06——qt opengl 立方体 ebo 贴图

qmyopenglwidget.h

#ifndef QMYOPENGLWIDGET_H
#define QMYOPENGLWIDGET_H

#include <QWidget>
#include <QOpenGLWidget>
#include <QOpenGLFunctions_3_3_Core>
#include <QOpenGLShaderProgram>

class QMyOpenglWidget : public QOpenGLWidget, QOpenGLFunctions_3_3_Core
{
public:
    enum EType {
        eNone,
        eFull,
        eLine,
        ePoint,

    };

    Q_OBJECT
public:
    explicit QMyOpenglWidget(QWidget* parent = nullptr);

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

public:
    void cretaeShader();
    void initDrawData(GLuint &vao, float *vertices, int vSize, GLuint &ebo);
    void modeChange(EType type = eLine);
    unsigned int setImage(const char *filename);

private:
    unsigned int vao1;
    unsigned int ebo1;
    QOpenGLShaderProgram program;

    GLuint programId;
    GLint mLocation;
    GLint vLocation;
    GLint pLocation;

    GLint vertexLocation;
    GLint colorLocation;
    GLint uvLocation;

    QMatrix4x4 mMatrix;
    QMatrix4x4 vMatrix;
    QMatrix4x4 pMatrix;

    unsigned int texture0;


signals:

public slots:


};

#endif // QMYOPENGLWIDGET_H

qmyopenglwidget.cpp

#include "qmyopenglwidget.h"
#include <QGLWidget>

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

}

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

    cretaeShader();

    //三角形顶点坐标
    float s = 2.0f/2;
    GLfloat vertices[] = {
        -s, -s, -s,
         s, -s, -s,
         s, -s,  s,
        -s, -s,  s,
        -s,  s, -s,
         s,  s, -s,
         s,  s,  s,
        -s,  s,  s,

        -s, -s, -s,
        -s, -s,  s,
        -s,  s,  s,
        -s,  s, -s,

         s, -s, -s,
         s, -s,  s,
         s,  s,  s,
         s,  s, -s,


    };

    initDrawData(vao1, vertices, sizeof(vertices), ebo1);

    glEnable(GL_CULL_FACE); //启动了背面裁剪
    glFrontFace(GL_CCW); //设置逆时针为正面
}

void QMyOpenglWidget::resizeGL(int w, int h)
{
    glViewport(0, 0, w, h);
    pMatrix.setToIdentity();
    float aspect = float(w*1.0)/ float(h);
    //printf("aspect = %f \n", aspect);
    qDebug()<<"aspect = "<<aspect<<" resizeGL";
    //aspect = int(aspect * 100) / 100.0f;
    //aspect = 1.42857f;
    pMatrix.perspective(45.0f, aspect, 0.000f, 100.f);
    //pMatrix.ortho(0, 0 , w, h, 0, 100);
    vMatrix.lookAt(QVector3D{0.0,0.0,-1.0}, QVector3D{0.0,0.0,1.0},QVector3D{0.0,1.0,0.0});
    mMatrix.setToIdentity();
    mMatrix.translate(QVector3D{0.0,0.0,3.0});

    mMatrix.rotate(-30, QVector3D{1.0,0.0,0.0});
    update();
}

void QMyOpenglWidget::paintGL()
{
    //qDebug()<<" paintGL";
    glClearColor(0.2f, 0.2f, 0.1f, 0.1f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glUniformMatrix4fv(mLocation, 1, GL_FALSE, mMatrix.data());
    glUniformMatrix4fv(vLocation, 1, GL_FALSE, vMatrix.data());
    glUniformMatrix4fv(pLocation, 1, GL_FALSE, pMatrix.data());

    //glActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, texture0);

    mMatrix.rotate(1, QVector3D{0.0,1.0,0.0});

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,ebo1);
    glBindVertexArray(vao1);

    glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_INT, nullptr);
    //glDrawArrays(GL_TRIANGLES, 0, 36);

    update();

    //draw(eLine);
}

void QMyOpenglWidget::cretaeShader()
{
    program.addShaderFromSourceFile(QOpenGLShader::Vertex, ":/vertex.vert");
    program.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/frag.frag");
    program.bind();
    program.link();

    programId = program.programId();
    mLocation = glGetUniformLocation(programId, "mMatrix");
    vLocation = glGetUniformLocation(programId, "vMatrix");
    pLocation = glGetUniformLocation(programId, "pMatrix");
    vertexLocation = glGetAttribLocation(programId, "pos");
    colorLocation = glGetAttribLocation(programId, "color");
    uvLocation = glGetAttribLocation(programId, "uv0");


    Q_ASSERT(mLocation != -1);
    Q_ASSERT(vLocation != -1);
    Q_ASSERT(pLocation != -1);
    Q_ASSERT(vertexLocation != -1);
    Q_ASSERT(colorLocation != -1);
}

void QMyOpenglWidget::initDrawData(GLuint &vao, float *vertices, int vSize, GLuint &ebo)
{


    //顶点索引
    GLuint indexs[] = {
        //0, 3, 4, 3, 7, 4, // 左 ADHE
        //1, 6, 2, 1, 5, 6, // 右 BCGF
        0, 5, 1, 0, 4, 5, // 前 ABFE
        2, 7, 3, 2, 6, 7,  // 后 DCGH
        7, 5, 4, 7, 6, 5, // 上 EFGH
        0, 1, 3, 1, 2, 3, // 下 ABCD

        8, 9, 11, 9, 10, 11, // 左 ADHE
        12, 14, 13, 12, 15, 14, // 右 BCGF


    };



    GLfloat uv[] = {0, 0,
                    1, 0,
                    1, 1,
                    0, 1,
                    0, 1,
                    1, 1,
                    1, 0,
                    0, 0,

                    0, 0,
                    1, 0,
                    1, 1,
                    0, 1,
                    0, 1,
                    1, 1,
                    1, 0,
                    0, 0,

                    };


    //顶点点颜色
    GLfloat colors[] = {  1.0f, 0.0f, 0.0f,1.0f ,  //红
                         0.0f, 1.0f, 0.0f ,1.0f ,  //绿
                         0.0f, 0.0f, 1.0f ,1.0f ,  //蓝
                         0.0f, 0.0f, 0.0f ,1.0f ,  //白
                          1.0f, 0.0f, 0.0f,1.0f ,  //红
                           0.0f, 1.0f, 0.0f ,1.0f ,  //绿
                           0.0f, 0.0f, 1.0f ,1.0f ,  //蓝
                           0.0f, 0.0f, 0.0f ,1.0f ,  //白

                          1.0f, 0.0f, 0.0f,1.0f ,  //红
                           0.0f, 1.0f, 0.0f ,1.0f ,  //绿
                           0.0f, 0.0f, 1.0f ,1.0f ,  //蓝
                           0.0f, 0.0f, 0.0f ,1.0f ,  //白
                            1.0f, 0.0f, 0.0f,1.0f ,  //红
                             0.0f, 1.0f, 0.0f ,1.0f ,  //绿
                             0.0f, 0.0f, 1.0f ,1.0f ,  //蓝
                             0.0f, 0.0f, 0.0f ,1.0f ,  //白
                       };


    //**************vao******************************//
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);

    //******************* Vbo vertices*******************//
    unsigned int vbo1;
    glGenBuffers(1, &vbo1);
    glBindBuffer(GL_ARRAY_BUFFER, vbo1);
    //为当前绑定到target 的缓冲区对象创建一个新的数据存储  //
    glBufferData(GL_ARRAY_BUFFER, vSize, vertices, GL_STATIC_DRAW);
    //告知显卡如何解析缓冲区里的属性值
    glVertexAttribPointer(vertexLocation, 3, GL_FLOAT, FALSE, 3*sizeof (GL_FLOAT), nullptr);
    //开启VAO管理的第一个属性
    glEnableVertexAttribArray(vertexLocation);

    //************** Vbo color**************************/
    unsigned int vboColor;
    glGenBuffers(1, &vboColor);
    glBindBuffer(GL_ARRAY_BUFFER, vboColor);
    //为当前绑定到target 的缓冲区对象创建一个新的数据存储  //
    glBufferData(GL_ARRAY_BUFFER, sizeof(colors), colors, GL_STATIC_DRAW);
    //告知显卡如何解析缓冲区里的属性值
    glVertexAttribPointer(colorLocation, 4, GL_FLOAT, FALSE, 4*sizeof (GL_FLOAT), nullptr);
    //开启VAO管理的第一个属性
    glEnableVertexAttribArray(colorLocation);


    glUniform1i(glGetUniformLocation(programId, "texture0"), 0);
    texture0 = setImage(":/n.jpg");


    //************** Vbo UV**************************/
    unsigned int vboUv;
    glGenBuffers(1, &vboUv);
    glBindBuffer(GL_ARRAY_BUFFER, vboUv);
    //为当前绑定到target 的缓冲区对象创建一个新的数据存储  //
    glBufferData(GL_ARRAY_BUFFER, sizeof(uv), uv, GL_STATIC_DRAW);
    //告知显卡如何解析缓冲区里的属性值
    glVertexAttribPointer(uvLocation, 2, GL_FLOAT, FALSE, 2*sizeof (GL_FLOAT), nullptr);
    //开启VAO管理的第一个属性
    glEnableVertexAttribArray(uvLocation);


    //***************EBO ******************************/
    glGenBuffers(1, &ebo);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof (indexs), indexs, GL_STATIC_DRAW);
}

unsigned int QMyOpenglWidget:: setImage(const char *filename)
{
    QImage image = QImage(filename);
    image = QGLWidget::convertToGLFormat(image); //格式转换

    unsigned int texture;
    glGenTextures(1, &texture);
    //glActiveTexture(textureNum);
    glBindTexture(GL_TEXTURE_2D, texture);

    // set the texture wrapping/filtering options (on the currently bound texture object)
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    // load and generate the texture
    int width, height, nrChannels;
    width = image.width();
    height = image.height();
    nrChannels = image.depth();
    Q_ASSERT(width>0 && height > 0);
    //unsigned char *data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);
    if (image.bits())
    {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image.bits());
        glGenerateMipmap(GL_TEXTURE_2D);
    }
    else
    {
        //std::cout << "Failed to load texture" << std::endl;
        Q_ASSERT(0);
    }


    return texture;

}

void QMyOpenglWidget::modeChange(QMyOpenglWidget::EType type)
{
    makeCurrent(); //设置当前opengl 渲染环境
    switch(type)
    {
        case eLine: {glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); break;}
        case eFull: {glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); break;}
        case ePoint: {glPolygonMode(GL_FRONT_AND_BACK, GL_POINT); break;}
        default: {glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); break;}
    }


    //glBindVertexArray(vao1);
    //glDrawArrays(GL_TRIANGLES, 0, 3);
    update();
    doneCurrent();
}

vertex.vert

#version 330 core
uniform mat4 pMatrix;
uniform mat4 vMatrix;
uniform mat4 mMatrix;
in vec3 pos;
in vec4 color;
in vec2 uv0;
out vec4 fcolor;
out vec2 TexCoord0;
void main(void)
{
    fcolor = color;
    gl_Position = pMatrix  * vMatrix * mMatrix * vec4(pos, 1.0);
    TexCoord0 = uv0;
}

frag.frag

#version 330 core
in vec4 fcolor;
out vec4 FragColor; //片段着色器输出
in vec2 TexCoord0;
uniform sampler2D texture0;
void main(void)
{
    FragColor = fcolor*0.3 +  texture2D(texture0, TexCoord0);
}