Jump to content
  • Advertisement
Sign in to follow this  
quickJava

OpenGL 3ds Max help.

This topic is 4122 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

Hi everyone, I'm opening my talk by mentioning that I'm Vietnamese so I'm sorry if my English is not good. Before answering my question, you may want to know where I am, and what I know. This might make it easy to know where to start answer to such a noob :). OK, my only major thing related to game programming was the project for my Graphics subject ( at university ) with a high mark. It was 3ds Max like. I just learned 3ds Max style and how comfortable it is to use. I didnt learned more than that since I wanted to make the program by myself, with my own imagination. just a book and no open source program was used. I created my own wireframe format, objects created with that format were filled using Phong shading and Lampard technique. Besides, I created some features such as: moving, creating object with mouse, selecting deleting, and a net-liked floor to help users have an awareness of where their objects are. These features are easy to use just by hot keys and mouse. Although I felt a little satisfy, now I know that I should use the world standards to do similar things. Before using those standards, I must learn them, of course. So now, I'm learning 3ds Max and OpenGL, and more. I need your help, about experience and knowledge. I would love small examples and hate complete sources. So here are my silly questions: - Is 3ds Max has its own standard to mark a particular data as basic object type or what? If yes, what are they? Although I know how to read the raw data, I don't know which data in the 3ds file is equivalent to a vertex on the output object that I'm seeing, for example. - I intend to create my own common graphic format to make it a standard for communication between engines and data. Is this a bad thought? Why? - What are the most common basic graphic definition used for rendering 3d object, for example, vertex, texture? __________________________________ Here's why I am asking you such silly questions. It's not important but if you want a reason, then it's here: I'm a last year IT student, and focusing on C/C++, Java technology. Besides, I love Math and Physics so I decided to create a Graphics engine for my graduate project although I have never create a part of a real game. I love Java for its elegant and erudite style. To me, JVM is a proof that Sun knew how right the standardization is long time ago, and how intelligent they are when they have successfully standardize many complex platforms just like the way we are standardizing everything now. I recently knew that Java's getting faster now. And Just-in-time programs run slower than pre-compiled programs is just a myth, not truth. With all these good news, I feel joyful continue using Java as one of my main languages. I love challenge, so I'm not worry that I'm still a game programming newbie. I have you help me :) P/S: Vietnameses are very friendly, If you had been here, you may be more than surprise. So if you feel free to be friendly as a Vietnamese, please fix my grammar or vocabulary errors. Thanks a lot.

Share this post


Link to post
Share on other sites
Advertisement
OK, I'm not sure if I fully understand what you're asking but I'll give it a try:

1)
Get the 3ds max SDK and the SDK help, there you can learn on how 3ds max organises 3d data. They use some common representations like triangles, edges etc. but they also use multiple normals per vertex which isn't the case in many engines as far as I know.

2)
Generally you should use a common file format like .3ds or .md3. There are plenty of editors that can read and write those formats out there so you could use them without having to write an exporter for each of those. Additionally the exisiting formats are proven, there exist many models stored in those formats and it should be easier to use them in your engine - either via a 3rd party library or your own importer/exporter.

I'd suggest you use the standard formats for the beginning. If you later discover that there is no format that meets your requirements you can create your own by then.

3)
Basic data for rendering an object are the vertex positions and definitions on what type of primitive is used (generally triangles) and of which vertices a primitive consists - either by position in the buffer or by index.

For lighting you need:
- normals for calculating light intensity (based on angle to light source)
- materials for defining light color and intensity (based on reflectance etc.)
- you can also use colors to define the materials instead of the material structure

For texturing you need texture coordinates and textures.

Other advanced features like animation use additional data per vertex but the above should suffice for a beginning.

Share this post


Link to post
Share on other sites
Hi.

Quote:
Original post by quickJava
- Is 3ds Max has its own standard to mark a particular data as basic object type or what? If yes, what are they? Although I know how to read the raw data, I don't know which data in the 3ds file is equivalent to a vertex on the output object that I'm seeing, for example.

There's a lot of info on the 3ds file format (Google "3ds file format"). Quick link to something you might find useful: an open-source project to write a library for loading 3ds files - 3DS File Format Library

Quote:
Original post by quickJava
- I intend to create my own common graphic format to make it a standard for communication between engines and data. Is this a bad thought? Why?

Do you mean something like COLLADA?. The problem with writing a "standard" for this kind of thing is that games have vastly different needs. A first-person shooter won't need the same data as a real-time strategy game, for example. It's a good idea to create game content in your favourite tool (3ds max, Maya, XSI, blender, whatever), then write an exporter to your own file format for use in your game or engine project.

Quote:
Original post by quickJava
- What are the most common basic graphic definition used for rendering 3d object, for example, vertex, texture?

Depends on how "high-level" the data is. In the native file formats used by content creation tools (3ds max, Maya, etc.), the data isn't stored as just vertex data, material data, and so on. It's stored in a very high-level form. 3ds max, for example, stores objects in .max files by writing the original object, then all of the modifiers which are applied to it. A saved, final object doesn't actually "exist" in the file at all. When you open the file, 3ds max reads the original object, then applies all of it's attached modifiers, creating the final object you saved.

Formats like 3ds and most model formats used by games and game engines do generally store objects as collections of vertex data, material data and animation data. I guess there are special cases, such as parameterized splines (eg. Bezier, Catmull-Rom) or surfaces (eg. NURBS) which could be built by the game or engine on-the-fly, but I've never come across anything like that.

If you like maths and physics, you might like to have a look at the md5mesh and md5anim files which the Doom 3 engine uses. They're human-readable 3D model files, which demonstrate how mesh and animation data is stored and utilized by a professional 3D engine. The models are skeletally-animated using quaternions (very useful, not too difficult to learn) and general 3D vector math. There's a lot of information on the md5 formats on the net. I found this one particularly helpful: http://tfc.duke.free.fr/coding/md5-specs-en.html. It might take a while to get going, but the rewards are great (animating Doom 3 monsters and marines [grin])

[Edited by - iNsAn1tY on March 3, 2007 6:11:09 PM]

Share this post


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

  • Advertisement
  • Advertisement
  • Popular Tags

  • Similar Content

    • 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.
       
      Examples: 
      - 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:
      http://filmicworlds.com/blog/filmic-tonemapping-operators/
      http://frictionalgames.blogspot.com/2012/09/tech-feature-hdr-lightning.html
      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
      Hi,
      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.
      Regards
    • 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.
    • By Lewa
      So, i stumbled upon the topic of gamma correction.
      https://learnopengl.com/Advanced-Lighting/Gamma-Correction
      So from what i've been able to gather: (Please correct me if i'm wrong)
      Old CRT monitors couldn't display color linearly, that's why gamma correction was nessecary. Modern LCD/LED monitors don't have this issue anymore but apply gamma correction anyway. (For compatibility reasons? Can this be disabled?) All games have to apply gamma correction? (unsure about that) All textures stored in file formats (.png for example) are essentially stored in SRGB color space (as what we see on the monitor is skewed due to gamma correction. So the pixel information is the same, the percieved colors are just wrong.) This makes textures loaded into the GL_RGB format non linear, thus all lighting calculations are wrong You have to always use the GL_SRGB format to gamma correct/linearise textures which are in SRGB format  
      Now, i'm kinda confused how to proceed with applying gamma correction in OpenGL.
      First of, how can i check if my Monitor is applying gamma correction? I noticed in my monitor settings that my color format is set to "RGB" (can't modify it though.) I'm connected to my PC via a HDMI cable. I'm also using the full RGB range (0-255, not the 16 to ~240 range)
       
      What i tried to do is to apply a gamma correction shader shown in the tutorial above which looks essentially like this: (it's a postprocess shader which is applied at the end of the renderpipeline)
      vec3 gammaCorrection(vec3 color){ // gamma correction color = pow(color, vec3(1.0/2.2)); return color; } void main() { vec3 color; vec3 tex = texture2D(texture_diffuse, vTexcoord).rgb; color = gammaCorrection(tex); outputF = vec4(color,1.0f); } The results look like this:
      No gamma correction:
      With gamma correction:
       
      The colors in the gamma corrected image look really wased out. (To the point that it's damn ugly. As if someone overlayed a white half transparent texture. I want the colors to pop.)
      Do i have to change the textures from GL_RGB to GL_SRGB in order to gamma correct them in addition to applying the post process gamma correction shader? Do i have to do the same thing with all FBOs? Or is this washed out look the intended behaviour?
  • Advertisement
  • Popular Now

  • Forum Statistics

    • Total Topics
      631373
    • Total Posts
      2999643
×

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!