qt-everywhere-src-5.14.1/qtbase/src/opengl/gl2paintengineex/qtextureglyphcache_gl.cpp - orbit - Git at Google

 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtOpenGL module of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
 ** GNU Lesser General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU Lesser
 ** General Public License version 3 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.LGPL3 included in the
 ** packaging of this file. Please review the following information to
 ** ensure the GNU Lesser General Public License version 3 requirements
 ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 2.0 or (at your option) the GNU General
 ** Public license version 3 or any later version approved by the KDE Free
 ** Qt Foundation. The licenses are as published by the Free Software
 ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
 ** included in the packaging of this file. Please review the following
 ** information to ensure the GNU General Public License requirements will
 ** be met: https://www.gnu.org/licenses/gpl-2.0.html and
 ** https://www.gnu.org/licenses/gpl-3.0.html.
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include "qtextureglyphcache_gl_p.h"
 #include "qpaintengineex_opengl2_p.h"
 #include "qglfunctions.h"
 #include "private/qglengineshadersource_p.h"

 QT_BEGIN_NAMESPACE


 static int next_qgltextureglyphcache_serial_number()
 {
     static QBasicAtomicInt serial = Q_BASIC_ATOMIC_INITIALIZER(0);
     return 1 + serial.fetchAndAddRelaxed(1);
 }

 QGLTextureGlyphCache::QGLTextureGlyphCache(QFontEngine::GlyphFormat format, const QTransform &matrix)
     : QImageTextureGlyphCache(format, matrix)
     , m_textureResource(0)
     , pex(0)
     , m_blitProgram(0)
     , m_filterMode(Nearest)
     , m_serialNumber(next_qgltextureglyphcache_serial_number())
 {
 #ifdef QT_GL_TEXTURE_GLYPH_CACHE_DEBUG
     qDebug(" -> QGLTextureGlyphCache() %p for context %p.", this, QOpenGLContext::currentContext());
 #endif
     m_vertexCoordinateArray[0] = -1.0f;
     m_vertexCoordinateArray[1] = -1.0f;
     m_vertexCoordinateArray[2] =  1.0f;
     m_vertexCoordinateArray[3] = -1.0f;
     m_vertexCoordinateArray[4] =  1.0f;
     m_vertexCoordinateArray[5] =  1.0f;
     m_vertexCoordinateArray[6] = -1.0f;
     m_vertexCoordinateArray[7] =  1.0f;

     m_textureCoordinateArray[0] = 0.0f;
     m_textureCoordinateArray[1] = 0.0f;
     m_textureCoordinateArray[2] = 1.0f;
     m_textureCoordinateArray[3] = 0.0f;
     m_textureCoordinateArray[4] = 1.0f;
     m_textureCoordinateArray[5] = 1.0f;
     m_textureCoordinateArray[6] = 0.0f;
     m_textureCoordinateArray[7] = 1.0f;
 }

 QGLTextureGlyphCache::~QGLTextureGlyphCache()
 {
 #ifdef QT_GL_TEXTURE_GLYPH_CACHE_DEBUG
     qDebug(" -> ~QGLTextureGlyphCache() %p.", this);
 #endif
     delete m_blitProgram;
     if (m_textureResource)
         m_textureResource->free();
 }

 void QGLTextureGlyphCache::createTextureData(int width, int height)
 {
     QGLContext *ctx = const_cast<QGLContext *>(QGLContext::currentContext());
     if (ctx == 0) {
         qWarning("QGLTextureGlyphCache::createTextureData: Called with no context");
         return;
     }
     QOpenGLFunctions *funcs = ctx->contextHandle()->functions();

     // create in QImageTextureGlyphCache baseclass is meant to be called
     // only to create the initial image and does not preserve the content,
     // so we don't call when this function is called from resize.
     if ((!QGLFramebufferObject::hasOpenGLFramebufferObjects() || ctx->d_ptr->workaround_brokenFBOReadBack) && image().isNull())
         QImageTextureGlyphCache::createTextureData(width, height);

     // Make the lower glyph texture size 16 x 16.
     if (width < 16)
         width = 16;
     if (height < 16)
         height = 16;

     if (m_textureResource && !m_textureResource->m_texture) {
         delete m_textureResource;
         m_textureResource = 0;
     }

     if (!m_textureResource)
         m_textureResource = new QGLGlyphTexture(ctx);

     funcs->glGenTextures(1, &m_textureResource->m_texture);
     funcs->glBindTexture(GL_TEXTURE_2D, m_textureResource->m_texture);

     m_textureResource->m_width = width;
     m_textureResource->m_height = height;

     if (m_format == QFontEngine::Format_A32) {
         QVarLengthArray<uchar> data(width * height * 4);
         for (int i = 0; i < data.size(); ++i)
             data[i] = 0;
         funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, &data[0]);
     } else {
         QVarLengthArray<uchar> data(width * height);
         for (int i = 0; i < data.size(); ++i)
             data[i] = 0;
         funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, &data[0]);
     }

     funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
     m_filterMode = Nearest;
 }

 void QGLTextureGlyphCache::resizeTextureData(int width, int height)
 {
     QGLContext *ctx = const_cast<QGLContext *>(QGLContext::currentContext());
     if (ctx == 0) {
         qWarning("QGLTextureGlyphCache::resizeTextureData: Called with no context");
         return;
     }
     QOpenGLFunctions *funcs = ctx->contextHandle()->functions();

     int oldWidth = m_textureResource->m_width;
     int oldHeight = m_textureResource->m_height;

     // Make the lower glyph texture size 16 x 16.
     if (width < 16)
         width = 16;
     if (height < 16)
         height = 16;

     GLuint oldTexture = m_textureResource->m_texture;
     createTextureData(width, height);

     if (!QGLFramebufferObject::hasOpenGLFramebufferObjects() || ctx->d_ptr->workaround_brokenFBOReadBack) {
         QImageTextureGlyphCache::resizeTextureData(width, height);
         Q_ASSERT(image().depth() == 8);
         funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, oldHeight, GL_ALPHA, GL_UNSIGNED_BYTE, image().constBits());
         funcs->glDeleteTextures(1, &oldTexture);
         return;
     }

     // ### the QTextureGlyphCache API needs to be reworked to allow
     // ### resizeTextureData to fail

     ctx->d_ptr->refreshCurrentFbo();

     funcs->glBindFramebuffer(GL_FRAMEBUFFER, m_textureResource->m_fbo);

     GLuint tmp_texture;
     funcs->glGenTextures(1, &tmp_texture);
     funcs->glBindTexture(GL_TEXTURE_2D, tmp_texture);
     funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, oldWidth, oldHeight, 0,
                         GL_RGBA, GL_UNSIGNED_BYTE, NULL);
     funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
     funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
     m_filterMode = Nearest;
     funcs->glBindTexture(GL_TEXTURE_2D, 0);
     funcs->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                   GL_TEXTURE_2D, tmp_texture, 0);

     funcs->glActiveTexture(GL_TEXTURE0 + QT_IMAGE_TEXTURE_UNIT);
     funcs->glBindTexture(GL_TEXTURE_2D, oldTexture);

     if (pex != 0)
         pex->transferMode(BrushDrawingMode);

     funcs->glDisable(GL_STENCIL_TEST);
     funcs->glDisable(GL_DEPTH_TEST);
     funcs->glDisable(GL_SCISSOR_TEST);
     funcs->glDisable(GL_BLEND);

     funcs->glViewport(0, 0, oldWidth, oldHeight);

     QGLShaderProgram *blitProgram = 0;
     if (pex == 0) {
         if (m_blitProgram == 0) {
             m_blitProgram = new QGLShaderProgram(ctx);

             {
                 QString source;
                 source.append(QLatin1String(qglslMainWithTexCoordsVertexShader));
                 source.append(QLatin1String(qglslUntransformedPositionVertexShader));

                 QGLShader *vertexShader = new QGLShader(QGLShader::Vertex, m_blitProgram);
                 vertexShader->compileSourceCode(source);

                 m_blitProgram->addShader(vertexShader);
             }

             {
                 QString source;
                 source.append(QLatin1String(qglslMainFragmentShader));
                 source.append(QLatin1String(qglslImageSrcFragmentShader));

                 QGLShader *fragmentShader = new QGLShader(QGLShader::Fragment, m_blitProgram);
                 fragmentShader->compileSourceCode(source);

                 m_blitProgram->addShader(fragmentShader);
             }

             m_blitProgram->bindAttributeLocation("vertexCoordsArray", QT_VERTEX_COORDS_ATTR);
             m_blitProgram->bindAttributeLocation("textureCoordArray", QT_TEXTURE_COORDS_ATTR);

             m_blitProgram->link();
         }

         funcs->glVertexAttribPointer(QT_VERTEX_COORDS_ATTR, 2, GL_FLOAT, GL_FALSE, 0, m_vertexCoordinateArray);
         funcs->glVertexAttribPointer(QT_TEXTURE_COORDS_ATTR, 2, GL_FLOAT, GL_FALSE, 0, m_textureCoordinateArray);

         m_blitProgram->bind();
         m_blitProgram->enableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
         m_blitProgram->enableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
         m_blitProgram->disableAttributeArray(int(QT_OPACITY_ATTR));

         blitProgram = m_blitProgram;

     } else {
         pex->setVertexAttributePointer(QT_VERTEX_COORDS_ATTR, m_vertexCoordinateArray);
         pex->setVertexAttributePointer(QT_TEXTURE_COORDS_ATTR, m_textureCoordinateArray);

         pex->shaderManager->useBlitProgram();
         blitProgram = pex->shaderManager->blitProgram();
     }

     blitProgram->setUniformValue("imageTexture", QT_IMAGE_TEXTURE_UNIT);

     funcs->glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

     funcs->glBindTexture(GL_TEXTURE_2D, m_textureResource->m_texture);

     funcs->glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, oldWidth, oldHeight);

     funcs->glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                      GL_RENDERBUFFER, 0);
     funcs->glDeleteTextures(1, &tmp_texture);
     funcs->glDeleteTextures(1, &oldTexture);

     funcs->glBindFramebuffer(GL_FRAMEBUFFER, ctx->d_ptr->current_fbo);

     if (pex != 0) {
         funcs->glViewport(0, 0, pex->width, pex->height);
         pex->updateClipScissorTest();
     }
 }

 void QGLTextureGlyphCache::fillTexture(const Coord &c, glyph_t glyph, QFixed subPixelPosition)
 {
     QGLContext *ctx = const_cast<QGLContext *>(QGLContext::currentContext());
     if (ctx == 0) {
         qWarning("QGLTextureGlyphCache::fillTexture: Called with no context");
         return;
     }
     QOpenGLFunctions *funcs = ctx->contextHandle()->functions();

     if (!QGLFramebufferObject::hasOpenGLFramebufferObjects() || ctx->d_ptr->workaround_brokenFBOReadBack) {
         QImageTextureGlyphCache::fillTexture(c, glyph, subPixelPosition);

         funcs->glBindTexture(GL_TEXTURE_2D, m_textureResource->m_texture);
         const QImage &texture = image();
         const uchar *bits = texture.constBits();
         bits += c.y * texture.bytesPerLine() + c.x;
         for (int i=0; i<c.h; ++i) {
             funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y + i, c.w, 1, GL_ALPHA, GL_UNSIGNED_BYTE, bits);
             bits += texture.bytesPerLine();
         }
         return;
     }

     QImage mask = textureMapForGlyph(glyph, subPixelPosition);
     const int maskWidth = mask.width();
     const int maskHeight = mask.height();

     if (mask.format() == QImage::Format_Mono) {
         mask = mask.convertToFormat(QImage::Format_Indexed8);
         for (int y = 0; y < maskHeight; ++y) {
             uchar *src = (uchar *) mask.scanLine(y);
             for (int x = 0; x < maskWidth; ++x)
                 src[x] = -src[x]; // convert 0 and 1 into 0 and 255
         }
     } else if (mask.depth() == 32) {
         // Make the alpha component equal to the average of the RGB values.
         // This is needed when drawing sub-pixel antialiased text on translucent targets.
         for (int y = 0; y < maskHeight; ++y) {
             quint32 *src = (quint32 *) mask.scanLine(y);
             for (int x = 0; x < maskWidth; ++x) {
                 int r = qRed(src[x]);
                 int g = qGreen(src[x]);
                 int b = qBlue(src[x]);
                 int avg;
                 if (mask.format() == QImage::Format_RGB32)
                     avg = (r + g + b + 1) / 3; // "+1" for rounding.
                 else // Format_ARGB_Premultiplied
                     avg = qAlpha(src[x]);
                 if (ctx->contextHandle()->isOpenGLES()) {
                     // swizzle the bits to accommodate for the GL_RGBA upload.
                     src[x] = (avg << 24) | (r << 0) | (g << 8) | (b << 16);
                 } else {
                     src[x] = (src[x] & 0x00ffffff) | (avg << 24);
                 }
             }
         }
     }

     funcs->glBindTexture(GL_TEXTURE_2D, m_textureResource->m_texture);
     if (mask.depth() == 32) {
         GLenum format = GL_RGBA;
 #if !defined(QT_OPENGL_ES_2)
         if (!ctx->contextHandle()->isOpenGLES())
             format = GL_BGRA;
 #endif
         funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y, maskWidth, maskHeight, format, GL_UNSIGNED_BYTE, mask.bits());
     } else {
         // glTexSubImage2D() might cause some garbage to appear in the texture if the mask width is
         // not a multiple of four bytes. The bug appeared on a computer with 32-bit Windows Vista
         // and nVidia GeForce 8500GT. GL_UNPACK_ALIGNMENT is set to four bytes, 'mask' has a
         // multiple of four bytes per line, and most of the glyph shows up correctly in the
         // texture, which makes me think that this is a driver bug.
         // One workaround is to make sure the mask width is a multiple of four bytes, for instance
         // by converting it to a format with four bytes per pixel. Another is to copy one line at a
         // time.

         if (!ctx->d_ptr->workaround_brokenAlphaTexSubImage_init) {
             // don't know which driver versions exhibit this bug, so be conservative for now
             const QByteArray vendorString(reinterpret_cast<const char*>(funcs->glGetString(GL_VENDOR)));
             ctx->d_ptr->workaround_brokenAlphaTexSubImage = vendorString.indexOf("NVIDIA") >= 0;
             ctx->d_ptr->workaround_brokenAlphaTexSubImage_init = true;
         }

         if (ctx->d_ptr->workaround_brokenAlphaTexSubImage) {
             for (int i = 0; i < maskHeight; ++i)
                 funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y + i, maskWidth, 1, GL_ALPHA, GL_UNSIGNED_BYTE, mask.scanLine(i));
         } else {
             funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y, maskWidth, maskHeight, GL_ALPHA, GL_UNSIGNED_BYTE, mask.bits());
         }
     }
 }

 int QGLTextureGlyphCache::glyphPadding() const
 {
     return 1;
 }

 int QGLTextureGlyphCache::maxTextureWidth() const
 {
     QGLContext *ctx = const_cast<QGLContext *>(QGLContext::currentContext());
     if (ctx == 0)
         return QImageTextureGlyphCache::maxTextureWidth();
     else
         return ctx->d_ptr->maxTextureSize();
 }

 int QGLTextureGlyphCache::maxTextureHeight() const
 {
     QGLContext *ctx = const_cast<QGLContext *>(QGLContext::currentContext());
     if (ctx == 0)
         return QImageTextureGlyphCache::maxTextureHeight();

     if (ctx->d_ptr->workaround_brokenTexSubImage)
         return qMin(1024, ctx->d_ptr->maxTextureSize());
     else
         return ctx->d_ptr->maxTextureSize();
 }

 void QGLTextureGlyphCache::clear()
 {
     m_textureResource->free();
     m_textureResource = 0;

     m_w = 0;
     m_h = 0;
     m_cx = 0;
     m_cy = 0;
     m_currentRowHeight = 0;
     coords.clear();
 }

 QT_END_NAMESPACE
	/****************************************************************************
	**
	** Copyright (C) 2016 The Qt Company Ltd.
	** Contact: https://www.qt.io/licensing/
	**
	** This file is part of the QtOpenGL module of the Qt Toolkit.
	**
	** $QT_BEGIN_LICENSE:LGPL$
	** Commercial License Usage
	** Licensees holding valid commercial Qt licenses may use this file in
	** accordance with the commercial license agreement provided with the
	** Software or, alternatively, in accordance with the terms contained in
	** a written agreement between you and The Qt Company. For licensing terms
	** and conditions see https://www.qt.io/terms-conditions. For further
	** information use the contact form at https://www.qt.io/contact-us.
	**
	** GNU Lesser General Public License Usage
	** Alternatively, this file may be used under the terms of the GNU Lesser
	** General Public License version 3 as published by the Free Software
	** Foundation and appearing in the file LICENSE.LGPL3 included in the
	** packaging of this file. Please review the following information to
	** ensure the GNU Lesser General Public License version 3 requirements
	** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
	**
	** GNU General Public License Usage
	** Alternatively, this file may be used under the terms of the GNU
	** General Public License version 2.0 or (at your option) the GNU General
	** Public license version 3 or any later version approved by the KDE Free
	** Qt Foundation. The licenses are as published by the Free Software
	** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
	** included in the packaging of this file. Please review the following
	** information to ensure the GNU General Public License requirements will
	** be met: https://www.gnu.org/licenses/gpl-2.0.html and
	** https://www.gnu.org/licenses/gpl-3.0.html.
	**
	** $QT_END_LICENSE$
	**
	****************************************************************************/

	#include "qtextureglyphcache_gl_p.h"
	#include "qpaintengineex_opengl2_p.h"
	#include "qglfunctions.h"
	#include "private/qglengineshadersource_p.h"

	QT_BEGIN_NAMESPACE


	static int next_qgltextureglyphcache_serial_number()
	{
	static QBasicAtomicInt serial = Q_BASIC_ATOMIC_INITIALIZER(0);
	return 1 + serial.fetchAndAddRelaxed(1);
	}

	QGLTextureGlyphCache::QGLTextureGlyphCache(QFontEngine::GlyphFormat format, const QTransform &matrix)
	: QImageTextureGlyphCache(format, matrix)
	, m_textureResource(0)
	, pex(0)
	, m_blitProgram(0)
	, m_filterMode(Nearest)
	, m_serialNumber(next_qgltextureglyphcache_serial_number())
	{
	#ifdef QT_GL_TEXTURE_GLYPH_CACHE_DEBUG
	qDebug(" -> QGLTextureGlyphCache() %p for context %p.", this, QOpenGLContext::currentContext());
	#endif
	m_vertexCoordinateArray[0] = -1.0f;
	m_vertexCoordinateArray[1] = -1.0f;
	m_vertexCoordinateArray[2] = 1.0f;
	m_vertexCoordinateArray[3] = -1.0f;
	m_vertexCoordinateArray[4] = 1.0f;
	m_vertexCoordinateArray[5] = 1.0f;
	m_vertexCoordinateArray[6] = -1.0f;
	m_vertexCoordinateArray[7] = 1.0f;

	m_textureCoordinateArray[0] = 0.0f;
	m_textureCoordinateArray[1] = 0.0f;
	m_textureCoordinateArray[2] = 1.0f;
	m_textureCoordinateArray[3] = 0.0f;
	m_textureCoordinateArray[4] = 1.0f;
	m_textureCoordinateArray[5] = 1.0f;
	m_textureCoordinateArray[6] = 0.0f;
	m_textureCoordinateArray[7] = 1.0f;
	}

	QGLTextureGlyphCache::~QGLTextureGlyphCache()
	{
	#ifdef QT_GL_TEXTURE_GLYPH_CACHE_DEBUG
	qDebug(" -> ~QGLTextureGlyphCache() %p.", this);
	#endif
	delete m_blitProgram;
	if (m_textureResource)
	m_textureResource->free();
	}

	void QGLTextureGlyphCache::createTextureData(int width, int height)
	{
	QGLContext ctx = const_cast<QGLContext >(QGLContext::currentContext());
	if (ctx == 0) {
	qWarning("QGLTextureGlyphCache::createTextureData: Called with no context");
	return;
	}
	QOpenGLFunctions *funcs = ctx->contextHandle()->functions();

	// create in QImageTextureGlyphCache baseclass is meant to be called
	// only to create the initial image and does not preserve the content,
	// so we don't call when this function is called from resize.
	if ((!QGLFramebufferObject::hasOpenGLFramebufferObjects() \|\| ctx->d_ptr->workaround_brokenFBOReadBack) && image().isNull())
	QImageTextureGlyphCache::createTextureData(width, height);

	// Make the lower glyph texture size 16 x 16.
	if (width < 16)
	width = 16;
	if (height < 16)
	height = 16;

	if (m_textureResource && !m_textureResource->m_texture) {
	delete m_textureResource;
	m_textureResource = 0;
	}

	if (!m_textureResource)
	m_textureResource = new QGLGlyphTexture(ctx);

	funcs->glGenTextures(1, &m_textureResource->m_texture);
	funcs->glBindTexture(GL_TEXTURE_2D, m_textureResource->m_texture);

	m_textureResource->m_width = width;
	m_textureResource->m_height = height;

	if (m_format == QFontEngine::Format_A32) {
	QVarLengthArray<uchar> data(width * height * 4);
	for (int i = 0; i < data.size(); ++i)
	data[i] = 0;
	funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, &data[0]);
	} else {
	QVarLengthArray<uchar> data(width * height);
	for (int i = 0; i < data.size(); ++i)
	data[i] = 0;
	funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, &data[0]);
	}

	funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	m_filterMode = Nearest;
	}

	void QGLTextureGlyphCache::resizeTextureData(int width, int height)
	{
	QGLContext ctx = const_cast<QGLContext >(QGLContext::currentContext());
	if (ctx == 0) {
	qWarning("QGLTextureGlyphCache::resizeTextureData: Called with no context");
	return;
	}
	QOpenGLFunctions *funcs = ctx->contextHandle()->functions();

	int oldWidth = m_textureResource->m_width;
	int oldHeight = m_textureResource->m_height;

	// Make the lower glyph texture size 16 x 16.
	if (width < 16)
	width = 16;
	if (height < 16)
	height = 16;

	GLuint oldTexture = m_textureResource->m_texture;
	createTextureData(width, height);

	if (!QGLFramebufferObject::hasOpenGLFramebufferObjects() \|\| ctx->d_ptr->workaround_brokenFBOReadBack) {
	QImageTextureGlyphCache::resizeTextureData(width, height);
	Q_ASSERT(image().depth() == 8);
	funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, oldHeight, GL_ALPHA, GL_UNSIGNED_BYTE, image().constBits());
	funcs->glDeleteTextures(1, &oldTexture);
	return;
	}

	// ### the QTextureGlyphCache API needs to be reworked to allow
	// ### resizeTextureData to fail

	ctx->d_ptr->refreshCurrentFbo();

	funcs->glBindFramebuffer(GL_FRAMEBUFFER, m_textureResource->m_fbo);

	GLuint tmp_texture;
	funcs->glGenTextures(1, &tmp_texture);
	funcs->glBindTexture(GL_TEXTURE_2D, tmp_texture);
	funcs->glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, oldWidth, oldHeight, 0,
	GL_RGBA, GL_UNSIGNED_BYTE, NULL);
	funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	funcs->glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	m_filterMode = Nearest;
	funcs->glBindTexture(GL_TEXTURE_2D, 0);
	funcs->glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
	GL_TEXTURE_2D, tmp_texture, 0);

	funcs->glActiveTexture(GL_TEXTURE0 + QT_IMAGE_TEXTURE_UNIT);
	funcs->glBindTexture(GL_TEXTURE_2D, oldTexture);

	if (pex != 0)
	pex->transferMode(BrushDrawingMode);

	funcs->glDisable(GL_STENCIL_TEST);
	funcs->glDisable(GL_DEPTH_TEST);
	funcs->glDisable(GL_SCISSOR_TEST);
	funcs->glDisable(GL_BLEND);

	funcs->glViewport(0, 0, oldWidth, oldHeight);

	QGLShaderProgram *blitProgram = 0;
	if (pex == 0) {
	if (m_blitProgram == 0) {
	m_blitProgram = new QGLShaderProgram(ctx);

	{
	QString source;
	source.append(QLatin1String(qglslMainWithTexCoordsVertexShader));
	source.append(QLatin1String(qglslUntransformedPositionVertexShader));

	QGLShader *vertexShader = new QGLShader(QGLShader::Vertex, m_blitProgram);
	vertexShader->compileSourceCode(source);

	m_blitProgram->addShader(vertexShader);
	}

	{
	QString source;
	source.append(QLatin1String(qglslMainFragmentShader));
	source.append(QLatin1String(qglslImageSrcFragmentShader));

	QGLShader *fragmentShader = new QGLShader(QGLShader::Fragment, m_blitProgram);
	fragmentShader->compileSourceCode(source);

	m_blitProgram->addShader(fragmentShader);
	}

	m_blitProgram->bindAttributeLocation("vertexCoordsArray", QT_VERTEX_COORDS_ATTR);
	m_blitProgram->bindAttributeLocation("textureCoordArray", QT_TEXTURE_COORDS_ATTR);

	m_blitProgram->link();
	}

	funcs->glVertexAttribPointer(QT_VERTEX_COORDS_ATTR, 2, GL_FLOAT, GL_FALSE, 0, m_vertexCoordinateArray);
	funcs->glVertexAttribPointer(QT_TEXTURE_COORDS_ATTR, 2, GL_FLOAT, GL_FALSE, 0, m_textureCoordinateArray);

	m_blitProgram->bind();
	m_blitProgram->enableAttributeArray(int(QT_VERTEX_COORDS_ATTR));
	m_blitProgram->enableAttributeArray(int(QT_TEXTURE_COORDS_ATTR));
	m_blitProgram->disableAttributeArray(int(QT_OPACITY_ATTR));

	blitProgram = m_blitProgram;

	} else {
	pex->setVertexAttributePointer(QT_VERTEX_COORDS_ATTR, m_vertexCoordinateArray);
	pex->setVertexAttributePointer(QT_TEXTURE_COORDS_ATTR, m_textureCoordinateArray);

	pex->shaderManager->useBlitProgram();
	blitProgram = pex->shaderManager->blitProgram();
	}

	blitProgram->setUniformValue("imageTexture", QT_IMAGE_TEXTURE_UNIT);

	funcs->glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

	funcs->glBindTexture(GL_TEXTURE_2D, m_textureResource->m_texture);

	funcs->glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, oldWidth, oldHeight);

	funcs->glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
	GL_RENDERBUFFER, 0);
	funcs->glDeleteTextures(1, &tmp_texture);
	funcs->glDeleteTextures(1, &oldTexture);

	funcs->glBindFramebuffer(GL_FRAMEBUFFER, ctx->d_ptr->current_fbo);

	if (pex != 0) {
	funcs->glViewport(0, 0, pex->width, pex->height);
	pex->updateClipScissorTest();
	}
	}

	void QGLTextureGlyphCache::fillTexture(const Coord &c, glyph_t glyph, QFixed subPixelPosition)
	{
	QGLContext ctx = const_cast<QGLContext >(QGLContext::currentContext());
	if (ctx == 0) {
	qWarning("QGLTextureGlyphCache::fillTexture: Called with no context");
	return;
	}
	QOpenGLFunctions *funcs = ctx->contextHandle()->functions();

	if (!QGLFramebufferObject::hasOpenGLFramebufferObjects() \|\| ctx->d_ptr->workaround_brokenFBOReadBack) {
	QImageTextureGlyphCache::fillTexture(c, glyph, subPixelPosition);

	funcs->glBindTexture(GL_TEXTURE_2D, m_textureResource->m_texture);
	const QImage &texture = image();
	const uchar *bits = texture.constBits();
	bits += c.y * texture.bytesPerLine() + c.x;
	for (int i=0; i<c.h; ++i) {
	funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y + i, c.w, 1, GL_ALPHA, GL_UNSIGNED_BYTE, bits);
	bits += texture.bytesPerLine();
	}
	return;
	}

	QImage mask = textureMapForGlyph(glyph, subPixelPosition);
	const int maskWidth = mask.width();
	const int maskHeight = mask.height();

	if (mask.format() == QImage::Format_Mono) {
	mask = mask.convertToFormat(QImage::Format_Indexed8);
	for (int y = 0; y < maskHeight; ++y) {
	uchar src = (uchar ) mask.scanLine(y);
	for (int x = 0; x < maskWidth; ++x)
	src[x] = -src[x]; // convert 0 and 1 into 0 and 255
	}
	} else if (mask.depth() == 32) {
	// Make the alpha component equal to the average of the RGB values.
	// This is needed when drawing sub-pixel antialiased text on translucent targets.
	for (int y = 0; y < maskHeight; ++y) {
	quint32 src = (quint32 ) mask.scanLine(y);
	for (int x = 0; x < maskWidth; ++x) {
	int r = qRed(src[x]);
	int g = qGreen(src[x]);
	int b = qBlue(src[x]);
	int avg;
	if (mask.format() == QImage::Format_RGB32)
	avg = (r + g + b + 1) / 3; // "+1" for rounding.
	else // Format_ARGB_Premultiplied
	avg = qAlpha(src[x]);
	if (ctx->contextHandle()->isOpenGLES()) {
	// swizzle the bits to accommodate for the GL_RGBA upload.
	src[x] = (avg << 24) \| (r << 0) \| (g << 8) \| (b << 16);
	} else {
	src[x] = (src[x] & 0x00ffffff) \| (avg << 24);
	}
	}
	}
	}

	funcs->glBindTexture(GL_TEXTURE_2D, m_textureResource->m_texture);
	if (mask.depth() == 32) {
	GLenum format = GL_RGBA;
	#if !defined(QT_OPENGL_ES_2)
	if (!ctx->contextHandle()->isOpenGLES())
	format = GL_BGRA;
	#endif
	funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y, maskWidth, maskHeight, format, GL_UNSIGNED_BYTE, mask.bits());
	} else {
	// glTexSubImage2D() might cause some garbage to appear in the texture if the mask width is
	// not a multiple of four bytes. The bug appeared on a computer with 32-bit Windows Vista
	// and nVidia GeForce 8500GT. GL_UNPACK_ALIGNMENT is set to four bytes, 'mask' has a
	// multiple of four bytes per line, and most of the glyph shows up correctly in the
	// texture, which makes me think that this is a driver bug.
	// One workaround is to make sure the mask width is a multiple of four bytes, for instance
	// by converting it to a format with four bytes per pixel. Another is to copy one line at a
	// time.

	if (!ctx->d_ptr->workaround_brokenAlphaTexSubImage_init) {
	// don't know which driver versions exhibit this bug, so be conservative for now
	const QByteArray vendorString(reinterpret_cast<const char*>(funcs->glGetString(GL_VENDOR)));
	ctx->d_ptr->workaround_brokenAlphaTexSubImage = vendorString.indexOf("NVIDIA") >= 0;
	ctx->d_ptr->workaround_brokenAlphaTexSubImage_init = true;
	}

	if (ctx->d_ptr->workaround_brokenAlphaTexSubImage) {
	for (int i = 0; i < maskHeight; ++i)
	funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y + i, maskWidth, 1, GL_ALPHA, GL_UNSIGNED_BYTE, mask.scanLine(i));
	} else {
	funcs->glTexSubImage2D(GL_TEXTURE_2D, 0, c.x, c.y, maskWidth, maskHeight, GL_ALPHA, GL_UNSIGNED_BYTE, mask.bits());
	}
	}
	}

	int QGLTextureGlyphCache::glyphPadding() const
	{
	return 1;
	}

	int QGLTextureGlyphCache::maxTextureWidth() const
	{
	QGLContext ctx = const_cast<QGLContext >(QGLContext::currentContext());
	if (ctx == 0)
	return QImageTextureGlyphCache::maxTextureWidth();
	else
	return ctx->d_ptr->maxTextureSize();
	}

	int QGLTextureGlyphCache::maxTextureHeight() const
	{
	QGLContext ctx = const_cast<QGLContext >(QGLContext::currentContext());
	if (ctx == 0)
	return QImageTextureGlyphCache::maxTextureHeight();

	if (ctx->d_ptr->workaround_brokenTexSubImage)
	return qMin(1024, ctx->d_ptr->maxTextureSize());
	else
	return ctx->d_ptr->maxTextureSize();
	}

	void QGLTextureGlyphCache::clear()
	{
	m_textureResource->free();
	m_textureResource = 0;

	m_w = 0;
	m_h = 0;
	m_cx = 0;
	m_cy = 0;
	m_currentRowHeight = 0;
	coords.clear();
	}

	QT_END_NAMESPACE