Obj Library (Download)

0. Contents
1. Overview
2. Design Goals
3. Zip Files
4. Source Code
5. Sample Programs
6. Extensions
7. Miscellaneous
8. Bottom of Page

0. The ObjLibrary should load and display OBJ models on the screen with OpenGL, of course. It would be kind of useless without that.
1. ObjLibrary shall be easy to use. Ideally, it shall be usable by people with no prior graphics programming experience.
2. ObjLibrary shall be fast.
3. The code for ObjLibrary shall be (relatively) easy to understand. This means no clever programming tricks and definately nothing that would qualify as magic.
4. The ObjLibrary shall be well-documented. This includes documentation for every function, even obvious ones and ones with file scope. Any confusing pieces of code should have an explanation with them. Documentation is not needed for most code.
5. The ObjLibrary shall use namespaces in .cpp files to enforce file scope instead of static variables and functions. Anonymous namespace are no longer used because they interact poorly with with unity/jumbo builds.
6. Variable and function names shall be self-documenting whenever possible. Long descriptive names are prefered to short ones (except as loop counters).

• GetGlut.h
• I have put this file one directory level up (with normal source code) because it is useful elsewhere in programs and having 2 copies can lead to inconsistancies.
• This file uses preprocessor macros to #include different headers based on your system. If you find a system that it doesn't work on, and you know how the #includes should be, please tell me.

• ObjSettings.h
• This file defines preprocessor macros to enable different global options. These options can affect the #includes that appear in some files.

• ObjTypes.h

• Vector2.h
• Vector2.cpp
• Vector3.h
• Vector3.cpp
• These are heavily inlined for speed reasons.
• These include a lot of functions (more than 100) for math operations. I am always on the lookout for more to add.
• These classes a somewhat of an exception to the simple code goal (#3). They will be used so often that need to be really fast.
• Documentation - somewhat out of date: more functions have been added

• SpriteFont.h
• SpriteFont.cpp
• Nothing to do with OBJ models (except that both load BMP files), but useful in the same circumstances.

• TextureBmp.h
• TextureBmp.cpp
• Texture.h
• Texture.cpp
• TextureManager.h
• TextureManager.cpp
• Material.h
• Material.cpp
• MtlLibrary.h
• MtlLibrary.cpp
• MtlLibraryManager.h
• MtlLibraryManager.cpp
• ObjModel.h
• ObjModel.cpp
• ObjStringParsing.h
• ObjStringParsing.cpp

• DisplayList.h
• DisplayList.cpp
• About the only thing this provides that the raw OpenGL ones don't is automatic reference counting and memory management. On the other hand, this allows them to be copied around at will without hassle.
• Display lists are normally considered to be rendered obsolete by shaders. They are not in the newer OpenGL standards. However, they are still (mostly) supported and very easy for beginners to use. Shaders, on the other hand, are hard.

• OBJ Compactor - reduces the file size of OBJ models
• TODO: Shader rendering example program
• TODO: More example programs?

• Adding PNG textures to the ObjLibrary
  • This only works on Windows, at least at present.
  • I did not write any of this code.
  • TODO: Better documentation. A page?
  
  
  1. Download ObjLibraryPng.zip and save it with you code files.
  2. Unzip the file. You should get 2 more folders named zlib and png, and 2 files named glpng.c and glpng.h. These should be on the same folder level as the ObjLibrary folder.
  3. Add all the files to your Visual Studio project. You probably want to make 2 more Visual Studio "folders" for the zlib and png libraries.
  4. In the ObjLibrary/ObjSettings.h file, uncomment the line that says
     #define OBJ_LIBRARY_LOAD_PNG_TEXTURES
     You will have to remove read-only-ness from the file. You can do this by hand, or Visual Studio will offer to do it for you when you try to save the file.
  5. Recompile everything. If you don't do this, it won't work.


• Adding interaction with glm to the ObjLibrary
  • glm (OpenGL Mathematics) is a math library designed to resemble GLSL, the OpenGL shader language.
  
  
  1. Download the newest version of the glm library and save it with you code files.
  2. Open the zip file. It will contain a folder named glm. Inside that, there will be more files and folders, including another folder named glm. Copy the inner glm folder in with your code files on the same level as the ObjLibrary folder. Everything else in the outer glm folder is fluff, and you can delete it.
  3. The glm library only contains header files, and they are so heavily templated that they are unreadable to humans. It may be a waste of time to added them to Visual Studio. If you want to, however, you probably should Visual Studio "folders" to correspond to the glm folder and its subfolders.
  4. In the ObjLibrary/ObjSettings.h file, uncomment the line that says
     #define OBJ_LIBRARY_GLM_INTERACTION
     You will have to remove read-only-ness from the file. You can do this by hand, or Visual Studio will offer to do it for you when you try to save the file.
  5. Recompile everything. If you don't do this, it won't work.
  
  
  • Note: The ObjLibrary will convert glm::vec2s to Vector2s and glm::vec3 to Vector3s automatically. However, the reverse is not true (due to template issues). To convert to glm::vec2s and glm::vec3s, you will need explicit typecasts:

    	glm::vec2 ones2 = (glm::vec2)(Vector2::ONE);
    	glm::vec3 ones3 = (glm::vec2)(Vector3::ONE);

• Changing the ObjLibrary to perform rendering using shaders
  1. Download ObjLibraryShaders.zip and save it with you code files.
  2. Unzip the file. You should get 23 more files in the ObjLibrary folder, and 4 files named GetGlutWithShaders.h, gl3w.h, gl3w.c, and glcorearb.h. These should be on the same folder level as the ObjLibrary folder.
  3. Add all the files to your Visual Studio project. You probably want to put the ones in the ObjLibrary folder in your Visual Studio "folder" of the same name.
  4. In the ObjLibrary/ObjSettings.h file, uncomment the line that says
     #define OBJ_LIBRARY_SHADER_DISPLAY
     You will have to remove read-only-ness from the file. You can do this by hand, or Visual Studio will offer to do it for you when you try to save the file.
  5. Recompile everything. If you don't do this, it won't work.
  
  
  • Note: Shader rendering depends on glm interaction, as explained above.
  • Note: Shader rendering cannot be combined with fixed-pipeline rendering. You have to pick one. This is a limitation of OpenGL, and most likely of the graphics hardware underneath.

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