Add GraphicsContext::supportsDrawBuffersBlend()

To check for availability of ARB_draw_buffers_blend

Task-number: QTBUG-50005
Change-Id: I8f4e11ff401a9e1e3751f61421572cb1fc323979
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

4 files changed, 9 insertions, 2 deletions

diff --git a/src/render/graphicshelpers/graphicscontext.cpp b/src/render/graphicshelpers/graphicscontext.cpp
index d934d33af..b5b2898db 100644
--- a/src/render/graphicshelpers/graphicscontext.cpp
+++ b/src/render/graphicshelpers/graphicscontext.cpp
@@ -604,6 +604,11 @@ QGraphicsApiFilter *GraphicsContext::contextInfo() const
     return m_contextInfo;
 }
 
+bool GraphicsContext::supportsDrawBuffersBlend() const
+{
+    return m_glHelper->supportsFeature(GraphicsHelperInterface::DrawBuffersBlend);
+}
+
 /*!
  * Wraps an OpenGL call to glDrawElementsInstanced.
  * If the call is not supported by the system's OpenGL version,
diff --git a/src/render/graphicshelpers/graphicscontext_p.h b/src/render/graphicshelpers/graphicscontext_p.h
index 98ca94559..51e6c8bc4 100644
--- a/src/render/graphicshelpers/graphicscontext_p.h
+++ b/src/render/graphicshelpers/graphicscontext_p.h
@@ -208,7 +208,7 @@ public:
     static GLuint byteSizeFromType(GLint type);
     static GLint glDataTypeFromAttributeDataType(QAttribute::DataType dataType);
 
-
+    bool supportsDrawBuffersBlend() const;
     bool supportsVAO() const { return m_supportsVAO; }
 
 private:
diff --git a/src/render/graphicshelpers/graphicshelpergl4.cpp b/src/render/graphicshelpers/graphicshelpergl4.cpp
index ca83589a4..332413d69 100644
--- a/src/render/graphicshelpers/graphicshelpergl4.cpp
+++ b/src/render/graphicshelpers/graphicshelpergl4.cpp
@@ -369,6 +369,7 @@ bool GraphicsHelperGL4::supportsFeature(GraphicsHelperInterface::Feature feature
     case TextureDimensionRetrieval:
     case ShaderStorageObject:
     case Compute:
+    case DrawBuffersBlend:
         return true;
     default:
         return false;
diff --git a/src/render/graphicshelpers/graphicshelperinterface_p.h b/src/render/graphicshelpers/graphicshelperinterface_p.h
index f7b5ddf8c..fe52b1607 100644
--- a/src/render/graphicshelpers/graphicshelperinterface_p.h
+++ b/src/render/graphicshelpers/graphicshelperinterface_p.h
@@ -72,7 +72,8 @@ public:
         RenderBufferDimensionRetrieval,
         TextureDimensionRetrieval,
         ShaderStorageObject,
-        Compute
+        Compute,
+        DrawBuffersBlend
     };
 
     virtual ~GraphicsHelperInterface() {}