From 91f795922d3cfcf5afdb5957d9b5d530ab34e945 Mon Sep 17 00:00:00 2001
From: Rivo Laks <rivolaks@hot.ee>
Date: Sun, 29 Apr 2007 15:53:56 +0000
Subject: [PATCH] Make Liquid effect work without NPOT textures as well.

svn path=/branches/work/kwin_composite/; revision=659161
---
 effects/data/liquid.frag |  6 +++---
 effects/demo_liquid.cpp  | 19 +++++++++++++++----
 2 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/effects/data/liquid.frag b/effects/data/liquid.frag
index 39ee0fce61..f2515fe845 100644
--- a/effects/data/liquid.frag
+++ b/effects/data/liquid.frag
@@ -1,6 +1,6 @@
 uniform sampler2D sceneTex;
-uniform float displayWidth;
-uniform float displayHeight;
+uniform float textureWidth;
+uniform float textureHeight;
 uniform float time;
 
 varying vec2 pos;
@@ -12,7 +12,7 @@ varying vec2 pos;
 // Converts pixel coordinates to texture coordinates
 vec2 pix2tex(vec2 pix)
 {
-    return vec2(pix.x / displayWidth, 1.0 - pix.y / displayHeight);
+    return vec2(pix.x / textureWidth, 1.0 - pix.y / textureHeight);
 }
 
 float wave(vec2 pos, vec2 wave_dir, float wave_length, float wave_speed)
diff --git a/effects/demo_liquid.cpp b/effects/demo_liquid.cpp
index 8cd3110a5c..707c891e26 100644
--- a/effects/demo_liquid.cpp
+++ b/effects/demo_liquid.cpp
@@ -45,8 +45,19 @@ LiquidEffect::~LiquidEffect()
 
 bool LiquidEffect::loadData()
     {
+    // If NPOT textures are not supported, use nearest power-of-two sized
+    //  texture. It wastes memory, but it's possible to support systems without
+    //  NPOT textures that way
+    int texw = displayWidth();
+    int texh = displayHeight();
+    if( !GLTexture::NPOTTextureSupported() )
+    {
+        kWarning( 1212 ) << k_funcinfo << "NPOT textures not supported, wasting some memory" << endl;
+        texw = nearestPowerOfTwo(texw);
+        texh = nearestPowerOfTwo(texh);
+    }
     // Create texture and render target
-    mTexture = new GLTexture(displayWidth(), displayHeight());
+    mTexture = new GLTexture(texw, texh);
     mTexture->setFilter(GL_LINEAR_MIPMAP_LINEAR);
     mTexture->setWrapMode(GL_CLAMP);
 
@@ -69,8 +80,8 @@ bool LiquidEffect::loadData()
     }
     mShader->bind();
     mShader->setUniform("sceneTex", 0);
-    mShader->setUniform("displayWidth", (float)displayWidth());
-    mShader->setUniform("displayHeight", (float)displayHeight());
+    mShader->setUniform("textureWidth", (float)texw);
+    mShader->setUniform("textureHeight", (float)texh);
     mShader->unbind();
 
     return true;
@@ -78,7 +89,7 @@ bool LiquidEffect::loadData()
 
 bool LiquidEffect::supported()
     {
-    return GLRenderTarget::supported() && GLTexture::NPOTTextureSupported() &&
+    return GLRenderTarget::supported() &&
             GLShader::fragmentShaderSupported() &&
             (effects->compositingType() == OpenGLCompositing);
     }