在Qt5中用OpenGL3.0做一个GLSL基本例子

GLSL(OpenGL Shading Language)是一个强大的渲染语言。

下面做一个：

RenderWindow.h

#ifndef RENDERWINDOW_H
#define RENDERWINDOW_H

//#include <QOpenGLWindow>

#include <GL/glu.h>
#include <QtOpenGL>
#include <QSurfaceFormat>
#include <QOpenGLFunctions>
#include <QOpenGLWindow>
#include <QOpenGLBuffer>
#include <QOpenGLVertexArrayObject>
#include <QOpenGLShader>
#include <QOpenGLShaderProgram>

class RenderWindow : public QOpenGLWindow
{
public:
    RenderWindow();
protected:
    void initializeGL();
    void paintGL();
    void paintEvent(QPaintEvent *event);
    void resizeEvent(QResizeEvent *event);
private:
    QOpenGLContext* openGLContext;
    QOpenGLFunctions* openGLFunctions;
    QOpenGLShaderProgram* shaderProgram;
    QOpenGLVertexArrayObject* vao;
    QOpenGLBuffer* vbo_vertices;
};

#endif // RENDERWINDOW_H

RenderWIndow.cpp

#include "renderwindow.h"

RenderWindow::RenderWindow()
{
    setSurfaceType(QWindow::OpenGLSurface);

    QSurfaceFormat format;
    format.setProfile(QSurfaceFormat::CoreProfile);
    format.setVersion(3, 2);
    setFormat(format);

    openGLContext = new QOpenGLContext();
    openGLContext->setFormat(format);
    openGLContext->create();
    openGLContext->makeCurrent(this);

    //设定窗口名称和大小，要有。
    setTitle("OpenGL3.0 Render Window");
    resize(640, 480);
}

void RenderWindow::initializeGL()
{
    openGLFunctions = openGLContext->functions();

    static const char *vertexShaderSource =
            "#version 330 core\n"
            "layout(location = 0) in vec2 posAttr;\n"
            "void main() {\n"
            "gl_Position = vec4(posAttr, 0.0, 1.0);}";

    static const char *fragmentShaderSource =
            "#version 330 core \n"
            "out vec4 col;\n"
            "void main() {\n"
            "col = vec4(1.0, 0.0, 0.0, 1.0);}";

    //设置GLSL
    shaderProgram = new QOpenGLShaderProgram(this);
    shaderProgram->addShaderFromSourceCode(QOpenGLShader::Vertex, vertexShaderSource);
    shaderProgram->addShaderFromSourceCode(QOpenGLShader::Fragment, fragmentShaderSource);
    shaderProgram->link();

    GLfloat vertices[] = {
        -1.0f, -1.0f,
        1.0f, -1.0f,
        0.0f, 1.0f
    };

    vao = new QOpenGLVertexArrayObject();
    vao->create();
    vao->bind();

    vbo_vertices = new QOpenGLBuffer(QOpenGLBuffer::VertexBuffer);
    vbo_vertices->create();
    vbo_vertices->setUsagePattern(QOpenGLBuffer::StaticDraw);
    vbo_vertices->bind();
    vbo_vertices->allocate(vertices, sizeof(vertices)*sizeof(GLfloat));

    vao->release();


}

void RenderWindow::paintGL()
{

}

void RenderWindow::paintEvent(QPaintEvent *event)
{
    Q_UNUSED(event);
    glViewport(0, 0, width(), height());
    glClearColor(0.39f, 0.58f, 0.93f, 1.f);
    glClear(GL_COLOR_BUFFER_BIT);

    vao->bind();
    shaderProgram->bind();
    shaderProgram->bindAttributeLocation("posAttr", 0);
    shaderProgram->enableAttributeArray(0);
    shaderProgram->setAttributeBuffer(0, GL_FLOAT, 0, 2);
    glDrawArrays(GL_TRIANGLES, 0, 3);
    shaderProgram->release();
    vao->release();
}

void RenderWindow::resizeEvent(QResizeEvent *event)
{
    Q_UNUSED(event);
    glViewport(0, 0, this->width(), this->height());
    this->update();
}

编译运行：

非常的鲜艳。

多谢，亲爱的美美。