main.cpp Example File

graphicsview/boxes/main.cpp
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//#include <GL/glew.h> #include "glextensions.h" #include "scene.h" #include <QtWidgets> #include <QGLWidget> class GraphicsView : public QGraphicsView { public: GraphicsView() { setWindowTitle(tr("Boxes")); setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform); //setRenderHints(QPainter::SmoothPixmapTransform); } protected: void resizeEvent(QResizeEvent *event) override { if (scene()) scene()->setSceneRect(QRect(QPoint(0, 0), event->size())); QGraphicsView::resizeEvent(event); } }; inline bool matchString(const char *extensionString, const char *subString) { int subStringLength = strlen(subString); return (strncmp(extensionString, subString, subStringLength) == 0) && ((extensionString[subStringLength] == ' ') || (extensionString[subStringLength] == '\0')); } bool necessaryExtensionsSupported() { const char *extensionString = reinterpret_cast<const char *>(glGetString(GL_EXTENSIONS)); const char *p = extensionString; const int GL_EXT_FBO = 1; const int GL_ARB_VS = 2; const int GL_ARB_FS = 4; const int GL_ARB_SO = 8; int extensions = 0; while (*p) { if (matchString(p, "GL_EXT_framebuffer_object")) extensions |= GL_EXT_FBO; else if (matchString(p, "GL_ARB_vertex_shader")) extensions |= GL_ARB_VS; else if (matchString(p, "GL_ARB_fragment_shader")) extensions |= GL_ARB_FS; else if (matchString(p, "GL_ARB_shader_objects")) extensions |= GL_ARB_SO; while ((*p != ' ') && (*p != '\0')) ++p; if (*p == ' ') ++p; } return (extensions == 15); } int main(int argc, char **argv) { QApplication app(argc, argv); if ((QGLFormat::openGLVersionFlags() & QGLFormat::OpenGL_Version_1_5) == 0) { QMessageBox::critical(0, "OpenGL features missing", "OpenGL version 1.5 or higher is required to run this demo.\n" "The program will now exit."); return -1; } int maxTextureSize = 1024; QGLWidget *widget = new QGLWidget(QGLFormat(QGL::SampleBuffers)); widget->makeCurrent(); if (!necessaryExtensionsSupported()) { QMessageBox::critical(0, "OpenGL features missing", "The OpenGL extensions required to run this demo are missing.\n" "The program will now exit."); delete widget; return -2; } // Check if all the necessary functions are resolved. if (!getGLExtensionFunctions().resolve(widget->context())) { QMessageBox::critical(0, "OpenGL features missing", "Failed to resolve OpenGL functions required to run this demo.\n" "The program will now exit."); delete widget; return -3; } // TODO: Make conditional for final release QMessageBox::information(0, "For your information", "This demo can be GPU and CPU intensive and may\n" "work poorly or not at all on your system."); widget->makeCurrent(); // The current context must be set before calling Scene's constructor Scene scene(1024, 768, maxTextureSize); GraphicsView view; view.setViewport(widget); view.setViewportUpdateMode(QGraphicsView::FullViewportUpdate); view.setScene(&scene); view.show(); return app.exec(); }

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