GPU Vulkan Display: don't recreate command buffer for mixing images

Author: davidrohr

GPU/GPUTracking/display/GPUDisplay.h

@@ -297,6 +297,7 @@ class GPUDisplay : public GPUDisplayInterface
   HighResTimer mAnimationTimer;
   int32_t mAnimationFrame = 0;
   int32_t mAnimationLastBase = 0;
+  int32_t mAnimationMixBase = -1; // Target keyframe of the current config blend (mixing), -1 = none
   int32_t mAnimateScreenshot = 0;
   int32_t mAnimationExport = 0;
   bool mAnimationChangeConfig = true;

GPU/GPUTracking/display/backend/GPUDisplayBackendVulkan.cxx

@@ -623,7 +623,8 @@ void GPUDisplayBackendVulkan::createCommandBuffers()
   allocInfo.commandPool = mCommandPool;
   allocInfo.level = vk::CommandBufferLevel::ePrimary;
   allocInfo.commandBufferCount = mImageCount;
-  mCommandBufferUpToDate.resize(mImageCount, false);
+  mCommandBufferUpToDate.assign(mImageCount, false);
+  mCommandBufferMixUpToDate.assign(mImageCount, false);
   mCommandBuffers = mDevice.allocateCommandBuffers(allocInfo);
   mCommandBuffersText = mDevice.allocateCommandBuffers(allocInfo);
   mCommandBuffersTexture = mDevice.allocateCommandBuffers(allocInfo);
@@ -1448,7 +1449,7 @@ uint32_t GPUDisplayBackendVulkan::drawVertices(const vboList& v, const drawType
   if (count == 0) {
     return 0;
   }
-  if (mCommandBufferUpToDate[mCurrentImageIndex]) {
+  if (upToDate()[mCurrentImageIndex]) {
     return count;
   }
 
@@ -1470,7 +1471,7 @@ uint32_t GPUDisplayBackendVulkan::drawVertices(const vboList& v, const drawType
 
 bool GPUDisplayBackendVulkan::prepareDraw(const hmm_mat4& proj, const hmm_mat4& view, bool requestScreenshot, bool toMixBuffer, float includeMixImage)
 {
-  if (mDisplay->updateDrawCommands() || toMixBuffer || includeMixImage > 0) {
+  if (mDisplay->updateDrawCommands()) { // Main and mix command buffers stay cached while mixing, only the blend pass with the alpha value is recorded per frame
     needRecordCommandBuffers();
   }
 
@@ -1535,7 +1536,8 @@ bool GPUDisplayBackendVulkan::prepareDraw(const hmm_mat4& proj, const hmm_mat4&
 
   mCurrentCommandBuffer = toMixBuffer ? mCommandBuffersMix[mCurrentImageIndex] : mCommandBuffers[mCurrentImageIndex];
   mCurrentCommandBufferLastPipeline = -1;
-  if (!mCommandBufferUpToDate[mCurrentImageIndex]) {
+  mRecordingMix = toMixBuffer;
+  if (!upToDate()[mCurrentImageIndex]) {
     startFillCommandBuffer(mCurrentCommandBuffer, mCurrentImageIndex, toMixBuffer);
   }
   return true;
@@ -1553,11 +1555,9 @@ void GPUDisplayBackendVulkan::handleSwapChainResult(vk::Result retVal)
 
 void GPUDisplayBackendVulkan::finishDraw(bool doScreenshot, bool toMixBuffer, float includeMixImage)
 {
-  if (!mCommandBufferUpToDate[mCurrentImageIndex]) {
+  if (!upToDate()[mCurrentImageIndex]) {
     endFillCommandBuffer(mCurrentCommandBuffer);
-    if (!toMixBuffer && includeMixImage == 0.f) {
-      mCommandBufferUpToDate[mCurrentImageIndex] = true;
-    }
+    upToDate()[mCurrentImageIndex] = true;
   }
 }
 
@@ -1762,15 +1762,15 @@ void GPUDisplayBackendVulkan::mixImages(vk::CommandBuffer commandBuffer, float m
 
 void GPUDisplayBackendVulkan::ActivateColor(std::array<float, 4>& color)
 {
-  if (mCommandBufferUpToDate[mCurrentImageIndex]) {
+  if (upToDate()[mCurrentImageIndex]) {
     return;
   }
   mCurrentCommandBuffer.pushConstants(mPipelineLayout, vk::ShaderStageFlagBits::eFragment, 0, sizeof(color), color.data());
 }
 
 void GPUDisplayBackendVulkan::pointSizeFactor(float factor)
 {
-  if (mCommandBufferUpToDate[mCurrentImageIndex]) {
+  if (upToDate()[mCurrentImageIndex]) {
     return;
   }
   float size = std::min(mDisplay->cfgL().pointSize * mDownsampleFactor * factor + (mDisplay->cfgL().smoothPoints ? SMOOTH_POINT_EXTRA_SIZE : 0.f), mMaxPointSize);
@@ -1789,7 +1789,7 @@ bool GPUDisplayBackendVulkan::useSmoothLineShader() const
 
 void GPUDisplayBackendVulkan::lineWidthFactor(float factor)
 {
-  if (mCommandBufferUpToDate[mCurrentImageIndex]) {
+  if (upToDate()[mCurrentImageIndex]) {
     return;
   }
   float width = mDisplay->cfgL().lineWidth * mDownsampleFactor * factor;
@@ -1805,6 +1805,7 @@ void GPUDisplayBackendVulkan::lineWidthFactor(float factor)
 void GPUDisplayBackendVulkan::needRecordCommandBuffers()
 {
   std::fill(mCommandBufferUpToDate.begin(), mCommandBufferUpToDate.end(), false);
+  std::fill(mCommandBufferMixUpToDate.begin(), mCommandBufferMixUpToDate.end(), false);
 }
 
 void GPUDisplayBackendVulkan::addFontSymbol(int32_t symbol, int32_t sizex, int32_t sizey, int32_t offsetx, int32_t offsety, int32_t advance, void* data)
@@ -2027,5 +2028,5 @@ uint32_t GPUDisplayBackendVulkan::DepthBits()
 
 bool GPUDisplayBackendVulkan::backendNeedRedraw()
 {
-  return !mCommandBufferUpToDate[mCurrentImageIndex];
+  return !upToDate()[mCurrentImageIndex];
 }

GPU/GPUTracking/display/backend/GPUDisplayBackendVulkan.h

@@ -185,7 +185,10 @@ class GPUDisplayBackendVulkan : public GPUDisplayBackend
   std::vector<vk::CommandBuffer> mCommandBuffersMix;
   std::vector<vk::CommandBuffer> mCommandBuffersPresent;
   std::vector<vk::CommandBufferSubmitInfo> mFrameCommandBuffers; // All command buffers of the current frame, submitted as one batch, ordered by barriers
-  std::vector<bool> mCommandBufferUpToDate;
+  std::vector<bool> mCommandBufferUpToDate;                      // Per image: main command buffer recorded and still valid (cached across frames)
+  std::vector<bool> mCommandBufferMixUpToDate;                   // Per image: same for the mix buffer command buffer (animation config blending)
+  bool mRecordingMix = false;                                    // Current command buffer renders to the mix buffer
+  std::vector<bool>& upToDate() { return mRecordingMix ? mCommandBufferMixUpToDate : mCommandBufferUpToDate; }
   std::vector<vk::Semaphore> mImageAvailableSemaphore;
   std::vector<vk::Semaphore> mPresentSemaphore;
   vk::Semaphore mTimelineSemaphore;          // Signaled with an increasing value by every queue submit, replaces fences

GPU/GPUTracking/display/helpers/GPUDisplayAnimation.cxx

@@ -102,6 +102,7 @@ void GPUDisplay::startAnimation()
   mAnimationFrame = 0;
   mAnimate = 1;
   mAnimationLastBase = 0;
+  mAnimationMixBase = -1;
 }
 
 int32_t GPUDisplay::animateCamera(float& animateTime, float& mixSlaveImage, hmm_mat4& nextViewMatrix)
@@ -141,7 +142,12 @@ int32_t GPUDisplay::animateCamera(float& animateTime, float& mixSlaveImage, hmm_
       mAnimationLastBase = base - 1;
     }
 
-    if (base != mAnimationLastBase && mAnimateVectors[0][mAnimationLastBase] != mAnimateVectors[0][base] && memcmp(&mAnimateConfig[base], &mAnimateConfig[mAnimationLastBase], sizeof(mAnimateConfig[base]))) {
+    const bool mixing = base != mAnimationLastBase && mAnimateVectors[0][mAnimationLastBase] != mAnimateVectors[0][base] && memcmp(&mAnimateConfig[base], &mAnimateConfig[mAnimationLastBase], sizeof(mAnimateConfig[base]));
+    if ((mixing ? base : -1) != mAnimationMixBase) { // Blended configs changed: cached (Vulkan) command buffers must be re-recorded, otherwise they are kept while mixing
+      mAnimationMixBase = mixing ? base : -1;
+      mUpdateDrawCommands = true;
+    }
+    if (mixing) {
       mixSlaveImage = 1.f - (time - mAnimateVectors[0][mAnimationLastBase]) / (mAnimateVectors[0][base] - mAnimateVectors[0][mAnimationLastBase]);
       if (mixSlaveImage > 0) {
         mCfgL = mAnimateConfig[mAnimationLastBase];