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# C++ std::thread finish implementation

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Guess i have a thread and im on main thread of app now i would like to wait until thread finishes to execute.

Thread Func

void ProcessServerFrame()
{

server_thread_free = false;

while (!server_thread_finished)
Do stuff

server_thread_free = true;
}

And then from main thread i would like to check whenever thread finished to work

void CreateDWMTCPServer()
{
if (server != 0)
{
server_thread_finished = true;
while (!server_thread_free) {}
delete server;
server = 0;
}

}

Now i am not sure if thread is allowed to read data when other is writing to it or maybe theres some kind of queue that prevents that from happening, basically i dont want to check for server_thread_free when thread marks it as true

any thoughts?

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There are a number of threading primitives that may be necessary here, but I'm not 100% sure what you are trying to accomplish.

To safely read a variable that is written to from another thread, you might consider using std::atomic (in this case, likely std::atomic_bool). Atomics ensure that writes will occur fully before reads see the changes, avoiding reading a partially-modified value.

If you are actually waiting for the worker thread to be entirely finished (i.e. reach the end of its main function), then you could call join() on it from the main thread. Join will block the main thread until the worker thread exits.

If instead this is a worker thread that works on many small tasks, and you want to wait for it to be finished with the current task, then you likely want std::condition_variable. Conditional variables let you block one thread until the other signals it, which would allow your thread to sleep until the other thread wakes it up.

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In the worker example; what I use to utilize is a double sleeved Semaphore that first locks and then awaits itself if std::condition_variable is not an option. Then another thread may come and release the Semaphore so you have the same effect at the end. I first used to go with Mutex but it showed that on Windows platform a mutex is protected against self locking

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• bs::framework is a newly released, free and open-source C++ game development framework. It aims to provide a modern C++14 API & codebase, focus on high-end technologies comparable to commercial engine offerings and a highly optimized core capable of running demanding projects. Additionally it aims to offer a clean, simple architecture with lightweight implementations that allow the framework to be easily enhanced with new features and therefore be ready for future growth.
Some of the currently available features include a physically based renderer based on Vulkan, DirectX and OpenGL, unified shading language, systems for animation, audio, GUI, physics, scripting, heavily multi-threaded core, full API documentation + user manuals, support for Windows, Linux and macOS and more.
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A complete editor based on the framework is also in development, currently available in pre-alpha stage.
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View full story

• bs::framework is a newly released, free and open-source C++ game development framework. It aims to provide a modern C++14 API & codebase, focus on high-end technologies comparable to commercial engine offerings and a highly optimized core capable of running demanding projects. Additionally it aims to offer a clean, simple architecture with lightweight implementations that allow the framework to be easily enhanced with new features and therefore be ready for future growth.
Some of the currently available features include a physically based renderer based on Vulkan, DirectX and OpenGL, unified shading language, systems for animation, audio, GUI, physics, scripting, heavily multi-threaded core, full API documentation + user manuals, support for Windows, Linux and macOS and more.
The next few updates are focusing on adding support for scripting languages like C#, Python and Lua, further enhancing the rendering fidelity and adding sub-systems for particle and terrain rendering.
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You can find out more information on www.bsframework.io.

• Hi again,  After some looking around I have decided to base my game directly on Direct X rather than using an existing game engine.  Because of the nature of the stuff I'm doing it just didn't seem to fit very well and I kept running into road blocks.  At this point I have a big blob of code for doing fractal world generation and some collision code,  and I'm trying to put it into some form that resembles a game engine.  Since I've never used one before It's a bit alien to me ..... so can someone direct me to a book, website, article, whatever... that covers this?  I'm mainly looking for stuff that covers C++ library design. I'm not adverse to using 3rd party tools for stuff I can used them for.
• By chiffre
Introduction:
In general my questions pertain to the differences between floating- and fixed-point data. Additionally I would like to understand when it can be advantageous to prefer fixed-point representation over floating-point representation in the context of vertex data and how the hardware deals with the different data-types. I believe I should be able to reduce the amount of data (bytes) necessary per vertex by choosing the most opportune representations for my vertex attributes. Thanks ahead of time if you, the reader, are considering the effort of reading this and helping me.
I found an old topic that shows this is possible in principal, but I am not sure I understand what the pitfalls are when using fixed-point representation and whether there are any hardware-based performance advantages/disadvantages.
(TLDR at bottom)
The Actual Post:
To my understanding HLSL/D3D11 offers not just the traditional floating point model in half-,single-, and double-precision, but also the fixed-point model in form of signed/unsigned normalized integers in 8-,10-,16-,24-, and 32-bit variants. Both models offer a finite sequence of "grid-points". The obvious difference between the two models is that the fixed-point model offers a constant spacing between values in the normalized range of [0,1] or [-1,1], while the floating point model allows for smaller "deltas" as you get closer to 0, and larger "deltas" the further you are away from 0.
To add some context, let me define a struct as an example:
struct VertexData { float[3] position; //3x32-bits float[2] texCoord; //2x32-bits float[3] normals; //3x32-bits } //Total of 32 bytes Every vertex gets a position, a coordinate on my texture, and a normal to do some light calculations. In this case we have 8x32=256bits per vertex. Since the texture coordinates lie in the interval [0,1] and the normal vector components are in the interval [-1,1] it would seem useful to use normalized representation as suggested in the topic linked at the top of the post. The texture coordinates might as well be represented in a fixed-point model, because it seems most useful to be able to sample the texture in a uniform manner, as the pixels don't get any "denser" as we get closer to 0. In other words the "delta" does not need to become any smaller as the texture coordinates approach (0,0). A similar argument can be made for the normal-vector, as a normal vector should be normalized anyway, and we want as many points as possible on the sphere around (0,0,0) with a radius of 1, and we don't care about precision around the origin. Even if we have large textures such as 4k by 4k (or the maximum allowed by D3D11, 16k by 16k) we only need as many grid-points on one axis, as there are pixels on one axis. An unsigned normalized 14 bit integer would be ideal, but because it is both unsupported and impractical, we will stick to an unsigned normalized 16 bit integer. The same type should take care of the normal vector coordinates, and might even be a bit overkill.
struct VertexData { float[3] position; //3x32-bits uint16_t[2] texCoord; //2x16bits uint16_t[3] normals; //3x16bits } //Total of 22 bytes Seems like a good start, and we might even be able to take it further, but before we pursue that path, here is my first question: can the GPU even work with the data in this format, or is all I have accomplished minimizing CPU-side RAM usage? Does the GPU have to convert the texture coordinates back to a floating-point model when I hand them over to the sampler in my pixel shader? I have looked up the data types for HLSL and I am not sure I even comprehend how to declare the vertex input type in HLSL. Would the following work?
struct VertexInputType { float3 pos; //this one is obvious unorm half2 tex; //half corresponds to a 16-bit float, so I assume this is wrong, but this the only 16-bit type I found on the linked MSDN site snorm half3 normal; //same as above } I assume this is possible somehow, as I have found input element formats such as: DXGI_FORMAT_R16G16B16A16_SNORM and DXGI_FORMAT_R16G16B16A16_UNORM (also available with a different number of components, as well as different component lengths). I might have to avoid 3-component vectors because there is no 3-component 16-bit input element format, but that is the least of my worries. The next question would be: what happens with my normals if I try to do lighting calculations with them in such a normalized-fixed-point format? Is there no issue as long as I take care not to mix floating- and fixed-point data? Or would that work as well? In general this gives rise to the question: how does the GPU handle fixed-point arithmetic? Is it the same as integer-arithmetic, and/or is it faster/slower than floating-point arithmetic?
Assuming that we still have a valid and useful VertexData format, how far could I take this while remaining on the sensible side of what could be called optimization? Theoretically I could use the an input element format such as DXGI_FORMAT_R10G10B10A2_UNORM to pack my normal coordinates into a 10-bit fixed-point format, and my verticies (in object space) might even be representable in a 16-bit unsigned normalized fixed-point format. That way I could end up with something like the following struct:
struct VertexData { uint16_t[3] pos; //3x16bits uint16_t[2] texCoord; //2x16bits uint32_t packedNormals; //10+10+10+2bits } //Total of 14 bytes Could I use a vertex structure like this without too much performance-loss on the GPU-side? If the GPU has to execute some sort of unpacking algorithm in the background I might as well let it be. In the end I have a functioning deferred renderer, but I would like to reduce the memory footprint of the huge amount of vertecies involved in rendering my landscape.
TLDR: I have a lot of vertices that I need to render and I want to reduce the RAM-usage without introducing crazy compression/decompression algorithms to the CPU or GPU. I am hoping to find a solution by involving fixed-point data-types, but I am not exactly sure how how that would work.

• Well i found out Here what's the problem and how to solve it (Something about world coordinates and object coordinates) but i can't understand how ti works. Can you show me some examples in code on how you implement this???

Scaling Matrix:
m_Impl->scale = glm::mat4(1.0f); m_Impl->scale = glm::scale(m_Impl->scale, glm::vec3(width, height, 0)); Verticies:
//Verticies. float verticies[] = { //Positions. //Texture Coordinates. 1.0f, 1.0f, 0.0f, 0.0f, 2.0f, 1.0f, 1.0f, 0.0f, 2.0f, 2.0f, 1.0f, 1.0f, 1.0f, 2.0f, 0.0f, 1.0f }; Rendering:
//Projection Matrix. glm::mat4 proj = glm::ortho(0.0f, (float)window->GetWidth(), 0.0f, (float)window->GetHeight(), -1.0f, 1.0f); //Set the uniform. material->program->setUniformMat4f("u_MVP", proj * model); //model is the scale matrix from the previous code. //Draw. glDrawElements(GL_TRIANGLES, material->ibo->GetCount(), GL_UNSIGNED_INT, NULL);
Shader:
#shader vertex #version 330 core layout(location = 0) in vec4 aPos; layout(location = 1) in vec2 aTexCoord; out vec2 texCoord; uniform mat4 u_MVP; void main() { gl_Position = u_MVP*aPos; texCoord = aTexCoord; } #shader fragment #version 330 core out vec4 colors; in vec2 texCoord; uniform sampler2D u_Texture; void main() { colors = texture(u_Texture, texCoord); }
Before Scaling (It's down there on the bottom left corner as a dot).

After Scaling

Problem: Why does the position also changes?? If you see my Verticies, the first position starts at 1.0f, 1.0f , so when i'm scaling it should stay at that position
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