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/qrhigles2_p_p.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'src/gui/rhi/qrhigles2_p_p.h')

diff --git a/src/gui/rhi/qrhigles2_p_p.h b/src/gui/rhi/qrhigles2_p_p.h
index a9b3022612..679f806004 100644
--- a/src/gui/rhi/qrhigles2_p_p.h
+++ b/src/gui/rhi/qrhigles2_p_p.h
@@ -521,6 +521,17 @@ struct QGles2CommandBuffer : public QRhiCommandBuffer
     QRhiShaderResourceBindings *currentComputeSrb;
     uint currentSrbGeneration;
 
+    struct ComputePassState {
+        enum Access {
+            Read = 0x01,
+            Write = 0x02
+        };
+        QHash<QRhiResource *, QPair<int, bool> > writtenResources;
+        void reset() {
+            writtenResources.clear();
+        }
+    } computePassState;
+
     QVector<QByteArray> dataRetainPool;
     QVector<QImage> imageRetainPool;
 
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