Archived

This topic is now archived and is closed to further replies.

JimboC

OpenGL Converting from Direct3D to OpenGL

Recommended Posts

JimboC    152
Question #1: I''m using Linux more and more on my home PC and I was starting to think about switching from DirectX to OpenGL. I''m not an expert with DirectX by any stretch of the imagination, but I''ve been playing around with it a since version 5 and I would say I have a good working knowledge of it. Would I be looking at a large learning curve to switch to OpenGL and other ''Open'' APIs? Question #2: I''ve been using .X files for my models, mostly because DirectX has some fairly straight forward ways to use them. I''ve got 3D Studio Max 3.1 (haven''t been able to keep up with the updates), which had a few .X exporters. Is there something similar I can use with OpenGL that provides for character animation and the like? Question #3: Is there a program similar to 3D Studio Max that works under Linux? Come springtime I''ll have money to either upgrade 3D Studio Max or get a different package that works under Linux or X-Windows. Anyone have a package they user for this?

Share this post


Link to post
Share on other sites
invective    118
If you are using OpenGL its very easy to switch to Direct 3D. I''m not so sure that the opposite is true; it really depends what features you use. You may find that if you move from DirectX to OpenGL you are losing a lot of functionality that you may have come to depend on (like the X files, mesh support, texture loading, the SIMD math library, Direct Input, Direct Play, Direct Sound, etc.), but if your programs don''t use any of these features, you should be able to port them very easily (you may have to use some OpenGL extensions to match some direct X features).

If you save your X files in text format it should be pretty straight forward to load them, but you have to code it yourself.

I don''t know of anything close to 3dsmax for linux. The only other programs i can think of are Maya and Lightwave, and they are both Windows/Mac only.

Share this post


Link to post
Share on other sites
Guest Anonymous Poster   
Guest Anonymous Poster
you could try http://www.tb-software.com/ (3dwin) it''s an exporte-importer for different formats, including x, opengl .c files, etc. may be milkshape helps, too, it has lots of converters.
i just did opengl, so i''m not sure about the difficulty going from direct3d to opengl.

Share this post


Link to post
Share on other sites
Nik02    4348
1: No. OGL is regarded by many as easier than D3D. D3D does have built-in file loaders, animation controllers, mesh objects and such to ease the actual development, though.

2: Define your own format. It''s not really that hard, just store/load the vertices, indices, material defs and stuff using your own convention. OR you can write x loader for use with OGL, but IMHO it''s too much of work.

3: Blender, a very good free modeler, works in Linux (and in almost all java-capable desktop os:s).
Also, a while ago i heard Maya was going to get ported to Linux.

Share this post


Link to post
Share on other sites
Guest Anonymous Poster   
Guest Anonymous Poster
I got a question regarding D3D, what does these funtions do?

D3DXQuaternionRotationAxis(vector1, vector2, float);

and

D3DXQuaternionSlerp(D3DXQUATERNION1, D3DXQUATERNION2, D3DXQUATERNIO, float);

Share this post


Link to post
Share on other sites
mhamlin    520
"I got a question regarding D3D, what does these funtions do?

D3DXQuaternionRotationAxis(vector1, vector2, float);

and

D3DXQuaternionSlerp(D3DXQUATERNION1, D3DXQUATERNION2, D3DXQUATERNIO, float);"

They appear to be Quaternion manipulation functions.

Share this post


Link to post
Share on other sites
Null and Void    1088
quote:
Original post by JimboC
Would I be looking at a large learning curve to switch to OpenGL and other ''Open'' APIs?

It should go relatively quickly.

quote:
Original post by JimboC
I''ve been using .X files for my models, mostly because DirectX has some fairly straight forward ways to use them. I''ve got 3D Studio Max 3.1 (haven''t been able to keep up with the updates), which had a few .X exporters. Is there something similar I can use with OpenGL that provides for character animation and the like?

Use an existing library for loading models from some format (e.g., lib3ds) or write your own format and/or your own loading library. OpenGL doesn''t do file related things for you since it''s out of its scope (clean design and all), as you apparently already realize.

quote:
Original post by JimboC
Is there a program similar to 3D Studio Max that works under Linux? Come springtime I''ll have money to either upgrade 3D Studio Max or get a different package that works under Linux or X-Windows. Anyone have a package they user for this?

Maya (commercial) and Blender (free) are the two most popular *nix modeling programs. (Replied primarly to fix misleading answers to this question.)

Share this post


Link to post
Share on other sites
JimboC    152
Thanks guys! Definitely think I''ll be looking into this. I''ve been toying with writing my own mesh format. I''m been most worried about making the exporter for 3DS Max, but like anything else, it will only take some time and patience to learn how to do it. Maybe I''ll also look into Maya Complete, which seems to be exactly what I''m looking for.

Share this post


Link to post
Share on other sites

  • Similar Content

    • By Kjell Andersson
      I'm trying to get some legacy OpenGL code to run with a shader pipeline,
      The legacy code uses glVertexPointer(), glColorPointer(), glNormalPointer() and glTexCoordPointer() to supply the vertex information.
      I know that it should be using setVertexAttribPointer() etc to clearly define the layout but that is not an option right now since the legacy code can't be modified to that extent.
      I've got a version 330 vertex shader to somewhat work:
      #version 330 uniform mat4 osg_ModelViewProjectionMatrix; uniform mat4 osg_ModelViewMatrix; layout(location = 0) in vec4 Vertex; layout(location = 2) in vec4 Normal; // Velocity layout(location = 3) in vec3 TexCoord; // TODO: is this the right layout location? out VertexData { vec4 color; vec3 velocity; float size; } VertexOut; void main(void) { vec4 p0 = Vertex; vec4 p1 = Vertex + vec4(Normal.x, Normal.y, Normal.z, 0.0f); vec3 velocity = (osg_ModelViewProjectionMatrix * p1 - osg_ModelViewProjectionMatrix * p0).xyz; VertexOut.velocity = velocity; VertexOut.size = TexCoord.y; gl_Position = osg_ModelViewMatrix * Vertex; } What works is the Vertex and Normal information that the legacy C++ OpenGL code seem to provide in layout location 0 and 2. This is fine.
      What I'm not getting to work is the TexCoord information that is supplied by a glTexCoordPointer() call in C++.
      Question:
      What layout location is the old standard pipeline using for glTexCoordPointer()? Or is this undefined?
       
      Side note: I'm trying to get an OpenSceneGraph 3.4.0 particle system to use custom vertex, geometry and fragment shaders for rendering the particles.
    • By markshaw001
      Hi i am new to this forum  i wanted to ask for help from all of you i want to generate real time terrain using a 32 bit heightmap i am good at c++ and have started learning Opengl as i am very interested in making landscapes in opengl i have looked around the internet for help about this topic but i am not getting the hang of the concepts and what they are doing can some here suggests me some good resources for making terrain engine please for example like tutorials,books etc so that i can understand the whole concept of terrain generation.
       
    • By KarimIO
      Hey guys. I'm trying to get my application to work on my Nvidia GTX 970 desktop. It currently works on my Intel HD 3000 laptop, but on the desktop, every bind textures specifically from framebuffers, I get half a second of lag. This is done 4 times as I have three RGBA textures and one depth 32F buffer. I tried to use debugging software for the first time - RenderDoc only shows SwapBuffers() and no OGL calls, while Nvidia Nsight crashes upon execution, so neither are helpful. Without binding it runs regularly. This does not happen with non-framebuffer binds.
      GLFramebuffer::GLFramebuffer(FramebufferCreateInfo createInfo) { glGenFramebuffers(1, &fbo); glBindFramebuffer(GL_FRAMEBUFFER, fbo); textures = new GLuint[createInfo.numColorTargets]; glGenTextures(createInfo.numColorTargets, textures); GLenum *DrawBuffers = new GLenum[createInfo.numColorTargets]; for (uint32_t i = 0; i < createInfo.numColorTargets; i++) { glBindTexture(GL_TEXTURE_2D, textures[i]); GLint internalFormat; GLenum format; TranslateFormats(createInfo.colorFormats[i], format, internalFormat); // returns GL_RGBA and GL_RGBA glTexImage2D(GL_TEXTURE_2D, 0, internalFormat, createInfo.width, createInfo.height, 0, format, GL_FLOAT, 0); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); DrawBuffers[i] = GL_COLOR_ATTACHMENT0 + i; glBindTexture(GL_TEXTURE_2D, 0); glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0 + i, textures[i], 0); } if (createInfo.depthFormat != FORMAT_DEPTH_NONE) { GLenum depthFormat; switch (createInfo.depthFormat) { case FORMAT_DEPTH_16: depthFormat = GL_DEPTH_COMPONENT16; break; case FORMAT_DEPTH_24: depthFormat = GL_DEPTH_COMPONENT24; break; case FORMAT_DEPTH_32: depthFormat = GL_DEPTH_COMPONENT32; break; case FORMAT_DEPTH_24_STENCIL_8: depthFormat = GL_DEPTH24_STENCIL8; break; case FORMAT_DEPTH_32_STENCIL_8: depthFormat = GL_DEPTH32F_STENCIL8; break; } glGenTextures(1, &depthrenderbuffer); glBindTexture(GL_TEXTURE_2D, depthrenderbuffer); glTexImage2D(GL_TEXTURE_2D, 0, depthFormat, createInfo.width, createInfo.height, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glBindTexture(GL_TEXTURE_2D, 0); glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, depthrenderbuffer, 0); } if (createInfo.numColorTargets > 0) glDrawBuffers(createInfo.numColorTargets, DrawBuffers); else glDrawBuffer(GL_NONE); if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) std::cout << "Framebuffer Incomplete\n"; glBindFramebuffer(GL_FRAMEBUFFER, 0); width = createInfo.width; height = createInfo.height; } // ... // FBO Creation FramebufferCreateInfo gbufferCI; gbufferCI.colorFormats = gbufferCFs.data(); gbufferCI.depthFormat = FORMAT_DEPTH_32; gbufferCI.numColorTargets = gbufferCFs.size(); gbufferCI.width = engine.settings.resolutionX; gbufferCI.height = engine.settings.resolutionY; gbufferCI.renderPass = nullptr; gbuffer = graphicsWrapper->CreateFramebuffer(gbufferCI); // Bind glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo); // Draw here... // Bind to textures glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, textures[0]); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, textures[1]); glActiveTexture(GL_TEXTURE2); glBindTexture(GL_TEXTURE_2D, textures[2]); glActiveTexture(GL_TEXTURE3); glBindTexture(GL_TEXTURE_2D, depthrenderbuffer); Here is an extract of my code. I can't think of anything else to include. I've really been butting my head into a wall trying to think of a reason but I can think of none and all my research yields nothing. Thanks in advance!
    • By Adrianensis
      Hi everyone, I've shared my 2D Game Engine source code. It's the result of 4 years working on it (and I still continue improving features ) and I want to share with the community. You can see some videos on youtube and some demo gifs on my twitter account.
      This Engine has been developed as End-of-Degree Project and it is coded in Javascript, WebGL and GLSL. The engine is written from scratch.
      This is not a professional engine but it's for learning purposes, so anyone can review the code an learn basis about graphics, physics or game engine architecture. Source code on this GitHub repository.
      I'm available for a good conversation about Game Engine / Graphics Programming
    • By C0dR
      I would like to introduce the first version of my physically based camera rendering library, written in C++, called PhysiCam.
      Physicam is an open source OpenGL C++ library, which provides physically based camera rendering and parameters. It is based on OpenGL and designed to be used as either static library or dynamic library and can be integrated in existing applications.
       
      The following features are implemented:
      Physically based sensor and focal length calculation Autoexposure Manual exposure Lense distortion Bloom (influenced by ISO, Shutter Speed, Sensor type etc.) Bokeh (influenced by Aperture, Sensor type and focal length) Tonemapping  
      You can find the repository at https://github.com/0x2A/physicam
       
      I would be happy about feedback, suggestions or contributions.

  • Popular Now