glwidget.cpp

#include "glwidget.h"

GLWidget::GLWidget(QWidget *parent) : QOpenGLWidget(parent)
{
    projectionMatrix.setToIdentity();
    projectionMatrix.ortho(-1, 1, -1, 1, 0, 2);
    viewMatrix.setToIdentity();
    viewMatrix.translate(0, 0, -1);
}

void GLWidget::initializeGL()
{
    initializeOpenGLFunctions();

    qDebug("OpenGL version: %s", glGetString(GL_VERSION));
    qDebug("GLSL %s", glGetString(GL_SHADING_LANGUAGE_VERSION));

    glEnable(GL_DEPTH_TEST);
}

void GLWidget::resizeGL(int w, int h)
{
    glViewport(0, 0, w, h);
}

void GLWidget::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    if (!model)
        return;

    int shaderProgramID = model->shaderProgram.at(model->shaderIndex);
    QVector4D ambientProduct = light.ambient*model->material.ambient;
    QVector4D diffuseProduct = light.diffuse*model->material.diffuse;
    QVector4D specularProduct = light.specular*model->material.specular;

    GLuint locShininess = glGetUniformLocation(shaderProgramID, "shininess");
    GLuint locProjection = glGetUniformLocation(shaderProgramID, "projection");
    GLuint locView = glGetUniformLocation(shaderProgramID, "view");
    GLuint locLightPosition = glGetUniformLocation(shaderProgramID, "lightPosition");
    GLuint locAmbientProduct = glGetUniformLocation(shaderProgramID, "ambientProduct");
    GLuint locDiffuseProduct = glGetUniformLocation(shaderProgramID, "diffuseProduct");
    GLuint locSpecularProduct = glGetUniformLocation(shaderProgramID, "specularProduct");

    glUniformMatrix4fv(locProjection, 1, GL_FALSE, projectionMatrix.data());
    glUniformMatrix4fv(locView, 1, GL_FALSE, viewMatrix.data());
    glUniform4fv(locLightPosition, 1, &(light.position[0]));
    glUniform4fv(locAmbientProduct, 1, &(ambientProduct[0]));
    glUniform4fv(locDiffuseProduct, 1, &(diffuseProduct[0]));
    glUniform4fv(locSpecularProduct, 1, &(specularProduct[0]));
    glUniform1f(locShininess, model->material.shininess);

    model->drawModel();
}

void GLWidget::changeShader(int shaderIndex)
{
    if(!model)
        return;
    model->shaderIndex = shaderIndex;
    update();
}

void GLWidget::showFileOpenDialog()
{
    QByteArray fileFormat = "off";
    QString fileName = QFileDialog::getOpenFileName(this,
      "Open File", QDir::homePath(),
      QString("\%1 Files(*.\%2)").arg(QString(fileFormat.toUpper())).arg(QString(fileFormat)), 0, nullptr);

    int shaderIndex = 0;

    if(!fileName.isEmpty())
    {
        if(model)
            shaderIndex = model->shaderIndex;

        model = std::make_shared<Model>(this);
        model->shaderIndex = shaderIndex;
        model->readOFFFile(fileName);
        emit statusBarMessage(QString("Vertices: \%1, Faces: \%2").arg(model->numVertices).arg(model->numFaces));
        emit enableComboShaders(true);
    }

    update();
}