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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:
      https://github.com/fleissna/flyEngine

      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
      - Hierarchical culling (detail + view frustum)
      - 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.

      Bye,

      Phil
    • 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 ==========  
       
      Renderer.cpp
      #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; }  
      Game.zip
    • 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!
       
      Eric
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OpenGL Translate OpenGL 2.1 to 3.3

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I have some (a lot) of old win32 C code that is OpenGL 2.1 compliant. The code still work on today's computers, but is in great need of support for shaders. Thus I need to translate it to at least OpenGL 3.3. So in interest of spending 1 month that I have instead of 1 year that I do not have doing the conversion. I have this questions. 

 

 

Is there any library that would emulate the missing functionality of OpenGL 2.1 under OpenGL 3.3?

 

Is there a way to automatize the process from 2.1 to 3.3?

 

Is there a way to at least identify the parts that are incompatible at compile time?

 

 

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Each GL_VERSION is a superset of all previous versions, so any valid GL 2.1 program is also a valid GL 3.3 program - I am assuming compatability contexts here.  What that means is that there is no translation necessary.

 

GL 2.1 also has full support for vertex and fragment shaders so you don't actually need to go to a higher version in order to use shaders.

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You could use the compatibility context but it sounds like you want to get rid of the old way of doing things so that's not much use.

 

Do you use a lot of glBegin()/glEnd()?

Do you rely on OpenGL to build your matrices (world transforms and cameras etc) using it's functions?

Do you use the opengl lights?

 

Off the top of my head I think those would be where the biggest work would be.

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Is there any library that would emulate the missing functionality of OpenGL 2.1 under OpenGL 3.3?

- There are plenty of libraries that help you with dealing with OpenGL. 

Some of them are low level helpers (Enscapsulates behavior such as VBO).

Some of them are complete rendering libraries.

However, Transition to those libraries would be even harder.

 

Is there a way to automatize the process from 2.1 to 3.3?

- Not that I know of.

 

Is there a way to at least identify the parts that are incompatible at compile time?

- Yes. 

As you said you want to support shaders, then identify the render methods: Matrices, fixed pipeline variables and render calls (glBegin/glEnd/Display lists).

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Is there any library that would emulate the missing functionality of OpenGL 2.1 under OpenGL 3.3?[/quote] "Yes, but..." There is GLIM: http://www.artifactgames.de/FILES/START.PHP?where=GLIM.PHP The thing is, however, that there is a good reason for the paradigm change between GL2 and GL3. GL3 somewhat (not too well, but at least somewhat) maps to how the hardware works and allows for much better CPU-GPU (and client-server) parallelism, which is one of the deciding factors in getting good utilisation and thus performance. GL2 does not map to how the hardware works in any way, and the immdiate mode model -- by design -- prevents parallelism to a wide extent. Which means none more and none less than either your graphics are simple enough so GL2 will "just do fine", then you can simply use a compatibility profile and change nothing. Throw in some shaders for eye candy if you like, no big difference. Or, you need to rethink the entire application. Using a library that implements immediate mode on top of retained mode will "work" but you throw most of the benefits overboard right away. One of the most crucial benefits of retained mode is that you can fill a buffer with some data (vertex or texture, or whatever) and transfer ownership to the GL. The driver can then overlap the time needed to transfer the data to the graphics card with some other things that are still running, and it can logically update/replace a buffer while it is really still being read from, etc. But that doesn't work too well if your thinking is still "immediate mode". Buffers are basically vertex arrays, which you already know from GL2 -- with the seemingly insignificant but very important difference that you don't own the buffer's contents. It takes a moment to get used to the idea, but once you grok it, it becomes obvious.

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Buffers are basically vertex arrays, which you already know from GL2

 

A correction to this is that buffers are actually available in GL 1.5; it's quite incorrect to think of them as a new, bleeding-edge, fancy, or whatever feature, because they're not.

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Buffers are basically vertex arrays, which you already know from GL2

A correction to this is that buffers are actually available in GL 1.5; it's quite incorrect to think of them as a new, bleeding-edge, fancy, or whatever feature, because they're not.
You are of course right (at least for vertex data). But that's not quite what I wanted to imply.

To explain, allow me to object that "buffers were already present in GL 1.5" is a bit like saying "Shaders were part of GL 2.0 already". They certainly were, but like buffers they were merely a very limited "fancy addition", or gimmick, not the one exclusive, main paradigm. Everybody using GL 2.0 knew Begin/End inside out, and everybody knew vertex arrays. Most people had probably heard of buffers, and of that thing called fragment shader. Some may even have used them. But it was not "the" mainstream paradigm, and each of these gimmicks was limited to very specific special cases.

In GL3/4, there exists no other thing. It is the only paradigm (except in compatibility mode, which is kind of "cheating").

Everything is about "buffers and shaders", and about having client and server run as asynchronously as possible (plus, more features, bigger textures, bigger viewports, more attachments, generally bigger limits, fences and queries, instancing, indirect calls, etc etc...).

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