From 930a9248c9ec2b6a488093d677c13b8fd4b43039 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lubo=C5=A1=20Lu=C5=88=C3=A1k?= <l.lunak@kde.org>
Date: Sun, 19 Nov 2006 20:29:41 +0000
Subject: [PATCH] Repainting of only changed areas, now also for OpenGL.

svn path=/branches/work/kwin_composite/; revision=606272
---
 glutils.cpp      |  5 +++--
 glutils.h        |  3 +++
 scene_opengl.cpp | 50 +++++++++++++++++++++++++++++++++++-------------
 scene_opengl.h   |  2 +-
 4 files changed, 44 insertions(+), 16 deletions(-)

diff --git a/glutils.cpp b/glutils.cpp
index 8e5375099f..9e00283933 100644
--- a/glutils.cpp
+++ b/glutils.cpp
@@ -31,6 +31,8 @@ glXReleaseTexImageEXT_func glXReleaseTexImageEXT;
 glXBindTexImageEXT_func glXBindTexImageEXT;
 // glActiveTexture
 glActiveTexture_func glActiveTexture;
+// glXCopySubBufferMESA
+glXCopySubBuffer_func glXCopySubBuffer;
 
 
 // Functions
@@ -52,7 +54,7 @@ void initGLX()
         glXGetProcAddress = (glXGetProcAddress_func) getProcAddress( "glxGetProcAddressARB" );
     glXBindTexImageEXT = (glXBindTexImageEXT_func) getProcAddress( "glXBindTexImageEXT" );
     glXReleaseTexImageEXT = (glXReleaseTexImageEXT_func) getProcAddress( "glXReleaseTexImageEXT" );
-
+    glXCopySubBuffer = (glXCopySubBuffer_func) getProcAddress( "glXCopySubBufferMESA" );
 
     // Get GLX version
     int major, minor;
@@ -70,7 +72,6 @@ void initGL()
     if( !glActiveTexture )
         glActiveTexture = (glActiveTexture_func) getProcAddress( "glActiveTextureARB" );
 
-
     // Get OpenGL version
     QString glversionstring = QString((const char*)glGetString(GL_VERSION));
     QStringList glversioninfo = glversionstring.left(glversionstring.indexOf(' ')).split('.');
diff --git a/glutils.h b/glutils.h
index 93886aea22..cc537f1170 100644
--- a/glutils.h
+++ b/glutils.h
@@ -82,6 +82,9 @@ extern glXBindTexImageEXT_func glXBindTexImageEXT;
 // glActiveTexture
 typedef void (*glActiveTexture_func)(GLenum);
 extern glActiveTexture_func glActiveTexture;
+// glXCopySubBufferMESA
+typedef void (*glXCopySubBuffer_func) ( Display* , GLXDrawable, int, int, int, int );
+extern glXCopySubBuffer_func glXCopySubBuffer;
 
 } // namespace
 
diff --git a/scene_opengl.cpp b/scene_opengl.cpp
index e17b7a59da..ccd902446b 100644
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -446,10 +446,40 @@ void SceneOpenGL::paint( QRegion damage, ToplevelList toplevels )
     int mask = 0;
     paintScreen( &mask, &damage ); // call generic implementation
     glPopMatrix();
-    // TODO only partial repaint for mask & PAINT_SCREEN_REGION
+    flushBuffer( mask, damage );
+    ungrabXServer();
+    }
+
+// actually paint to the screen (double-buffer swap or copy from pixmap buffer)
+void SceneOpenGL::flushBuffer( int mask, const QRegion& damage )
+    {
     if( db )
         {
-        glXSwapBuffers( display(), glxbuffer );
+        if( mask & PAINT_SCREEN_REGION )
+            {
+            if( glXCopySubBuffer )
+                {
+                foreach( QRect r, damage.rects())
+                    glXCopySubBuffer( display(), glxbuffer, r.x(), r.y(), r.width(), r.height());
+                }
+            else
+                { // no idea why glScissor() is used, but Compiz has it and it doesn't seem to hurt
+                glEnable( GL_SCISSOR_TEST );
+                glDrawBuffer( GL_FRONT );
+                foreach( QRect r, damage.rects())
+                    {
+                    // convert to OpenGL coordinates
+                    int y = displayHeight() - r.y() - r.height();
+                    glRasterPos2f( r.x(), r.y() + r.height());
+                    glScissor( r.x(), y, r.width(), r.height());
+                    glCopyPixels( r.x(), y, r.width(), r.height(), GL_COLOR );
+                    }
+                glDrawBuffer( GL_BACK );
+                glDisable( GL_SCISSOR_TEST );
+                }
+            }
+        else
+            glXSwapBuffers( display(), glxbuffer );
         glXWaitGL();
         XFlush( display());
         }
@@ -457,10 +487,13 @@ void SceneOpenGL::paint( QRegion damage, ToplevelList toplevels )
         {
         glFlush();
         glXWaitGL();
-        XCopyArea( display(), buffer, rootWindow(), gcroot, 0, 0, displayWidth(), displayHeight(), 0, 0 );
+        if( mask & PAINT_SCREEN_REGION )
+            foreach( QRect r, damage.rects())
+                XCopyArea( display(), buffer, rootWindow(), gcroot, r.x(), r.y(), r.width(), r.height(), r.x(), r.y());
+        else
+            XCopyArea( display(), buffer, rootWindow(), gcroot, 0, 0, displayWidth(), displayHeight(), 0, 0 );
         XFlush( display());
         }
-    ungrabXServer();
     }
 
 void SceneOpenGL::paintGenericScreen( int mask, ScreenPaintData data )
@@ -475,15 +508,6 @@ void SceneOpenGL::paintGenericScreen( int mask, ScreenPaintData data )
         glPopMatrix();
     }
 
-// the optimized case without any transformations at all
-void SceneOpenGL::paintSimpleScreen( int mask, QRegion region )
-    {
-    // TODO repaint only damaged areas (means also don't do glXSwapBuffers and similar)
-    // For now always force redrawing of the whole area.
-    region = QRegion( 0, 0, displayWidth(), displayHeight());
-    Scene::paintSimpleScreen( mask, region );
-    }
-
 void SceneOpenGL::paintBackground( QRegion )
     {
 // TODO?
diff --git a/scene_opengl.h b/scene_opengl.h
index fd20b8e8e7..b55a58fe10 100644
--- a/scene_opengl.h
+++ b/scene_opengl.h
@@ -35,7 +35,6 @@ class SceneOpenGL
         virtual void windowDeleted( Toplevel* );
     protected:
         virtual void paintGenericScreen( int mask, ScreenPaintData data );
-        virtual void paintSimpleScreen( int mask, QRegion region );
         virtual void paintBackground( QRegion region );
     private:
         void selectMode();
@@ -45,6 +44,7 @@ class SceneOpenGL
         void initBuffer();
         void initRenderingContext();
         bool findConfig( const int* attrs, GLXFBConfig* config, VisualID visual = None );
+        void flushBuffer( int mask, const QRegion& damage );
         typedef GLuint Texture;
         GC gcroot;
         Drawable buffer;