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• ### Similar Content

• 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

# OpenGL Freetype2 - Arial gives weird 'i' at 13 pixels

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Hey, I've been making my own wrapper around Freetype2 for OpenGL. However, I can't seem to easily fix this bug...it's bugging me ^^ Whenever I render the Arial font at 13 pixels height, the 'i' seems to be too high or w/e happens...this only happens when I use the Smooth feature of my wrapper, the Sharp feature works fine. Examples: 14 pixels smooth 13 pixels sharp 13 pixels smooth This is the code I use (without error handling):
                FT_Load_Char(face, character, FT_LOAD_RENDER);

FT_GlyphSlot &glyph = face->glyph;

FT_Glyph bbox_glyph;
FT_Get_Glyph(glyph, &bbox_glyph);

FT_BBox bbox;
FT_Glyph_Get_CBox(bbox_glyph, FT_GLYPH_BBOX_TRUNCATE, &bbox);

int width = pow2(glyph->bitmap.width);
int height = pow2(glyph->bitmap.rows);

if (width && height) // not a space character
{
GLuint texture = 0;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

GLubyte *buffer = NULL;
if (_sharpness == Sharpness::Smooth)
{
buffer = new GLubyte[height * width];
memset(buffer, 0x00, height * width);

for (int j = 0; j < glyph->bitmap.rows; j++)
{
memcpy(buffer + (j * width), glyph->bitmap.buffer + (j * glyph->bitmap.pitch), glyph->bitmap.pitch);
}

glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA8, width, height, 0, GL_ALPHA, GL_UNSIGNED_BYTE, buffer);
}
else if (_sharpness == Sharpness::Sharp)
{
buffer = new GLubyte[height * width * 2];
memset(buffer, 0x00, height * width * 2);

for (int j = 0; j < glyph->bitmap.rows; j++)
{
for (int i = 0; i < glyph->bitmap.pitch; i++)
{
buffer[(j * width * 2) + (i * 2)] = buffer[(j * width * 2) + (i * 2) + 1] = glyph->bitmap.buffer[(j * glyph->bitmap.pitch) + i];
}
}

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, buffer);
}
delete[] buffer;
}

// when drawing I use something like
glBindTexture(GL_TEXTURE_2D, character.texture);
glTexCoord2d(0,            0);            glVertex2f(0,           0);
glTexCoord2d(0,            (float) glyph->bitmap.rows / (float) height); glVertex2f(0,           glyph->bitmap.rows);
glTexCoord2d((float) glyph->bitmap.pitch / (float) width, (float) glyph->bitmap.rows / (float) height); glVertex2f(glyph->bitmap.pitch, glyph->bitmap.rows);
glTexCoord2d((float) glyph->bitmap.pitch / (float) width, 0);            glVertex2f(glyph->bitmap.pitch, 0);
glEnd();


What could possibly be wrong in the pixel copying (since I guess it's the pixel copying part, it only applies to Smooth not Sharp)? Thanks in advance.

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NeHe Productions has a very nice OpenGL text tutorial. I don't think it even relies on FreeType2. On the other hand I'm pretty sure it uses Windows-only functions. I followed it and never had any funny defects. Check it out if you haven't already. If you aren't using Windows, I apologize for making that assumption. I also don't understand why you calculate your width and height by using pow2(). Is pow2() your own function? I only know about pow().

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Hello fellow citizen! :)

I've written a font render engine once, only for learning how to do font rendering and for testing purposes. Didn't test it very well, so it might show the same problems. Anyway: I used the tutorials on the freetype 2 website itself and I found them quite easy to follow. It gave me results quickly.

My program ran on Linux using OpenGL and the tutorial I used can be found here:
http://www.freetype.org/freetype2/docs/tutorial/step1.html

You might want to compare your steps with the ones in this tutorial if you haven't seen it yet.

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@kittycat
I would like to use TTF fonts using FreeType2, and draw them in OpenGL. Don't want to be bound to windows only ;). And pow2 outputs the next following power of 2, which is needed for OGL textures (for older cards).

@TheFlyingDutchman

Hey, greetings! Nice weather eh xD

I followed the same tutorial ;). It works perfectly fine for almost anything, except this weird little bug. I think it has to do with the connection of FT2 with OpenGL...ie, the pixel copying. Not 100% sure, but it looks like it. Either that or the texture coordinates are wrong (which I don't think, since I had some rather random results...as if it was unused memory).

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You might want to try this, as I remember correctly I have seen several implementations having image corruption problems because the texture parameters weren't setup correctly:

glPixelStorei(GL_UNPACK_ALIGNMENT, 1);glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texSize, texSize, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, data);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

Especially the first line of code is important (the last four don't really matter for this I'd say). Hope this helps.