Don't do anything OpenGL-related inside Camera itself.

* The user might not want to call Framebuffer::clear(), because there
   could be something already rendered with another camera.
 * The user might not want to call Framebuffer::setViewport(), because
   there could be different framebuffer attached.

src/SceneGraph/Camera.cpp

@@ -14,7 +14,6 @@
 */
 
 #include "Camera.h"
-#include "Framebuffer.h"
 #include "Scene.h"
 
 using namespace std;
@@ -49,7 +48,6 @@ template Matrix4 aspectRatioFix<Matrix4>(AspectRatioPolicy, const Vector2&, cons
 template<class MatrixType, class VectorType, class ObjectType, class SceneType, class CameraType> Camera<MatrixType, VectorType, ObjectType, SceneType, CameraType>::Camera(ObjectType* parent): ObjectType(parent), _aspectRatioPolicy(AspectRatioPolicy::NotPreserved) {}
 
 template<class MatrixType, class VectorType, class ObjectType, class SceneType, class CameraType> void Camera<MatrixType, VectorType, ObjectType, SceneType, CameraType>::setViewport(const Math::Vector2<GLsizei>& size) {
-    Framebuffer::setViewport({0, 0}, size);
 
     _viewport = size;
     fixAspectRatio();
@@ -65,8 +63,6 @@ template<class MatrixType, class VectorType, class ObjectType, class SceneType,
     SceneType* s = this->scene();
     CORRADE_ASSERT(s, "Camera: cannot draw without camera attached to scene", );
 
-    Framebuffer::clear();
-
     /* Recursively draw child objects */
     drawChildren(s, cameraMatrix());
 }

src/SceneGraph/Camera.h

@@ -112,17 +112,16 @@ template<class MatrixType, class VectorType, class ObjectType, class SceneType,
         /**
          * @brief Set viewport size
          *
-         * Call when window size changes.
-         *
-         * Calls Framebuffer::setViewport() and stores viewport size
-         * internally.
+         * Stores viewport size internally and recalculates projection matrix
+         * according to aspect ratio policy.
+         * @see setAspectRatioPolicy()
          */
         virtual void setViewport(const Math::Vector2<GLsizei>& size);
 
         /**
          * @brief Draw the scene
          *
-         * Calls Framebuffer::clear() and draws the scene using drawChildren().
+         * Draws the scene using drawChildren().
          */
         virtual void draw();