Add GL_EXT_discard_framebuffer to QOpenGLExtensions

Change-Id: I57e8dd2ea2e6f018a46eaabed2ca8b6d417358a3
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

2 files changed, 22 insertions, 1 deletions

diff --git a/src/gui/opengl/qopenglextensions_p.h b/src/gui/opengl/qopenglextensions_p.h
index 23cfe16467..0d0cfd26ba 100644
--- a/src/gui/opengl/qopenglextensions_p.h
+++ b/src/gui/opengl/qopenglextensions_p.h
@@ -81,7 +81,8 @@ public:
         MapBuffer               = 0x00040000,
         GeometryShaders         = 0x00080000,
         MapBufferRange          = 0x00100000,
-        Sized8Formats           = 0x00200000
+        Sized8Formats           = 0x00200000,
+        DiscardFramebuffer      = 0x00400000
     };
     Q_DECLARE_FLAGS(OpenGLExtensions, OpenGLExtension)
 
@@ -102,6 +103,8 @@ public:
 
     void glGetBufferSubData(GLenum target, qopengl_GLintptr offset, qopengl_GLsizeiptr size, GLvoid *data);
 
+    void glDiscardFramebufferEXT (GLenum target, GLsizei numAttachments, const GLenum *attachments);
+
 private:
     static bool isInitialized(const QOpenGLFunctionsPrivate *d) { return d != 0; }
 };
@@ -124,6 +127,7 @@ public:
                                           GLenum internalFormat,
                                           GLsizei width, GLsizei height);
     void (QOPENGLF_APIENTRYP GetBufferSubData)(GLenum target, qopengl_GLintptr offset, qopengl_GLsizeiptr size, GLvoid *data);
+    void (QOPENGLF_APIENTRYP DiscardFramebuffer)(GLenum target, GLsizei numAttachments, const GLenum *attachments);
 };
 
 inline GLvoid *QOpenGLExtensions::glMapBuffer(GLenum target, GLenum access)
@@ -182,6 +186,14 @@ inline void QOpenGLExtensions::glGetBufferSubData(GLenum target, qopengl_GLintpt
     Q_OPENGL_FUNCTIONS_DEBUG
 }
 
+
+inline void QOpenGLExtensions::glDiscardFramebufferEXT (GLenum target, GLsizei numAttachments, const GLenum *attachments)
+{
+    Q_D(QOpenGLExtensions);
+    Q_ASSERT(QOpenGLExtensions::isInitialized(d));
+    d->DiscardFramebuffer(target,numAttachments, attachments);
+    Q_OPENGL_FUNCTIONS_DEBUG
+}
 QT_END_NAMESPACE
 
 #endif // QOPENGL_EXTENSIONS_P_H
diff --git a/src/gui/opengl/qopenglfunctions.cpp b/src/gui/opengl/qopenglfunctions.cpp
index 3631c019d3..99604ca8b2 100644
--- a/src/gui/opengl/qopenglfunctions.cpp
+++ b/src/gui/opengl/qopenglfunctions.cpp
@@ -415,6 +415,9 @@ static int qt_gl_resolve_extensions()
         // We don't match GL_APPLE_texture_format_BGRA8888 here because it has different semantics.
         if (extensionMatcher.match("GL_IMG_texture_format_BGRA8888") || extensionMatcher.match("GL_EXT_texture_format_BGRA8888"))
             extensions |= QOpenGLExtensions::BGRATextureFormat;
+
+        if (extensionMatcher.match("GL_EXT_discard_framebuffer"))
+            extensions |= QOpenGLExtensions::DiscardFramebuffer;
     } else {
         extensions |= QOpenGLExtensions::ElementIndexUint | QOpenGLExtensions::MapBuffer;
 
@@ -3257,6 +3260,11 @@ static void QOPENGLF_APIENTRY qopenglfResolveGetBufferSubData(GLenum target, qop
         (target, offset, size, data);
 }
 
+static void QOPENGLF_APIENTRY qopenglfResolveDiscardFramebuffer(GLenum target, GLsizei numAttachments, const GLenum *attachments)
+{
+    RESOLVE_FUNC_VOID(ResolveEXT, DiscardFramebuffer)(target, numAttachments, attachments);
+}
+
 #if !defined(QT_OPENGL_ES_2) && !defined(QT_OPENGL_DYNAMIC)
 // Special translation functions for ES-specific calls on desktop GL
 
@@ -3495,6 +3503,7 @@ QOpenGLExtensionsPrivate::QOpenGLExtensionsPrivate(QOpenGLContext *ctx)
     BlitFramebuffer = qopenglfResolveBlitFramebuffer;
     RenderbufferStorageMultisample = qopenglfResolveRenderbufferStorageMultisample;
     GetBufferSubData = qopenglfResolveGetBufferSubData;
+    DiscardFramebuffer = qopenglfResolveDiscardFramebuffer;
 }
 
 QT_END_NAMESPACE