From 066a6483a0badf9b533d2e77b4b3b7a6e8768971 Mon Sep 17 00:00:00 2001
From: Brad Davis <bdavis@saintandreas.org>
Date: Fri, 10 Feb 2017 11:23:37 -0800
Subject: [PATCH] Code comments

---
 libraries/gpu-gl/src/gpu/gl45/GL45Backend.h         | 13 +++++++++++--
 .../src/gpu/gl45/GL45BackendVariableTexture.cpp     |  3 +++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/libraries/gpu-gl/src/gpu/gl45/GL45Backend.h b/libraries/gpu-gl/src/gpu/gl45/GL45Backend.h
index 1983088ca5..d2d17160ba 100644
--- a/libraries/gpu-gl/src/gpu/gl45/GL45Backend.h
+++ b/libraries/gpu-gl/src/gpu/gl45/GL45Backend.h
@@ -134,10 +134,20 @@ public:
         virtual void promote() = 0;
         virtual void demote() = 0;
 
-        uint16 _populatedMip { 0 };
+        // The allocated mip level, relative to the number of mips in the gpu::Texture object 
+        // The relationship between a given glMip to the original gpu::Texture mip is always 
+        // glMip + _allocatedMip
         uint16 _allocatedMip { 0 };
+        // The populated mip level, relative to the number of mips in the gpu::Texture object
+        // This must always be >= the allocated mip
+        uint16 _populatedMip { 0 };
+        // The highest (lowest resolution) mip that we will support, relative to the number 
+        // of mips in the gpu::Texture object
         uint16 _maxAllocatedMip { 0 };
         uint32 _size { 0 };
+        // Contains a series of lambdas that when executed will transfer data to the GPU, modify 
+        // the _populatedMip and update the sampler in order to fully populate the allocated texture 
+        // until _populatedMip == _allocatedMip
         std::queue<PromoteLambda> _pendingTransfers;
     };
 
@@ -154,7 +164,6 @@ public:
 
         void allocateStorage(uint16 mip);
         void copyMipsFromTexture();
-    private:
     };
 
 #if 0
diff --git a/libraries/gpu-gl/src/gpu/gl45/GL45BackendVariableTexture.cpp b/libraries/gpu-gl/src/gpu/gl45/GL45BackendVariableTexture.cpp
index 22bb26cc10..597e35750a 100644
--- a/libraries/gpu-gl/src/gpu/gl45/GL45BackendVariableTexture.cpp
+++ b/libraries/gpu-gl/src/gpu/gl45/GL45BackendVariableTexture.cpp
@@ -56,18 +56,21 @@ void GL45VariableAllocationTexture::addToWorkQueue(const TexturePointer& texture
     switch (_memoryPressureState) {
         case MemoryPressureState::Oversubscribed:
             if (object->canDemote()) {
+                // Demote largest first
                 _demoteQueue.push({ texturePointer, (float)object->size() });
             }
             break;
 
         case MemoryPressureState::Undersubscribed:
             if (object->canPromote()) {
+                // Promote smallest first
                 _promoteQueue.push({ texturePointer, 1.0f / (float)object->size() });
             }
             break;
 
         case MemoryPressureState::Transfer:
             if (object->hasPendingTransfers()) {
+                // Transfer priority given to smaller mips first
                 _transferQueue.push({ texturePointer, 1.0f / (float)object->_gpuObject.evalMipSize(object->_populatedMip) });
             }
             break;