rhi: Auto-rebuild rt by tracking attachment id and generation

Unlike the shader resource binding lists that automatically recognize
in setShaderResources() when a referenced QRhiResource has been rebuilt
in the meantime (create() was called i.e. there may be completely
different native objects underneath), QRhiTextureRenderTarget has no
such thing. This leads to an asymmetric API and requires also rebuilding
the rt whenever an attachment is rebuilt:

rt = rhi->newTextureRenderTarget({ { texture } })
rt->create()
cb->beginPass(rt, ...)
texture->setPixelSize(...)
texture->create()
rt->create() // this should not be needed
cb->beginPass(rt, ...)

Avoid having to do that second rt->create().

Change-Id: If14eaa7aac3530950498bbdf834324d0741a7c4d
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gui/rhi/qrhimetal.mm b/src/gui/rhi/qrhimetal.mm
index 5219b5c71d..626eac433b 100644
--- a/src/gui/rhi/qrhimetal.mm
+++ b/src/gui/rhi/qrhimetal.mm
@@ -296,6 +296,8 @@ struct QMetalRenderTargetData
         bool hasStencil = false;
         bool depthNeedsStore = false;
     } fb;
+
+    QRhiRenderTargetAttachmentTracker::ResIdList currentResIdList;
 };
 
 struct QMetalGraphicsPipelineData
@@ -2030,6 +2032,8 @@ void QRhiMetal::beginPass(QRhiCommandBuffer *cb,
     {
         QMetalTextureRenderTarget *rtTex = QRHI_RES(QMetalTextureRenderTarget, rt);
         rtD = rtTex->d;
+        if (!QRhiRenderTargetAttachmentTracker::isUpToDate<QMetalTexture, QMetalRenderBuffer>(rtTex->description(), rtD->currentResIdList))
+            rtTex->create();
         cbD->d->currentPassRpDesc = d->createDefaultRenderPass(rtD->dsAttCount, colorClearValue, depthStencilClearValue, rtD->colorAttCount);
         if (rtTex->m_flags.testFlag(QRhiTextureRenderTarget::PreserveColorContents)) {
             for (uint i = 0; i < uint(rtD->colorAttCount); ++i)
@@ -3181,6 +3185,8 @@ bool QMetalTextureRenderTarget::create()
         d->dsAttCount = 0;
     }
 
+    QRhiRenderTargetAttachmentTracker::updateResIdList<QMetalTexture, QMetalRenderBuffer>(m_desc, &d->currentResIdList);
+
     return true;
 }