Vulkan: Optimize changing texture max level

src/libANGLE/Texture.cpp

@@ -97,7 +97,7 @@ TextureState::TextureState(TextureType type)
       mSamplerState(SamplerState::CreateDefaultForTarget(type)),
       mSrgbOverride(SrgbOverride::Default),
       mBaseLevel(0),
-      mMaxLevel(1000),
+      mMaxLevel(kInitialMaxLevel),
       mDepthStencilTextureMode(GL_DEPTH_COMPONENT),
       mImmutableFormat(false),
       mImmutableLevels(0),

src/libANGLE/Texture.h

@@ -48,6 +48,8 @@ class Sampler;
 class State;
 class Texture;
 
+constexpr GLuint kInitialMaxLevel = 1000;
+
 bool IsMipmapFiltered(const SamplerState &samplerState);
 
 struct ImageDesc final

src/libANGLE/renderer/vulkan/TextureVk.cpp

@@ -1523,9 +1523,11 @@ angle::Result TextureVk::updateBaseMaxLevels(ContextVk *contextVk,
 
     // Track the previous levels for use in update loop below
     uint32_t previousBaseLevel = mImage->getBaseLevel();
+    uint32_t previousMaxLevel  = mImage->getMaxLevel();
 
+    ASSERT(baseLevel <= maxLevel);
     bool baseLevelChanged = baseLevel != previousBaseLevel;
-    bool maxLevelChanged  = (mImage->getLevelCount() + previousBaseLevel) != (maxLevel + 1);
+    bool maxLevelChanged  = (previousMaxLevel != maxLevel);
 
     if (!(baseLevelChanged || maxLevelChanged))
     {
@@ -1543,6 +1545,33 @@ angle::Result TextureVk::updateBaseMaxLevels(ContextVk *contextVk,
         return angle::Result::Continue;
     }
 
+    // With a valid image, check if only changing the maxLevel to a subset of the texture's actual
+    // number of mip levels
+    if (!baseLevelChanged && (maxLevel < baseLevel + mImage->getLevelCount()))
+    {
+        // Don't need to respecify the texture; just redo the texture's vkImageViews
+        ASSERT(maxLevelChanged);
+
+        // Release the current vkImageViews
+        RendererVk *renderer = contextVk->getRenderer();
+        mImageViews.release(renderer);
+
+        // Track the levels in our ImageHelper
+        mImage->setBaseAndMaxLevels(baseLevel, maxLevel);
+
+        // Update the texture's serial so that the descriptor set is updated correctly
+        mSerial = contextVk->generateTextureSerial();
+
+        // Change the vkImageViews
+        const gl::ImageDesc &baseLevelDesc = mState.getBaseLevelDesc();
+        // We use a special layer count here to handle EGLImages. They might only be
+        // looking at one layer of a cube or 2D array texture.
+        uint32_t layerCount =
+            mState.getType() == gl::TextureType::_2D ? 1 : mImage->getLayerCount();
+        return initImageViews(contextVk, mImage->getFormat(), baseLevelDesc.format.info->sized,
+                              maxLevel - baseLevel + 1, layerCount);
+    }
+
     return respecifyImageAttributesAndLevels(contextVk, previousBaseLevel, baseLevel, maxLevel);
 }
 

src/libANGLE/renderer/vulkan/vk_helpers.h

@@ -1361,6 +1361,7 @@ class ImageHelper final : public Resource, public angle::Subject
 
     uint32_t getBaseLevel() const { return mBaseLevel; }
     void setBaseAndMaxLevels(uint32_t baseLevel, uint32_t maxLevel);
+    uint32_t getMaxLevel() const { return mMaxLevel; }
 
     angle::Result copyImageDataToBuffer(ContextVk *contextVk,
                                         size_t sourceLevelGL,