/* -*- 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/.
*/
#version 130
uniform sampler2D sampler;
uniform int swidth;
uniform int sheight;
uniform float xscale;
uniform float yscale;
uniform float xoffset;
uniform float yoffset;
uniform float xfrompixelratio;
uniform float yfrompixelratio;
uniform float xtopixelratio;
uniform float ytopixelratio;
varying vec2 tex_coord;
// This mode makes the scaling work like maskedTextureFragmentShader.glsl
// (instead of like plain textureVertexShader.glsl).
#ifdef MASKED
varying vec2 mask_coord;
uniform sampler2D mask;
#endif
#ifdef USE_REDUCED_REGISTER_VARIANT
vec4 getTexel(int x, int y)
{
vec2 pos = vec2( x * xfrompixelratio + xoffset, y * yfrompixelratio + yoffset );
vec4 texel = texture2D(sampler, pos);
#ifdef MASKED
texel.a = 1.0 - texture2D(mask, pos - tex_coord.st + mask_coord.st).r;
#endif
return texel;
}
void main(void)
{
// Convert to pixel coordinates again.
int dx = int(( tex_coord.s - xoffset ) * xtopixelratio );
int dy = int(( tex_coord.t - yoffset ) * ytopixelratio );
// Compute the range of source pixels which will make up this destination pixel.
float fsx1 = min(dx * xscale, float(swidth - 1));
float fsx2 = min(fsx1 + xscale, float(swidth - 1));
float fsy1 = min(dy * yscale, float(sheight - 1));
float fsy2 = min(fsy1 + yscale, float(sheight - 1));
// To whole pixel coordinates.
int xstart = int(floor(fsx1));
int xend = int(floor(fsx2));
int ystart = int(floor(fsy1));
int yend = int(floor(fsy2));
float xlength = fsx2 - fsx1;
float ylength = fsy2 - fsy1;
float xContribution[3];
xContribution[0] = (1.0 - max(0.0, fsx1 - xstart)) / xlength;
xContribution[1] = 1.0 / xlength;
xContribution[2] = (1.0 - max(0.0, (xend + 1) - fsx2)) / xlength;
float yContribution[3];
yContribution[0] = (1.0 - max(0.0, fsy1 - ystart)) / ylength;
yContribution[1] = 1.0 / ylength;
yContribution[2] = (1.0 - max(0.0, (yend + 1) - fsy2)) / ylength;
vec4 sumAll = vec4(0.0, 0.0, 0.0, 0.0);
vec4 texel;
// First Y pass
{
vec4 sumX = vec4(0.0, 0.0, 0.0, 0.0);
sumX += getTexel(xstart, ystart) * xContribution[0];
for (int x = xstart + 1; x < xend; ++x)
{
sumX += getTexel(x, ystart) * xContribution[1];
}
sumX += getTexel(xend, ystart) * xContribution[2];
sumAll += sumX * yContribution[0];
}
// Middle Y Passes
for (int y = ystart + 1; y < yend; ++y)
{
vec4 sumX = vec4(0.0, 0.0, 0.0, 0.0);
sumX += getTexel(xstart, y) * xContribution[0];
for (int x = xstart + 1; x < xend; ++x)
{
sumX += getTexel(x, y) * xContribution[1];
}
sumX += getTexel(xend, y) * xContribution[2];
sumAll += sumX * yContribution[1];
}
// Last Y pass
{
vec4 sumX = vec4(0.0, 0.0, 0.0, 0.0);
sumX += getTexel(xstart, yend) * xContribution[0];
for (int x = xstart + 1; x < xend; ++x)
{
sumX += getTexel(x, yend) * xContribution[1];
}
sumX += getTexel(xend, yend) * xContribution[2];
sumAll += sumX * yContribution[2];
}
gl_FragColor = sumAll;
}
#else
void main(void)
{
// Convert to pixel coordinates again.
int dx = int(( tex_coord.s - xoffset ) * xtopixelratio );
int dy = int(( tex_coord.t - yoffset ) * ytopixelratio );
// How much each column/row will contribute to the resulting pixel.
// Note: These values are always the same for the same X (or Y),
// so they could be precalculated in C++ and passed to the shader,
// but GLSL has limits on the size of uniforms passed to it,
// so it'd need something like texture buffer objects from newer
// GLSL versions, and it seems the hassle is not really worth it.
float xratio[ 16 + 2 ];
float yratio[ 16 + 2 ];
// For finding the first and last source pixel.
int xpixel[ 16 + 2 ];
int ypixel[ 16 + 2 ];
int xpos = 0;
int ypos = 0;
// Compute the range of source pixels which will make up this destination pixel.
float fsx1 = dx * xscale;
float fsx2 = fsx1 + xscale;
// To whole pixel coordinates.
int sx1 = int( ceil( fsx1 ) );
int sx2 = int( floor( fsx2 ) );
// Range checking.
sx2 = min( sx2, swidth - 1 );
sx1 = min( sx1, sx2 );
// How much one full column contributes to the resulting pixel.
float width = min( xscale, swidth - fsx1 );
if( sx1 - fsx1 > 0.001 )
{ // The first column contributes only partially.
xpixel[ xpos ] = sx1 - 1;
xratio[ xpos ] = ( sx1 - fsx1 ) / width;
++xpos;
}
for( int sx = sx1; sx < sx2; ++sx )
{ // Columns that fully contribute to the resulting pixel.
xpixel[ xpos ] = sx;
xratio[ xpos ] = 1.0 / width;
++xpos;
}
if( fsx2 - sx2 > 0.001 )
{ // The last column contributes only partially.
xpixel[ xpos ] = sx2;
xratio[ xpos ] = min( min( fsx2 - sx2, 1.0 ) / width, 1.0 );
++xpos;
}
// The same for Y.
float fsy1 = dy * yscale;
float fsy2 = fsy1 + yscale;
int sy1 = int( ceil( fsy1 ) );
int sy2 = int( floor( fsy2 ) );
sy2 = min( sy2, sheight - 1 );
sy1 = min( sy1, sy2 );
float height = min( yscale, sheight - fsy1 );
if( sy1 - fsy1 > 0.001 )
{
ypixel[ ypos ] = sy1 - 1;
yratio[ ypos ] = ( sy1 - fsy1 ) / height;
++ypos;
}
for( int sy = sy1; sy < sy2; ++sy )
{
ypixel[ ypos ] = sy;
yratio[ ypos ] = 1.0 / height;
++ypos;
}
if( fsy2 - sy2 > 0.001 )
{
ypixel[ ypos ] = sy2;
yratio[ ypos ] = min( min( fsy2 - sy2, 1.0 ) / height, 1.0 );
++ypos;
}
int xstart = xpixel[ 0 ];
int xend = xpixel[ xpos - 1 ];
int ystart = ypixel[ 0 ];
int yend = ypixel[ ypos - 1 ];
vec4 sum = vec4( 0.0, 0.0, 0.0, 0.0 );
ypos = 0;
for( int y = ystart; y <= yend; ++y, ++ypos )
{
vec4 tmp = vec4( 0.0, 0.0, 0.0, 0.0 );
xpos = 0;
for( int x = xstart; x <= xend; ++x, ++xpos )
{
vec2 pos = vec2( x * xfrompixelratio + xoffset, y * yfrompixelratio + yoffset );
#ifndef MASKED
tmp += texture2D( sampler, pos ) * xratio[ xpos ];
#else
vec4 texel;
texel = texture2D( sampler, pos );
texel.a = 1.0 - texture2D( mask, pos - tex_coord.st + mask_coord.st ).r;
tmp += texel * xratio[ xpos ];
#endif
}
sum += tmp * yratio[ ypos ];
}
gl_FragColor = sum;
}
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */