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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 Is redundant state checking still a thing?

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Is redundant state checking still a thing? I'm interested in D3D11 and OpenGL3+.

I've got a D3D11ContextStateCache, and GLContextStateCache objects that keep track of the current state and skip calls that would do nothing, i also got an option to disable redundant state checking and directly call the API function, and for my surprise there was absoluetley no difference.
(3600 draw calls with same vb, input layout and a texture, 1 ConstBuffer update via Map(hmmm???))

The same thing goes to OpenGL.

 

Note that I'm not calming anything as my scene may not be optimal for the case (and as I'm writing this I start to get doubts about it).

 

And one additional question, Is there any point of using D3D11_USAGE_IMMUTABLE in practice, again I see no different betteen that one and 
D3D11_USAGE_DEFAULT?

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>>  and for my surprise there was absoluetley no difference.

 

you would only see a difference if:

1. the calls you make are calls that will introduce delays when called redundantly.

 

= AND =

 

2. you actually makes redundant calls of that type in the first place - enough to be noticeable.

 

there's a good chance you're not making enough redundant calls that introduce delay to see a difference. which would indicate you can reduce or perhaps eliminate state checks, assuming your code stays well organized with respect to draw call order and state changes. if you make no redundant calls, there's technically no need for state management.

Edited by Norman Barrows

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To clarify myself : 

I currently draw a low-poly model (can't tell you the primitive count currently). 
I draw that model 100 000 times with different position (this is why I call Map/Unmap on a ConstatBuffer), the resources needed to draw the object do not change (one texture and one vertex buffer), and in that case, there is no difference if i bind those once (for frame 1) vs vs binding them every frame, so in my case:

bind_vertexbuffer();
bind_texture();
bind_cb();
for(i = 0; i < 100000; ++i){
   update_cb(i);
   draw();
}

has the same performance as:

for(i = 0; i < 100000; ++i){
   bind_vertexbuffer();
   bind_texture();
   bind_cb()
   update_cb(i);
   draw();
}
Edited by imoogiBG

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I'm with hodgman on this one. In times where performance is key and you want clean and futureproof code, it's good to be in control of states. With the benefit that you automatically have an opportunity to see current states, using the same state manager which prevents redundant state changes.

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I'm guessing here the driver is actually checking if the bindings are actually changed before doing anything when you rebind the resources. Rebinding the same resources again and again makes it go through this fast path so you see no differences.

 

Thing is, you'd be relying on driver specific behavior. You should try on different hardware.

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To clarify myself : 

I currently draw a low-poly model (can't tell you the primitive count currently). 
I draw that model 100 000 times with different position (this is why I call Map/Unmap on a ConstatBuffer), the resources needed to draw the object do not change (one texture and one vertex buffer), and in that case, there is no difference if i bind those once (for frame 1) vs vs binding them every frame,

So you're actually dynamically making 100k cbuffers per frame and handing them all to the garbage collector. In both your loops, this will be the bulk of the cost.

 

Seeing every draw is using a different cbuffer, the driver does have to emit new resource bindings per draw.
Try pre-creating 100k static cbuffers and pre-filling them with data so you don't need to do this work per frame, and see how that affects performance.

Or just for testing, use a single static cbuffer so that the driver doesn't have to rebind resources per draw, and see how that performs.

Edited by Hodgman

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The CBuffer in my example above is also 1 cbuffer for all 100k drawcalls, it's just updated with map/unmap before every drawcall.

So you're actually dynamically making 100k

If map/unmap reallocation is making than yes.

 

as far is i rememember "measuring" cbuffer binding alone is much more expensive compared to map/unmap.

Edited by imoogiBG

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The CBuffer in my example above is also 1 cbuffer for all 100k drawcalls, it's just updated with map/unmap before every drawcall.

So you're actually dynamically making 100k
If map/unmap reallocation is making than yes.
 
as far is i rememember "measuring" cbuffer binding alone is much more expensive compared to map/unmap.

 

That's what I meant before:

Side note - updating a constant buffer causes resource renaming within the driver -- your resource handle (D3D COM pointer) now points to a different memory allocation than before, which probably forces D3D to set a whole bunch of internal dirty flags that get checked on the next update.
So, actually updating the constant buffer is probably hiding the cost of a PSSetConstantBuffers call (as it's probably also just setting the same dirty flags, to be checked on next draw).

You can't edit a resource that's in use by the GPU. The GPU is one frame behind the CPU. Therefore in order to make it look like you're editing a resource, the driver is actually performing reallocation. If you update the resource 100k times per frame, you're peforming 100k reallocations, and asking a garbage collector to delete them in a few frame's time when the GPU has finished using them.

 

Binding the same resource repeatedly might be cheap, but each one of your draw calls is actually binding different resources. So both of your loops have a high memory allocation cost and resource binding cost per draw call.

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Can't speak for desktop but I recently did some optimization on a WebGL game and one of the first things I did was introduce dumb "if(g_currentBoundTexture === newTexture) doNothing(); else bindTexture" and similar checks and gained a very much appreciated (ballpark) 5% or so speedup for maybe half an hour of work.

 

Through some dirty happenings this goes down from actual Javascript WebGL code to Chrome native to ANGLE and then to the the eventual Direct3D 9 implementation (on Windows), so some part of it probably means "in D3D9 on desktop state redundancy checking is still pretty good".

Edited by agleed

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