Prefer glDrawBuffers over glDrawBuffer

[libs/gl.git] / source / framebuffer.cpp

diff --git a/source/framebuffer.cpp b/source/framebuffer.cpp
index ae8f4dd471a936881f77e8e569de8e97ba5bc8c0..f4e5a9445e0bce678292c6da327995daef70cc0a 100644 (file)
--- a/source/framebuffer.cpp
+++ b/source/framebuffer.cpp
@@ -55,10 +55,9 @@ Framebuffer::Framebuffer(unsigned i):
        if(id)
                throw invalid_argument("System framebuffer must have id 0");
 
-       int viewport[4];
-       glGetIntegerv(GL_VIEWPORT, viewport);
-       width = viewport[2];
-       height = viewport[3];
+       glGetIntegerv(GL_VIEWPORT, &view.left);
+       width = view.width;
+       height = view.height;
 }
 
 Framebuffer::Framebuffer():
@@ -110,22 +109,16 @@ void Framebuffer::update_attachment(unsigned mask) const
                                color_bufs.push_back(attch.attachment);
                }
 
-               if(color_bufs.empty())
-               {
-                       glDrawBuffer(GL_NONE);
-                       glReadBuffer(GL_NONE);
-               }
-               else if(color_bufs.size()==1)
-               {
-                       glDrawBuffer(color_bufs.front());
-                       glReadBuffer(color_bufs.front());
-               }
-               else
-               {
+               if(color_bufs.size()>1)
                        static Require _req(ARB_draw_buffers);
+
+               GLenum first_buffer = (color_bufs.empty() ? GL_NONE : color_bufs.front());
+               if(ARB_draw_buffers)
                        glDrawBuffers(color_bufs.size(), &color_bufs[0]);
-                       glReadBuffer(color_bufs.front());
-               }
+               else
+                       glDrawBuffer(first_buffer);
+
+               glReadBuffer(first_buffer);
        }
        else
                dirty |= mask;
@@ -133,6 +126,7 @@ void Framebuffer::update_attachment(unsigned mask) const
 
 void Framebuffer::check_size()
 {
+       bool full_viewport = (view.left==0 && view.bottom==0 && view.width==width && view.height==height);
        for(vector<Attachment>::iterator i=attachments.begin(); i!=attachments.end(); ++i)
                if(i->type)
                {
@@ -152,8 +146,8 @@ void Framebuffer::check_size()
                                width = static_cast<TextureCube *>(i->tex)->get_size();
                                height = width;
                        }
-                       if(current()==this)
-                               glViewport(0, 0, width, height);
+                       if(full_viewport)
+                               reset_viewport();
                        break;
                }
 }
@@ -213,7 +207,7 @@ void Framebuffer::detach(FramebufferAttachment attch)
 
 FramebufferStatus Framebuffer::check_status() const
 {
-       Bind _bind(this, true);
+       BindRestore _bind(this);
        return static_cast<FramebufferStatus>(glCheckFramebufferStatus(GL_FRAMEBUFFER));
 }
 
@@ -224,9 +218,25 @@ void Framebuffer::require_complete() const
                throw framebuffer_incomplete(status);
 }
 
+void Framebuffer::viewport(int l, int b, unsigned w, unsigned h)
+{
+       view.left = l;
+       view.bottom = b;
+       view.width = w;
+       view.height = h;
+
+       if(current()==this)
+               glViewport(view.left, view.bottom, view.width, view.height);
+}
+
+void Framebuffer::reset_viewport()
+{
+       viewport(0, 0, width, height);
+}
+
 void Framebuffer::clear(BufferBits bits)
 {
-       Bind _bind(this, true);
+       BindRestore _bind(this);
        glClear(bits);
 }
 
@@ -273,8 +283,9 @@ void Framebuffer::bind() const
                        update_attachment(dirty);
                        dirty = 0;
                }
+
                if(width && height)
-                       glViewport(0, 0, width, height);
+                       glViewport(view.left, view.bottom, view.width, view.height);
        }
 }
 
@@ -323,5 +334,13 @@ void Framebuffer::Attachment::clear()
        type = 0;
 }
 
+
+Framebuffer::Viewport::Viewport():
+       left(0),
+       bottom(0),
+       width(0),
+       height(0)
+{ }
+
 } // namespace GL
 } // namespace Msp