From fd3d228b044dee8071afe8f7407dc6d2ac0092d6 Mon Sep 17 00:00:00 2001
From: Miikka Heikkinen <miikka.heikkinen@theqtcompany.com>
Date: Tue, 21 Apr 2015 12:08:43 +0300
Subject: [PATCH] Fix readPixels for antialiased buffers.
MIME-Version: 1.0
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When calling readPixels from javascript, we need to blit the
antialiased fbo into the render fbo before we can read the pixel.
Change-Id: I342342f396c42f3d5320105552838cd7c99d1c4b
Task-number: QTBUG-45373
Reviewed-by: Tomi Korpipää <tomi.korpipaa@theqtcompany.com>
Reviewed-by: Pasi Keränen <pasi.keranen@digia.com>
---
src/imports/qtcanvas3d/canvas3d.cpp | 27 +++++++++++++++++++--------
src/imports/qtcanvas3d/canvas3d_p.h | 1 +
src/imports/qtcanvas3d/context3d.cpp | 11 +++++++++++
3 files changed, 31 insertions(+), 8 deletions(-)
diff --git a/src/imports/qtcanvas3d/canvas3d.cpp b/src/imports/qtcanvas3d/canvas3d.cpp
index 159e24d..f1f6213 100644
--- a/src/imports/qtcanvas3d/canvas3d.cpp
+++ b/src/imports/qtcanvas3d/canvas3d.cpp
@@ -582,6 +582,23 @@ void Canvas::updateWindowParameters()
}
}
+/*!
+ * \internal
+ *
+ * Blits the antialias fbo into the final render fbo.
+ * Returns the final render fbo handle.
+ */
+GLuint Canvas::resolveMSAAFbo()
+{
+ qCDebug(canvas3drendering).nospace() << "Canvas3D::" << __FUNCTION__
+ << " Resolving MSAA from FBO:"
+ << m_antialiasFbo->handle()
+ << " to FBO:" << m_renderFbo->handle();
+ QOpenGLFramebufferObject::blitFramebuffer(m_renderFbo, m_antialiasFbo);
+
+ return m_renderFbo->handle();
+}
+
/*!
* \internal
*/
@@ -791,14 +808,8 @@ void Canvas::renderNext()
<< " Emit paintGL() signal";
emit paintGL();
- // Resolve MSAA
- if (m_contextAttribs.antialias()) {
- qCDebug(canvas3drendering).nospace() << "Canvas3D::" << __FUNCTION__
- << " Resolving MSAA from FBO:"
- << m_antialiasFbo->handle()
- << " to FBO:" << m_renderFbo->handle();
- QOpenGLFramebufferObject::blitFramebuffer(m_renderFbo, m_antialiasFbo);
- }
+ if (m_contextAttribs.antialias())
+ resolveMSAAFbo();
// We need to flush the contents to the FBO before posting
// the texture to the other thread, otherwise, we might
diff --git a/src/imports/qtcanvas3d/canvas3d_p.h b/src/imports/qtcanvas3d/canvas3d_p.h
index fe7f0d5..08be21a 100644
--- a/src/imports/qtcanvas3d/canvas3d_p.h
+++ b/src/imports/qtcanvas3d/canvas3d_p.h
@@ -93,6 +93,7 @@ public:
void createFBOs();
void bindCurrentRenderTarget();
+ GLuint resolveMSAAFbo();
uint fps();
diff --git a/src/imports/qtcanvas3d/context3d.cpp b/src/imports/qtcanvas3d/context3d.cpp
index 234765a..38e0487 100644
--- a/src/imports/qtcanvas3d/context3d.cpp
+++ b/src/imports/qtcanvas3d/context3d.cpp
@@ -5214,7 +5214,18 @@ void CanvasContext::readPixels(int x, int y, long width, long height, glEnums fo
return;
}
+ // Check if the buffer is antialiased. If it is, we need to blit to the final buffer before
+ // reading the value.
+ if (m_contextAttributes.antialias()) {
+ GLuint readFbo = m_canvas->resolveMSAAFbo();
+ glBindFramebuffer(GL_FRAMEBUFFER, readFbo);
+ }
+
glReadPixels(x, y, width, height, format, type, bufferPtr);
+
+ if (m_contextAttributes.antialias())
+ m_canvas->bindCurrentRenderTarget();
+
logAllGLErrors(__FUNCTION__);
}
--
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