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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 Implementing LOD based Terrain

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Hey folks! Im currently trying to implement a satisfying terrain with LOD. My requirements are:
1. Tremendous height map => streaming
2. Dynamic lighting and shadowing
3. More might appear while I progress, but right now its just those 2...

I would like some advanced people to guide me through this... I have already implemented (2^n + 1) x (2^n + 1) height map convertion into the simple quad tree of chunks, which contain their own VB, IB and AABB. The incoming information for this convertion is:

1. Height Map size: (2^n + 1) x (2^n + 1);
2. Vertex number per quad: vertexNumberPerQuad = 2^i + 1, i = 0...n =>
=> Number of LODs (quad tree depth): numberOfLODs = (n + 1) - log2(vertexNumberPerQuad - 1), so 1 <= numberOfLODs <= (n + 1);
3. Root deviation;

I compute deviation for each chunk as:

Deviation(L + 1) = Deviation(L) / 2

On rendering stage all I do is traversing top-bottom this tree and cheking a simple equation:

p = K * (d / D), K = viewport_width / [2 * tan(horizontal_fov / 2)];

p - maximum screen-space vertex error;
d - deviation of current chunk;
D - distance from camera to the center of AABB of current chunk;

As you can notice on the picture I use triangle strips "snake" approach to render a chunk.


Chunked LOD


For now thats it (quite simple right? :])... I can't go further due to the lack of experience and poor knowledge of recent trends in this subject, moreover its a little bit hard for me to understand algorithms, while reading papers, since papers are very short and provide little information...

So first of all, tell me if I am heading the right way by making a kind of "Chunked LOD"?

And, secondly, if I am on a right way, then it seems like the next step is crack elimination: which approach would you recommend? Personally I dont like skirts, since they might look ugly when textured. But avoiding skirts leads to 2 different approaches that have problems, which I dunno how to solve:

1. If adjacent chunks differ in 2 or more LODs, I have to omit more than 1 vertex in a T-junction;

2. If I stick stricktly with a rule "adjacent chunks may differ only in 1 LOD", consequently I get another headache - make some restricktions to quad tree;

Have no idea about both :[
I also appreciate any suggestions about mixing different algorithms!

Using OpenGL + Java btw. Thanks!

[Edited by - Haroogan on October 21, 2010 3:45:15 PM]

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If you're going stick with geometry based terrain, you can use RobMaddison's Terrain LOD stitching on the GPU. It's very easy to implement (4 lines of shader code). BTW Rob, if you read this, please check your PM's lol.

Quote:
Original post by spacerat
Why using triangles ? Its easier to raycast the terrain - you dont need to worry about geometry in this case.
http://msdn.microsoft.com/en-us/library/ee416425%28VS.85%29.aspx


niiiiiiice!

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First of all I dont really understand whats the essence of raycasting and why is it good for terrain? Does it simplify terrain assembling? Does it simplify texturing and lighting? Does it bring decent FPS rates...? And is it useful in making planet-like terrain, since, for instance, chuncked LOD is!

Well about Rob Maddison... ummmhh, u know his algorithm is described too shallowly, isnt it? Again the lack of direct and structured information :[

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Quote:
Original post by Haroogan
First of all I dont really understand whats the essence of raycasting and why is it good for terrain? Does it simplify terrain assembling? Does it simplify texturing and lighting? Does it bring decent FPS rates...? And is it useful in making planet-like terrain, since, for instance, chuncked LOD is!

Well about Rob Maddison... ummmhh, u know his algorithm is described too shallowly, isnt it? Again the lack of direct and structured information :[


There's an executable of the raycasting sample in the dx sdk.

I could actually extract enough information out of Rob Maddison's post to write a well working implementation. After being stitched with his algorithm (which is basically a modulo operation on the patch edges) the grid looks like this:



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Before you start with raycasting on such a scale, you should consider a few things:
- Raycasting does not (cannot) make use of MSAA (other than triangles)
- Cone step mapping as proposed in this article, requires non-trivial preprocessing. We are talking about several minutes to hours for a large texture. Editing in or close to real time is out of the question.
- Most other raycasting algorithms are either very slow or inaccurate (or both).
- Raycasting requires the pixel shader to output depth for proper results, which means you have no Z-Cull

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>> why is it good for terrain?

you can do terrain with displacementmapping in one pass

>> Does it simplify terrain assembling?

yes - you have unlimited geometry details and no trouble with triangle count

>>Does it simplify texturing and lighting?

no - thats the same

>>Does it bring decent FPS rates...?

yes. my volume terrain raycaster gets about 100fps just for the terrain without SSAO&SSDM (
>
)

>>And is it useful in making planet-like terrain, since, for instance, chuncked LOD is!

if you need a complex distance or angle function to calc the texture coord on a sphere it might slow down...

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So u've dropped down ur FPS to 100 just by adding terrain on GTX 285? lawl... How about additional geometry and high polygonal animated models then? And as I understand raycasting is able only on very recent graphic cards right?

Now about Maddison:

"During this stage, fill in a matrix of LOD levels - for a 4096x4096 terrain with a 32x32 high-LOD patch size, this involves filling a matrix of [128][128] - but only those elements that fall within the viewing frustum and only the outer edges of each of those elements need to be set."

What matrix? Does he mean just to create a 2-dimensional array of 128x128 and fill it with pointers to chuncks that are going to rendered, and those who shouldnt be rendered must have null pointers in the appropriate position of this 2-dimensional array? He wants to do it every frame?

"and only the outer edges of each of those elements need to be set."

What are outer edges of those elements?

"I believe this is standard practise for pre-determining the LODs of neighbouring patches."

After filling this matrix he learns about neighbours of each chunk? How?

"front-to-back-sorted"

WTF?

BTW, ur screenshot looks like GeoClipMapping, I mean nested LOD layers?

[Edited by - Haroogan on October 23, 2010 5:10:54 AM]

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Quote:
Original post by Haroogan
What matrix? Does he mean just to create a 2-dimensional array of 128x128 and fill it with pointers to chuncks that are going to rendered, and those who shouldnt be rendered must have null pointers in the appropriate position of this 2-dimensional array?


Yes i think you got it. You first figure out which nodes are going to be rendered and write their LOD's (or pointer to the node) into the matrix. If a node isn't visible, you don't have to write it into the matrix because invisible nodes don't cause cracks :)

This is blazingly fast since you only do the outer edges. You could bake the LOD-Matrix on the GPU but it's not even worth it. Here's my code for this step:


void CeTerrain::buildRenderQueue(node& n)
{
if(!Ce::cam->InFrustumAABB(&n.aabb)) return;

n.lod = max(n.depth / 2, computeLOD(n));

if(n.lod <= n.depth)
{
UINT nodeSize = lodMatrixSize / n.depth;
UINT coord = n.pos.y * lodMatrixSize + n.pos.x;

node** lodPtr = &LODMATRIX[coord];

for(UINT i = 0; i < nodeSize; ++i)
{
*(lodPtr + i * lodMatrixSize) = &n;
*(lodPtr + i * lodMatrixSize + (nodeSize - 1)) = &n;
*(lodPtr + i) = &n;
*(lodPtr + i + lodMatrixSize * (nodeSize - 1)) = &n;
}

renderQueue.push(&n);

return;
}

for(UINT i = 0; i < 4; ++i) buildRenderQueue(*n.child);
}



Quote:

He wants to do it every frame?


Only when the camera moves, unless you have some kind of animated terrain.

Quote:

What are outer edges of those elements?


I can best explain it with an image. The colored borders are the edges of the nodes.



Quote:

After filling this matrix he learns about neighbours of each chunk? How?


You look it up in the LOD matrix or you store pointers in the nodes to the neighbours in the LOD matrix and just dereference them before you render the node.

Quote:

"front-to-back-sorted"


This would just require to push the nodes into a priority queue with the distance as comparison key. Or use a vector and sort it after the LOD step. It's not required but prevents some overdraw on the GPU for better performance.

Quote:

BTW, ur screenshot looks like GeoClipMapping, I mean nested LOD layers?


Hugues Hoppe's geometry clipmaps are a little different as far as i can tell.

[Edited by - Daniel E on October 23, 2010 11:23:55 AM]

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For completeness, here's the shader code for stitching patches on the GPU:

with conditions:

VS_output vs_terr(VS_input input)
{
VS_output output;

float4 pos = { input.pos.x, 0, input.pos.y, 1 };

if (pos.x < 0.5f) pos.z -= pos.z % nLODs.x;
else if (pos.x > NUMVERTS - 0.5f) pos.z -= pos.z % nLODs.z;

if (pos.z < 0.5f) pos.x -= pos.x % nLODs.y;
else if (pos.z > NUMVERTS - 0.5f) pos.x -= pos.x % nLODs.w;
}



no conditions:


VS_output vs_terr(VS_input input)
{
VS_output output;

float4 pos = { input.pos.x, 0, input.pos.y, 1 };

pos.z -= input.isEdge.x * (pos.z % nLODs.x);
pos.z -= input.isEdge.z * (pos.z % nLODs.z);

pos.x -= input.isEdge.y * (pos.x % nLODs.y);
pos.x -= input.isEdge.w * (pos.x % nLODs.w);
}

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