I want to make a 3D model in Blender and load it in OpenGL. Can someone give a step-by-step approach on how to do so. I tried to google but did not get any proper results.
Programming language: C++,
Tools: GLFW + GLAD + GLM
Its a 3 step process, using external libraries.
Model in blender. Export from Blender to .obj format (also containing .mtl file with reference to textures used).
Refer to
https://blender.stackexchange.com/questions/121/how-do-i-export-a-model-to-obj-format
Use a library like Assimp to produce vertices and attributes.
Use the vertices and attributes in your OpenGL application, using a method like described in,
https://nickthecoder.wordpress.com/2013/01/20/mesh-loading-with-assimp/
Related
I am starting with 3D objects in C++. There are many tutorials on OpenGL on the internet but I wanted to know: How can you render basic 3D shapes in C++ without using OpenGL. I will be using .obj files so I wanted to know how to import and export these files without OpenGL.
I have a file from CAD in format .obj and I want to render with rototranslation and get the position in 2D for my different object.
I use C/C++ and OPENGL. With the library assimp I can load the object and do the rototranslation.
But my problem is: how I can export this information with the attribute of object? Because I have to use this information with OPENCV.
You might be interested in Transform Feedback. Or you just do the matrix math on the CPU without OpenGL, because Transform Feedback is the only way, when using OpenGL to address your problem actually makes sense.
I have these files: sample.obj, sample.mtl and a folder sample containing image jpg. Can somebody give me an example code of opengl texture mapping using above input.
Your problem is not just texture mapping. What you are asking for is loading an Wavefront OBJ model and its material library, then passing this data to OpenGL rendering commands. Depending on how many preexisting code you want (not) to use this takes different amounts of code. However there's no such thing like a simple OpenGL function that does it all in a black box.
Although this is a FAQ and Google brings you some results I didn't find a tutorial that really explains what's going on.
If you want it to be really simple, use a Wavefront loader and render library:
http://www.evl.uic.edu/pape/sw/libwave.html
I am trying to develop a 3D game in openGL and i need to create many 3D objects.. I am a begginner in openGL.. I have tried with many 3D softwares like Blender , MODO, Unity 3D and Cheetah.
I am easily able to create my objects with these and exporting as Wavefront .OBJ, and converting it to a header file using a perl script. This header file is added to my openGL project..
The 3D objects are seen, but its not perfect. The script i used is to convert the .OBJ to .h using TRIANGLES.. And the object is seen with triangles. Its not full.. No way when i used TRIANGLE STRIP,FAN..? Problems with the vertices..
Is the problem with my Script or is it the wrong way i have gone..?? Or is there any other best ways to directly import 3D objects to openGL..??
The below link is the best one which you can get for 3D objects to openGL.. i got the scripts from these..
http://www.heikobehrens.net/2009/08/27/obj2opengl/
please help..
You don't want to go that way. Direct drawing mode (using TRIANGLE and friends) is extremely slow in OpenGL.
Instead, you should pick a decent format and write a loader for it (or use one found on the web). Good formats would be 3ds, obj if gzipped, collada.
Here's an example tutorial on loading from Milkshape files.
Once you load your objects programatically, you can use Vertex Arrays, or even better VBO's to display them. This is waaay faster.
Google for a mesh loader for your favorite format, or write one yourself.
I have written a reader/renderer for AC3D files that works fine on the iPhone (OpenGL ES)
Feel free to have a look at it here.
There is also an obj loader by Jeff Lamarche at google code.
AC3D can reduce the triangle count pretty good and as an alternative I ported QVis to the mac. My reader/renderer also tries to build tri-strips.
About VBO's. I have not seen any gained performance when using them in the iPhone. I'm not the only one.
I am trying to assemble a scene in opengl, using already made objects. The problem is that the object are in .max format and have no external textures. How could I import my objects in opengl, without retexturing them. I am thinking about exporting them to 3ds and using a 3ds file loader. Could you recommend one, and of course it has to work only with the 3ds file itself, no external texture files.
3ds max already allows me to export the file to obj. I have an object that has no external texture file, but it is already fully colored as a 3ds file. Is there any way to import in opengl and have the same colors, for the trunk, leaves?
You might want to check out lib3ds which will parse the 3ds binary format for you and give you access to all of the objects properties. I think Autodesk also has their own toolkit for doing this.
You should look at this link. It is a 3DS viewer with source code that renders using OpenGL. The code is simple.
Another option could be Assimp, an open source asset import library for C or C++, which seems like a pretty good way to get 3DS assets into an opengl program. It'd be especially useful if you want it for skeletal animations, and supports embedded textures. Though at this point, this answer may be less for you than it is for other people coming across this question.
If I remember correctly, the 3ds file does not store the vertex normals so you will probably have to calculate them yourself somehow or otherwise it will use the normal of the face itself which is will be quite ugly.