I have been following a tutorial but the triangle doesn't show up for me and I have no idea what is wrong with my code for the triangle not to be appearing.

I am using OpenTK version 4.7.1

Here is my code:

This is Window.cs Here is where I write OpenGl code

using OpenTK.Windowing.Common;
using OpenTK.Windowing.Desktop;
using OpenTK.Graphics.OpenGL4;
using OpenTK.Mathematics;
using System;
using System.Collections.Generic;
using System.Text;

namespace Models
{
    public class Window : GameWindow
    {
        private int vertexBufferHandle;
        private int shaderProgramHandle;
        private int vertexArrayHandle;

        public Window() : base(GameWindowSettings.Default, NativeWindowSettings.Default)
        {
            this.CenterWindow(new Vector2i(1280, 760));
        }

        protected override void OnResize(ResizeEventArgs e)
        {
            GL.Viewport(0, 0, e.Width, e.Height);
            base.OnResize(e);
        }

        protected override void onl oad()
        {
            GL.ClearColor(new Color4(0.3f, 0.4f, 0.5f, 1f));

            float[] vertices = 
            {
                 0f,    0.5f,
                 0.5f, -0.5f,
                -0.5f, -0.5f
            };

            vertexBufferHandle = GL.GenBuffer();
            GL.BindBuffer(BufferTarget.ArrayBuffer, vertexBufferHandle);
            GL.BufferData(BufferTarget.ArrayBuffer, vertices.Length * sizeof(float), vertices, BufferUsageHint.StaticDraw);
      
            GL.BindBuffer(BufferTarget.ArrayBuffer, 0);

            vertexArrayHandle = GL.GenVertexArray();
            GL.BindVertexArray(vertexArrayHandle);

            GL.BindBuffer(BufferTarget.ArrayBuffer, vertexBufferHandle);
            GL.VertexAttribPointer(0, 2, VertexAttribPointerType.Float, false, 2 * sizeof(float), 0);
            GL.EnableVertexAttribArray(0);

            GL.BindVertexArray(0);

            string vertexShader =
               @"#version 330 core
                                    layout (location = 0) in vec2 aPosition;
                                    
                                    void main()
                                    {
                                        gl_Position = vec4(aPosition, 0, 1.0);
                                    }";

            string pixelShader =
                @"#version 330 core
                                        out vec4 FragColor;
                                        
                                        void main()
                                        {
                                            FragColor = vec4(0.8, 0.2, 0.5, 1);
                                        }";

            int vertexShaderHandle = GL.CreateShader(ShaderType.VertexShader);
            GL.ShaderSource(vertexShaderHandle, vertexShader);
            GL.CompileShader(vertexShaderHandle);

            int pixelShaderHandle = GL.CreateShader(ShaderType.FragmentShader);
            GL.ShaderSource(pixelShaderHandle, pixelShader);
            GL.CompileShader(pixelShaderHandle);

            shaderProgramHandle = GL.CreateProgram();
            GL.AttachShader(shaderProgramHandle, vertexShaderHandle);
            GL.AttachShader(shaderProgramHandle, pixelShaderHandle);

            GL.LinkProgram(shaderProgramHandle);

            GL.DetachShader(shaderProgramHandle, vertexShaderHandle);
            GL.DetachShader(shaderProgramHandle, pixelShaderHandle);

            GL.DeleteShader(vertexShaderHandle);
            GL.DeleteShader(pixelShaderHandle);

            base.OnLoad();
        }

        protected override void OnUnload()
        {
            GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
            GL.DeleteBuffer(vertexBufferHandle);
            GL.UseProgram(0);
            GL.DeleteProgram(shaderProgramHandle);
            base.OnUnload();
        }

        protected override void OnUpdateFrame(FrameEventArgs args)
        {
            base.OnUpdateFrame(args);
        }

        protected override void OnRenderFrame(FrameEventArgs args)
        {
            GL.Clear(ClearBufferMask.ColorBufferBit);

            GL.UseProgram(shaderProgramHandle);

            GL.BindVertexArray(vertexArrayHandle);

            GL.DrawArrays(PrimitiveType.Triangles, 0, 1);

            Context.SwapBuffers();
            base.OnRenderFrame(args);
        }

    }
}

and this is the Program.cs Here is where I run all the code

using OpenTK;
using OpenTK.Windowing.Common;
using OpenTK.Windowing.Desktop;
using OpenTK.Mathematics;
using System;

namespace Models
{
    class Program
    {
        static void Main(string[] args)
        {
            using (var window = new Window())
            {
                window.Run();
            }
        }
    }
}

CodePudding user response：

The last argument of DrawArrays is not the number of primitives but the number of vertices:

GL.DrawArrays(PrimitiveType.Triangles, 0, 1);

GL.DrawArrays(PrimitiveType.Triangles, 0, 3);