Another demo effect which uses shader and render target to turn your screen into a liquid, wavy surface.

Soon we'll have more silly effects than Beryl/Compiz ;-)

svn path=/branches/work/kwin_composite/; revision=655575

effects/CMakeLists.txt

@@ -46,6 +46,7 @@ if(OPENGL_FOUND)
         )
     SET(kwin4_effect_tests_sources ${kwin4_effect_tests_sources}
         test_fbo.cpp
+        demo_liquid.cpp
         )
 
     install( FILES
@@ -54,6 +55,7 @@ if(OPENGL_FOUND)
         trackmouse.desktop
         wavywindows.desktop
         test_fbo.desktop
+        demo_liquid.desktop
         DESTINATION ${DATA_INSTALL_DIR}/kwin/effects )
 
     install( FILES
@@ -62,6 +64,8 @@ if(OPENGL_FOUND)
         data/explosion.vert
         data/explosion-start.png
         data/explosion-end.png
+        data/liquid.frag
+        data/liquid.vert
         DESTINATION  ${DATA_INSTALL_DIR}/kwin )
 endif(OPENGL_FOUND)
 

effects/data/liquid.frag

@@ -0,0 +1,50 @@
+uniform sampler2D sceneTex;
+uniform float displayWidth;
+uniform float displayHeight;
+uniform float time;
+
+varying vec2 pos;
+
+
+#define DEG2RAD (6.2832/360.0)
+
+
+// Converts pixel coordinates to texture coordinates
+vec2 pix2tex(vec2 pix)
+{
+    return vec2(pix.x / displayWidth, 1.0 - pix.y / displayHeight);
+}
+
+float wave(vec2 pos, vec2 wave_dir, float wave_length, float wave_speed)
+{
+    return sin(((pos.x * wave_dir.x) + (pos.y * wave_dir.y)) * 6.2832 / wave_length +
+            time * wave_speed * 6.2832 / wave_length);
+}
+
+vec2 displacement(float wave_angle, float wave_length, float wave_speed, float wave_height)
+{
+    vec2 wave_dir = vec2(cos(wave_angle * DEG2RAD), sin(wave_angle * DEG2RAD));
+    return wave_dir * (wave(pos, wave_dir, wave_length, wave_speed) * wave_height);
+}
+
+// Only for debugging
+float wave_color(float wave_angle, float wave_length, float wave_speed, float wave_height)
+{
+    vec2 wave_dir = vec2(cos(wave_angle * DEG2RAD), sin(wave_angle * DEG2RAD));
+    return wave(pos, wave_dir, wave_length, wave_speed) * 0.5 + 0.5;
+}
+
+void main()
+{
+    vec2 texpos = pos;
+    texpos += displacement( 20.0, 250.0, 120.0, 4.0);
+    texpos += displacement(-40.0, 350.0, 100.0, 4.0);
+    texpos += displacement(240.0, 1000.0, 100.0, 12.0);
+    texpos += displacement(160.0, 50.0, 30.0, 2.0);
+
+    vec3 tex = texture2D(sceneTex, pix2tex(texpos)).rgb;
+    //tex.r = wave_color( 20, 250, 150, 4);  // debug
+
+    gl_FragColor = vec4(tex, 1.0);
+}
+

effects/data/liquid.vert

@@ -0,0 +1,7 @@
+varying vec2 pos;
+
+void main()
+{
+    pos = gl_Vertex.xy;
+    gl_Position = ftransform();
+}

effects/demo_liquid.cpp

@@ -0,0 +1,122 @@
+/*****************************************************************
+ KWin - the KDE window manager
+ This file is part of the KDE project.
+
+Copyright (C) 2007 Rivo Laks <rivolaks@hot.ee>
+
+You can Freely distribute this program under the GNU General Public
+License. See the file "COPYING" for the exact licensing terms.
+******************************************************************/
+
+
+#include "demo_liquid.h"
+
+#include <kwinglutils.h>
+
+#include <QString>
+#include <KStandardDirs>
+
+#include <kdebug.h>
+
+
+namespace KWin
+{
+
+KWIN_EFFECT( Demo_Liquid, LiquidEffect );
+KWIN_EFFECT_SUPPORTED( Demo_Liquid, LiquidEffect::supported() );
+
+
+LiquidEffect::LiquidEffect() : Effect()
+    {
+    mTime = 0.0f;
+    mValid = loadData();
+    }
+
+bool LiquidEffect::loadData()
+    {
+    // Create texture and render target
+    mTexture = new GLTexture(displayWidth(), displayHeight());
+    mTexture->setFilter(GL_LINEAR_MIPMAP_LINEAR);
+
+    mRenderTarget = new GLRenderTarget(mTexture);
+    if( !mRenderTarget->valid() )
+        return false;
+
+    QString fragmentshader =  KGlobal::dirs()->findResource("data", "kwin/liquid.frag");
+    QString vertexshader =  KGlobal::dirs()->findResource("data", "kwin/liquid.vert");
+    if(fragmentshader.isEmpty() || vertexshader.isEmpty())
+    {
+        kError() << k_funcinfo << "Couldn't locate shader files" << endl;
+        return false;
+    }
+    mShader = new GLShader(vertexshader, fragmentshader);
+    if(!mShader->isValid())
+    {
+        kError() << k_funcinfo << "The shader failed to load!" << endl;
+        return false;
+    }
+    mShader->bind();
+    mShader->setUniform("sceneTex", 0);
+    mShader->setUniform("displayWidth", (float)displayWidth());
+    mShader->setUniform("displayHeight", (float)displayHeight());
+    mShader->unbind();
+
+    return true;
+    }
+
+bool LiquidEffect::supported()
+    {
+    return hasGLExtension("GL_EXT_framebuffer_object") &&
+            GLShader::fragmentShaderSupported() &&
+            (effects->compositingType() == OpenGLCompositing);
+    }
+
+
+void LiquidEffect::prePaintScreen( int* mask, QRegion* region, int time )
+    {
+    mTime += time / 1000.0f;
+    if(mValid)
+        {
+        *mask |= PAINT_SCREEN_WITH_TRANSFORMED_WINDOWS;
+        // Start rendering to texture
+        mRenderTarget->enable();
+        }
+
+    effects->prePaintScreen(mask, region, time);
+    }
+
+void LiquidEffect::postPaintScreen()
+    {
+    // Call the next effect.
+    effects->postPaintScreen();
+
+    if(mValid)
+        {
+        // Disable render texture
+        mRenderTarget->disable();
+        mTexture->bind();
+
+        // Use the shader
+        mShader->bind();
+        mShader->setUniform("time", mTime);
+
+        // Render fullscreen quad with screen contents
+        glBegin(GL_QUADS);
+            glVertex2f(0.0, displayHeight());
+            glVertex2f(displayWidth(), displayHeight());
+            glVertex2f(displayWidth(), 0.0);
+            glVertex2f(0.0, 0.0);
+        glEnd();
+
+        mShader->unbind();
+        mTexture->unbind();
+
+        // Make sure the animation continues
+        effects->addRepaintFull();
+        }
+
+    }
+
+
+} // namespace
+

effects/demo_liquid.desktop

@@ -0,0 +1,4 @@
+[Desktop Entry]
+Encoding=UTF-8
+Name=Demo_Liquid
+X-KDE-Library=kwin4_effect_tests

effects/demo_liquid.h

@@ -0,0 +1,51 @@
+/*****************************************************************
+ KWin - the KDE window manager
+ This file is part of the KDE project.
+
+Copyright (C) 2007 Rivo Laks <rivolaks@hot.ee>
+
+You can Freely distribute this program under the GNU General Public
+License. See the file "COPYING" for the exact licensing terms.
+******************************************************************/
+
+#ifndef KWIN_DEMO_LIQUID_H
+#define KWIN_DEMO_LIQUID_H
+
+// Include with base class for effects.
+#include <kwineffects.h>
+
+namespace KWin
+{
+
+class GLRenderTarget;
+class GLTexture;
+class GLShader;
+
+/**
+ * Turns your desktop into a wavy (liquid) surface
+ **/
+class LiquidEffect : public Effect
+    {
+    public:
+        LiquidEffect();
+
+        virtual void prePaintScreen( int* mask, QRegion* region, int time );
+        virtual void postPaintScreen();
+
+        static bool supported();
+
+    protected:
+        bool loadData();
+
+    private:
+        GLTexture* mTexture;
+        GLRenderTarget* mRenderTarget;
+        GLShader* mShader;
+        bool mValid;
+
+        float mTime;
+    };
+
+} // namespace
+
+#endif