kwin/effects/data/snow.vert
Martin Gräßlin e1d4d50cd6 Some more optimizations to snow effect:
* move position updates of flakes to shader
* remove the for-loop which updates the flakes. This is handled in the loop for painting the flakes
* Don't test in each frame if a flake is on the screen. Precalculate the number of frames when then flake is on the screen and count the flakes.
* Set PAINT_SCREEN_TRANSFORMED
* Remove all unneeded code (like a QTime object when we already get the time in the method)

Now it takes ~ 17 % of CPU usage on my system. Seems to be the maximum of what is possible.

svn path=/trunk/KDE/kdebase/workspace/; revision=884305
2008-11-14 16:18:34 +00:00

47 lines
1.7 KiB
GLSL

/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright (C) 2008 Martin Gräßlin <ubuntu@martin-graesslin.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
uniform float angle;
uniform int x;
uniform int width;
uniform int height;
varying float discarding;
uniform int hSpeed;
uniform int vSpeed;
uniform int frames;
void main()
{
gl_TexCoord[0] = gl_MultiTexCoord0;
float radian = radians( angle*float(frames) );
mat2 rotation = mat2( cos(radian), sin(radian), -sin(radian), cos(radian) );
float xCoord;
float yCoord;
if( gl_MultiTexCoord0.s == 0.0 )
xCoord = -float(width)*0.5;
else
xCoord = float(width)*0.5;
if( gl_MultiTexCoord0.t == 0.0 )
yCoord = -float(height)*0.5;
else
yCoord = float(height)*0.5;
vec2 vertex = vec2( xCoord, yCoord );
vertex = (vertex)*rotation + vec2( float(x), 0.0 ) + vec2(hSpeed, vSpeed)*float(frames);
gl_Position = gl_ModelViewProjectionMatrix * vec4(vertex, gl_Vertex.zw);
}