rhi: Allow null resources in srb

In this case the srb represents the layout only, and can still be used
to create a pipeline. For setShaderResources() one will then need to use
another, layout compatible, srb that references valid resources.

Change-Id: I3ea5b63df3be8847540ca4c0c40fbd29dbed8fb7
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 195 insertions, 4 deletions

diff --git a/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp b/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
index f559b40cf6..ee14116e1c 100644
--- a/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
+++ b/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
@@ -91,6 +91,13 @@ private slots:
     void resourceUpdateBatchRGBATextureMip();
     void invalidPipeline_data();
     void invalidPipeline();
+    void srbLayoutCompatibility_data();
+    void srbLayoutCompatibility();
+    void srbWithNoResource_data();
+    void srbWithNoResource();
+    void renderPassDescriptorCompatibility_data();
+    void renderPassDescriptorCompatibility();
+
     void renderToTextureSimple_data();
     void renderToTextureSimple();
     void renderToTextureMip_data();
@@ -103,14 +110,12 @@ private slots:
     void renderToTextureArrayOfTexturedQuad();
     void renderToTextureTexturedQuadAndUniformBuffer_data();
     void renderToTextureTexturedQuadAndUniformBuffer();
+    void renderToTextureDeferredSrb_data();
+    void renderToTextureDeferredSrb();
     void renderToWindowSimple_data();
     void renderToWindowSimple();
     void finishWithinSwapchainFrame_data();
     void finishWithinSwapchainFrame();
-    void srbLayoutCompatibility_data();
-    void srbLayoutCompatibility();
-    void renderPassDescriptorCompatibility_data();
-    void renderPassDescriptorCompatibility();
 
 private:
     void setWindowType(QWindow *window, QRhi::Implementation impl);
@@ -2212,6 +2217,150 @@ void tst_QRhi::renderToTextureTexturedQuadAndUniformBuffer()
     QCOMPARE(result1.pixel(28, 178), empty);
 }
 
+void tst_QRhi::renderToTextureDeferredSrb_data()
+{
+    rhiTestData();
+}
+
+void tst_QRhi::renderToTextureDeferredSrb()
+{
+    QFETCH(QRhi::Implementation, impl);
+    QFETCH(QRhiInitParams *, initParams);
+
+    QScopedPointer<QRhi> rhi(QRhi::create(impl, initParams, QRhi::Flags(), nullptr));
+    if (!rhi)
+        QSKIP("QRhi could not be created, skipping testing rendering");
+
+    QImage inputImage;
+    inputImage.load(QLatin1String(":/data/qt256.png"));
+    QVERIFY(!inputImage.isNull());
+
+    QScopedPointer<QRhiTexture> texture(rhi->newTexture(QRhiTexture::RGBA8, inputImage.size(), 1,
+                                                        QRhiTexture::RenderTarget | QRhiTexture::UsedAsTransferSource));
+    QVERIFY(texture->create());
+
+    QScopedPointer<QRhiTextureRenderTarget> rt(rhi->newTextureRenderTarget({ texture.data() }));
+    QScopedPointer<QRhiRenderPassDescriptor> rpDesc(rt->newCompatibleRenderPassDescriptor());
+    rt->setRenderPassDescriptor(rpDesc.data());
+    QVERIFY(rt->create());
+
+    QRhiCommandBuffer *cb = nullptr;
+    QVERIFY(rhi->beginOffscreenFrame(&cb) == QRhi::FrameOpSuccess);
+    QVERIFY(cb);
+
+    QRhiResourceUpdateBatch *updates = rhi->nextResourceUpdateBatch();
+
+    static const float verticesUvs[] = {
+        -1.0f, -1.0f,   0.0f, 0.0f,
+        1.0f, -1.0f,    1.0f, 0.0f,
+        -1.0f, 1.0f,    0.0f, 1.0f,
+        1.0f, 1.0f,     1.0f, 1.0f
+    };
+    QScopedPointer<QRhiBuffer> vbuf(rhi->newBuffer(QRhiBuffer::Immutable, QRhiBuffer::VertexBuffer, sizeof(verticesUvs)));
+    QVERIFY(vbuf->create());
+    updates->uploadStaticBuffer(vbuf.data(), verticesUvs);
+
+    QScopedPointer<QRhiTexture> inputTexture(rhi->newTexture(QRhiTexture::RGBA8, inputImage.size()));
+    QVERIFY(inputTexture->create());
+    updates->uploadTexture(inputTexture.data(), inputImage);
+
+    QScopedPointer<QRhiSampler> sampler(rhi->newSampler(QRhiSampler::Nearest, QRhiSampler::Nearest, QRhiSampler::None,
+                                                        QRhiSampler::ClampToEdge, QRhiSampler::ClampToEdge));
+    QVERIFY(sampler->create());
+
+    QScopedPointer<QRhiBuffer> ubuf(rhi->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 64 + 4));
+    QVERIFY(ubuf->create());
+
+    QMatrix4x4 matrix;
+    updates->updateDynamicBuffer(ubuf.data(), 0, 64, matrix.constData());
+    float opacity = 0.5f;
+    updates->updateDynamicBuffer(ubuf.data(), 64, 4, &opacity);
+
+    // this is the specific thing to test here: an srb with null resources
+    const QRhiShaderResourceBinding::StageFlags commonVisibility = QRhiShaderResourceBinding::VertexStage | QRhiShaderResourceBinding::FragmentStage;
+    QScopedPointer<QRhiShaderResourceBindings> layoutOnlySrb(rhi->newShaderResourceBindings());
+    layoutOnlySrb->setBindings({
+                         QRhiShaderResourceBinding::uniformBuffer(0, commonVisibility, nullptr),
+                         QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, nullptr, nullptr)
+                     });
+    QVERIFY(layoutOnlySrb->create());
+
+    QScopedPointer<QRhiGraphicsPipeline> pipeline(rhi->newGraphicsPipeline());
+    pipeline->setTopology(QRhiGraphicsPipeline::TriangleStrip);
+    QShader vs = loadShader(":/data/textured.vert.qsb");
+    QVERIFY(vs.isValid());
+    QShader fs = loadShader(":/data/textured.frag.qsb");
+    QVERIFY(fs.isValid());
+    pipeline->setShaderStages({ { QRhiShaderStage::Vertex, vs }, { QRhiShaderStage::Fragment, fs } });
+    QRhiVertexInputLayout inputLayout;
+    inputLayout.setBindings({ { 4 * sizeof(float) } });
+    inputLayout.setAttributes({
+                                  { 0, 0, QRhiVertexInputAttribute::Float2, 0 },
+                                  { 0, 1, QRhiVertexInputAttribute::Float2, 2 * sizeof(float) }
+                              });
+    pipeline->setVertexInputLayout(inputLayout);
+    pipeline->setShaderResourceBindings(layoutOnlySrb.data()); // no resources needed yet
+    pipeline->setRenderPassDescriptor(rpDesc.data());
+
+    QVERIFY(pipeline->create());
+
+    // another, layout compatible, srb with the actual resources
+    QScopedPointer<QRhiShaderResourceBindings> layoutCompatibleSrbWithResources(rhi->newShaderResourceBindings());
+    layoutCompatibleSrbWithResources->setBindings({
+                         QRhiShaderResourceBinding::uniformBuffer(0, commonVisibility, ubuf.data()),
+                         QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, inputTexture.data(), sampler.data())
+                     });
+    QVERIFY(layoutCompatibleSrbWithResources->create());
+
+    cb->beginPass(rt.data(), Qt::black, { 1.0f, 0 }, updates);
+    cb->setGraphicsPipeline(pipeline.data());
+    cb->setShaderResources(layoutCompatibleSrbWithResources.data()); // here we must use the srb referencing the resources
+    cb->setViewport({ 0, 0, float(texture->pixelSize().width()), float(texture->pixelSize().height()) });
+    QRhiCommandBuffer::VertexInput vbindings(vbuf.data(), 0);
+    cb->setVertexInput(0, 1, &vbindings);
+    cb->draw(4);
+
+    QRhiReadbackResult readResult;
+    QImage result;
+    readResult.completed = [&readResult, &result] {
+        result = QImage(reinterpret_cast<const uchar *>(readResult.data.constData()),
+                        readResult.pixelSize.width(), readResult.pixelSize.height(),
+                        QImage::Format_RGBA8888_Premultiplied);
+    };
+    QRhiResourceUpdateBatch *readbackBatch = rhi->nextResourceUpdateBatch();
+    readbackBatch->readBackTexture({ texture.data() }, &readResult);
+    cb->endPass(readbackBatch);
+
+    rhi->endOffscreenFrame();
+
+    QVERIFY(!result.isNull());
+
+    if (impl == QRhi::Null)
+        return;
+
+    if (rhi->isYUpInFramebuffer() != rhi->isYUpInNDC())
+        result = std::move(result).mirrored();
+
+    // opacity 0.5 (premultiplied)
+    static const auto checkSemiWhite = [](const QRgb &c) {
+        QRgb semiWhite127 = qPremultiply(qRgba(255, 255, 255, 127));
+        QRgb semiWhite128 = qPremultiply(qRgba(255, 255, 255, 128));
+        return c == semiWhite127 || c == semiWhite128;
+    };
+    QVERIFY(checkSemiWhite(result.pixel(79, 77)));
+    QVERIFY(checkSemiWhite(result.pixel(124, 81)));
+    QVERIFY(checkSemiWhite(result.pixel(128, 149)));
+    QVERIFY(checkSemiWhite(result.pixel(120, 189)));
+    QVERIFY(checkSemiWhite(result.pixel(116, 185)));
+    QVERIFY(checkSemiWhite(result.pixel(191, 172)));
+
+    QRgb empty = qRgba(0, 0, 0, 0);
+    QCOMPARE(result.pixel(11, 45), empty);
+    QCOMPARE(result.pixel(246, 202), empty);
+    QCOMPARE(result.pixel(130, 18), empty);
+    QCOMPARE(result.pixel(4, 227), empty);
+}
+
 void tst_QRhi::setWindowType(QWindow *window, QRhi::Implementation impl)
 {
     switch (impl) {
@@ -2630,6 +2779,48 @@ void tst_QRhi::srbLayoutCompatibility()
     }
 }
 
+void tst_QRhi::srbWithNoResource_data()
+{
+    rhiTestData();
+}
+
+void tst_QRhi::srbWithNoResource()
+{
+    QFETCH(QRhi::Implementation, impl);
+    QFETCH(QRhiInitParams *, initParams);
+
+    QScopedPointer<QRhi> rhi(QRhi::create(impl, initParams, QRhi::Flags(), nullptr));
+    if (!rhi)
+        QSKIP("QRhi could not be created, skipping testing srb");
+
+    QScopedPointer<QRhiTexture> texture(rhi->newTexture(QRhiTexture::RGBA8, QSize(512, 512)));
+    QVERIFY(texture->create());
+    QScopedPointer<QRhiSampler> sampler(rhi->newSampler(QRhiSampler::Nearest, QRhiSampler::Nearest, QRhiSampler::None,
+                                                        QRhiSampler::ClampToEdge, QRhiSampler::ClampToEdge));
+    QVERIFY(sampler->create());
+    QScopedPointer<QRhiBuffer> buf(rhi->newBuffer(QRhiBuffer::Dynamic, QRhiBuffer::UniformBuffer, 1024));
+    QVERIFY(buf->create());
+
+    {
+        QScopedPointer<QRhiShaderResourceBindings> srb1(rhi->newShaderResourceBindings());
+        srb1->setBindings({
+                             QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage, nullptr),
+                             QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, nullptr, nullptr)
+                         });
+        QVERIFY(srb1->create());
+
+        QScopedPointer<QRhiShaderResourceBindings> srb2(rhi->newShaderResourceBindings());
+        srb2->setBindings({
+                             QRhiShaderResourceBinding::uniformBuffer(0, QRhiShaderResourceBinding::VertexStage, buf.data()),
+                             QRhiShaderResourceBinding::sampledTexture(1, QRhiShaderResourceBinding::FragmentStage, texture.data(), sampler.data())
+                         });
+        QVERIFY(srb2->create());
+
+        QVERIFY(srb1->isLayoutCompatible(srb2.data()));
+        QVERIFY(srb2->isLayoutCompatible(srb1.data()));
+    }
+}
+
 void tst_QRhi::renderPassDescriptorCompatibility_data()
 {
     rhiTestData();