Jump to content
  • Advertisement
Sign in to follow this  

OpenGL Unsure how exactly to properly begin with OpenGL and 3D Maths/Games

This topic is 2126 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I know this must be a common theme here and there's a helpful Getting Started box at the side, but I'm wondering about a few things that I thought I'd ask some more experienced coders about and have a better idea before going down the wrong route.
Sorry if it winds up being longer than maybe it should be.

Firstly, a summary of my experience in game development/general programming so far:
- Started trying to get into game development seriously about 4-5 years ago.
- That consisted of starting by learning the basics of C++ (something I admit I regret starting with now, in typical fashion), then moving into how to create 2D games with Direct3D (again, something I regret that caused me no end of beginner frustration and lost time but you live and learn).
- I made a few basic 2D games like that, such as Pong, Tetris, Breakout, Space Invaders etc.
- I've also recently completed a Computer Science degree, during which I learned mostly Java but also did 2 game projects in C++ with DirectX that were great learning experiences but didn't exactly turn out as I'd hoped, largely due to my wrong-headed way of approaching things (overcomplication and such beginner mistakes) and sticking with that combination of language and API that perhaps I should've abandoned earlier for something more user-friendly and forgiving.
- As you can tell, I've decided I somewhat took the wrong path in learning game development for longer than I would've liked. Recently I've tried my hand at game development in Java, messing around and making a basic 2D platformer engine of sorts using Slick 2D. That was a nice exercise but I couldn't think of a great deal to do with it and was having trouble coming up with 2D game ideas I found interesting.

Where I am now:
Recently, I've taken more of an interest in the 3D and more mathematical side of things. Properly understanding the concepts involved in 3D games (and pseudo-3D effects involving maths like Mode 7 or just interesting effects in general) has always been a goal of mine but I've never been able to figure out where exactly to start, and then how exactly to progress through it in a logical manner that lets me cover what I need to know and not get lost and be unsure where to turn to get a grip on what I'm not understanding.
I've been going through the tutorials for jMonkey, and while it looks like an interesting and straightforward tool, it's not exactly where I want to be going since it's understandably skipping over the complicated stuff that I'd rather not have as a mysterious black box in my head for the rest of my life and so it just feels like more avoidance of what I need to be studying and finally understanding.
Getting a simple 3D gameworld up and running with a few easy steps is nice but it feels a bit shallow and unrewarding because I'm not really learning much and I feel most of it is always going to be hidden.

From here:
I suppose right now I'm more interested in feeling confident with understanding the technical concepts behind 3D games and the underpinning 3D maths than actually realizing any specific 3D game ideas e.g. by taking a shortcut through something like jMonkey.

I've had a bad start with Direct3D and heard some people say OpenGL can be easier to learn etc. so I think OpenGL would be a good choice to study. I know you can use OpenGL through Java with JOGL and LWJGL and I've heard the bindings make it nearly the same as using OpenGL in C++.
Would it be advisable to start with OpenGL using Java, or would starting with C++ be better practice somehow? I think I heard people say following C++ OpenGL tutorials would work alright for OpenGL with Java since the function calls are meant to be the same or thereabouts.

Either way, where should I start and how should I continue? I looked on the Wiki, it doesn't have many tutorials though the Getting Started section seems to have some useful links, and I'm not sure what OpenGL version I should be using.
Should I jump into OpenGL, or are there a lot of 3D concepts I really need to cover beforehand?

This looks interesting but doesn't really seem to cover much actual OpenGL, just lots of general 3D concepts:

I'd like at first to work up to developing some kind of simple strategy game or maybe shoot 'em up on a 3D landscape of some kind. Maybe a basic clone of some early flat-shaded 3D games like on Amiga.
I've noticed some people do 3D (or pseudo-3D) games from scratch for Ludum Dare. They've interested me and I've looked at the code sometimes but without real experience in that kind of thing, it hasn't helped.

Thanks for reading. I hope I made things clear enough.

Share this post

Link to post
Share on other sites
If you want to start with java i dont see why not! LWJGL is basically a wrapper around OpenGL so you can use it in Java. All the methods and calls are literally 99.9% the same, the only difference is that many of them are preceded by GL11.openGlFunctionNameHere.

As for mathematics you dont INITIALLY need to be very well versed in it if you are starting to learn OpenGL, but you will want to be well versed with things like matrix's, vectors, quaternions, planes, essentially linear algebra.

I know some examples of LWJGL are hard to find on the internet, but basically its exactly the same as opengl so any opengl example you find in C++ you should be able to EASILY convert to LWJGL + java. If you are really interested PM me with you'r email or some way to contact you and I will be more than happy to take an hour or so to guide you through setting it up initially and transfer you some of my own source code so you can get started.

Share this post

Link to post
Share on other sites

If you want to start with java i dont see why not! LWJGL is basically a wrapper around OpenGL so you can use it in Java. All the methods and calls are literally 99.9% the same, the only difference is that many of them are preceded by GL11.openGlFunctionNameHere.

Cool, I thought I more or less heard it was like that.

I know some examples of LWJGL are hard to find on the internet, but basically its
exactly the same as opengl so any opengl example you find in C++ you should be able to EASILY convert to LWJGL + java.

Right. I suppose I'll install LWJGL and see how to set that up, then try to start whatever OpenGL tuts I can find.

Is it important what version of OpenGL is being used? I think I heard NeHe's tutorials used to be good, but that they were horribly out of date with modern OpenGL good practice or something to that effect and that it wasn't a good idea to use those anymore.

Are there any particularly good reference books or the like that cover most of the important stuff in OpenGL? I just wish I could find most relevant stuff in one place.

If you are really interested PM me with you'r email or some way to contact you and I will be more than happy to take an hour or so to guide you through setting it up initially and transfer you some of my own source code so you can get started.

Thanks, I'll send a PM if I get into much difficulty starting out.

Share this post

Link to post
Share on other sites
The book that got me started on OpenGL Programming (which I would highly recommened is OpenGL Game Programming By Hawkin/Astles. Though I think there are probably newer books that would be better for the current times. But I did find it a very easy and enjoyable read myself.

As far as the nehe tutorials alot of the stuff is still good, except there are certain things that are dated, some of which you wont have to worry since you are working with Java, LWJGL. But for the most part you can still learn alot from them.

You don't really have to worry what OpenGL you'r using if you are going down the LWJGL route. They will provide you with the DLL's and libraries you will need to get started. Whatever you do, don't get discouraged, I say this because I remember when I started I would find myself so frustrated that the simplest examples I could never get to work (I.E setting up my environment to use LWJGL and render a triangle!!!). But that's part of the learning phase and you will find that alot of these issues will have relatively simple solutions.

Share this post

Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
  • Advertisement
  • Popular Tags

  • Similar Content

    • By nOoNEE
      hello guys , i have some questions  what does glLinkProgram  and  glBindAttribLocation do?  i searched but there wasnt any good resource 
    • By owenjr
      Hi, I'm a Multimedia Engineering student. I am about to finish my dergree and I'm already thinking about what topic to cover in my final college project.
      I'm interested in the procedural animation with c++ and OpenGL of creatures, something like a spider for example. Can someone tell me what are the issues I should investigate to carry it out? I understand that it has some dependence on artificial intelligence but I do not know to what extent. Can someone help me to find information about it? Thank you very much.
      - Procedural multi-legged walking animation
      - Procedural Locomotion of Multi-Legged Characters in Dynamic Environments
    • By Lewa
      So, i'm still on my quest to unterstanding the intricacies of HDR and implementing this into my engine. Currently i'm at the step to implementing tonemapping. I stumbled upon this blogposts:
      and tried to implement some of those mentioned tonemapping methods into my postprocessing shader.
      The issue is that none of them creates the same results as shown in the blogpost which definitely has to do with the initial range in which the values are stored in the HDR buffer. For simplicity sake i store the values between 0 and 1 in the HDR buffer (ambient light is 0.3, directional light is 0.7)
      This is the tonemapping code:
      vec3 Uncharted2Tonemap(vec3 x) { float A = 0.15; float B = 0.50; float C = 0.10; float D = 0.20; float E = 0.02; float F = 0.30; return ((x*(A*x+C*B)+D*E)/(x*(A*x+B)+D*F))-E/F; } This is without the uncharted tonemapping:
      This is with the uncharted tonemapping:
      Which makes the image a lot darker.
      The shader code looks like this:
      void main() { vec3 color = texture2D(texture_diffuse, vTexcoord).rgb; color = Uncharted2Tonemap(color); //gamma correction (use only if not done in tonemapping code) color = gammaCorrection(color); outputF = vec4(color,1.0f); } Now, from my understanding is that tonemapping should bring the range down from HDR to 0-1.
      But the output of the tonemapping function heavily depends on the initial range of the values in the HDR buffer. (You can't expect to set the sun intensity the first time to 10 and the second time to 1000 and excpect the same result if you feed that into the tonemapper.) So i suppose that this also depends on the exposure which i have to implement?
      To check this i plotted the tonemapping curve:
      You can see that the curve goes only up to around to a value of 0.21 (while being fed a value of 1) and then basically flattens out. (which would explain why the image got darker.)
      My guestion is: In what range should the values in the HDR buffer be which then get tonemapped? Do i have to bring them down to a range of 0-1 by multiplying with the exposure?
      For example, if i increase the values of the light by 10 (directional light would be 7 and ambient light 3) then i would need to divide HDR values by 10 in order to get a value range of 0-1 which then could be fed into the tonemapping curve. Is that correct?
    • By nOoNEE
      i am reading this book : link
      in the OpenGL Rendering Pipeline section there is a picture like this: link
      but the question is this i dont really understand why it is necessary to turn pixel data in to fragment and then fragment into pixel could please give me a source or a clear Explanation that why it is necessary ? thank you so mu
    • By Inbar_xz
      I'm using the OPENGL with eclipse+JOGL.
      My goal is to create movement of the camera and the player.
      I create main class, which create some box in 3D and hold 
      an object of PlayerAxis.
      I create PlayerAxis class which hold the axis of the player.
      If we want to move the camera, then in the main class I call to 
      the func "cameraMove"(from PlayerAxis) and it update the player axis.
      That's work good.
      The problem start if I move the camera on 2 axis, 
      for example if I move with the camera right(that's on the y axis)
      and then down(on the x axis) -
      in some point the move front is not to the front anymore..
      In order to move to the front, I do
      player.playerMoving(0, 0, 1);
      And I learn that in order to keep the front move, 
      I need to convert (0, 0, 1) to the player axis, and then add this.
      I think I dont do the convert right.. 
      I will be glad for help!

      Here is part of my PlayerAxis class:
      //player coordinate float x[] = new float[3]; float y[] = new float[3]; float z[] = new float[3]; public PlayerAxis(float move_step, float angle_move) { x[0] = 1; y[1] = 1; z[2] = -1; step = move_step; angle = angle_move; setTransMatrix(); } public void cameraMoving(float angle_step, String axis) { float[] new_x = x; float[] new_y = y; float[] new_z = z; float alfa = angle_step * angle; switch(axis) { case "x": new_z = addVectors(multScalar(z, COS(alfa)), multScalar(y, SIN(alfa))); new_y = subVectors(multScalar(y, COS(alfa)), multScalar(z, SIN(alfa))); break; case "y": new_x = addVectors(multScalar(x, COS(alfa)), multScalar(z, SIN(alfa))); new_z = subVectors(multScalar(z, COS(alfa)), multScalar(x, SIN(alfa))); break; case "z": new_x = addVectors(multScalar(x, COS(alfa)), multScalar(y, SIN(alfa))); new_y = subVectors(multScalar(y, COS(alfa)), multScalar(x, SIN(alfa))); } x = new_x; y = new_y; z = new_z; normalization(); } public void playerMoving(float x_move, float y_move, float z_move) { float[] move = new float[3]; move[0] = x_move; move[1] = y_move; move[2] = z_move; setTransMatrix(); float[] trans_move = transVector(move); position[0] = position[0] + step*trans_move[0]; position[1] = position[1] + step*trans_move[1]; position[2] = position[2] + step*trans_move[2]; } public void setTransMatrix() { for (int i = 0; i < 3; i++) { coordiTrans[0][i] = x[i]; coordiTrans[1][i] = y[i]; coordiTrans[2][i] = z[i]; } } public float[] transVector(float[] v) { return multiplyMatrixInVector(coordiTrans, v); }  
      and in the main class i have this:
      public void keyPressed(KeyEvent e) { if (e.getKeyCode()== KeyEvent.VK_ESCAPE) { System.exit(0); //player move } else if (e.getKeyCode()== KeyEvent.VK_W) { //front //moveAmount[2] += -0.1f; player.playerMoving(0, 0, 1); } else if (e.getKeyCode()== KeyEvent.VK_S) { //back //moveAmount[2] += 0.1f; player.playerMoving(0, 0, -1); } else if (e.getKeyCode()== KeyEvent.VK_A) { //left //moveAmount[0] += -0.1f; player.playerMoving(-1, 0, 0); } else if (e.getKeyCode()== KeyEvent.VK_D) { //right //moveAmount[0] += 0.1f; player.playerMoving(1, 0, 0); } else if (e.getKeyCode()== KeyEvent.VK_E) { //moveAmount[0] += 0.1f; player.playerMoving(0, 1, 0); } else if (e.getKeyCode()== KeyEvent.VK_Q) { //moveAmount[0] += 0.1f; player.playerMoving(0, -1, 0); //camera move } else if (e.getKeyCode()== KeyEvent.VK_I) { //up player.cameraMoving(1, "x"); } else if (e.getKeyCode()== KeyEvent.VK_K) { //down player.cameraMoving(-1, "x"); } else if (e.getKeyCode()== KeyEvent.VK_L) { //right player.cameraMoving(-1, "y"); } else if (e.getKeyCode()== KeyEvent.VK_J) { //left player.cameraMoving(1, "y"); } else if (e.getKeyCode()== KeyEvent.VK_O) { //right round player.cameraMoving(-1, "z"); } else if (e.getKeyCode()== KeyEvent.VK_U) { //left round player.cameraMoving(1, "z"); } }  
      finallt found it.... i confused with the transformation matrix row and col. thanks anyway!
    • By Lewa
      So, i'm currently trying to implement an SSAO shader from THIS tutorial and i'm running into a few issues here.
      Now, this SSAO method requires view space positions and normals. I'm storing the normals in my deferred renderer in world-space so i had to do a conversion and reconstruct the position from the depth buffer.
      And something there goes horribly wrong (which has probably to do with worldspace to viewspace transformations).
      (here is the full shader source code if someone wants to take a look at it)
      Now, i suspect that the normals are the culprit.
      vec3 normal = ((uNormalViewMatrix*vec4(normalize(texture2D(sNormals, vTexcoord).rgb),1.0)).xyz); "sNormals" is a 2D texture which stores the normals in world space in a RGB FP16 buffer.
      Now i can't use the camera viewspace matrix to transform the normals into viewspace as the cameras position isn't set at (0,0,0), thus skewing the result.
      So what i did is to create a new viewmatrix specifically for this normal without the position at vec3(0,0,0);
      //"camera" is the camera which was used for rendering the normal buffer renderer.setUniform4m(ressources->shaderSSAO->getUniform("uNormalViewMatrix"), glmExt::createViewMatrix(glm::vec3(0,0,0),camera.getForward(),camera.getUp())//parameters are (position,forwardVector,upVector) ); Though i have the feeling this is the wrong approach. Is this right or is there a better/correct way of transforming a world space normal into viewspace?
    • By HawkDeath
      I'm trying mix two textures using own shader system, but I have a problem (I think) with uniforms.
      Code: https://github.com/HawkDeath/shader/tree/test
      To debug I use RenderDocs, but I did not receive good results. In the first attachment is my result, in the second attachment is what should be.
      PS. I base on this tutorial https://learnopengl.com/Getting-started/Textures.

    • By norman784
      I'm having issues loading textures, as I'm clueless on how to handle / load images maybe I missing something, but the past few days I just google a lot to try to find a solution. Well theres two issues I think, one I'm using Kotlin Native (EAP) and OpenGL wrapper / STB image, so I'm not quite sure wheres the issue, if someone with more experience could give me some hints on how to solve this issue?
      The code is here, if I'm not mistaken the workflow is pretty straight forward, stbi_load returns the pixels of the image (as char array or byte array) and you need to pass those pixels directly to glTexImage2D, so a I'm missing something here it seems.
    • By Hashbrown
      I've noticed in most post processing tutorials several shaders are used one after another: one for bloom, another for contrast, and so on. For example: 
      postprocessing.quad.bind() // Effect 1 effect1.shader.bind(); postprocessing.texture.bind(); postprocessing.quad.draw(); postprocessing.texture.unbind(); effect1.shader.unbind(); // Effect 2 effect2.shader.bind(); // ...and so on postprocessing.quad.unbind() Is this good practice, how many shaders can I bind and unbind before I hit performance issues? I'm afraid I don't know what the good practices are in open/webGL regarding binding and unbinding resources. 
      I'm guessing binding many shaders at post processing is okay since the scene has already been updated and I'm just working on a quad and texture at that moment. Or is it more optimal to put shader code in chunks and bind less frequently? I'd love to use several shaders at post though. 
      Another example of what I'm doing at the moment:
      1) Loop through GameObjects, bind its phong shader (send color, shadow, spec, normal samplers), unbind all.
      2) At post: bind post processor quad, and loop/bind through different shader effects, and so on ...
      Thanks all! 
    • By phil67rpg
      void collision(int v) { collision_bug_one(0.0f, 10.0f); glutPostRedisplay(); glutTimerFunc(1000, collision, 0); } void coll_sprite() { if (board[0][0] == 1) { collision(0); flag[0][0] = 1; } } void erase_sprite() { if (flag[0][0] == 1) { glColor3f(0.0f, 0.0f, 0.0f); glBegin(GL_POLYGON); glVertex3f(0.0f, 10.0f, 0.0f); glVertex3f(0.0f, 9.0f, 0.0f); glVertex3f(1.0f, 9.0f, 0.0f); glVertex3f(1.0f, 10.0f, 0.0f); glEnd(); } } I am using glutTimerFunc to wait a small amount of time to display a collision sprite before I black out the sprite. unfortunately my code only blacks out the said sprite without drawing the collision sprite, I have done a great deal of research on the glutTimerFunc and  animation.
  • Advertisement
  • Popular Now

  • Forum Statistics

    • Total Topics
    • Total Posts

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

Participate in the game development conversation and more when you create an account on GameDev.net!

Sign me up!