Question

我搜索了很多，没有回答我的问题。我正在学习OpenGL，而且我正在使用Qt编写小程序，因为我想使用Raspberry PI 2。

我正在努力学习一个简单的程序：绘制一个矩形（带有索引的4个顶点）和一个纹理。正如我所说，我使用的是Qt，因此是QOpenGLWidget的子类。

当我为桌面编译这个程序时，它运行得很好。在这种情况下，我猜Qt使用OpenGL。当我打开ARM时，我想使用OpenGL ES 2.0进行Qt编译。而且我没有看到直肠。哪里错了？我疯了。

头文件;

 #ifndef MYGLWIDGET_H
 #define MYGLWIDGET_H

    #include <QOpenGLWidget>
    #include <QOpenGLFunctions>
    #include <QOpenGLBuffer>
    #include <QOpenGLShader>
    #include <QOpenGLTexture>

    class MyGLWidget : public QOpenGLWidget, protected QOpenGLFunctions
    {
        Q_OBJECT
    public:
        explicit MyGLWidget(QWidget *parent = 0);
        ~MyGLWidget();

        static const GLfloat vertices[];
        static const GLuint indices[];
        static const GLfloat textureVertex[];


    protected:
        void resizeGL(int w, int h) Q_DECL_OVERRIDE;
        void paintGL() Q_DECL_OVERRIDE;
        void initializeGL() Q_DECL_OVERRIDE;

    private:
         QOpenGLShader *m_vshader1;
         QOpenGLShader *m_fshader1;
         QOpenGLShaderProgram *m_program1;
         QOpenGLBuffer m_vbo1;
         int m_vertexAttr1;
         int m_texAttr1;
         QOpenGLTexture *_texture;

    signals:

    public slots:
    };

    #endif // MYGLWIDGET_H

CPP文件：

#include "myglwidget.h"

//Set up vertex data (and buffer(s)) and attribute pointers
const GLfloat  MyGLWidget::vertices[] = {
             0.5f,  0.5f, 0.0f,  // Top Right
             0.5f, -0.5f, 0.0f,// Bottom Right
            -0.5f, -0.5f, 0.0f,// Bottom Left
            -0.5f,  0.5f, 0.0f// Top Left
  };

//setup the order of vertices (indexes)
const GLuint MyGLWidget::indices[] = {  // Note that we start from 0!
       0, 3, 2,  // First Triangle
       2, 1, 0   // Second Triangle 0, 1, 2
   };


//Set up vertex for textures
const GLfloat  MyGLWidget::textureVertex[] = {

          1.0f,  1.0f,  // Top Right
          1.0f,  0.0f,// Bottom Right
          0.0f,  0.0f,// Bottom Left
          0.0f,  1.0f// Top Left
};

MyGLWidget::MyGLWidget(QWidget *parent):
  QOpenGLWidget(parent)
{

}

MyGLWidget::~MyGLWidget()
{
    // And now release all OpenGL resources.
    makeCurrent();

    delete m_vshader1;
    delete m_fshader1;
    delete _texture;
    delete m_program1;
    m_vbo1.destroy();
    doneCurrent();
}


void MyGLWidget::initializeGL()
{
    initializeOpenGLFunctions();
    m_vshader1 = new QOpenGLShader(QOpenGLShader::Vertex);
    const char *vsrc1 =
            "attribute vec3 aPosition; \n"
            "attribute vec2 aTexCoord; \n"
            "varying vec2 vTexCoord; \n"
            "void main() \n"
            "{ \n"
            " gl_Position = vec4(aPosition, 1.0); \n"
            " vTexCoord = aTexCoord; \n"
            "} \n";

    bool r = m_vshader1->compileSourceCode(vsrc1);
    qDebug()<<"Compilation shader = "<<r;

    m_fshader1 = new QOpenGLShader(QOpenGLShader::Fragment);
    const char *fsrc1 =
            "varying vec2 vTexCoord; \n"
            "uniform sampler2D ourTexture; \n"
            "void main() \n"
            "{ \n"
           " gl_FragColor =texture2D(ourTexture, vTexCoord); \n"
            "} \n";
    r = m_fshader1->compileSourceCode(fsrc1);
    qDebug()<<"Compilation shaders = "<<r;

    m_program1 = new QOpenGLShaderProgram;
    m_program1->addShader(m_vshader1);
    m_program1->addShader(m_fshader1);
    qDebug()<<"Link = "<<m_program1->link();

    m_vertexAttr1 = m_program1->attributeLocation("aPosition");
    qDebug()<<"Aposition index = "<<m_vertexAttr1;
    m_texAttr1 = m_program1->attributeLocation("aTexCoord");
    qDebug()<<"aTexCoord index = "<<m_texAttr1;


    // Use a vertex buffer object. Client-side pointers are old-school and should be avoided.
    m_vbo1.create();
    m_vbo1.bind();
    m_vbo1.allocate(sizeof(vertices) + sizeof(textureVertex));
    //add vertices
    m_vbo1.write(0, vertices, sizeof(vertices));
    //add texture vertices
    m_vbo1.write(sizeof(vertices), textureVertex, sizeof(textureVertex));

    //texture
    QImage image("./oneframe.png");
    qDebug()<<"Image = "<<image.byteCount()<<" bytes";
    _texture = new QOpenGLTexture(QImage("./oneframe.png").mirrored());
    _texture->setMinificationFilter(QOpenGLTexture::LinearMipMapLinear);
    _texture->setMagnificationFilter(QOpenGLTexture::Linear);

    m_vbo1.release();

}

void MyGLWidget::resizeGL(int w, int h)
{

}


void MyGLWidget::paintGL()
{
    glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    m_program1->bind();
    m_program1->enableAttributeArray(m_vertexAttr1);
    m_program1->enableAttributeArray(m_texAttr1);

    m_vbo1.bind();
    m_program1->setAttributeBuffer(m_vertexAttr1, GL_FLOAT, 0, 3);
    m_program1->setAttributeBuffer(m_texAttr1, GL_FLOAT, sizeof(vertices), 2);


    _texture->bind();
    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, indices);

      m_vbo1.release();


    m_program1->disableAttributeArray(m_vertexAttr1);
    m_program1->disableAttributeArray(m_texAttr1);
    m_program1->release();
}

在桌面上，我看到矩形中带有纹理的主窗口。

我在Raspberry下运行此程序时看到的只是具有背景颜色的主窗口...没有三角形可见。 PNG文件位于同一目录中。

感谢您的帮助。

克里斯蒂

Qt OpenGL ES 2.0 - 无法绘制矩形

0 个答案: