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authorQt by Nokia <qt-info@nokia.com>2011-04-27 12:05:43 +0200
committeraxis <qt-info@nokia.com>2011-04-27 12:05:43 +0200
commit38be0d13830efd2d98281c645c3a60afe05ffece (patch)
tree6ea73f3ec77f7d153333779883e8120f82820abe /src/opengl/qgraphicsshadereffect.cpp
Initial import from the monolithic Qt.
This is the beginning of revision history for this module. If you want to look at revision history older than this, please refer to the Qt Git wiki for how to use Git history grafting. At the time of writing, this wiki is located here: http://qt.gitorious.org/qt/pages/GitIntroductionWithQt If you have already performed the grafting and you don't see any history beyond this commit, try running "git log" with the "--follow" argument. Branched from the monolithic repo, Qt master branch, at commit 896db169ea224deb96c59ce8af800d019de63f12
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+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtOpenGL module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qgraphicsshadereffect_p.h"
+#if !defined(QT_OPENGL_ES_1)
+#include "qglshaderprogram.h"
+#include "gl2paintengineex/qglcustomshaderstage_p.h"
+#define QGL_HAVE_CUSTOM_SHADERS 1
+#endif
+#include <QtGui/qpainter.h>
+#include <QtGui/qgraphicsitem.h>
+#include <QtGui/private/qgraphicseffect_p.h>
+
+QT_BEGIN_NAMESPACE
+
+/*#
+ \class QGraphicsShaderEffect
+ \brief The QGraphicsShaderEffect class is the base class for creating
+ custom GLSL shader effects in a QGraphicsScene.
+ \since 4.6
+ \ingroup multimedia
+ \ingroup graphicsview-api
+
+ The specific effect is defined by a fragment of GLSL source code
+ supplied to setPixelShaderFragment(). This source code must define a
+ function with the signature
+ \c{lowp vec4 customShader(lowp sampler2D imageTexture, highp vec2 textureCoords)}
+ that returns the source pixel value
+ to use in the paint engine's shader program. The shader fragment
+ is linked with the regular shader code used by the GL2 paint engine
+ to construct a complete QGLShaderProgram.
+
+ The following example shader converts the incoming pixmap to
+ grayscale and then applies a colorize operation using the
+ \c effectColor value:
+
+ \code
+ static char const colorizeShaderCode[] =
+ "uniform lowp vec4 effectColor;\n"
+ "lowp vec4 customShader(lowp sampler2D imageTexture, highp vec2 textureCoords) {\n"
+ " vec4 src = texture2D(imageTexture, textureCoords);\n"
+ " float gray = dot(src.rgb, vec3(0.212671, 0.715160, 0.072169));\n"
+ " vec4 colorize = 1.0-((1.0-gray)*(1.0-effectColor));\n"
+ " return vec4(colorize.rgb, src.a);\n"
+ "}";
+ \endcode
+
+ To use this shader code, it is necessary to define a subclass
+ of QGraphicsShaderEffect as follows:
+
+ \code
+ class ColorizeEffect : public QGraphicsShaderEffect
+ {
+ Q_OBJECT
+ public:
+ ColorizeEffect(QObject *parent = 0)
+ : QGraphicsShaderEffect(parent), color(Qt::black)
+ {
+ setPixelShaderFragment(colorizeShaderCode);
+ }
+
+ QColor effectColor() const { return color; }
+ void setEffectColor(const QColor& c)
+ {
+ color = c;
+ setUniformsDirty();
+ }
+
+ protected:
+ void setUniforms(QGLShaderProgram *program)
+ {
+ program->setUniformValue("effectColor", color);
+ }
+
+ private:
+ QColor color;
+ };
+ \endcode
+
+ The setUniforms() function is called when the effect is about
+ to be used for drawing to give the subclass the opportunity to
+ set effect-specific uniform variables.
+
+ QGraphicsShaderEffect is only supported when the GL2 paint engine
+ is in use. When any other paint engine is in use (GL1, raster, etc),
+ the drawItem() method will draw its item argument directly with
+ no effect applied.
+
+ \sa QGraphicsEffect
+*/
+
+static const char qglslDefaultImageFragmentShader[] = "\
+ lowp vec4 customShader(lowp sampler2D imageTexture, highp vec2 textureCoords) { \
+ return texture2D(imageTexture, textureCoords); \
+ }\n";
+
+#ifdef QGL_HAVE_CUSTOM_SHADERS
+
+class QGLCustomShaderEffectStage : public QGLCustomShaderStage
+{
+public:
+ QGLCustomShaderEffectStage
+ (QGraphicsShaderEffect *e, const QByteArray& source)
+ : QGLCustomShaderStage(),
+ effect(e)
+ {
+ setSource(source);
+ }
+
+ void setUniforms(QGLShaderProgram *program);
+
+ QGraphicsShaderEffect *effect;
+};
+
+void QGLCustomShaderEffectStage::setUniforms(QGLShaderProgram *program)
+{
+ effect->setUniforms(program);
+}
+
+#endif
+
+class QGraphicsShaderEffectPrivate : public QGraphicsEffectPrivate
+{
+ Q_DECLARE_PUBLIC(QGraphicsShaderEffect)
+public:
+ QGraphicsShaderEffectPrivate()
+ : pixelShaderFragment(qglslDefaultImageFragmentShader)
+#ifdef QGL_HAVE_CUSTOM_SHADERS
+ , customShaderStage(0)
+#endif
+ {
+ }
+
+ QByteArray pixelShaderFragment;
+#ifdef QGL_HAVE_CUSTOM_SHADERS
+ QGLCustomShaderEffectStage *customShaderStage;
+#endif
+};
+
+/*#
+ Constructs a shader effect and attaches it to \a parent.
+*/
+QGraphicsShaderEffect::QGraphicsShaderEffect(QObject *parent)
+ : QGraphicsEffect(*new QGraphicsShaderEffectPrivate(), parent)
+{
+}
+
+/*#
+ Destroys this shader effect.
+*/
+QGraphicsShaderEffect::~QGraphicsShaderEffect()
+{
+#ifdef QGL_HAVE_CUSTOM_SHADERS
+ Q_D(QGraphicsShaderEffect);
+ delete d->customShaderStage;
+#endif
+}
+
+/*#
+ Returns the source code for the pixel shader fragment for
+ this shader effect. The default is a shader that copies
+ its incoming pixmap directly to the output with no effect
+ applied.
+
+ \sa setPixelShaderFragment()
+*/
+QByteArray QGraphicsShaderEffect::pixelShaderFragment() const
+{
+ Q_D(const QGraphicsShaderEffect);
+ return d->pixelShaderFragment;
+}
+
+/*#
+ Sets the source code for the pixel shader fragment for
+ this shader effect to \a code.
+
+ The \a code must define a GLSL function with the signature
+ \c{lowp vec4 customShader(lowp sampler2D imageTexture, highp vec2 textureCoords)}
+ that returns the source pixel value to use in the paint engine's
+ shader program. The following is the default pixel shader fragment,
+ which draws a pixmap with no effect applied:
+
+ \code
+ lowp vec4 customShader(lowp sampler2D imageTexture, highp vec2 textureCoords) {
+ return texture2D(imageTexture, textureCoords);
+ }
+ \endcode
+
+ \sa pixelShaderFragment(), setUniforms()
+*/
+void QGraphicsShaderEffect::setPixelShaderFragment(const QByteArray& code)
+{
+ Q_D(QGraphicsShaderEffect);
+ if (d->pixelShaderFragment != code) {
+ d->pixelShaderFragment = code;
+#ifdef QGL_HAVE_CUSTOM_SHADERS
+ delete d->customShaderStage;
+ d->customShaderStage = 0;
+#endif
+ }
+}
+
+/*#
+ \reimp
+*/
+void QGraphicsShaderEffect::draw(QPainter *painter)
+{
+ Q_D(QGraphicsShaderEffect);
+
+#ifdef QGL_HAVE_CUSTOM_SHADERS
+ // Set the custom shader on the paint engine. The setOnPainter()
+ // call may fail if the paint engine is not GL2. In that case,
+ // we fall through to drawing the pixmap normally.
+ if (!d->customShaderStage) {
+ d->customShaderStage = new QGLCustomShaderEffectStage
+ (this, d->pixelShaderFragment);
+ }
+ bool usingShader = d->customShaderStage->setOnPainter(painter);
+
+ QPoint offset;
+ if (sourceIsPixmap()) {
+ // No point in drawing in device coordinates (pixmap will be scaled anyways).
+ const QPixmap pixmap = sourcePixmap(Qt::LogicalCoordinates, &offset);
+ painter->drawPixmap(offset, pixmap);
+ } else {
+ // Draw pixmap in device coordinates to avoid pixmap scaling.
+ const QPixmap pixmap = sourcePixmap(Qt::DeviceCoordinates, &offset);
+ QTransform restoreTransform = painter->worldTransform();
+ painter->setWorldTransform(QTransform());
+ painter->drawPixmap(offset, pixmap);
+ painter->setWorldTransform(restoreTransform);
+ }
+
+ // Remove the custom shader to return to normal painting operations.
+ if (usingShader)
+ d->customShaderStage->removeFromPainter(painter);
+#else
+ drawSource(painter);
+#endif
+}
+
+/*#
+ Sets the custom uniform variables on this shader effect to
+ be dirty. The setUniforms() function will be called the next
+ time the shader program corresponding to this effect is used.
+
+ This function is typically called by subclasses when an
+ effect-specific parameter is changed by the application.
+
+ \sa setUniforms()
+*/
+void QGraphicsShaderEffect::setUniformsDirty()
+{
+#ifdef QGL_HAVE_CUSTOM_SHADERS
+ Q_D(QGraphicsShaderEffect);
+ if (d->customShaderStage)
+ d->customShaderStage->setUniformsDirty();
+#endif
+}
+
+/*#
+ Sets custom uniform variables on the current GL context when
+ \a program is about to be used by the paint engine.
+
+ This function should be overridden if the shader set with
+ setPixelShaderFragment() has additional parameters beyond
+ those that the paint engine normally sets itself.
+
+ \sa setUniformsDirty()
+*/
+void QGraphicsShaderEffect::setUniforms(QGLShaderProgram *program)
+{
+ Q_UNUSED(program);
+}
+
+QT_END_NAMESPACE