diff --git a/RenderingManager.cpp b/RenderingManager.cpp
index e658528..6b54290 100644
--- a/RenderingManager.cpp
+++ b/RenderingManager.cpp
@@ -2,7 +2,6 @@
 #include <thread>
 #include <mutex>
 #include <chrono>
-#include <assert.h>
 
 // Desktop OpenGL function loader
 #include <glad/glad.h>  // Initialized with gladLoadGLLoader()
@@ -37,7 +36,6 @@
 
 // standalone image loader
 #include <stb_image.h>
-#include <stb_image_write.h>
 
 // vmix
 #include "defines.h"
@@ -234,9 +232,7 @@ bool Rendering::Begin()
     }
 
     // handle window resize
-	glfwGetFramebufferSize(window, &render_width, &render_height);
-
-    // handle window resize
+    glfwGetFramebufferSize(window, &render_width, &render_height);
 	glViewport(0, 0, render_width, render_height);
 
     // GL Colors
@@ -286,7 +282,8 @@ void Rendering::Close()
 }
 
 
-glm::mat4 Rendering::Projection() {
+glm::mat4 Rendering::Projection()
+{
     glm::mat4 projection = glm::ortho(-5.0, 5.0, -5.0, 5.0);
     glm::mat4 scale = glm::scale(glm::mat4(1.0f), glm::vec3(1.f, AspectRatio(), 1.f));
 
@@ -351,82 +348,6 @@ void Rendering::RequestScreenshot()
     request_screenshot = true; 
 }
 
-void Screenshot::CreateEmpty(int w, int h) 
-{
-    Clear();
-    Width = w;
-    Height = h;
-    Data = (unsigned int*) malloc(Width * Height * 4 * sizeof(unsigned int));
-    memset(Data, 0, Width * Height * 4);
-}
-
-void Screenshot::CreateFromCaptureGL(int x, int y, int w, int h) 
-{
-    Clear();
-    Width = w;
-    Height = h;
-    Data = (unsigned int*) malloc(Width * Height * 4);
-
-    // actual capture of frame buffer
-    glPixelStorei(GL_PACK_ALIGNMENT, 1);
-    glReadPixels(x, y, w, h, GL_RGBA, GL_UNSIGNED_BYTE, Data);
-
-    // make it usable
-    RemoveAlpha();
-    FlipVertical();
-}
-
-void Screenshot::SaveFile(const char* filename)
-{
-    if (Data)
-        stbi_write_png(filename, Width, Height, 4, Data, Width * 4);
-}
-
-void Screenshot::RemoveAlpha()
-{
-    unsigned int* p = Data;
-    int n = Width * Height;
-    while (n-- > 0)
-    {
-        *p |= 0xFF000000;
-        p++;
-    }
-}
-
-void Screenshot::BlitTo(Screenshot* dst, int src_x, int src_y, int dst_x, int dst_y, int w, int h) const
-{
-    const Screenshot* src = this;
-    assert(dst != src);
-    assert(dst != NULL);
-    assert(src_x >= 0 && src_y >= 0);
-    assert(src_x + w <= src->Width);
-    assert(src_y + h <= src->Height);
-    assert(dst_x >= 0 && dst_y >= 0);
-    assert(dst_x + w <= dst->Width);
-    assert(dst_y + h <= dst->Height);
-    for (int y = 0; y < h; y++)
-        memcpy(dst->Data + dst_x + (dst_y + y) * dst->Width, src->Data + src_x + (src_y + y) * src->Width, w * 4);
-}
-
-void Screenshot::FlipVertical()
-{
-    int comp = 4;
-    int stride = Width * comp;
-    unsigned char* line_tmp = new unsigned char[stride];
-    unsigned char* line_a = (unsigned char*)Data;
-    unsigned char* line_b = (unsigned char*)Data + (stride * (Height - 1));
-    while (line_a < line_b)
-    {
-        memcpy(line_tmp, line_a, stride);
-        memcpy(line_a, line_b, stride);
-        memcpy(line_b, line_tmp, stride);
-        line_a += stride;
-        line_b -= stride;
-    }
-    delete[] line_tmp;
-}
-
-
 
 //
 // Discarded because not working under OSX - kept in case it would become useful
diff --git a/RenderingManager.h b/RenderingManager.h
index 0e320c4..f29abc2 100644
--- a/RenderingManager.h
+++ b/RenderingManager.h
@@ -7,28 +7,16 @@
 #include <gst/gl/gl.h>
 #include <glm/glm.hpp> 
 
-class Screenshot
+#include "Screenshot.h"
+
+struct RenderingAttrib
 {
-    int             Width, Height;
-    unsigned int *  Data;
-
-public:
-    Screenshot()    { Width = Height = 0; Data = nullptr; }
-    ~Screenshot()   { Clear(); }
-
-    bool IsFull()   { return Data != nullptr; }
-    void Clear()    { if (IsFull()) free(Data); Data = nullptr; }
-
-    void CreateEmpty(int w, int h);
-    void CreateFromCaptureGL(int x, int y, int w, int h);
-
-    void RemoveAlpha();
-    void FlipVertical();
-
-    void SaveFile(const char* filename);
-    void BlitTo(Screenshot* dst, int src_x, int src_y, int dst_x, int dst_y, int w, int h) const;
+    RenderingAttrib() {}
+    glm::ivec4 viewport;
+    glm::vec3 clear_color;
 };
 
+
 class Rendering
 {
     friend class UserInterface;
@@ -70,10 +58,14 @@ public:
     void PushFrontDrawCallback(RenderingCallback function);
     void PushBackDrawCallback(RenderingCallback function);
 
+    // push and pop rendering attributes
+    void PushAttrib(glm::ivec4 viewport, glm::vec3 color);
+    void PopAttrib();
+
     // request screenshot
     void RequestScreenshot();
     // get Screenshot
-    Screenshot *CurrentScreenshot();
+    class Screenshot *CurrentScreenshot();
     
     // request fullscreen
     void ToggleFullscreen();
@@ -97,6 +89,9 @@ private:
     // loop update end frame
     void End();
 
+    // list of rendering attributes
+    std::list<RenderingAttrib> drawAttributes;
+
     // list of functions to call at each Draw
     std::list<RenderingCallback> drawCallbacks;
 
diff --git a/Screenshot.cpp b/Screenshot.cpp
new file mode 100644
index 0000000..21c011c
--- /dev/null
+++ b/Screenshot.cpp
@@ -0,0 +1,109 @@
+#include "Screenshot.h"
+
+#include <memory.h>
+#include <assert.h>
+
+#include <glad/glad.h>
+
+// standalone image loader
+#include <stb_image.h>
+#include <stb_image_write.h>
+
+Screenshot::Screenshot()
+{
+    Width = Height = 0;
+    Data = nullptr;
+}
+
+Screenshot::~Screenshot()
+{
+    Clear();
+}
+
+bool Screenshot::IsFull()
+{
+    return Data != nullptr;
+}
+
+void Screenshot::Clear()
+{
+    if (IsFull())
+        free(Data);
+    Data = nullptr;
+}
+
+void Screenshot::CreateEmpty(int w, int h)
+{
+    Clear();
+    Width = w;
+    Height = h;
+    Data = (unsigned int*) malloc(Width * Height * 4 * sizeof(unsigned int));
+    memset(Data, 0, Width * Height * 4);
+}
+
+void Screenshot::CreateFromCaptureGL(int x, int y, int w, int h)
+{
+    Clear();
+    Width = w;
+    Height = h;
+    Data = (unsigned int*) malloc(Width * Height * 4);
+
+    // actual capture of frame buffer
+    glPixelStorei(GL_PACK_ALIGNMENT, 1);
+    glReadPixels(x, y, w, h, GL_RGBA, GL_UNSIGNED_BYTE, Data);
+
+    // make it usable
+    RemoveAlpha();
+    FlipVertical();
+}
+
+void Screenshot::SaveFile(const char* filename)
+{
+    if (Data)
+        stbi_write_png(filename, Width, Height, 4, Data, Width * 4);
+}
+
+void Screenshot::RemoveAlpha()
+{
+    unsigned int* p = Data;
+    int n = Width * Height;
+    while (n-- > 0)
+    {
+        *p |= 0xFF000000;
+        p++;
+    }
+}
+
+void Screenshot::BlitTo(Screenshot* dst, int src_x, int src_y, int dst_x, int dst_y, int w, int h) const
+{
+    const Screenshot* src = this;
+    assert(dst != src);
+    assert(dst != NULL);
+    assert(src_x >= 0 && src_y >= 0);
+    assert(src_x + w <= src->Width);
+    assert(src_y + h <= src->Height);
+    assert(dst_x >= 0 && dst_y >= 0);
+    assert(dst_x + w <= dst->Width);
+    assert(dst_y + h <= dst->Height);
+    for (int y = 0; y < h; y++)
+        memcpy(dst->Data + dst_x + (dst_y + y) * dst->Width, src->Data + src_x + (src_y + y) * src->Width, w * 4);
+}
+
+void Screenshot::FlipVertical()
+{
+    int comp = 4;
+    int stride = Width * comp;
+    unsigned char* line_tmp = new unsigned char[stride];
+    unsigned char* line_a = (unsigned char*)Data;
+    unsigned char* line_b = (unsigned char*)Data + (stride * (Height - 1));
+    while (line_a < line_b)
+    {
+        memcpy(line_tmp, line_a, stride);
+        memcpy(line_a, line_b, stride);
+        memcpy(line_b, line_tmp, stride);
+        line_a += stride;
+        line_b -= stride;
+    }
+    delete[] line_tmp;
+}
+
diff --git a/Screenshot.h b/Screenshot.h
new file mode 100644
index 0000000..5e2da51
--- /dev/null
+++ b/Screenshot.h
@@ -0,0 +1,26 @@
+#ifndef SCREENSHOT_H
+#define SCREENSHOT_H
+
+class Screenshot
+{
+    int             Width, Height;
+    unsigned int *  Data;
+
+public:
+    Screenshot();
+    ~Screenshot();
+
+    bool IsFull();
+    void Clear();
+
+    void CreateEmpty(int w, int h);
+    void CreateFromCaptureGL(int x, int y, int w, int h);
+
+    void RemoveAlpha();
+    void FlipVertical();
+
+    void SaveFile(const char* filename);
+    void BlitTo(Screenshot* dst, int src_x, int src_y, int dst_x, int dst_y, int w, int h) const;
+};
+
+#endif // SCREENSHOT_H