepthMask(false);