• 11
• 11
• 12
• 10
• 11
• ### Similar Content

• 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

• Good evening everyone!

I was wondering if there is something equivalent of  GL_NV_blend_equation_advanced for AMD?
Basically I'm trying to find more compatible version of it.

Thank you!

• Hello guys,

How do I know? Why does wavefront not show for me?
I already checked I have non errors yet.

And my download (mega.nz) should it is original but I tried no success...
- Add blend source and png file here I have tried tried,.....

PS: Why is our community not active? I wait very longer. Stop to lie me!
Thanks !

# OpenGL Engine works fine on Ubuntu but has issues on Windows

This topic is 582 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

Hello everyone!

I've been recently porting my Direct3D engine to OpenGL so it could run on platforms other than Windows, but it didn't work as intended. After a lot of debugging (using ApiTrace) I'd decided to try to run it on Ubuntu and guess what? It worked exactly like I wanted it to. Earlier this afternoon I tried to use llvmpipe (a software rasterizer) on Windows and it ran just like it did on Ubuntu.

Most objects seem to be rendered at the same place (maybe it's (0,0,0)?) and all of them have the same color so I'm thinking it may be a problem with the uniform buffers, but ApiTrace doesn't give any related error and the values seem OK.

This is how it looks like with llvmpipe:

[attachment=33261:Should.png]

This is how it looks like without it:

[attachment=33262:Windows.png]

I don't know if ApiTrace .trace files are machine independent, but I'm including one in case someone has time to take a look at it:

[attachment=33267:Test.zip]

Now, there's something very important that I should say. My laptop has Intel integrated graphics which is known to have very crappy OpenGL drivers on Windows (supports 3.1), but the MESA driver on Ubuntu is much better (supports 3.3 core). Also, when on Windows it runs on a OpenGL 3.1 context, but on Ubuntu and when using llvmpipe it runs on a OpenGL 3.3 core context. I don't know if that could make a difference.

Does someone have any idea of what it could be? Could it be a driver bug? Could MESA drivers be allowing something that shouldn't be?

Thank you for reading. Best regards.

##### Share on other sites

Do you have any immediate mode code at all?

Are you checking for errors in Ubuntu, even though it looks correct?

Can you compile and/or run it as OpenGL 3.1 under Ubuntu to see if you get similar results as Windows?

Edited by fleabay

##### Share on other sites

It sounds that your Intel Chip has some unsupported extensions you are using that the Ubuntu driver support so you may need to check the extension string and shader compiler output eve if it dosent fail there may be warnings in it. At least check the error code of GetLastError() Winapi. Remember that glGetError may be resetted when running any gl function after that one that fails so you need to double check this too.

##### Share on other sites

This is classic driver incompatibility.  Your using things on the Ubuntu side that your intel driver can't do.  Do yourself a favor and test it on a proper windows gaming pc (nvidia or amd card) to verify.

The biggest hurtle I had when porting my XNA engine to OpenGL was to remember to check glGetError after each call in DEBUG mode so I knew exactly which lines were failing.  There's a lot more error checking done in OpenGL that I was used to.  I found that even the same code that rendered fine on OSX and Linux, showed up wonky on windows.  My issue was driver defaults.  On windows, my driver defaulted some state (blend state and cull states) that weren't done on OSX and Linux.  I had to write a state manager for my engine to maintain it's own state and not rely on OpenGL's.

One would think that it would be easy to take a standard api and make something cross platform.  Except there are small nuances with the platforms that you have to kinda navigate with your code.

EDIT: Also, test with something basic and small, set to an identity matrix, test across all platforms and see if it's the same.  A simple cube at 0,0,0 should suffice.  This will allow you to start to pinpoint where the differences are.

Edited by gabereiser

##### Share on other sites

Hi again. Sorry for the late reply. Thank you to everyone who's trying to help me.

Do you have any immediate mode code at all?

I had to google a bit to remember what that meant. No, I don't have any immediate mode code.

Are you checking for errors in Ubuntu, even though it looks correct?

I'm not checking for errors through glGetError yet (because of lazyness) but I'm using GL_KHR_debug which reports even performance warnings.

Can you compile and/or run it as OpenGL 3.1 under Ubuntu to see if you get similar results as Windows?

That's tricky. The Ubuntu driver only supports 3.2 and 3.3 when using the core context. The greatest non-core version available is 3.0, so the best I could do would be having a 3.0 context and loading 3.1 extensions. I'll try that if nothing else works.

It sounds that your Intel Chip has some unsupported extensions you are using that the Ubuntu driver support so you may need to check the extension string

That's true. The Windows driver doesn't support geometry shaders, for example. But my engine checks if all needed extensions are present, so unless I'm missing an extension (which I don't think I am) that's also not it. I'm going to take a look at it anyway.

and shader compiler output eve if it dosent fail there may be warnings in it.

My engine always does that.

At least check the error code of GetLastError() Winapi.

I don't know what GetLastError has to do with anything, but I'll take a look at that.

Remember that glGetError may be resetted when running any gl function after that one that fails so you need to double check this too.

I don't think so. According to the reference "No other errors are recorded until glGetError is called, the error code is returned, and the flag is reset to GL_NO_ERROR.". Also, ApiTrace always lists all errors and warnings.

Do yourself a favor and test it on a proper windows gaming pc (nvidia or amd card) to verify.

If I had a "proper Windows gaming PC" I wouldn't be using a laptop. Decent computers are pretty expensive where I live, so it's not that simple. Remember: just because you can afford a good computer it doesn't mean everybody can.  :)

The biggest hurtle I had when porting my XNA engine to OpenGL was to remember to check glGetError after each call in DEBUG mode so I knew exactly which lines were failing.

Yeah, that's something I should do now. Even though ApiTrace verifies errors after each call, it's better to do it on my own.

My issue was driver defaults.  On windows, my driver defaulted some state (blend state and cull states) that weren't done on OSX and Linux.  I had to write a state manager for my engine to maintain it's own state and not rely on OpenGL's.

My engine is designed not to assume any kind of default value.

Also, test with something basic and small, set to an identity matrix, test across all platforms and see if it's the same.  A simple cube at 0,0,0 should suffice.  This will allow you to start to pinpoint where the differences are.

THIS. For some reason, I haven't even thought about using a simpler scene. Doing this will probably make finding the problem much easier.

Again, thank you to everyone who replied. Have a nice day.

Edited by LHLaurini

##### Share on other sites

Hi.

I made some tests with a simpler scene. First, some code (this is a very simplified version of the code):

UpdateBuffer(Mesh, &Object->WorldMatrix, Material);
glBindBuffer(GL_UNIFORM_BUFFER, <UBO>);
char* Ptr = reinterpret_cast<char*>(glMapBuffer(GL_UNIFORM_BUFFER, GL_WRITE_ONLY));
if (Ptr)
{
std::copy(<Buffer source>, <Buffer source> + <Buffer size>, Ptr);
glUnmapBuffer(GL_UNIFORM_BUFFER);
}
glBindVertexArray(<Object's vertex array>);
glDrawArrays(GL_TRIANGLES, <First vertex>, <Vertex count>);


The code above is executed once per object. The results seem to change if I use glBufferSubData instead of glMapBuffer, so here's a "table":

UBO update method | 1 object | 2 objects¹ | 3 objects¹
------------------+----------+-------------------------
glMapBuffer       |    OK    |     OK     | WRONG (1)
glBufferSubData   |    OK    |  WRONG (2) | WRONG (3)

¹ It didn't matter if the objects used the same VBO or not.


What I mean by "wrong" depends on the combination.

For (1), it rendered the first object ok, the second one disappeared and the third one was rendered with the wrong VBO, but with the right world matrix and material.

For (2) and (3), it rendered only the last object, with the right world matrix and material, but with the wrong VBO.

Okay, we're getting closer. The UBO update method really matters. Let's try something.

UBO update method | Run until the UBO update for the 2nd object | Run until the UBO update for the 3rd object
------------------+---------------------------------------------+---------------------------------------------
glMapBuffer       |                      OK                     |             Same as (1) above
glBufferSubData   |               Same as (2) above             |             Same as (3) above

Hmm, interesting. So glMapBuffer is erasing the second object after it's been already drawn and glBufferSubData is erasing everything.

Now, as you may know, I have no f***ing idea what the f*** is happening. I feel like even if I manage to solve this issue, another issue even worse is going to appear, so that's why I'm officially giving up support for Intel Windows OpenGL drivers. It's just not worth it. I've spent two weeks trying to solve it. But that's not a big deal since Intel GPU users on Windows can still use Direct3D 10.1.

So thanks to everyone who tried to help me and sorry that I wasted your time by not being able to solve this issue. Best regards.

Edited by LHLaurini

##### Share on other sites

Yeah Intel stuff in Windows didn't get good until the GL 4.2+ GPUs started to come out. If you have no issues with maintaining a D3D pipeline, thats prolly your best option. Otherwise just target core 3.3 on both platforms and scrap older Intel GPUs on Windows.

AMD supported GL3 cards up to GL 4.2, so you get a couple of nice GL4 extensions supported in GL3 hardware (arb_shading_language_420pack, arb_texture_storage, etc). nVidia went a bit further (you can find 4.4 extensions in GL3 cards). Intel just implements what it wants on Windows (sometimes GL 3.1, sometimes GL 4.1, sometimes GL 4.2, its a lottery). Although on Linux they do support some GL4 extensions on GL3 hardware.

Thus why GL 3.3 core is a nice "middle ground" context to target on most places.