201 lines
6.3 KiB
C++
201 lines
6.3 KiB
C++
/****************************************************************************
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**
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** Copyright (C) 2017 The Qt Company Ltd.
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** Contact: https://www.qt.io/licensing/
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**
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** This file is part of the examples of the Qt Toolkit.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** Commercial License Usage
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** Licensees holding valid commercial Qt licenses may use this file in
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** accordance with the commercial license agreement provided with the
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** Software or, alternatively, in accordance with the terms contained in
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** a written agreement between you and The Qt Company. For licensing terms
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** and conditions see https://www.qt.io/terms-conditions. For further
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** information use the contact form at https://www.qt.io/contact-us.
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**
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** BSD License Usage
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** Alternatively, you may use this file under the terms of the BSD license
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** as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of The Qt Company Ltd nor the names of its
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** contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include "openglrenderer.h"
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#include <QQuickItem>
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#if QT_CONFIG(opengl)
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#include <QOpenGLShaderProgram>
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#include <QOpenGLBuffer>
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#include <QOpenGLFunctions>
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//! [1]
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OpenGLRenderNode::~OpenGLRenderNode()
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{
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releaseResources();
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}
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void OpenGLRenderNode::releaseResources()
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{
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delete m_program;
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m_program = nullptr;
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delete m_vbo;
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m_vbo = nullptr;
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}
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//! [1]
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void OpenGLRenderNode::init()
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{
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m_program = new QOpenGLShaderProgram;
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static const char *vertexShaderSource =
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"attribute highp vec4 posAttr;\n"
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"attribute lowp vec4 colAttr;\n"
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"varying lowp vec4 col;\n"
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"uniform highp mat4 matrix;\n"
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"void main() {\n"
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" col = colAttr;\n"
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" gl_Position = matrix * posAttr;\n"
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"}\n";
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static const char *fragmentShaderSource =
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"varying lowp vec4 col;\n"
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"uniform lowp float opacity;\n"
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"void main() {\n"
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" gl_FragColor = col * opacity;\n"
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"}\n";
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m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
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m_program->addCacheableShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
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m_program->bindAttributeLocation("posAttr", 0);
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m_program->bindAttributeLocation("colAttr", 1);
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m_program->link();
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m_matrixUniform = m_program->uniformLocation("matrix");
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m_opacityUniform = m_program->uniformLocation("opacity");
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const int VERTEX_SIZE = 6 * sizeof(GLfloat);
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static GLfloat colors[] = {
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1.0f, 0.0f, 0.0f,
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0.0f, 1.0f, 0.0f,
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0.0f, 0.0f, 1.0f
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};
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m_vbo = new QOpenGLBuffer;
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m_vbo->create();
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m_vbo->bind();
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m_vbo->allocate(VERTEX_SIZE + sizeof(colors));
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m_vbo->write(VERTEX_SIZE, colors, sizeof(colors));
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m_vbo->release();
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}
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//! [2]
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void OpenGLRenderNode::render(const RenderState *state)
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{
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if (!m_program)
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init();
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QOpenGLFunctions *f = QOpenGLContext::currentContext()->functions();
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m_program->bind();
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m_program->setUniformValue(m_matrixUniform, *state->projectionMatrix() * *matrix());
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m_program->setUniformValue(m_opacityUniform, float(inheritedOpacity()));
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//! [2]
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m_vbo->bind();
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//! [5]
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QPointF p0(m_width - 1, m_height - 1);
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QPointF p1(0, 0);
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QPointF p2(0, m_height - 1);
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GLfloat vertices[6] = { GLfloat(p0.x()), GLfloat(p0.y()),
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GLfloat(p1.x()), GLfloat(p1.y()),
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GLfloat(p2.x()), GLfloat(p2.y()) };
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m_vbo->write(0, vertices, sizeof(vertices));
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//! [5]
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m_program->setAttributeBuffer(0, GL_FLOAT, 0, 2);
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m_program->setAttributeBuffer(1, GL_FLOAT, sizeof(vertices), 3);
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m_program->enableAttributeArray(0);
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m_program->enableAttributeArray(1);
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// We are prepared both for the legacy (direct OpenGL) and the modern
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// (abstracted by RHI) OpenGL scenegraph. So set all the states that are
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// important to us.
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//! [3]
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f->glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
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f->glEnable(GL_BLEND);
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f->glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
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// Clip support.
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if (state->scissorEnabled()) {
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f->glEnable(GL_SCISSOR_TEST);
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const QRect r = state->scissorRect(); // already bottom-up
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f->glScissor(r.x(), r.y(), r.width(), r.height());
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}
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if (state->stencilEnabled()) {
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f->glEnable(GL_STENCIL_TEST);
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f->glStencilFunc(GL_EQUAL, state->stencilValue(), 0xFF);
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f->glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
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}
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f->glDrawArrays(GL_TRIANGLES, 0, 3);
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//! [3]
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}
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//! [4]
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QSGRenderNode::StateFlags OpenGLRenderNode::changedStates() const
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{
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return BlendState | ScissorState | StencilState;
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}
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QSGRenderNode::RenderingFlags OpenGLRenderNode::flags() const
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{
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return BoundedRectRendering | DepthAwareRendering;
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}
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QRectF OpenGLRenderNode::rect() const
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{
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return QRect(0, 0, m_width, m_height);
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}
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//! [4]
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void OpenGLRenderNode::sync(QQuickItem *item)
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{
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m_width = item->width();
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m_height = item->height();
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}
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#endif // opengl
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