1 Introduction
OpenGL (English: Open Graphics Library, translated name: Open Graphics Library or "Open Graphics Library") is a cross-language, cross-platform application programming interface (API) for rendering 2D and 3D vector graphics. This interface consists of nearly 350 different function calls, used to draw from simple graphics to more complex three-dimensional scenes. Yet another program interface system is Direct3D on Microsoft Windows only. OpenGL is commonly used in CAD, virtual reality, scientific visualization programs, and video game development.
Efficient implementations of OpenGL (that take advantage of graphics acceleration hardware) exist on Windows, some UNIX platforms, and Mac OS. These implementations are generally provided by display device manufacturers, and are very dependent on the hardware provided by the manufacturer. The open source library Mesa is a pure software-based graphics API whose code is compatible with OpenGL. However, for license reasons, it only claims to be a "very similar" API.
Today, OpenGL is the most widely accepted API for processing 2D/3D graphics in the video industry. On this basis, in order to be used in the research of computer vision technology, it has spawned application functions on various computer platforms and on-device of many applications. It is independent of the Windows operating system and operating system platform, and can carry out development and content creation in a variety of different fields. In short, it helps developers to realize PCs, workstations, supercomputers and various industrial computers. Realize the development of high-performance, high-visual graphics processing software with extremely high visual requirements.
2. Tools
Calling OpenGL functions directly in C# is cumbersome and generally not used directly. We can use third-party open source libraries, such as SharpGL, CsGL, OpenTK, Tao framework, etc. The following introduces these frameworks one by one. Among them, Tao has stopped maintaining and updating, and can be replaced by OpenTK, so I won’t introduce it here.
3. Winform draws a cube
VS2019，.NetFramework4.7
1. Create an empty solution project OpenGLProjectApp
2. Delete the generated project, right-click the solution to add the project, select windows form application, and the project name is SharpGLFormsApp1
3. Add sharpgl reference to the project
It can be seen that the project references the dll successfully, and at the same time, there is an additional category in the toolbox
4. Drag in different controls, the page layout is as shown in the figure:
5. Write the events of each control, the focus is on the GDIDraw event of openglcontrol, complete code:
using SharpGL;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace SharpGLFormsApp1
{
public partial class Form1 : Form
{
/// <summary>
/// 默认绘画模式为线条
/// </summary>
private uint _model = OpenGL.GL_LINE_LOOP;
/// <summary>
/// X轴坐标
/// </summary>
private float _x = 0;
/// <summary>
/// Y轴坐标
/// </summary>
private float _y = 0;
/// <summary>
/// Z轴坐标
/// </summary>
private float _z = 0;
public Form1()
{
InitializeComponent();
}
/// <summary>
/// 复位事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void button1_Click(object sender, EventArgs e)
{
_x = _y = _z = 0;
tbX.Value = tbY.Value = tbZ.Value = Convert.ToInt32(_x);
label1.Text = "X轴" ;
label2.Text = "Y轴";
label3.Text = "Z轴";
}
/// <summary>
/// 线条选择事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void rbline_CheckedChanged(object sender, EventArgs e)
{
_model = OpenGL.GL_LINE_LOOP;
}
/// <summary>
/// 球面事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void rbfull_CheckedChanged(object sender, EventArgs e)
{
_model = OpenGL.GL_QUADS;
}
/// <summary>
/// 控件绘图事件
/// </summary>
/// <param name="sender"></param>
/// <param name="args"></param>
private void openGLControl1_GDIDraw(object sender, RenderEventArgs args)
{
// 创建一个GL对象
SharpGL.OpenGL gl = this.openGLControl1.OpenGL;
gl.Clear(OpenGL.GL_COLOR_BUFFER_BIT | OpenGL.GL_DEPTH_BUFFER_BIT); // 清空屏幕
gl.LoadIdentity(); // 重置
gl.Translate(0.0f, 0.0f, -6.0f); // 设置坐标，距离屏幕距离为6
gl.Rotate(_x, 1.0f, 0.0f, 0.0f); // 绕X轴旋转
gl.Rotate(_y, 0.0f, 1.0f, 0.0f); // 绕Y轴旋转
gl.Rotate(_z, 0.0f, 0.0f, 1.0f); // 绕Z轴旋转
gl.Begin(_model); // 绘制立方体
gl.Color(0.0f, 1.0f, 0.0f); // 设置颜色
//绘制其中一个面
gl.Vertex(1.0f, 1.0f, -1.0f);
gl.Vertex(-1.0f, 1.0f, -1.0f);
gl.Vertex(-1.0f, 1.0f, 1.0f);
gl.Vertex(1.0f, 1.0f, 1.0f);
//如下类同
gl.Color(1.0f, 0.5f, 0.0f);
gl.Vertex(1.0f, -1.0f, 1.0f);
gl.Vertex(-1.0f, -1.0f, 1.0f);
gl.Vertex(-1.0f, -1.0f, -1.0f);
gl.Vertex(1.0f, -1.0f, -1.0f);
gl.Color(1.0f, 0.0f, 0.0f);
gl.Vertex(1.0f, 1.0f, 1.0f);
gl.Vertex(-1.0f, 1.0f, 1.0f);
gl.Vertex(-1.0f, -1.0f, 1.0f);
gl.Vertex(1.0f, -1.0f, 1.0f);
gl.Color(1.0f, 1.0f, 0.0f);
gl.Vertex(1.0f, -1.0f, -1.0f);
gl.Vertex(-1.0f, -1.0f, -1.0f);
gl.Vertex(-1.0f, 1.0f, -1.0f);
gl.Vertex(1.0f, 1.0f, -1.0f);
gl.Color(0.0f, 0.0f, 1.0f);
gl.Vertex(-1.0f, 1.0f, 1.0f);
gl.Vertex(-1.0f, 1.0f, -1.0f);
gl.Vertex(-1.0f, -1.0f, -1.0f);
gl.Vertex(-1.0f, -1.0f, 1.0f);
gl.Color(1.0f, 0.0f, 1.0f);
gl.Vertex(1.0f, 1.0f, -1.0f);
gl.Vertex(1.0f, 1.0f, 1.0f);
gl.Vertex(1.0f, -1.0f, 1.0f);
gl.Vertex(1.0f, -1.0f, -1.0f);
gl.End(); // 结束绘制
}
/// <summary>
/// X轴拖动事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void tbX_Scroll(object sender, EventArgs e)
{
int x = tbX.Value;
_x = x;
label1.Text = "X:" + x;
}
/// <summary>
/// Y轴拖动事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void tbY_Scroll(object sender, EventArgs e)
{
int y = tbY.Value;
_y = y;
label2.Text = "Y:" + y;
}
/// <summary>
///Z轴拖动事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void tbZ_Scroll(object sender, EventArgs e)
{
int z = tbZ.Value;
_z = z;
label3.Text = "Z:" + z;
}
}
}
6. Operation effect
