rhi: gl: Add support for importing an existing renderbuffer object

Normally we only allow creating wrappers for texture objects. These
can then be used with a QRhiTextureRenderTarget to allow rendering into
an externally created texture.

With OpenGL (ES), there are additional, special cases, especially on
embedded. Consider EGLImages for example. An EGLImageKHR can be bound to
a renderbuffer object (glEGLImageTargetRenderbufferStorageOES), which
can then be associated with a framebuffer object to allow rendering into
the external buffer represented by the EGLImage. To implement the same
via QRhi one needs a way to create a wrapping QRhiRenderBuffer for the
native OpenGL renderbuffer object.

Here we add a createFrom() to QRhiRenderBuffer, while providing a dummy,
default implementation. The only real implementation is in the OpenGL
backend, which simply takes a renderbuffer id, without taking ownership.

Task-number: QTBUG-92116
Change-Id: I4e68e665fb35a7d7803b7780db901c8bed5740e2
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

1 files changed, 139 insertions, 1 deletions

diff --git a/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp b/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
index 076106a589..18eebaae1e 100644
--- a/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
+++ b/tests/auto/gui/rhi/qrhi/tst_qrhi.cpp
@@ -37,6 +37,7 @@
 
 #if QT_CONFIG(opengl)
 # include <QOpenGLContext>
+# include <QOpenGLFunctions>
 # include <QtGui/private/qrhigles2_p.h>
 # define TST_GL
 #endif
@@ -70,6 +71,7 @@ private slots:
     void cleanupTestCase();
 
     void rhiTestData();
+    void rhiTestDataOpenGL();
     void create_data();
     void create();
     void nativeHandles_data();
@@ -129,6 +131,10 @@ private slots:
 
     void pipelineCache_data();
     void pipelineCache();
+    void textureImportOpenGL_data();
+    void textureImportOpenGL();
+    void renderbufferImportOpenGL_data();
+    void renderbufferImportOpenGL();
 
 private:
     void setWindowType(QWindow *window, QRhi::Implementation impl);
@@ -214,6 +220,16 @@ void tst_QRhi::rhiTestData()
 #endif
 }
 
+void tst_QRhi::rhiTestDataOpenGL()
+{
+    QTest::addColumn<QRhi::Implementation>("impl");
+    QTest::addColumn<QRhiInitParams *>("initParams");
+
+#ifdef TST_GL
+    QTest::newRow("OpenGL") << QRhi::OpenGLES2 << static_cast<QRhiInitParams *>(&initParams.gl);
+#endif
+}
+
 void tst_QRhi::create_data()
 {
     rhiTestData();
@@ -351,7 +367,8 @@ void tst_QRhi::create()
             QRhi::ScreenSpaceDerivatives,
             QRhi::ReadBackAnyTextureFormat,
             QRhi::PipelineCacheDataLoadSave,
-            QRhi::ImageDataStride
+            QRhi::ImageDataStride,
+            QRhi::RenderBufferImport
         };
         for (size_t i = 0; i <sizeof(features) / sizeof(QRhi::Feature); ++i)
             rhi->isFeatureSupported(features[i]);
@@ -3689,5 +3706,126 @@ void tst_QRhi::pipelineCache()
     }
 }
 
+void tst_QRhi::textureImportOpenGL_data()
+{
+    rhiTestDataOpenGL();
+}
+
+void tst_QRhi::textureImportOpenGL()
+{
+    QFETCH(QRhi::Implementation, impl);
+    if (impl != QRhi::OpenGLES2)
+        QSKIP("Skipping OpenGL-dependent test");
+
+#ifdef TST_GL
+    QFETCH(QRhiInitParams *, initParams);
+
+    QScopedPointer<QRhi> rhi(QRhi::create(impl, initParams, QRhi::Flags(), nullptr));
+    if (!rhi)
+        QSKIP("QRhi could not be created, skipping testing native texture");
+
+    QVERIFY(rhi->makeThreadLocalNativeContextCurrent());
+    QOpenGLContext *ctx = QOpenGLContext::currentContext();
+    QVERIFY(ctx);
+    QOpenGLFunctions *f = ctx->functions();
+
+    QImage image(320, 200, QImage::Format_RGBA8888_Premultiplied);
+    image.fill(Qt::red);
+
+    GLuint t = 0;
+    f->glGenTextures(1, &t);
+    f->glBindTexture(GL_TEXTURE_2D, t);
+    f->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width(), image.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, image.constBits());
+
+    QScopedPointer<QRhiTexture> tex(rhi->newTexture(QRhiTexture::RGBA8, image.size()));
+    QRhiTexture::NativeTexture nativeTex = { t, 0 };
+    QVERIFY(tex->createFrom(nativeTex));
+    QCOMPARE(tex->nativeTexture().object, nativeTex.object);
+
+    QRhiReadbackResult readResult;
+    bool readCompleted = false;
+    readResult.completed = [&readCompleted] { readCompleted = true; };
+    QRhiResourceUpdateBatch *batch = rhi->nextResourceUpdateBatch();
+    batch->readBackTexture(tex.data(), &readResult);
+    QVERIFY(submitResourceUpdates(rhi.data(), batch));
+    QVERIFY(readCompleted);
+    QCOMPARE(readResult.format, QRhiTexture::RGBA8);
+    QCOMPARE(readResult.pixelSize, image.size());
+    QImage wrapperImage(reinterpret_cast<const uchar *>(readResult.data.constData()),
+                        readResult.pixelSize.width(), readResult.pixelSize.height(),
+                        image.format());
+    QVERIFY(imageRGBAEquals(image, wrapperImage));
+
+    f->glDeleteTextures(1, &t);
+#endif
+}
+
+void tst_QRhi::renderbufferImportOpenGL_data()
+{
+    rhiTestDataOpenGL();
+}
+
+void tst_QRhi::renderbufferImportOpenGL()
+{
+    QFETCH(QRhi::Implementation, impl);
+    if (impl != QRhi::OpenGLES2)
+        QSKIP("Skipping OpenGL-dependent test");
+
+#ifdef TST_GL
+    QFETCH(QRhiInitParams *, initParams);
+
+    QScopedPointer<QRhi> rhi(QRhi::create(impl, initParams, QRhi::Flags(), nullptr));
+    if (!rhi)
+        QSKIP("QRhi could not be created, skipping testing native texture");
+
+    QVERIFY(rhi->makeThreadLocalNativeContextCurrent());
+    QOpenGLContext *ctx = QOpenGLContext::currentContext();
+    QVERIFY(ctx);
+    QOpenGLFunctions *f = ctx->functions();
+
+    const QSize size(320, 200);
+    GLuint b = 0;
+    f->glGenRenderbuffers(1, &b);
+    f->glBindRenderbuffer(GL_RENDERBUFFER, b);
+    // in a real world use case this would be some extension, e.g. glEGLImageTargetRenderbufferStorageOES instead
+    f->glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA4, size.width(), size.height());
+    f->glBindRenderbuffer(GL_RENDERBUFFER, 0);
+
+    QScopedPointer<QRhiRenderBuffer> rb(rhi->newRenderBuffer(QRhiRenderBuffer::Color, size));
+    QVERIFY(rb->createFrom({ b }));
+
+    QScopedPointer<QRhiRenderBuffer> depthStencil(rhi->newRenderBuffer(QRhiRenderBuffer::DepthStencil, size));
+    QVERIFY(depthStencil->create());
+    QRhiColorAttachment att(rb.data());
+    QRhiTextureRenderTargetDescription rtDesc(att);
+    rtDesc.setDepthStencilBuffer(depthStencil.data());
+    QScopedPointer<QRhiTextureRenderTarget> rt(rhi->newTextureRenderTarget(rtDesc));
+    QScopedPointer<QRhiRenderPassDescriptor> rp(rt->newCompatibleRenderPassDescriptor());
+    rt->setRenderPassDescriptor(rp.data());
+    QVERIFY(rt->create());
+
+    QRhiCommandBuffer *cb = nullptr;
+    QVERIFY(rhi->beginOffscreenFrame(&cb) == QRhi::FrameOpSuccess);
+    QVERIFY(cb);
+    cb->beginPass(rt.data(), Qt::red, { 1.0f, 0 }, nullptr, QRhiCommandBuffer::ExternalContent);
+    cb->beginExternal();
+    QByteArray tmpBuf;
+    tmpBuf.resize(size.width() * size.height() * 4);
+    f->glReadPixels(0, 0, size.width(), size.height(), GL_RGBA, GL_UNSIGNED_BYTE, tmpBuf.data());
+    cb->endExternal();
+    cb->endPass();
+    rhi->endOffscreenFrame();
+
+    f->glDeleteRenderbuffers(1, &b);
+
+    QImage wrapperImage(reinterpret_cast<const uchar *>(tmpBuf.constData()),
+                        size.width(), size.height(), QImage::Format_RGBA8888_Premultiplied);
+
+    QImage image(320, 200, QImage::Format_RGBA8888_Premultiplied);
+    image.fill(Qt::red);
+    QVERIFY(imageRGBAEquals(image, wrapperImage));
+#endif
+}
+
 #include <tst_qrhi.moc>
 QTEST_MAIN(tst_QRhi)