顶点着色器代码：

#version 330 core
layout(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, 1.0f);
    ourColor=aColor;
}

片段着色器代码：

#version 330 core
out vec4 FragColor;
in vec3 ourColor;
void main(){
    FragColor = vec4(ourColor, 1.0f);
}

顶点坐标：

float vertices[] = { // positions // colors
	0.5f, 0.5f, 0.0f, 1.0f, 0.0f, 0.0f,	
	0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f,	
	-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 	
	-0.5f, 0.5f, 0.0f, 0.5f, 0.5f, 0.5f,	
};
unsigned int indices[] = { 
	0, 1, 3, 
	1, 2, 3 
};

initializeGL()函数：

	initializeOpenGLFunctions();
	//创建VBO和VAO对象，并赋予ID
	glGenVertexArrays(1, &VAO);
	glGenBuffers(1, &VBO);
	//绑定VBO和VAO对象
	glBindVertexArray(VAO);
	glBindBuffer(GL_ARRAY_BUFFER, VBO);
	//为当前绑定到target的缓冲区对象创建一个新的数据存储。
	//如果data不是NULL，则使用来自此指针的数据初始化数据存储
	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
	//告知显卡如何解析缓冲里的属性值
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
	//开启VAO管理的第一个属性值
	glEnableVertexAttribArray(0);
	//告知显卡如何解析缓冲里的属性值
	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
	//开启VAO管理的第二个属性值
	glEnableVertexAttribArray(1);
	glBindBuffer(GL_ARRAY_BUFFER, 0);
	bool success;
	shaderProgram.addShaderFromSourceFile(QOpenGLShader::Vertex, "shaders/shapes.vert");
shaderProgram.addShaderFromSourceFile(QOpenGLShader::Fragment, "shaders/shapes.frag");
	success = shaderProgram.link();
	if (!success)
		qDebug() << "ERR:" << shaderProgram.log();
	// glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
	glGenBuffers(1, &EBO);
	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
	glBindVertexArray(0);

paintGL函数():

	glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
	glClear(GL_COLOR_BUFFER_BIT);
	shaderProgram.bind();
	glBindVertexArray(VAO);
	glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, NULL);