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++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
++
++ #include "openglwindow.h"
++
++ #include <QGuiApplication>
++ #include <QMatrix4x4>
++ #include <QOpenGLShaderProgram>
++ #include <QOpenGLBuffer>
++ #include <QScreen>
++ #include <QtMath>
++
++ //! [1]
++ class TriangleWindow : public OpenGLWindow
++ {
++ public:
++ using OpenGLWindow::OpenGLWindow;
++
++ void initialize() override;
++ void render() override;
++
++ private:
++ GLint m_matrixUniform = 0;
++ QOpenGLBuffer m_vbo;
++ QOpenGLShaderProgram *m_program = nullptr;
++ int m_frame = 0;
++ };
++ //! [1]
++
++ //! [2]
++ int main(int argc, char **argv)
++ {
++ QGuiApplication app(argc, argv);
++
++ QSurfaceFormat format;
++ format.setSamples(16);
++
++ TriangleWindow window;
++ window.setFormat(format);
++ window.resize(640, 480);
++ window.show();
++
++ window.setAnimating(true);
++
++ return app.exec();
++ }
++ //! [2]
++
++ //! [3]
++ static const char *vertexShaderSource = "attribute highp vec4 posAttr;\n"
++ "attribute lowp vec4 colAttr;\n"
++ "varying lowp vec4 col;\n"
++ "uniform highp mat4 matrix;\n"
++ "void main() {\n"
++ " col = colAttr;\n"
++ " gl_Position = matrix * posAttr;\n"
++ "}\n";
++
++ static const char *fragmentShaderSource = "varying lowp vec4 col;\n"
++ "void main() {\n"
++ " gl_FragColor = col;\n"
++ "}\n";
++ //! [3]
++
++ //! [4]
++ void TriangleWindow::initialize()
++ {
++ static const GLfloat vertices_colors[] = { +0.0f, +0.707f, 1.0f, 0.0f, 0.0f,
++ -0.5f, -0.500f, 0.0f, 1.0f, 0.0f,
++ +0.5f, -0.500f, 0.0f, 0.0f, 1.0f };
++
++ m_vbo.create();
++ m_vbo.bind();
++ m_vbo.allocate(vertices_colors, sizeof(vertices_colors));
++
++ glEnableVertexAttribArray(0);
++ glEnableVertexAttribArray(1);
++
++ glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat), nullptr);
++ glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(GLfloat),
++ reinterpret_cast<void *>(2 * sizeof(GLfloat)));
++
++ m_program = new QOpenGLShaderProgram(this);
++ m_program->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
++ m_program->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
++ m_program->bindAttributeLocation("posAttr", 0);
++ m_program->bindAttributeLocation("colAttr", 1);
++ m_program->link();
++ m_program->bind();
++
++ m_matrixUniform = m_program->uniformLocation("matrix");
++ Q_ASSERT(m_matrixUniform != -1);
++ }
++ //! [4]
++
++ //! [5]
++ void TriangleWindow::render()
++ {
++ const qreal retinaScale = devicePixelRatio();
++ glViewport(0, 0, width() * retinaScale, height() * retinaScale);
++
++ glClear(GL_COLOR_BUFFER_BIT);
++
++ m_program->bind();
++
++ QMatrix4x4 matrix;
++ matrix.perspective(60.0f, 4.0f / 3.0f, 0.1f, 100.0f);
++ matrix.translate(0, 0, -2);
++ matrix.rotate(100.0f * m_frame / screen()->refreshRate(), 0, 1, 0);
++
++ m_program->setUniformValue(m_matrixUniform, matrix);
++
++ glEnableVertexAttribArray(0);
++ glEnableVertexAttribArray(1);
++
++ glDrawArrays(GL_TRIANGLES, 0, 3);
++
++ glDisableVertexAttribArray(0);
++ glDisableVertexAttribArray(1);
++
++ m_program->release();
++
++ ++m_frame;
++ }
++ //! [5]