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    • By racarate
      Hey everybody!
      I am trying to replicate all these cool on-screen debug visuals I see in all the SIGGRAPH and GDC talks, but I really don't know where to start.  The only resource I know of is almost 16 years old:
      http://number-none.com/product/Interactive Profiling, Part 1/index.html
      Does anybody have a more up-to-date reference?  Do people use minimal UI libraries like Dear ImgGui?  Also, If I am profiling OpenGL ES 3.0 (which doesn't have timer queries) is there really anything I can do to measure performance GPU-wise?  Or should I just chart CPU-side frame time?  I feel like this is something people re-invent for every game there has gotta be a tutorial out there... right?
    • By Achivai
      Hey, I am semi-new to 3d-programming and I've hit a snag. I have one object, let's call it Object A. This object has a long int array of 3d xyz-positions stored in it's vbo as an instanced attribute. I am using these numbers to instance object A a couple of thousand times. So far so good. 
      Now I've hit a point where I want to remove one of these instances of object A while the game is running, but I'm not quite sure how to go about it. At first my thought was to update the instanced attribute of Object A and change the positions to some dummy number that I could catch in the vertex shader and then decide there whether to draw the instance of Object A or not, but I think that would be expensive to do while the game is running, considering that it might have to be done several times every frame in some cases. 
      I'm not sure how to proceed, anyone have any tips?
    • By fleissi
      Hey guys!

      I'm new here and I recently started developing my own rendering engine. It's open source, based on OpenGL/DirectX and C++.
      The full source code is hosted on github:

      I would appreciate if people with experience in game development / engine desgin could take a look at my source code. I'm looking for honest, constructive criticism on how to improve the engine.
      I'm currently writing my master's thesis in computer science and in the recent year I've gone through all the basics about graphics programming, learned DirectX and OpenGL, read some articles on Nvidia GPU Gems, read books and integrated some of this stuff step by step into the engine.

      I know about the basics, but I feel like there is some missing link that I didn't get yet to merge all those little pieces together.

      Features I have so far:
      - Dynamic shader generation based on material properties
      - Dynamic sorting of meshes to be renderd based on shader and material
      - Rendering large amounts of static meshes
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      - Limited support for dynamic (i.e. moving) meshes
      - Normal, Parallax and Relief Mapping implementations
      - Wind animations based on vertex displacement
      - A very basic integration of the Bullet physics engine
      - Procedural Grass generation
      - Some post processing effects (Depth of Field, Light Volumes, Screen Space Reflections, God Rays)
      - Caching mechanisms for textures, shaders, materials and meshes

      Features I would like to have:
      - Global illumination methods
      - Scalable physics
      - Occlusion culling
      - A nice procedural terrain generator
      - Scripting
      - Level Editing
      - Sound system
      - Optimization techniques

      Books I have so far:
      - Real-Time Rendering Third Edition
      - 3D Game Programming with DirectX 11
      - Vulkan Cookbook (not started yet)

      I hope you guys can take a look at my source code and if you're really motivated, feel free to contribute :-)
      There are some videos on youtube that demonstrate some of the features:
      Procedural grass on the GPU
      Procedural Terrain Engine
      Quadtree detail and view frustum culling

      The long term goal is to turn this into a commercial game engine. I'm aware that this is a very ambitious goal, but I'm sure it's possible if you work hard for it.


    • By tj8146
      I have attached my project in a .zip file if you wish to run it for yourself.
      I am making a simple 2d top-down game and I am trying to run my code to see if my window creation is working and to see if my timer is also working with it. Every time I run it though I get errors. And when I fix those errors, more come, then the same errors keep appearing. I end up just going round in circles.  Is there anyone who could help with this? 
      Errors when I build my code:
      1>Renderer.cpp 1>c:\users\documents\opengl\game\game\renderer.h(15): error C2039: 'string': is not a member of 'std' 1>c:\program files (x86)\windows kits\10\include\10.0.16299.0\ucrt\stddef.h(18): note: see declaration of 'std' 1>c:\users\documents\opengl\game\game\renderer.h(15): error C2061: syntax error: identifier 'string' 1>c:\users\documents\opengl\game\game\renderer.cpp(28): error C2511: 'bool Game::Rendering::initialize(int,int,bool,std::string)': overloaded member function not found in 'Game::Rendering' 1>c:\users\documents\opengl\game\game\renderer.h(9): note: see declaration of 'Game::Rendering' 1>c:\users\documents\opengl\game\game\renderer.cpp(35): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>c:\users\documents\opengl\game\game\renderer.cpp(36): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>c:\users\documents\opengl\game\game\renderer.cpp(43): error C2597: illegal reference to non-static member 'Game::Rendering::window' 1>Done building project "Game.vcxproj" -- FAILED. ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========  
      #include <GL/glew.h> #include <GLFW/glfw3.h> #include "Renderer.h" #include "Timer.h" #include <iostream> namespace Game { GLFWwindow* window; /* Initialize the library */ Rendering::Rendering() { mClock = new Clock; } Rendering::~Rendering() { shutdown(); } bool Rendering::initialize(uint width, uint height, bool fullscreen, std::string window_title) { if (!glfwInit()) { return -1; } /* Create a windowed mode window and its OpenGL context */ window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL); if (!window) { glfwTerminate(); return -1; } /* Make the window's context current */ glfwMakeContextCurrent(window); glViewport(0, 0, (GLsizei)width, (GLsizei)height); glOrtho(0, (GLsizei)width, (GLsizei)height, 0, 1, -1); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glfwSwapInterval(1); glEnable(GL_SMOOTH); glEnable(GL_DEPTH_TEST); glEnable(GL_BLEND); glDepthFunc(GL_LEQUAL); glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); glEnable(GL_TEXTURE_2D); glLoadIdentity(); return true; } bool Rendering::render() { /* Loop until the user closes the window */ if (!glfwWindowShouldClose(window)) return false; /* Render here */ mClock->reset(); glfwPollEvents(); if (mClock->step()) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glfwSwapBuffers(window); mClock->update(); } return true; } void Rendering::shutdown() { glfwDestroyWindow(window); glfwTerminate(); } GLFWwindow* Rendering::getCurrentWindow() { return window; } } Renderer.h
      #pragma once namespace Game { class Clock; class Rendering { public: Rendering(); ~Rendering(); bool initialize(uint width, uint height, bool fullscreen, std::string window_title = "Rendering window"); void shutdown(); bool render(); GLFWwindow* getCurrentWindow(); private: GLFWwindow * window; Clock* mClock; }; } Timer.cpp
      #include <GL/glew.h> #include <GLFW/glfw3.h> #include <time.h> #include "Timer.h" namespace Game { Clock::Clock() : mTicksPerSecond(50), mSkipTics(1000 / mTicksPerSecond), mMaxFrameSkip(10), mLoops(0) { mLastTick = tick(); } Clock::~Clock() { } bool Clock::step() { if (tick() > mLastTick && mLoops < mMaxFrameSkip) return true; return false; } void Clock::reset() { mLoops = 0; } void Clock::update() { mLastTick += mSkipTics; mLoops++; } clock_t Clock::tick() { return clock(); } } TImer.h
      #pragma once #include "Common.h" namespace Game { class Clock { public: Clock(); ~Clock(); void update(); bool step(); void reset(); clock_t tick(); private: uint mTicksPerSecond; ufloat mSkipTics; uint mMaxFrameSkip; uint mLoops; uint mLastTick; }; } Common.h
      #pragma once #include <cstdio> #include <cstdlib> #include <ctime> #include <cstring> #include <cmath> #include <iostream> namespace Game { typedef unsigned char uchar; typedef unsigned short ushort; typedef unsigned int uint; typedef unsigned long ulong; typedef float ufloat; }  
    • By lxjk
      Hi guys,
      There are many ways to do light culling in tile-based shading. I've been playing with this idea for a while, and just want to throw it out there.
      Because tile frustums are general small compared to light radius, I tried using cone test to reduce false positives introduced by commonly used sphere-frustum test.
      On top of that, I use distance to camera rather than depth for near/far test (aka. sliced by spheres).
      This method can be naturally extended to clustered light culling as well.
      The following image shows the general ideas

      Performance-wise I get around 15% improvement over sphere-frustum test. You can also see how a single light performs as the following: from left to right (1) standard rendering of a point light; then tiles passed the test of (2) sphere-frustum test; (3) cone test; (4) spherical-sliced cone test

      I put the details in my blog post (https://lxjk.github.io/2018/03/25/Improve-Tile-based-Light-Culling-with-Spherical-sliced-Cone.html), GLSL source code included!
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OpenGL Best 3d format for models

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Hi all, i'm new here so hello all... I'm using C++/OpenGL for a while now but i couldn't find an answer for my question on google so thats why i came here :D. My question: Which 3d-format is the best for using in OpenGL and how can i use them? I'm able to use the following formats: 3ds, ac, fbx, dae, off, x, lwo, mot, md2, flt, iv, map, raw, fix, x3d and obj. Thanks! Jasper

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I've heard people enjoy working with md2, but that's from a small group of programmers, but i would wait for more experienced people to reply besides my own.

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It really depends on your needs. If you just need to load mesh data, stick with simple ones. OBJ is human readable and easy to load. You have to write a parse to pull out what you need, so the readability is helpful for your first format.

Here's a page about OBJ.

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Yep, it all depends on what you are looking todo.

Of the formats your have mentioned, the only ones I know a little about are 3ds, md2, map, and obj.

Basically, if you are starting out and wish to code your own model/mesh loader, I would highly recommend the WaveFront *.OBJ format, as it has a very simple ASCII format. It supports vertex position/normal/texcoord, and quad/triangle index data. I think it also supports some form of material data.

If you are looking for a nice allround format that supports skeletal animation, then I highly recommend the DirectX *.X format. Hmm, although you didn't mention this format, I think it's quite well supported by various 3d software packages or whatever. There is a text/ascii, and binary version of this format, but I think the text/ascii is most supported, although it might be harder to process.

Otherwise you could always just design your own format, and make an exporter for it.

BTW, if you want to find docs on any of these formats, then let me know and I'll dig something up for ya.

Well thought I'd tell you my probs with the formats you mentioned that I know of.

3ds: Although I think it supports some form of animation, I don't think it properly supports either mesh or skeletal animation.

md2: Vertex point/normal data is compressed into 1 BYTE per coordinate, and texcoord data is represented with 2 BYTES per coordinate. Hmm, incase you don't know, usually vertex point/normal/texcoord data is represented with 4 BYTES per coordinate, this means there is much less precision.

map: Assuming this is the Quake3, or simular HalfLife format, then this format is only useful for maps. The problem is that these are quite hard to load, as geometry is represented by these things called brushes, and to construct your mesh from these brushes you must perform some quite tricky CSG (Constructive Solid Geometry) operations.

Although I know very little about the Collada *.DAE format, what I think I do know is that it's designed to be like a standard middle ground format, and thus should support anything common to many 3d software packages. I'm not sure how well this format is supported, but it certainly would be worth looking into.

Hmm, my only concern is that I think this format is XML based, so I think it may not be so strait forward to read/load data and such from it. I think you would need to implement an XML parser or whatever, but I'm quite sure there would be some libs for such things.


[Edited by - yosh64 on July 14, 2007 1:55:38 AM]

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My two cents: don't even think at using a shared assets format for your technology. It's not a good idea, really.

My two cents about the formats I know...
Original post by Jasper91
3ds, fbx
3DStudio and Maya respectively. You don't want to support this natively, although a filter to your own (more restrictive) format is highly desiderable. Even in this case however, only partial support will likely suffice. Camera entities for example will unlikely be useful unless you intend to use them as portals.
Original post by Jasper91
This is a bit outdated for today' standards. Theorically, you don't want to support it but it happens so many programs support it you pratically must have a filter. It must also work fast and work out-of-core. It's tremendously easy for a OBJ file to weight far over 100MB. Although this isn't really a problem on today's PC by itself, some care must be taken to avoid blow up your heap (the one malloc and new takes memory from), especially for DCC software which may be running other tasks as well.
Original post by Jasper91
As yosh64 said, this is Collada. Supporting it thoroughtly is above human capabilities. ;-) The format is terribly complex and feature rich. Sticking to a choosen subset will likely cut it most of the time. Don't even think at having NATIVE support for it (unless you're writing DCC software). Collada is designed to be put in filters. The format itself as all XML based things is terribly redundant, even worse than others such as OBJ or whatever.
Original post by Jasper91
I see very little reason to support this one. I've had a quick glance at it a few time ago and I remember it wasn't exactly nice, it's still far better than having to parse ASCII.
Personally I don't like it much, but I recognize it can be useful.
Original post by yosh64
map: Assuming this is the Quake3, or simular HalfLife format, then this format is only useful for maps. The problem is that these are quite hard to load, as geometry is represented by these things called brushes, and to construct your mesh from these brushes you must perform some quite tricky CSG (Constructive Solid Geometry) operations.

Not exactly.
Most editors will give you pre-mangled .map files.
Then, each brush will be represented by a bounduary-representation polygons (think at it as some kind of "local" BSP).

Mangling the various polygons, even when "predigested" isn't exactly easy. GtkRadiant does have an implementation which takes a bit of memory, works on doubles and produces pleasing results - it's possible to break it in some extreme cases but this happens VERY rarely even on assets designed for the purpose.

Again, don't even think at supporting this natively (quakeX doesn't do for a reason).
There are very good assets around using this format and this means that a filter is desiderable to tap the available resource.

I would suggest to roll your own format and then write filters to "convert" the assets.
Anyway, if you can work with a "well known" format then I suggest to choose a binary based one. The structure of binary files ensure that most errors are trivially detected and rejected. With ASCII, it's often far from easy.

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Another format worth mentioning is Valve's SMD format. It's been around for almost ten years, it's a text-based format, and it supports skinned meshes. AFAIK there are exporters for every major 3D package for it.

The downside, of course, is its legality is ambiguous given it's a private format used by a commercial game developer. But then I've seen a couple of projects that use Half-Life .maps which is just as ambiguous.

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Hopefully this post isn't dead but I just want to say, if you invest in learning python, you can create your own export model format which will be easy, as you made it so you'll know all the specs.

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Original post by ViperG
I've heard people enjoy working with md2, but that's from a small group of programmers, but i would wait for more experienced people to reply besides my own.

I'd prefer md3 over md2...

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the format selection depends on your needs. Stick to some easy format like md2 if you're just learning or in need of a quick and easy way to get some modeldata imported.

If you're disposed to invest some time you should take a look at collada. It seems to be quite complex, but it contains all you need. Using a simple format starts to hurt when you're trying to get more complex information from your model (material, shader, bones, animations). Typically you start to change your format (what doesn't meet all your requirements) and finally you are writing your own exporter (which is limited to one modelling program). If you invest the time in collada, you will benefit from it in the long term. Here are the most important advantages of collada:

1. It is free, human readable(XML) and a standard ! (Think of OpenGL/DirectX)
2. It contains all you need (including bone infomation, animation, materials ...)
3. There are free support libraries: domCollada (open-source, api to access the xml file) and FCollada (high level access).
4. almost every important modeling tool supports collada: maya, max, blender ...

My suggestion:
Take blender (free modelling tool), make a textures cube, export it to collada and start writing a simple import module using domCollada or FCollada. After extensive testing take a md2 model and import/export it with blender to collada. Extend your import program when needed.


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