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    • By Jens Eckervogt
      Hello guys, 
       
      Please tell me! 
      How do I know? Why does wavefront not show for me?
      I already checked I have non errors yet.
      using OpenTK; using System; using System.Collections.Generic; using System.IO; namespace Tutorial_08.net.sourceskyboxer { public class WaveFrontLoader { private static List<Vector3> vertices; private static List<Vector2> textures; private static List<Vector3> normals; private static List<int> indices; private static float[] verticesArray; private static float[] normalsArray; private static float[] texturesArray; private static int[] indicesArray; private static string[] lines; public static RawModel LoadObjModel(string filename, Loader loader) { if (!File.Exists("Contents/" + filename + ".obj")) { throw new FileNotFoundException("Error: wavefront file doesn't exist path: " + filename + ".png"); } vertices = new List<Vector3>(); textures = new List<Vector2>(); normals = new List<Vector3>(); indices = new List<int>(); lines = File.ReadAllLines("Contents/" + filename + ".obj"); try { foreach (string line in lines) { if (line == "" || line.StartsWith("#")) continue; string[] token = line.Split(' '); switch(token[0]) { case ("o"): string o = token[1]; break; case "v": Vector3 vertex = new Vector3(float.Parse(token[1]), float.Parse(token[2]), float.Parse(token[3])); vertices.Add(vertex); break; case "vn": Vector3 normal = new Vector3(float.Parse(token[1]), float.Parse(token[2]), float.Parse(token[3])); normals.Add(normal); break; case "vt": Vector2 texture = new Vector2(float.Parse(token[1]), float.Parse(token[2])); textures.Add(texture); break; case "f": texturesArray = new float[vertices.Count * 2]; normalsArray = new float[vertices.Count * 3]; verticesArray = new float[vertices.Count * 3]; indicesArray = new int[indices.Count]; int vertexPointer = 0; foreach (Vector3 vex in vertices) { verticesArray[vertexPointer++] = vex.X; verticesArray[vertexPointer++] = vex.Y; verticesArray[vertexPointer++] = vex.Z; } for (int i = 0; i < indices.Count; i++) { indicesArray[i] = indices[i]; } break; } } } catch (FileNotFoundException f) { throw new FileNotFoundException($"OBJ file not found: {f.FileName}", f); } catch (ArgumentException ae) { throw new ArgumentException("OBJ file is damaged", ae); } return loader.loadToVAO(verticesArray, texturesArray, indicesArray); } } } And It have tried other method but it can't show for me.  I am mad now. Because any OpenTK developers won't help me.
      Please help me how do I fix.

      And my download (mega.nz) should it is original but I tried no success...
      - Add blend source and png file here I have tried tried,.....  
       
      PS: Why is our community not active? I wait very longer. Stop to lie me!
      Thanks !
    • By codelyoko373
      I wasn't sure if this would be the right place for a topic like this so sorry if it isn't.
      I'm currently working on a project for Uni using FreeGLUT to make a simple solar system simulation. I've got to the point where I've implemented all the planets and have used a Scene Graph to link them all together. The issue I'm having with now though is basically the planets and moons orbit correctly at their own orbit speeds.
      I'm not really experienced with using matrices for stuff like this so It's likely why I can't figure out how exactly to get it working. This is where I'm applying the transformation matrices, as well as pushing and popping them. This is within the Render function that every planet including the sun and moons will have and run.
      if (tag != "Sun") { glRotatef(orbitAngle, orbitRotation.X, orbitRotation.Y, orbitRotation.Z); } glPushMatrix(); glTranslatef(position.X, position.Y, position.Z); glRotatef(rotationAngle, rotation.X, rotation.Y, rotation.Z); glScalef(scale.X, scale.Y, scale.Z); glDrawElements(GL_TRIANGLES, mesh->indiceCount, GL_UNSIGNED_SHORT, mesh->indices); if (tag != "Sun") { glPopMatrix(); } The "If(tag != "Sun")" parts are my attempts are getting the planets to orbit correctly though it likely isn't the way I'm meant to be doing it. So I was wondering if someone would be able to help me? As I really don't have an idea on what I would do to get it working. Using the if statement is truthfully the closest I've got to it working but there are still weird effects like the planets orbiting faster then they should depending on the number of planets actually be updated/rendered.
    • By Jens Eckervogt
      Hello everyone, 
      I have problem with texture
      using System; using OpenTK; using OpenTK.Input; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL4; using System.Drawing; using System.Reflection; namespace Tutorial_05 { class Game : GameWindow { private static int WIDTH = 1200; private static int HEIGHT = 720; private static KeyboardState keyState; private int vaoID; private int vboID; private int iboID; private Vector3[] vertices = { new Vector3(-0.5f, 0.5f, 0.0f), // V0 new Vector3(-0.5f, -0.5f, 0.0f), // V1 new Vector3(0.5f, -0.5f, 0.0f), // V2 new Vector3(0.5f, 0.5f, 0.0f) // V3 }; private Vector2[] texcoords = { new Vector2(0, 0), new Vector2(0, 1), new Vector2(1, 1), new Vector2(1, 0) }; private int[] indices = { 0, 1, 3, 3, 1, 2 }; private string vertsrc = @"#version 450 core in vec3 position; in vec2 textureCoords; out vec2 pass_textureCoords; void main(void) { gl_Position = vec4(position, 1.0); pass_textureCoords = textureCoords; }"; private string fragsrc = @"#version 450 core in vec2 pass_textureCoords; out vec4 out_color; uniform sampler2D textureSampler; void main(void) { out_color = texture(textureSampler, pass_textureCoords); }"; private int programID; private int vertexShaderID; private int fragmentShaderID; private int textureID; private Bitmap texsrc; public Game() : base(WIDTH, HEIGHT, GraphicsMode.Default, "Tutorial 05 - Texturing", GameWindowFlags.Default, DisplayDevice.Default, 4, 5, GraphicsContextFlags.Default) { } protected override void OnLoad(EventArgs e) { base.OnLoad(e); CursorVisible = true; GL.GenVertexArrays(1, out vaoID); GL.BindVertexArray(vaoID); GL.GenBuffers(1, out vboID); GL.BindBuffer(BufferTarget.ArrayBuffer, vboID); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(vertices.Length * Vector3.SizeInBytes), vertices, BufferUsageHint.StaticDraw); GL.GenBuffers(1, out iboID); GL.BindBuffer(BufferTarget.ElementArrayBuffer, iboID); GL.BufferData(BufferTarget.ElementArrayBuffer, (IntPtr)(indices.Length * sizeof(int)), indices, BufferUsageHint.StaticDraw); vertexShaderID = GL.CreateShader(ShaderType.VertexShader); GL.ShaderSource(vertexShaderID, vertsrc); GL.CompileShader(vertexShaderID); fragmentShaderID = GL.CreateShader(ShaderType.FragmentShader); GL.ShaderSource(fragmentShaderID, fragsrc); GL.CompileShader(fragmentShaderID); programID = GL.CreateProgram(); GL.AttachShader(programID, vertexShaderID); GL.AttachShader(programID, fragmentShaderID); GL.LinkProgram(programID); // Loading texture from embedded resource texsrc = new Bitmap(Assembly.GetEntryAssembly().GetManifestResourceStream("Tutorial_05.example.png")); textureID = GL.GenTexture(); GL.BindTexture(TextureTarget.Texture2D, textureID); GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)All.Linear); GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)All.Linear); GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, texsrc.Width, texsrc.Height, 0, PixelFormat.Bgra, PixelType.UnsignedByte, IntPtr.Zero); System.Drawing.Imaging.BitmapData bitmap_data = texsrc.LockBits(new Rectangle(0, 0, texsrc.Width, texsrc.Height), System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppRgb); GL.TexSubImage2D(TextureTarget.Texture2D, 0, 0, 0, texsrc.Width, texsrc.Height, PixelFormat.Bgra, PixelType.UnsignedByte, bitmap_data.Scan0); texsrc.UnlockBits(bitmap_data); GL.Enable(EnableCap.Texture2D); GL.BufferData(BufferTarget.TextureBuffer, (IntPtr)(texcoords.Length * Vector2.SizeInBytes), texcoords, BufferUsageHint.StaticDraw); GL.BindAttribLocation(programID, 0, "position"); GL.BindAttribLocation(programID, 1, "textureCoords"); } protected override void OnResize(EventArgs e) { base.OnResize(e); GL.Viewport(0, 0, ClientRectangle.Width, ClientRectangle.Height); } protected override void OnUpdateFrame(FrameEventArgs e) { base.OnUpdateFrame(e); keyState = Keyboard.GetState(); if (keyState.IsKeyDown(Key.Escape)) { Exit(); } } protected override void OnRenderFrame(FrameEventArgs e) { base.OnRenderFrame(e); // Prepare for background GL.Clear(ClearBufferMask.ColorBufferBit); GL.ClearColor(Color4.Red); // Draw traingles GL.EnableVertexAttribArray(0); GL.EnableVertexAttribArray(1); GL.BindVertexArray(vaoID); GL.UseProgram(programID); GL.BindBuffer(BufferTarget.ArrayBuffer, vboID); GL.VertexAttribPointer(0, 3, VertexAttribPointerType.Float, false, 0, IntPtr.Zero); GL.ActiveTexture(TextureUnit.Texture0); GL.BindTexture(TextureTarget.Texture3D, textureID); GL.BindBuffer(BufferTarget.ElementArrayBuffer, iboID); GL.DrawElements(BeginMode.Triangles, indices.Length, DrawElementsType.UnsignedInt, 0); GL.DisableVertexAttribArray(0); GL.DisableVertexAttribArray(1); SwapBuffers(); } protected override void OnClosed(EventArgs e) { base.OnClosed(e); GL.DeleteVertexArray(vaoID); GL.DeleteBuffer(vboID); } } } I can not remember where do I add GL.Uniform2();
    • By Jens Eckervogt
      Hello everyone
      For @80bserver8 nice job - I have found Google search. How did you port from Javascript WebGL to C# OpenTK.?
      I have been searched Google but it shows f***ing Unity 3D. I really want know how do I understand I want start with OpenTK But I want know where is porting of Javascript and C#?
       
      Thanks!
    • By mike44
      Hi
      I draw in a OpenGL framebuffer. All is fine but it eats FPS (frames per second), hence I wonder if I could execute the framebuffer drawing only every 5-10th loop or so?
      Many thanks
       
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OpenGL Wrapping OpenGL Calls

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I'm tired of my code being littered with verbose GL calls. I've been wondering if there's any way to wrap things up in small classes without a serious loss of performance and generality. For example, if I want to have a VBO class, every member function that does something with a VBO needs to make sure it is bound first. If I want to render it, I need to make sure all the client states (e.g. glEnableClientState(GL_VERTEX_ARRAY)) and pointers (e.g. glVertexPointer(...)) are set up correctly. The only robust way to do that is to set all relevant global state in every member function call, even when it's unnecessary. Wouldn't all this state-changing cause some serious performance issues?

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Yes it's possible, it's called object orientation. You create classes with specific responsibilities. This will add a very tiny mini overhead but it's more than worth it. The trick is to pull your classes to an as high as possible level of abstraction without creating overly complex class responsibilities. For example, who sais you're using VBOs, maybe you've just got some vertex data that needs to be rendered however the implementation sees fit.

To counter the state changes you might end up with a state manager which only changes state if it is required.

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Yes it's possible, it's called object orientation. You create classes with specific responsibilities. This will add a very tiny mini overhead but it's more than worth it. The trick is to pull your classes to an as high as possible level of abstraction without creating overly complex class responsibilities. For example, who sais you're using VBOs, maybe you've just got some vertex data that needs to be rendered however the implementation sees fit.

To counter the state changes you might end up with a state manager which only changes state if it is required.


I thought it was clear from my OP that object orientation is what I'm trying to achieve. I'm just worried about the performance penalties from redundant state changes.
I just want a thin and convenient layer on top of plain OpenGL to ease up the task of writing a higher-level graphics engine. I thought about making a state manager, but I'm not sure how to go about it. How would you go about wrapping "void glBindBuffer( GLenum target, GLuint buffer)", for example?

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well, while wrapping the whole api is possible, in my opinion its rather pointless. You might want to write a state manager as suggested, but I think that you shouldn't wrap everything, but rather certain functionality (mesh loading, texture loading, shader loading etc.) which enables you to use OGL without making a single error, because the wrapper class takes care of it.

for ex. you could say that the current buffer stored would be:
struct buffer_state
{
GLuint buffer;
GLenum target;
} current_buffer_state;

and you could implement a function that checks if the current buffer bound is the one you pass to it, and in that case it wouldn't call the OGL function:
void my_bind_buffer(GLenum target, GLuint buffer)
{
if(current_buffer_state.buffer != buffer || current_buffer_state.target != target) //check the current state
{
if(glIsBuffer(buffer)) //check if it is really a buffer
{
glBindBuffer(target, buffer);
}
}
}

or something like this...
you might want to check out pixellight for a whole api wrap example.

when your app starts up you could just simply query the current gl state with glGet* to initialize your states

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well, while wrapping the whole api is possible, in my opinion its rather pointless. You might want to write a state manager as suggested, but I think that you shouldn't wrap everything, but rather certain functionality (mesh loading, texture loading, shader loading etc.) which enables you to use OGL without making a single error, because the wrapper class takes care of it.

for ex. you could say that the current buffer stored would be:
struct buffer_state
{
GLuint buffer;
GLenum target;
} current_buffer_state;

and you could implement a function that checks if the current buffer bound is the one you pass to it, and in that case it wouldn't call the OGL function:
void my_bind_buffer(GLenum target, GLuint buffer)
{
if(current_buffer_state.buffer != buffer || current_buffer_state.target != target) //check the current state
{
if(glIsBuffer(buffer)) //check if it is really a buffer
{
glBindBuffer(target, buffer);
}
}
}

or something like this...
you might want to check out pixellight for a whole api wrap example.

when your app starts up you could just simply query the current gl state with glGet* to initialize your states


Basically, here's my problem:
I need to write my own versions of the OGL state-setter functions I care for that check for redundant state changes. Some of those functions take a parameter that specifies which state to change, like glBindBuffer. Ideally, if I write a glBindBuffer wrapper, it better act like the original, accept a target parameter and handle it correctly. How do I do that without manually writing special code for every type of target?

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If you're going for a higher level graphics engine you should not think about how to wrap OpenGL. Instead you should think about how you'd like to make the calls to render something and then fill that in by using OpenGL. You might need a few iterations of adjusting requirements due to api specific limitations but you'll end up with a system that's easy to use, which is one of the most important things for anything high level.

To answer your question, my glBindBuffer calls are checked in the implementation of the Renderer class just by comparing ints like suggested by the poster above. I'm not doing this in the state manager because i've defined that to be managing render states like cullmode, blend mode, alpha testing etc etc. I gues you could do that in the state manager aswell, it doesnt really matter.

On a side note, maybe managing glBindBuffer calls isn't your biggest problem if you're worried about redundant state changes performance loss. Other state changes like shader and texture binds will probably be a lot more expensive and your buffer count will be very low when you've implemented batching.

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oh woot simultaneous post. I dont think you want to go about wrapping single methods. At least take it higher and use a VBO. Then when making a render call to it, check if it's allready bound and rebind if needed.

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If you're going for a higher level graphics engine you should not think about how to wrap OpenGL. Instead you should think about how you'd like to make the calls to render something and then fill that in by using OpenGL. You might need a few iterations of adjusting requirements due to api specific limitations but you'll end up with a system that's easy to use, which is one of the most important things for anything high level.

To answer your question, my glBindBuffer calls are checked in the implementation of the Renderer class just by comparing ints like suggested by the poster above. I'm not doing this in the state manager because i've defined that to be managing render states like cullmode, blend mode, alpha testing etc etc. I gues you could do that in the state manager aswell, it doesnt really matter.

On a side note, maybe managing glBindBuffer calls isn't your biggest problem if you're worried about redundant state changes performance loss. Other state changes like shader and texture binds will probably be a lot more expensive and your buffer count will be very low when you've implemented batching.


What's wrong with an intermediate layer to ease up the task of writing a higher-level engine? I have no intentions of writing a big general-purpose graphics engine. If I wanted one, there are many available. I write small apps with widely varying requirements that don't usually fit a standard engine architecture and I find myself writing over and over again heaps of OGL code to handle low-level tasks like setting up and rendering FBOs, VBOs etc.

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only you can know how much abstraction you need or want. just make sure there is some. Wrapping glEnable(Gluint) into myEnable(unsigned int) or into myEnableDepthTest() / myDisableDepthTest() doesn't strike me as an effective way to make the program any more manageable.

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The way I did this was to create a set of classes to totally hide the gl calls and provide additional boiler plate functionality. Basically I've got the following classes:


[indent=1]ArrayBufferGL

[indent=1]IndexBufferGL

[indent=1]VertexBufferGL

[indent=1]GeometryShaderGL

[indent=1]VertexShaderGL

[indent=1]PixelShaderGL

[indent=1]ShaderProgramGL

[indent=1]ShaderVariablesGL

[indent=1]StateGL

[indent=1]FrameBufferGL
[indent=1]RenderBufferGL
[indent=1]SamplerGL
[indent=1]TextureMapGL
[indent=1]TextureArrayGL

After writing these classes, I then implemented a factory template to create instances of them:

template< class GraphicsDevice,
class VertexBuffer,
class IndexBuffer,
class ArrayBuffer,
class TextureMap,
class TextureArray,
class FrameBuffer,
class RenderBuffer,
class PixelShader,
class VertexShader,
class GeometryShader,
class ShaderProgram,
class ShaderVariables,
class Sampler,
class GraphicsState>
class GraphicsFacade
{
...
};


The facade just contains a set of Createxxxxx methods that return shared_ptr to one of the items. I can instantiate the template with D3D versions if I want to at compile time. As kunos says, simply wrapping things like glEnable(x) with your own method is a bit pointless. But hiding the gl- nature of the functionality in an OO way can be really useful.

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