From 9a0ab41f28042c7f27208337e419435d16f00006 Mon Sep 17 00:00:00 2001
From: Laszlo Agocs <laszlo.agocs@qt.io>
Date: Wed, 8 Jan 2020 12:55:57 +0100
Subject: rhi: gl: vulkan: Generate barriers between dispatches in a compute
 pass

The new float16texture_with_compute manual test demonstrates a case
that was not handled correctly before: multiple dispatch() calls in
a row storing to and then loading from the same subresource(s).
Without the appropriate barriers subtle data corruption issues appear.

For Vulkan this also adds better batching for image/buffer barriers when
using deferred recording.

Also, for OpenGL this fixes the case of updating a buffer or rendering into
a texture and then using it for load/store in a compute pass (previously this
also lacked an appropriate glMemoryBarrier).

Task-number: QTBUG-81217
Change-Id: I7970c445564473f9452662f4b1a20618cb8627a3
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
Reviewed-by: Johan Helsing <johan.helsing@qt.io>
---
 src/gui/rhi/qrhivulkan_p_p.h | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

(limited to 'src/gui/rhi/qrhivulkan_p_p.h')

diff --git a/src/gui/rhi/qrhivulkan_p_p.h b/src/gui/rhi/qrhivulkan_p_p.h
index 9f18d0bf5e..b0e90dae56 100644
--- a/src/gui/rhi/qrhivulkan_p_p.h
+++ b/src/gui/rhi/qrhivulkan_p_p.h
@@ -370,6 +370,13 @@ struct QVkCommandBuffer : public QRhiCommandBuffer
     QVarLengthArray<VkCommandBuffer, 4> secondaryCbs;
     bool inExternal;
 
+    struct {
+        QHash<QRhiResource *, QPair<VkAccessFlags, bool> > writtenResources;
+        void reset() {
+            writtenResources.clear();
+        }
+    } computePassState;
+
     struct Command {
         enum Cmd {
             CopyBuffer,
@@ -429,12 +436,14 @@ struct QVkCommandBuffer : public QRhiCommandBuffer
             struct {
                 VkPipelineStageFlags srcStageMask;
                 VkPipelineStageFlags dstStageMask;
-                VkImageMemoryBarrier desc;
+                int count;
+                int index;
             } imageBarrier;
             struct {
                 VkPipelineStageFlags srcStageMask;
                 VkPipelineStageFlags dstStageMask;
-                VkBufferMemoryBarrier desc;
+                int count;
+                int index;
             } bufferBarrier;
             struct {
                 VkImage src;
@@ -537,6 +546,8 @@ struct QVkCommandBuffer : public QRhiCommandBuffer
         pools.vertexBuffer.clear();
         pools.vertexBufferOffset.clear();
         pools.debugMarkerData.clear();
+        pools.imageBarrier.clear();
+        pools.bufferBarrier.clear();
     }
 
     struct {
@@ -546,6 +557,8 @@ struct QVkCommandBuffer : public QRhiCommandBuffer
         QVarLengthArray<VkBuffer, 4> vertexBuffer;
         QVarLengthArray<VkDeviceSize, 4> vertexBufferOffset;
         QVarLengthArray<QByteArray, 4> debugMarkerData;
+        QVarLengthArray<VkImageMemoryBarrier, 8> imageBarrier;
+        QVarLengthArray<VkBufferMemoryBarrier, 8> bufferBarrier;
     } pools;
 
     friend class QRhiVulkan;
-- 
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