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/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the Qt scene graph research project.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
import QtQuick 2.0
Rectangle {
id: main
width: 800
height: 600
focus: true
Item {
anchors.centerIn: parent
id: text
width: 1024
height: 1024
Text {
anchors.centerIn: parent
text: "a"
font.pixelSize: 1024
}
}
Text {
id: reference
text: "a"
font.pixelSize: 64
x: (main.width / 4) * 3 - width / 2; y: main.height / 2 - height / 2 - scale * 4
smooth: true
}
ShaderEffectSource {
id: theDistTransSource
sourceItem: text
filtering: ShaderEffectSource.Nearest
horizontalWrap: ShaderEffectSource.ClampToEdge
verticalWrap: ShaderEffectSource.ClampToEdge
}
// Shader generating the distance transform of the glyph
ShaderEffectItem {
id: distanceTransform
property variant source: theDistTransSource
property real psize: 1 / text.width
property real spread: 30
anchors.centerIn: text
width: 64
height: width
smooth: true
fragmentShader: "varying highp vec2 qt_TexCoord0; \n" +
"uniform sampler2D source; \n" +
"uniform highp float psize; \n" +
"uniform lowp float spread; \n" +
"void main() { \n" +
" highp vec4 p = texture2D(source, qt_TexCoord0); \n" +
" lowp float sp = step(0.5, p.a); \n" +
" mediump float dist = spread * psize; \n" +
" for (mediump float sy = clamp(qt_TexCoord0.y - spread * psize, 0.0, 1.0); sy < clamp(qt_TexCoord0.y + spread * psize, 0.0, 1.0); sy += psize) { \n" +
" for (mediump float sx = clamp(qt_TexCoord0.x - spread * psize, 0.0, 1.0); sx < clamp(qt_TexCoord0.x + spread * psize, 0.0, 1.0); sx += psize) { \n" +
" lowp float t = step(0.5, texture2D(source, vec2(sx, sy)).a); \n" +
" dist = mix(dist, min(dist, length(vec2(sx - qt_TexCoord0.x,sy - qt_TexCoord0.y))), abs(sp - t)); \n" +
" } \n" +
" } \n" +
" mediump float a = ((dist - psize) * (0.0 - 0.50)) / (spread * psize - psize) + 0.50; \n" +
" mediump float b = ((dist - psize) * (1.0 - 0.51)) / (spread * psize - psize) + 0.51; \n" +
" mediump float alpha = mix(a, b, sp); \n" +
" gl_FragColor = vec4(0.0, 0.0, 0.0, alpha); \n" +
"}"
}
ShaderEffectSource {
id: theAlphaTestSource
sourceItem: distanceTransform
filtering: ShaderEffectSource.Linear
horizontalWrap: ShaderEffectSource.ClampToEdge
verticalWrap: ShaderEffectSource.ClampToEdge
}
// Shader doing the alpha test on the distance transform
ShaderEffectItem {
id: alphaTest
property variant source: theAlphaTestSource
property real eps: 0.2
property real scalep: alphaTest.scale
width: distanceTransform.width; height: distanceTransform.height
x: main.width / 4 - width / 2; y: main.height / 2 - height / 2 - scale * 4
smooth: true
fragmentShader: "varying highp vec2 qt_TexCoord0; \n" +
"uniform sampler2D source; \n" +
"uniform lowp float scalep; \n" +
"uniform lowp float eps; \n" +
"void main() { \n" +
" gl_FragColor = vec4(0.0, 0.0, 0.0, \n" +
" smoothstep(clamp(0.5 - eps / scalep, 0.0, 0.5), \n" +
" clamp(0.5 + eps / scalep, 0.5, 1.0), \n" +
" texture2D(source, qt_TexCoord0).a)); \n" +
"}"
}
Rectangle {
id: plus
width: 40; height: 40
color: "lightgray"
radius: width / 2
border.color: "black"
border.width: 3
anchors.right: parent.right; anchors.rightMargin: 30
anchors.verticalCenter: parent.verticalCenter
anchors.verticalCenterOffset: -40
Text {
text: "+"
font.family: "Arial"
font.pointSize: 38
anchors.centerIn: parent
anchors.verticalCenterOffset: 1.5
anchors.horizontalCenterOffset: 0.5
}
MouseArea {
anchors.fill: parent
onClicked: {
alphaTest.scale *= 1.5;
reference.scale *= 1.5
}
}
}
Rectangle {
width: 40; height: 40
color: "lightgray"
radius: width / 2
border.color: "black"
border.width: 3
anchors.horizontalCenter: plus.horizontalCenter
anchors.verticalCenter: parent.verticalCenter
anchors.verticalCenterOffset: 40
Text {
text: "-"
font.family: "Arial"
font.pointSize: 42
anchors.centerIn: parent
anchors.verticalCenterOffset: -4
anchors.horizontalCenterOffset: 1
}
MouseArea {
anchors.fill: parent
onClicked: {
alphaTest.scale /= 1.5;
reference.scale /= 1.5
}
}
}
}
|
