GL.DrawArrays上的系统访问冲突

Question

我在运行此代码时遇到访问冲突：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using OpenTK;
using OpenTK.Graphics;
using OpenTK.Graphics.OpenGL;
using OpenTK.Input;
using System.IO;

namespace OpenTKTutorial1
{
    class Game : GameWindow
    {
        int pgmID;
        int vsID;
        int fsID;

        int attribute_vcol;
        int attribute_vpos;
        int uniform_mview;

        int vbo_position;
        int vbo_color;
        int vbo_mview;

        Vector3[] vertdata;
        Vector3[] coldata;
        Matrix4[] mviewdata;

        void initProgram()
        {
            pgmID = GL.CreateProgram();

            loadShader("vs.glsl", ShaderType.VertexShader, pgmID, out vsID);
            loadShader("fs.glsl", ShaderType.FragmentShader, pgmID, out fsID);

            GL.LinkProgram(pgmID);
            Console.WriteLine(GL.GetProgramInfoLog(pgmID));

            attribute_vpos = GL.GetAttribLocation(pgmID, "vPosition");
            attribute_vcol = GL.GetAttribLocation(pgmID, "vColor");
            uniform_mview = GL.GetUniformLocation(pgmID, "modelview");

            if (attribute_vpos == -1 || attribute_vcol == -1 || uniform_mview == -1)
            {
                Console.WriteLine("Error binding attirbutes");
            }

            GL.GenBuffers(1, out vbo_position);
            GL.GenBuffers(1, out vbo_color);
            GL.GenBuffers(1, out vbo_mview);
        }

        void loadShader(String filename, ShaderType type, int program, out int address)
        {
            address = GL.CreateShader(type);
            using (StreamReader sr = new StreamReader(filename))
            {
                GL.ShaderSource(address, sr.ReadToEnd());
            }
            GL.CompileShader(address);
            GL.AttachShader(program, address);
            Console.WriteLine(GL.GetShaderInfoLog(address));
        }

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            initProgram();

            vertdata = new Vector3[]{
                new Vector3(-0.8f, -0.8f, 0f),
                new Vector3(0.8f, -0.8f, 0f),
                new Vector3(0f, 0.8f, 0f)};

            coldata = new Vector3[]{
                new Vector3(1f, 0f, 0f),
                new Vector3(0f, 0f, 1f),
                new Vector3(0f, 1f, 0f)};


            mviewdata = new Matrix4[]{
                Matrix4.Identity};

            Title = "Title";
            GL.ClearColor(Color.CornflowerBlue);
            GL.PointSize(5f);
        }

        protected override void OnRenderFrame(FrameEventArgs e)
        {
            base.OnRenderFrame(e);

            GL.Viewport(0, 0, Width, Height);
            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
            GL.Enable(EnableCap.DepthTest);

            GL.EnableVertexAttribArray(attribute_vpos);
            GL.EnableVertexAttribArray(attribute_vcol);

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

            GL.DisableVertexAttribArray(attribute_vpos);
            GL.DisableVertexAttribArray(attribute_vcol);

            GL.Flush();

            //Everything before this
            SwapBuffers();
        }

        protected override void OnUpdateFrame(FrameEventArgs e)
        {
            base.OnUpdateFrame(e);

            GL.BindBuffer(BufferTarget.ArrayBuffer, vbo_position);
            GL.BufferData<Vector3>(BufferTarget.ArrayBuffer, (IntPtr)(vertdata.Length * Vector3.SizeInBytes), vertdata, BufferUsageHint.StaticDraw);
            GL.VertexAttribPointer(attribute_vpos, 3, VertexAttribPointerType.Float, false, 0, 0);

            GL.BindBuffer(BufferTarget.ArrayBuffer, vbo_color);
            GL.BufferData<Vector3>(BufferTarget.ArrayBuffer, (IntPtr)(coldata.Length * Vector3.SizeInBytes), coldata, BufferUsageHint.StaticDraw);
            GL.VertexAttribPointer(attribute_vcol, 3, VertexAttribPointerType.Float, true, 0, 0);

            GL.UniformMatrix4(uniform_mview, false, ref mviewdata[0]);

            GL.UseProgram(pgmID);

            GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
        }
    }
}

它使渲染背景然后崩溃。

我对OpenTK和OpenGL很陌生，所以我不能100％确定问题是什么。

错误发生在

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

Answer 1

您的代码存在一些小问题，但它适用于我而无需更改。

无论如何，我做了一些修改并添加了解释来解释原因，或许有些东西可以帮到你。如果没有，请发布您的着色器以及有关确切异常的更多详细信息（如果有）。

using System;
using System.Drawing;
using System.IO;
using OpenTK;
using OpenTK.Graphics.OpenGL;

namespace OpenTKTutorial1
{
    public class Game
        : GameWindow
    {
        int pgmID;
        int vsID;
        int fsID;

        int attribute_vcol;
        int attribute_vpos;
        int uniform_mview;

        int vbo_position;
        int vbo_color;
        int vbo_mview;

        Vector3[] vertdata;
        Vector3[] coldata;
        Matrix4[] mviewdata;

        public Game()
        {
            // better use the events instead of overriding the inherited methods
            // at least thats what the documentation on Update- and RenderFrame says
            Load += OnLoad;
            UpdateFrame += OnUpdateFrame;
            RenderFrame += OnRenderFrame;
        }

        void InitProgram()
        {
            pgmID = GL.CreateProgram();

            LoadShader("vs.glsl", ShaderType.VertexShader, pgmID, out vsID);
            LoadShader("fs.glsl", ShaderType.FragmentShader, pgmID, out fsID);

            GL.LinkProgram(pgmID);
            Console.WriteLine(GL.GetProgramInfoLog(pgmID));

            attribute_vpos = GL.GetAttribLocation(pgmID, "vPosition");
            attribute_vcol = GL.GetAttribLocation(pgmID, "vColor");
            uniform_mview = GL.GetUniformLocation(pgmID, "modelview");

            if (attribute_vpos == -1 || attribute_vcol == -1 || uniform_mview == -1)
            {
                Console.WriteLine("Error binding attributes");
            }

            GL.GenBuffers(1, out vbo_position);
            GL.GenBuffers(1, out vbo_color);

            // what is this buffer for?
            //GL.GenBuffers(1, out vbo_mview);
        }

        void LoadShader(String filename, ShaderType type, int program, out int address)
        {
            address = GL.CreateShader(type);
            using (StreamReader sr = new StreamReader(filename))
            {
                GL.ShaderSource(address, sr.ReadToEnd());
            }
            GL.CompileShader(address);
            GL.AttachShader(program, address);
            Console.WriteLine(GL.GetShaderInfoLog(address));
        }

        protected void OnLoad(object sender, EventArgs eventArgs)
        {
            InitProgram();

            vertdata = new Vector3[]{
                new Vector3(-0.8f, -0.8f, 0f),
                new Vector3(0.8f, -0.8f, 0f),
                new Vector3(0f, 0.8f, 0f)};

            coldata = new Vector3[]{
                new Vector3(1f, 0f, 0f),
                new Vector3(0f, 0f, 1f),
                new Vector3(0f, 1f, 0f)};


            mviewdata = new Matrix4[]{
                Matrix4.Identity};

            Title = "Title";
            GL.ClearColor(Color.CornflowerBlue);
            GL.PointSize(5f);
        }

        protected void OnRenderFrame(object sender, FrameEventArgs frameEventArgs)
        {
            // if you only have one viewport you can safely move this to the OnResize event
            GL.Viewport(0, 0, Width, Height);

            // if the state never changes move it to OnLoad
            GL.Enable(EnableCap.DepthTest);

            GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);

            GL.EnableVertexAttribArray(attribute_vpos);
            GL.EnableVertexAttribArray(attribute_vcol);

            // always make sure the program is enabled ..
            GL.UseProgram(pgmID);
            // .. before you set any uniforms 
            GL.UniformMatrix4(uniform_mview, false, ref mviewdata[0]);
            // .. or draw anything
            GL.DrawArrays(PrimitiveType.Triangles, 0, 3);

            GL.DisableVertexAttribArray(attribute_vpos);
            GL.DisableVertexAttribArray(attribute_vcol);

            // do not call glFlush unless you have a very good reason to
            // it can result in significant slow downs
            //GL.Flush();

            SwapBuffers();
        }

        protected void OnUpdateFrame(object sender, FrameEventArgs frameEventArgs)
        {
            // your vertex and color data never changes, thus everything you do here
            // could be moved to OnLoad instead of having it repeated all the time
            GL.BindBuffer(BufferTarget.ArrayBuffer, vbo_position);
            GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(vertdata.Length * Vector3.SizeInBytes), vertdata, BufferUsageHint.StaticDraw);
            GL.VertexAttribPointer(attribute_vpos, 3, VertexAttribPointerType.Float, false, 0, 0);

            GL.BindBuffer(BufferTarget.ArrayBuffer, vbo_color);
            GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(coldata.Length * Vector3.SizeInBytes), coldata, BufferUsageHint.StaticDraw);
            GL.VertexAttribPointer(attribute_vcol, 3, VertexAttribPointerType.Float, true, 0, 0);

            GL.BindBuffer(BufferTarget.ArrayBuffer, 0);
        }
    }
}