Added mipmap property to QGLFramebufferObjectFormat.

If the mipmap property is set, QGLFramebufferObject will
allocate memory for mipmap levels.

Reviewed-by: Gunnar

3 files changed, 49 insertions, 7 deletions

diff --git a/src/opengl/qglframebufferobject.cpp b/src/opengl/qglframebufferobject.cpp
index 8915b5e4af..a7e81b2da1 100644
--- a/src/opengl/qglframebufferobject.cpp
+++ b/src/opengl/qglframebufferobject.cpp
@@ -202,6 +202,35 @@ int QGLFramebufferObjectFormat::samples() const
 }
 
 /*!
+    \since 4.8
+
+    Enables or disables mipmapping. Mipmapping is disabled by default.
+    If mipmapping is enabled, additional memory will be allocated for
+    the mipmap levels. The mipmap levels can be updated by binding the
+    texture and calling glGenerateMipmap(). Mipmapping cannot be enabled
+    for multisampled framebuffer objects.
+
+    \sa mipmap(), texture()
+*/
+void QGLFramebufferObjectFormat::setMipmap(bool enabled)
+{
+    detach();
+    d->mipmap = enabled;
+}
+
+/*!
+    \since 4.8
+
+    Returns true if mipmapping is enabled.
+
+    \sa setMipmap()
+*/
+bool QGLFramebufferObjectFormat::mipmap() const
+{
+    return d->mipmap;
+}
+
+/*!
     Sets the attachment configuration of a framebuffer object to \a attachment.
 
     \sa attachment()
@@ -398,7 +427,8 @@ bool QGLFramebufferObjectPrivate::checkFramebufferStatus() const
 
 void QGLFramebufferObjectPrivate::init(QGLFramebufferObject *q, const QSize &sz,
                                        QGLFramebufferObject::Attachment attachment,
-                                       GLenum texture_target, GLenum internal_format, GLint samples)
+                                       GLenum texture_target, GLenum internal_format,
+                                       GLint samples, bool mipmap)
 {
     QGLContext *ctx = const_cast<QGLContext *>(QGLContext::currentContext());
     fbo_guard.setContext(ctx);
@@ -426,6 +456,8 @@ void QGLFramebufferObjectPrivate::init(QGLFramebufferObject *q, const QSize &sz,
         glBindTexture(target, texture);
         glTexImage2D(target, 0, internal_format, size.width(), size.height(), 0,
                 GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+        if (mipmap)
+            glGenerateMipmap(GL_TEXTURE_2D);
 #ifndef QT_OPENGL_ES
         glTexParameteri(target, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
         glTexParameteri(target, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
@@ -446,6 +478,7 @@ void QGLFramebufferObjectPrivate::init(QGLFramebufferObject *q, const QSize &sz,
 
         color_buffer = 0;
     } else {
+        mipmap = false;
         GLint maxSamples;
         glGetIntegerv(GL_MAX_SAMPLES_EXT, &maxSamples);
 
@@ -606,6 +639,7 @@ void QGLFramebufferObjectPrivate::init(QGLFramebufferObject *q, const QSize &sz,
     format.setSamples(int(samples));
     format.setAttachment(fbo_attachment);
     format.setInternalTextureFormat(internal_format);
+    format.setMipmap(mipmap);
 }
 
 /*!
@@ -777,7 +811,7 @@ QGLFramebufferObject::QGLFramebufferObject(const QSize &size, const QGLFramebuff
 {
     Q_D(QGLFramebufferObject);
     d->init(this, size, format.attachment(), format.textureTarget(), format.internalTextureFormat(),
-            format.samples());
+            format.samples(), format.mipmap());
 }
 
 /*! \overload
@@ -791,7 +825,7 @@ QGLFramebufferObject::QGLFramebufferObject(int width, int height, const QGLFrame
 {
     Q_D(QGLFramebufferObject);
     d->init(this, QSize(width, height), format.attachment(), format.textureTarget(),
-            format.internalTextureFormat(), format.samples());
+            format.internalTextureFormat(), format.samples(), format.mipmap());
 }
 
 #ifdef Q_MAC_COMPAT_GL_FUNCTIONS
diff --git a/src/opengl/qglframebufferobject.h b/src/opengl/qglframebufferobject.h
index 6ff66457f7..70d6eb2971 100644
--- a/src/opengl/qglframebufferobject.h
+++ b/src/opengl/qglframebufferobject.h
@@ -148,6 +148,9 @@ public:
     void setSamples(int samples);
     int samples() const;
 
+    void setMipmap(bool enabled);
+    bool mipmap() const;
+
     void setAttachment(QGLFramebufferObject::Attachment attachment);
     QGLFramebufferObject::Attachment attachment() const;
 
diff --git a/src/opengl/qglframebufferobject_p.h b/src/opengl/qglframebufferobject_p.h
index 58b4e9e973..373878030c 100644
--- a/src/opengl/qglframebufferobject_p.h
+++ b/src/opengl/qglframebufferobject_p.h
@@ -77,7 +77,8 @@ public:
           samples(0),
           attachment(QGLFramebufferObject::NoAttachment),
           target(GL_TEXTURE_2D),
-          internal_format(DEFAULT_FORMAT)
+          internal_format(DEFAULT_FORMAT),
+          mipmap(false)
     {
     }
     QGLFramebufferObjectFormatPrivate
@@ -86,7 +87,8 @@ public:
           samples(other->samples),
           attachment(other->attachment),
           target(other->target),
-          internal_format(other->internal_format)
+          internal_format(other->internal_format),
+          mipmap(other->mipmap)
     {
     }
     bool equals(const QGLFramebufferObjectFormatPrivate *other)
@@ -94,7 +96,8 @@ public:
         return samples == other->samples &&
                attachment == other->attachment &&
                target == other->target &&
-               internal_format == other->internal_format;
+               internal_format == other->internal_format &&
+               mipmap == other->mipmap;
     }
 
     QAtomicInt ref;
@@ -102,6 +105,7 @@ public:
     QGLFramebufferObject::Attachment attachment;
     GLenum target;
     GLenum internal_format;
+    uint mipmap : 1;
 };
 
 class QGLFBOGLPaintDevice : public QGLPaintDevice
@@ -132,7 +136,8 @@ public:
 
     void init(QGLFramebufferObject *q, const QSize& sz,
               QGLFramebufferObject::Attachment attachment,
-              GLenum internal_format, GLenum texture_target, GLint samples = 0);
+              GLenum internal_format, GLenum texture_target,
+              GLint samples = 0, bool mipmap = false);
     bool checkFramebufferStatus() const;
     QGLSharedResourceGuard fbo_guard;
     GLuint texture;