From 19e7ebe1d8508cfe5f931542c0d4e5c0178672f7 Mon Sep 17 00:00:00 2001
From: Rivo Laks <rivolaks@hot.ee>
Date: Fri, 16 Mar 2007 13:00:01 +0000
Subject: [PATCH] Add shader support.   Effects can use setShader() method to
 set a custom shader for window rendering.

svn path=/branches/work/kwin_composite/; revision=643131
---
 scene_opengl.cpp | 38 ++++++++++++++++++++++++++++++++++++--
 scene_opengl.h   |  6 ++++++
 2 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/scene_opengl.cpp b/scene_opengl.cpp
index 6465a42f0c..2016a53ce5 100644
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -811,6 +811,9 @@ void SceneOpenGL::Window::prepareVertices()
     // Reset requests for the next painting
     requestedXResolution = 0;
     requestedYResolution = 0;
+
+    // Reset shader. If effect wants to use shader, it has to set it in paint pass
+    shader = 0;
     }
 
 void SceneOpenGL::Window::prepareForPainting()
@@ -1177,7 +1180,10 @@ void SceneOpenGL::Window::performPaint( int mask, QRegion region, WindowPaintDat
     if(( mask & PAINT_WINDOW_TRANSFORMED ) && ( data.xScale != 1 || data.yScale != 1 ))
         glScalef( data.xScale, data.yScale, 1 );
 
-    prepareRenderStates( mask, data );
+    if(shader)
+        prepareShaderRenderStates( mask, data );
+    else
+        prepareRenderStates( mask, data );
     enableTexture();
 
     // update texture matrix to handle GL_TEXTURE_2D and GL_TEXTURE_RECTANGLE
@@ -1202,12 +1208,32 @@ void SceneOpenGL::Window::performPaint( int mask, QRegion region, WindowPaintDat
     glMatrixMode( GL_MODELVIEW );
     glPopMatrix();
 
-    restoreRenderStates( mask, data );
+    if(shader)
+        restoreShaderRenderStates( mask, data );
+    else
+        restoreRenderStates( mask, data );
     disableTexture();
     }
 
+void SceneOpenGL::Window::prepareShaderRenderStates( int mask, WindowPaintData data )
+    {
+    Q_UNUSED( mask );
+    // setup blending of transparent windows
+    glPushAttrib( GL_ENABLE_BIT );
+    bool opaque = isOpaque() && data.opacity == 1.0;
+    if( !opaque )
+        {
+        glEnable( GL_BLEND );
+        glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
+        }
+    shader->setUniform("opacity", (float)data.opacity);
+    shader->setUniform("saturation", (float)data.saturation);
+    shader->setUniform("brightness", (float)data.brightness);
+    }
+
 void SceneOpenGL::Window::prepareRenderStates( int mask, WindowPaintData data )
     {
+    Q_UNUSED( mask );
     // setup blending of transparent windows
     glPushAttrib( GL_ENABLE_BIT );
     bool opaque = isOpaque() && data.opacity == 1.0;
@@ -1364,8 +1390,16 @@ void SceneOpenGL::Window::renderGeometry( int mask, QRegion region )
     glDisableClientState( GL_TEXTURE_COORD_ARRAY );
     }
 
+void SceneOpenGL::Window::restoreShaderRenderStates( int mask, WindowPaintData data )
+    {
+    Q_UNUSED( mask );
+    Q_UNUSED( data );
+    glPopAttrib();  // ENABLE_BIT
+    }
+
 void SceneOpenGL::Window::restoreRenderStates( int mask, WindowPaintData data )
     {
+    Q_UNUSED( mask );
     if( data.opacity != 1.0 || data.saturation != 1.0 || data.brightness != 1.0f )
         {
         if( data.saturation != 1.0 && supports_saturation )
diff --git a/scene_opengl.h b/scene_opengl.h
index 514dcf0482..fe673bdef7 100644
--- a/scene_opengl.h
+++ b/scene_opengl.h
@@ -130,6 +130,9 @@ class SceneOpenGL::Window
         // Marks vertices of the window as dirty. Call this if you change
         //  position of the vertices
         void markVerticesDirty()  { verticesDirty = true; }
+
+        void setShader( GLShader* s )  { shader = s; }
+
     protected:
         // Makes sure that vertex grid requests are fulfilled and that vertices
         //  aren't dirty. Call this before paint pass
@@ -138,8 +141,10 @@ class SceneOpenGL::Window
         void resetVertices();  // Resets positions of vertices
 
         void prepareRenderStates( int mask, WindowPaintData data );
+        void prepareShaderRenderStates( int mask, WindowPaintData data );
         void renderGeometry( int mask, QRegion region );
         void restoreRenderStates( int mask, WindowPaintData data );
+        void restoreShaderRenderStates( int mask, WindowPaintData data );
 
     private:
         QRegion optimizeBindDamage( const QRegion& reg, int limit );
@@ -161,6 +166,7 @@ class SceneOpenGL::Window
         int requestedXResolution;
         int requestedYResolution;
         bool verticesDirty;  // vertices have been modified in some way
+        GLShader* shader;  // shader to be used for rendering, if any
     };
 
 } // namespace