• 12
• 14
• 13
• 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 How would I draw a line between two world-coordinate points using OpenGL?

This topic is 828 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

Hi all, hopefully you can help me understand how to approach this line drawing question I have.

I have a basic 3D demo set up drawing lines with OpenGL using VAO's and shaders, and a first person camera to move around.

Key snippets:

// Example vertices
float[] verts = {
1f, 1f, 1f,
0f, 0f, 0f
};

// Draw call
glBindVertexArray(vaoID);
glDrawArrays(GL_LINES, 0, 2);


?Vertex shader is basic, no model matrix in use at the moment:

gl_Position = projectionMatrix * viewMatrix * vec4(position, 1.0


This outputs the line drawn properly in the 3D world, but the start/end points are based on the vertex positions only which isn't too useful.

My question is: how can I specify the start and end locations in my world coordinates and draw a line between those points? My first thought was about transforming each vertex by a different model matrix, but I asked this earlier also on stackoverflow and had a comment saying:

"You'd apply the same transformation to both points. The transformation matrix needs to contain a scaling to (p2-p1) first and then a translation to p1(x,y,z). Oh and you chose the vertices of (0,0,0) and (1,1,1) correctly."

Unfortunately that reply just left me even more confused about how to do this. How would the scaling work with the original vertices? If I need to move vertex 1 to 20x, 20y, 20z and vertex 2 to 20x, 100y, 100z then I'm not clear how this would work, and how the original vertices relate to the final world coordinates I want.

I'd really appreciate any help with what I hope is a simple question. I'm using Java and LWJGL if that affects anything, but I think the concept will be the same regardless of language.

Thanks!

##### Share on other sites
The stackoverflow reply sounds fine to me.

If you imagine your two vertices are a model, your 0,0,0 is the "center" of the model and isn't changed by scaling.

The 0,0,0 point stays at 0,0,0 no matter how much you scale it, and then moves exactly by your translation amount.
The 1,1,1 point first moves to a point equal to the scaling (x,y,z), and then has the translation added to the result.

Therefore, translation controls your 0,0,0 point's final location and scaling only controls the 1,1,1 point's location relative to wherever your 0,0,0 point is.

Point A = 0,0,0
Point A transformed = (0,0,0) * (scaling) + (translation)
// (0,0,0) * scaling = (0,0,0), so this simplifies to:
Point A transformed = (0,0,0) + (translation)
Point A transformed = (translation)

Point B = 1,1,1
Point B transformed = (1,1,1) * (scaling) + (translation)
// (1,1,1) * scaling = scaling, so this simplifies to:
Point B transformed = (scaling) + (translation)

So this means you can control the exact location by using:
Point A transformed = Desired point A location
Point B transformed = Desired point B location

Substituting:
Desired point A location = translation

Desired point B location = (scaling) + (translation)

Subtracting translation from both sides:
Desired point B location - (translation) = (scaling)

Substituting:
Desired point B location - Desired point A location = scaling Edited by Nypyren

##### Share on other sites

Thanks so much, that was exactly the explanation I needed to understand what was going on, and of course it makes total sense as soon as I read over your post :) Seems to be working great.

##### Share on other sites

Worth pointing out that your terminology is confusing. Since you aren't applying a model matrix anywhere, your points *are already* in world space (not necessarily what you think of as 'world coordinates' right now).

In general it's all much simpler if you setup your camera transform such that OpenGL's world space is the same as your world coordinates, or you are in for a world of confusion down the line.

##### Share on other sites

Thanks for the pointer swiftcoder. I think I'm a little mixed up on the terms then, as the things I've been reading talk about "world space" meaning after it's been transformed by the model matrix so that it's world coordinate position / rotation / scale is taken into account, but it sounds like that's not the correct way to think about it then?

Could you elaborate on what you meant with your second point about setting up the camera transform in a way to avoid later confusion? Thanks!

##### Share on other sites

as the things I've been reading talk about "world space" meaning after it's been transformed by the model matrix

Yes, that's a reasonable way to look at it. And since your original post doesn't use a model matrix, therefore your points are being specified in world space.

Or, in other words, the answer to your question "how can I specify the start and end locations in my world coordinates and draw a line between those points?" is that you are already doing so.

Could you elaborate on what you meant with your second point about setting up the camera transform in a way to avoid later confusion?

What I mean is that there is no particular requirement that your game world actually correspond to OpenGL's world space. For example, a large open-world game may experience floating point precision problems if placed in standard world space, in which case they'll have to move the origin of OpenGL's world space around in their game world.

From your post, I had reached the conclusion that you were trying to draw your line in some different world coordinate space, and my point was that it is much simpler if you don't introduce additional coordinate spaces, and just treat OpenGL's world space as your word coordinates.