Replace canPopulate with _minAllocatedMip

libraries/gpu-gl/src/gpu/gl/GLTexture.cpp

@@ -437,7 +437,6 @@ void GLVariableAllocationSupport::updateMemoryPressure() {
     size_t idealMemoryAllocation = 0;
     bool canDemote = false;
     bool canPromote = false;
-    bool canPopulate = false;
     bool hasTransfers = false;
     for (const auto& texture : strongTextures) {
         // Race conditions can still leave nulls in the list, so we need to check
@@ -452,7 +451,6 @@ void GLVariableAllocationSupport::updateMemoryPressure() {
         totalVariableMemoryAllocation += gltexture->size();
         canDemote |= vartexture->canDemote();
         canPromote |= vartexture->canPromote();
-        canPopulate |= vartexture->canPopulate();
         hasTransfers |= vartexture->hasPendingTransfers();
     }
 
@@ -464,7 +462,7 @@ void GLVariableAllocationSupport::updateMemoryPressure() {
         newState = MemoryPressureState::Transfer;
     } else if (pressure > OVERSUBSCRIBED_PRESSURE_VALUE && canDemote) {
         newState = MemoryPressureState::Oversubscribed;
-    } else if (pressure < UNDERSUBSCRIBED_PRESSURE_VALUE && ((unallocated != 0 && canPromote) && canPopulate)) {
+    } else if (pressure < UNDERSUBSCRIBED_PRESSURE_VALUE && (unallocated != 0 && canPromote)) {
         newState = MemoryPressureState::Undersubscribed;
     }
 
@@ -521,7 +519,7 @@ void GLVariableAllocationSupport::processWorkQueues() {
             vartexture->demote();
             _memoryPressureStateStale = true;
         } else if (MemoryPressureState::Undersubscribed == _memoryPressureState) {
-            if (!vartexture->canPromote() || !vartexture->canPopulate()) {
+            if (!vartexture->canPromote()) {
                 continue;
             }
             vartexture->promote();

libraries/gpu-gl/src/gpu/gl/GLTexture.h

@@ -112,8 +112,7 @@ protected:
     static void manageMemory();
 
     //bool canPromoteNoAllocate() const { return _allocatedMip < _populatedMip; }
-    virtual bool canPopulate() const = 0;
+    bool canPromote() const { return _allocatedMip > _minAllocatedMip; }
-    bool canPromote() const { return _allocatedMip > 0; }
     bool canDemote() const { return _allocatedMip < _maxAllocatedMip; }
     bool hasPendingTransfers() const { return _pendingTransfers.size() > 0; }
     void executeNextTransfer(const TexturePointer& currentTexture);
@@ -131,6 +130,9 @@ protected:
     // The highest (lowest resolution) mip that we will support, relative to the number 
     // of mips in the gpu::Texture object
     uint16 _maxAllocatedMip { 0 };
+    // The lowest (highest resolution) mip that we will support, relative to the number
+    // of mips in the gpu::Texture object
+    uint16 _minAllocatedMip { 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

libraries/gpu-gl/src/gpu/gl41/GL41Backend.h

@@ -100,7 +100,6 @@ public:
         GL41VariableAllocationTexture(const std::weak_ptr<GLBackend>& backend, const Texture& texture);
         ~GL41VariableAllocationTexture();
 
-        bool canPopulate() const override { return _gpuObject.isStoredMipFaceAvailable(_populatedMip - 1, 0); }
         void allocateStorage(uint16 allocatedMip);
         void syncSampler() const override;
         void promote() override;

libraries/gpu-gl/src/gpu/gl41/GL41BackendTexture.cpp

@@ -55,6 +55,18 @@ GLTexture* GL41Backend::syncGPUObject(const TexturePointer& texturePointer) {
             default:
                 Q_UNREACHABLE();
         }
+    } else {
+        if (texture.getUsageType() == TextureUsageType::RESOURCE) {
+            auto varTex = static_cast<GL41VariableAllocationTexture*> (object);
+
+            if (varTex->_minAllocatedMip > 0) {
+                auto minAvailableMip = texture.minAvailableMipLevel();
+                if (minAvailableMip < varTex->_minAllocatedMip) {
+                    varTex->_minAllocatedMip = minAvailableMip;
+                    GL41VariableAllocationTexture::_memoryPressureStateStale = true;
+                }
+            }
+        }
     }
 
     return object;

libraries/gpu-gl/src/gpu/gl45/GL45Backend.h

@@ -100,7 +100,6 @@ public:
         GL45VariableAllocationTexture(const std::weak_ptr<GLBackend>& backend, const Texture& texture);
         ~GL45VariableAllocationTexture();
         Size size() const override { return _size; }
-        bool canPopulate() const override { return _gpuObject.isStoredMipFaceAvailable(_populatedMip - 1, 0); }
         Size _size { 0 };
     };
 

libraries/gpu-gl/src/gpu/gl45/GL45BackendTexture.cpp

@@ -85,10 +85,13 @@ GLTexture* GL45Backend::syncGPUObject(const TexturePointer& texturePointer) {
         if (texture.getUsageType() == TextureUsageType::RESOURCE) {
             auto varTex = static_cast<GL45VariableAllocationTexture*> (object);
 
-            if (varTex->canPromote() && varTex->canPopulate()) {
+            if (varTex->_minAllocatedMip > 0) {
-                GL45VariableAllocationTexture::_memoryPressureStateStale = true;
+                auto minAvailableMip = texture.minAvailableMipLevel();
+                if (minAvailableMip < varTex->_minAllocatedMip) {
+                    varTex->_minAllocatedMip = minAvailableMip;
+                    GL45VariableAllocationTexture::_memoryPressureStateStale = true;
+                }
             }
-
         }
     }