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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#define M_PI 3.1415926535897932384626433832795
uniform float time;
uniform ivec2 numTiles;
uniform sampler2D permTexture;
attribute vec2 tileCenter;
attribute int tileXIndex;
attribute int tileYIndex;
attribute int vertexIndexInTile;
varying vec2 v_texturePosition;
varying float v_textureSelect;
float snoise(vec2 p)
{
return texture2D(permTexture, p).r;
}
mat4 rotationMatrix(vec3 axis, float angle)
{
axis = normalize(axis);
float s = sin(angle);
float c = cos(angle);
float oc = 1.0 - c;
return mat4(oc * axis.x * axis.x + c, oc * axis.x * axis.y - axis.z * s, oc * axis.z * axis.x + axis.y * s, 0.0,
oc * axis.x * axis.y + axis.z * s, oc * axis.y * axis.y + c, oc * axis.y * axis.z - axis.x * s, 0.0,
oc * axis.z * axis.x - axis.y * s, oc * axis.y * axis.z + axis.x * s, oc * axis.z * axis.z + c, 0.0,
0.0, 0.0, 0.0, 1.0);
}
void main( void )
{
vec4 v = gl_Vertex;
// Of course this is nothing like what it will eventually be; just
// experimenting to get at least something.
// Move the tile on a semicircular path so that it will end up at the correct place
// Move half the tiles one way, half the other.
// Each tile moves during only half of the transition. The letmost
// tiles start moving immediately and arrive at their end position
// at time=0.5, when the tiles there (the rightmost ones) start
// moving.
float startTime = float(tileXIndex)/(numTiles.x-1) * 0.5;
float endTime = startTime + 0.5;
if (time <= startTime)
{
// Still at start location, nothing needed
v_textureSelect = 0;
}
else if (time > startTime && time <= endTime)
{
// Moving
float moveTime = (time - startTime) * 2;
// First: Rotate the tile around its Y axis,
// It rotates 180 degrees during the transition.
// Translate to origin, rotate.
v -= vec4(tileCenter, 0, 0);
// A semi-random number 0..1, different for neighbouring tiles
float fuzz = snoise(256*vec2(float(tileXIndex)/(numTiles.x-1), float(tileYIndex)/(numTiles.y-1)));
float rotation = moveTime;
// experiment: perturb rotation a bit randomly
// rotation = moveTime - fuzz*(0.5-abs(time - 0.5));
v = rotationMatrix(vec3(0, 1, 0), rotation*M_PI) * v;
v.x += tileCenter.x * cos(moveTime*M_PI);
v.y += tileCenter.y;
v.z += (fuzz < 0.5 ? -1 : 1) * tileCenter.x * sin(moveTime*M_PI);
// Perturb z a bit randomly
v.z += ((((tileXIndex << 3) ^ tileYIndex) % 10) - 5) * (1 - abs(time-0.5)*2);
v_textureSelect = float(rotation > 0.5);
}
else
{
// At end location. Tile is 180 degrees rotated
v -= vec4(tileCenter, 0, 0);
v = rotationMatrix(vec3(0, 1, 0), M_PI) * v;
v += vec4(-tileCenter.x, tileCenter.y, 0, 0);
v_textureSelect = 1;
}
gl_Position = gl_ProjectionMatrix * gl_ModelViewMatrix * v;
v_texturePosition = gl_MultiTexCoord0.xy;
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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