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OpenGL: QOpenGLShaderProgram

news 来源：原创 2025/9/21 23:13:36

一、QOpenGLShaderProgram 编译过程的封装
1、bool addShaderFromSourceCode(QGLShader::ShaderType type, const char * source);
2、bool addShaderFromSourceFile(QGLShader::ShaderType type, const QString & fileName);
3、virtual bool link();
4、bool bind();
5、QString log() const;
6、一般将顶点着色器和片段着色器源码放入文件，后缀分别为.vert和.frag。
7、着色器文件可以放入工程目录中，但更推荐放入Qt资源文件中。
8、为了在Qt中正常加载并编辑shader文件，shader文件设置编码为: UTF-8。

二、代码示例

//MyOpenGLWidget.h
#pragma once//需要两个头文件
#include <QOpenGLWidget>
#include <QOpenGLFunctions_4_5_Core>
#include <QOpenGLShaderProgram>class MyOpenGLWidget : public QOpenGLWidget, QOpenGLFunctions_4_5_Core
{Q_OBJECTpublic:MyOpenGLWidget(QWidget * parent = nullptr);~MyOpenGLWidget();enum Shape { None, Rect, Circle, Triangle };void DrawShape(Shape shape);void WireFrame(bool bWire);protected:void initializeGL() override;void resizeGL(int w, int h) override;void paintGL() override;private:unsigned int VAO;unsigned int VBO;unsigned int EBO;Shape m_shape = None;QOpenGLShaderProgram m_shaderProgram;
};//MyOpenGLWidget.cpp
#include "MyOpenGLWidget.h"
#include <QDebug>MyOpenGLWidget::MyOpenGLWidget(QWidget * parent) : QOpenGLWidget(parent)
{
}MyOpenGLWidget::~MyOpenGLWidget()
{makeCurrent();glDeleteBuffers(1, &VBO);glDeleteBuffers(1, &EBO);glDeleteVertexArrays(1, &VAO);doneCurrent();
}void MyOpenGLWidget::DrawShape(Shape shape)
{//触发重新绘制m_shape = shape;update();
}void MyOpenGLWidget::WireFrame(bool bWire)
{makeCurrent();if (bWire){glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);}else{glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);}doneCurrent();update();
}void MyOpenGLWidget::initializeGL()
{initializeOpenGLFunctions();//创建VAO、VBO、EBO，并赋予IDglGenVertexArrays(1, &VAO);glGenBuffers(1, &VBO);glGenBuffers(1, &EBO);//绑定VAO、VBO、EBO对象glBindVertexArray(VAO);glBindBuffer(GL_ARRAY_BUFFER, VBO);glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);  //注意, 因为VAO已经绑定，此句会被VAO的最后一个指针偷偷记录下来, 指向EBO。//顶点数据float vertices[] = {//位置                //颜色0.5f,  0.5f,  0.0f,  1.0f, 0.0f, 0.0f,   // 右上角0.5f, -0.5f,  0.0f,  0.0f, 1.0f, 0.0f,   // 右下角-0.5f, -0.5f,  0.0f,  0.0f, 0.0f, 1.0f,   // 左下角-0.5f,  0.5f,  0.0f,  0.3f, 0.5f, 0.8f,   // 左上角};glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);//索引数据unsigned int indices[] = {0, 1, 3, // 第一个三角形1, 2, 3  // 第二个三角形};glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);//配置VAO位置属性指针glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);glEnableVertexAttribArray(0);//配置VAO颜色属性指针glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)(3 * sizeof(float)));glEnableVertexAttribArray(1);//解绑VAO、VBO、EBOglBindVertexArray(0);glBindBuffer(GL_ARRAY_BUFFER, 0);glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);   //注意，因为VAO已经解绑了，所以此句不会被VAO记录下来，VAO的最后一个指针依然指向EBO，这样好处是绘制前，只要再绑定VAO即可，EBO、VBO都不用再绑定。//着色器程序m_shaderProgram.addShaderFromSourceFile(QOpenGLShader::Vertex, ":/shaders/1_shader.vert");m_shaderProgram.addShaderFromSourceFile(QOpenGLShader::Fragment, ":/shaders/1_shader.frag");bool success = m_shaderProgram.link();if (!success){qDebug() << "ERROR: " << m_shaderProgram.log();}
}void MyOpenGLWidget::resizeGL(int w, int h)
{
}//绘制都是在此函数中，其它地方都是触发绘制
void MyOpenGLWidget::paintGL()
{glClearColor(0.2f, 0.3f, 0.3f, 1.0f);glClear(GL_COLOR_BUFFER_BIT);glBindVertexArray(VAO);m_shaderProgram.bind();switch (m_shape){case MyOpenGLWidget::None:break;case MyOpenGLWidget::Rect:{glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);break;}case MyOpenGLWidget::Circle:break;case MyOpenGLWidget::Triangle:break;default:break;}
}//MainWindow.h
#pragma once#include <QtWidgets/QMainWindow>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindowClass; };
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget * parent = nullptr);~MainWindow();private:void ActDrawRectTriggered(bool checked);void ActClearTriggered(bool checked);void ActWireFrameTriggered(bool checked);private:Ui::MainWindowClass * ui;
};//MainWindow.cpp
#include "MainWindow.h"
#include "ui_MainWindow.h"MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindowClass())
{ui->setupUi(this);setCentralWidget(ui->openGLWidget);connect(ui->actDrawRect, &QAction::triggered, this, &MainWindow::ActDrawRectTriggered);connect(ui->actClear, &QAction::triggered, this, &MainWindow::ActClearTriggered);connect(ui->actWireFrame, &QAction::triggered, this, &MainWindow::ActWireFrameTriggered);
}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::ActDrawRectTriggered(bool checked)
{ui->openGLWidget->DrawShape(MaLanOpenGLWidget::Rect);
}void MainWindow::ActClearTriggered(bool checked)
{ui->openGLWidget->DrawShape(MaLanOpenGLWidget::None);
}void MainWindow::ActWireFrameTriggered(bool checked)
{ui->openGLWidget->WireFrame(checked);
}//1_shader.vert
#version 330 corelayout(location = 0) in vec3 aPos;
layout(location = 1) in vec3 aColor;out vec3 ourColor;void main()
{gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);ourColor = aColor;
}//1_shader.frag
#version 330 corein vec3 ourColor;
out vec4 FragColor;void main()
{FragColor = vec4(ourColor, 1.0);
}

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