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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 Rendering strategy for 2d

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Hi folks!

 

Been struggling with finding good information on how to set up my rendering strategy for a home rolled html5 webgl game engine that I'm working on.

I'm doing 2d mostly, but might mix some 3d into it at a later stage. I wonder if there's some good practice I should keep to when it comes to render calls, shader programs and textures.

 

Right now I'm trying to cram as much into one rendercall and use a large texture map for most of my textures, this works pretty well and I'm getting a great performance, so it makes me wonder how far I can push the GPU and perhaps do some crazy/fun things when it comes to shaders in future development. I'm also thinking that I should perhaps see the renderer through a more shader centric viewpoint, which means that I have some fun rewriting ahead of me.

 

Right now I have a pretty general purpose 2d shader that handles most of my draw calls, it can blend colors or just render primitives with colors, or it can render textures. Maybe I can do more specific shaders for specific tasks and add some more shader programs when rendering a scene, what amount of shaders is common for a single scene? can I use 1-5 or maybe 10-20 without worrying?

 

Same goes with textures, now I'm pretty hardcore, everything I render comes from like 1-3 textures these days, in one game that I'm working on the texture map is pretty large as well (4096^2) Is it good to have large texture maps like that, or should I keep them around 512/1024^2'ish instead?

What are common when it comes to texture binding within a specific scene?

 

I started OpenGL when it was fixed pipeline, and I've mostly learned through basic OpenGL literature, it seems hard to get good info about a real implementation as most is basic stuff on that level. I really want to get to the next stage when it comes to graphical programming, and those questions have bothered me to no end! Hope to get some good insight from you guys!

 

Cheerz!

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Hi Fagertveit,

 

Your questions are a little tricky to answer, because they're fairly general. I don't have an experience with webgl, but I'll try to give you what advice I can.

 

It sounds like you're concerned about state thrashing. Some of the approaches you mention were used in DX9 generation engines for reducing state changes -- back in those days, state changes were such a huge concern that they would cast shadows on other forms of optimisation. That was caused by CPU overhead within the DX9 drivers, and also by pipeline flushes in the GPU hardware.

 

I'm not sure about webgl, but most of the time it's less of a concern nowadays. If you have a very big scene, with thousands of objects and lot of detail, then maybe it would be an issue... But most of the time, you should be fine even with hundreds of shaders and many textures. Modern hardware and drivers are pretty forgiving.

 

My feeling is that you're best bet is to make these decisions based on what is easiest for creating content -- not performance. That is, if using many smaller textures is easier to create models, then just do it. As long as you have mipmaps, small or large textures will rasterize at similar speeds.

 

You can use just a single shader, if you want, just with a bunch of "[branch] if(...)" statements. This is called an ubershader, and it's a viable approach. But you could also just have many small shaders.

 

A great way to get more information is to use RenderDoc or GPA to profile another application. These can be used to profile and debug your own work; but they can also be used to see what other games do. If you can find a project that is similar to what you want to do, then just open it up in a debugger and see how they approached these questions.

 

You also (sometimes) open up commercial games like that... And you'll probably see that they are using thousands of resources, with all different formats and dimensions. That can be a great way to learn practical approaches to things. And I think you'll find that sometimes even very popular games often use very simple methods!

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@dpj: Thanks for the answer, it's pretty much what I wanted to know as well, I think I've been a bit to restrictive when it comes to state changes, and need to lighten up some, I think my greatest bottleneck has been to prepare the data for the shaders really, and I will redesign this somewhat.

 

I've done one ubershader for all my 2d rendering, but I think I can start dividing these to more specialized ones to get the most oumph out of the system, I don't think I'll reach more than 20 programs at tops. And 2d games works well with texture atlases, so textures might be around that count as well, but as I've done in the past I've pretty much tried to keep textures in the count of 2-3 hehe, with some being really big!

 

Good advice to check out other applications and games, I think Firefox has great debugtools for WebGL where you can se which shaders are in use and how they impact performance, so I'll try to find some games that work in similar way like mine and do some digging.

 

The boring things with most webgl games is that they are made with some of the big frameworks that have somewhat singular rendering pipelines, but the is bound to be some golden nuggets out there somewhere! :)

 

Many thanks for the reply!

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