• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
spek

OpenGL
Loading textures in another thread & reserving memory

9 posts in this topic

About texture / VBO loading,
 
I have a roaming world so it happens quite a lot that textures or object-geometry needs to be loaded or removed on the fly. Although the image loading happens in a background-thread, the main thread is still used to generate the texture and copy the image pixels into it, which halts the main thread.
 
 
I've seen multi-threading with OpenGL is possible by sharing:
So I guess I should look into that first. But maybe OpenGL (3.x) also has special functions for smoothly loading texture data nowadays?
 
 
Second, is it useful to reuse texture/buffer objects? Right new each new texture calls glGenerateTextures() and fills it with pixels. Obsolete textures call glDeleteTextures() again. But instead of throwing them away, I could also put new textures in unused "slots" (if the resolution / format equals of course). Is that useful?
 
The same question for VBO's. Objects are generated and removed all the time, but maybe I can reuse those as well. Although chances are very little that we find a VBO with exact the same vertices of course. Would it hurt to put a (slight) smaller object into a bigger VBO?
 
 
Rick
0

Share this post


Link to post
Share on other sites

But maybe OpenGL (3.x) also has special functions for smoothly loading texture data nowadays?

Nope.

But instead of throwing them away, I could also put new textures in unused "slots" (if the resolution / format equals of course). Is that useful?

Not really. Instead of issuing a glDeleteTextures + glGenTextures + glTexture2d, you could just issue a glTexture2d call to resize the currently bound texture. This may help in some minor edge cases, but in the bigger scheme of things, it's unlikely to make a difference. If anything, keeping the symmetry in your code (i.e. create/destroy) will make the code easier to maintain.

The same question for VBO's.

glBufferData if you need to rezise the buffer, otherwise keep the symmetry to keep the code clean.

1

Share this post


Link to post
Share on other sites

Ok. Just using the default GL functions sure is easier.

 

But I would think glGenerate and other functions to copy image data into a buffer, involves reserving memory and such. So the idea is that if I need to load a 512x512 texture for example, it will look for an unused 512x512 buffer. If there is none, it will generate a new texture, but otherwise it uses a buffer that has already been reserved in the memory.

 

But maybe OpenGL already does this internally somehow?

0

Share this post


Link to post
Share on other sites

Again, no, OpenGL does not have similar functionality.  And, again, ::glGenTextures(), ::glDeleteTextures(), etc., are all dwarfed by ::glTexImage2D().

When you upload new texture data the driver (depending on the implementation—for reference here I am using a common implementation known to be used in various devices and hardware) will create a copy of your data which in itself is slow.

 

But the real slow happens the first time you render with that texture and its updated data.

When you actually try to render with a modified texture, the driver makes another copy where it performs swizzling into the GPU’s native format etc.  And no I am not talking about channel swizzling and RGB vs. BGR.  That is only a channel swizzle, not a pixel swizzle, which is another swizzle necessary for many GPU’s.

 

Because this happens when you actually draw with the modified texture, you can’t offload it to another thread or make it transparent.

So:

#1: You will have some kind of jitter in OpenGL no matter what, at least if the most common implementation is used by your drivers.

#2: Even if it is not, all these processes still happen at some point in the pipeline, and they consume so many cycles that anything you save by not calling ::glGenTextures() is completely moot.  It isn’t worth making a sharing system and searching for previous matches etc.  In fact you are just as likely to cause GPU stalls by overwriting a texture that is currently in use by the GPU even though it was already flagged by your CPU side as being unused after its last render.

 

 

L. Spiro

1

Share this post


Link to post
Share on other sites

Hmmm, I see.

Then that leads to the following question; how to smoothly stream a scene then? I'm sure that has been done before with OpenGL.

 

Seems that no matter where and how I load it, the "slap in the face" comes when walking into that room where its textures finally get rendered, right? To spread the workload, would it be a good idea to render new textures, one-by-one, in an invisible background buffer to ensure they have been handled before walking into a new room and freezing?

 

Second I wonder how big the impact really is. In my case, some of the bigger textures are 1024 x 1024 RGBA8 images, or even bigger ("2048 x 1024") but using DXT compression. I assume that even loading just one of those, already hurts. Or is it so small that, if I spread it out with some time intervals, it wouldn't be very noticable? For the info, I'm working on a 2009 laptop videocard, not the fastest thing in the world anymore hehe.

 

Thanks for the info!

Edited by spek
0

Share this post


Link to post
Share on other sites

For starters don't upload more than one texture per frame to GL, to minimize performance hitches, and also make sure you issue a fake draw call for each texture to force to GPU to make it 'ready' as L.Spiro mentioned. Maybe even performing this readying step on a different frame to the uploading step...

 

I'd also recommend using DXT compression as much as possible, because not only will it reduce the amount of data that has to be copied around, but it will likely reduce the costs of the 'readying' steps in the driver too (they're less likely to swizzle a DXT texture than a plain old uncompressed one).

 

I'd make sure that all my disk loading code (outside of GL) ran fine in the background first, so that you can stream in the assets to RAM without any performance issues. Then as each texture is loaded into RAM, put them into a queue for copying over to GL one by one.

 

The only way to find out is to try it and see what kind of performance you get ;)

2

Share this post


Link to post
Share on other sites

Allright, shizzle swizzle

 

The image loading already happens in a background thread, and one texture per cycle is made. But I didn't do the fake drawing call, so that explains why the program still chokes.

 

DXT compression is also used, though I found the results often a bit too crappy for normalMaps or specular stored in alpha channels. So there are quite some textures still uncompressed. Maybe I'm not using the right compression settings (using the ATI libraryand compressing to either DXT1, DXT3 or DXT5).

 

 

Oh btw, what exactly would be a cheap way to do a fake drawing? Do I really need to draw a quad or something, or is binding enough to trigger the process?

 

Well, thanks, I know what to do now biggrin.png

 

Rick

Edited by spek
0

Share this post


Link to post
Share on other sites
doing things like loading in a separate thread can help performance IME, but isn't so much related to GPU related reasons (like uploading the texture) as much as more CPU-related tasks: decoding the textures and converting them to DXT. also things like parsing 3D models, ...

(for example, decoding PNG / JPEG / 3D models / ... while not that expensive, isn't free either...).

(though, I later ended up having to move some of this stuff back into the main thread for now, as my engine falls a little short of being thread-safe... and worse performance was preferable to data trampling / crashes / ...).


the GPU stalls in question aren't usually the big obvious stalls (like, enter a room and wait 1/2 second...), but are usually much smaller (microseconds?), so while they may kill the framerate if done regularly mid-render, they can still be used for "reasonably transparent" loading.

it is in-fact possible to stream things like video and similar to the GPU without hurting things too badly (though you might want to make sure any DXTn encoding/... is done before passing them off to OpenGL).


ADD: I don't know about fake drawing... I had just been calling 'glFinish();' after uploading which seems to do something at least...

granted, I can't really claim to be an 'expert' on all this... Edited by cr88192
0

Share this post


Link to post
Share on other sites

Just added the fake draw step (the background image loading and pushing textures one by one was already implemented). Not sure if it's done 100% correctly, I simply binded the texture and drawed a triangle very, very far away from the camera (is it a problem if its outside the view frustum?).

 

It's still noticable when a texture gets loaded, though its more equal spread all over now. It may also be the hardware though, I get the feeling that this laptop is going to a digital heaven soon... My desktop loads the entire thing way faster, even though that videocard is slowly starting to date as well. Not only the loading goes slow, the entire game runs slow so its add up.

 

 

 

This would bring me to the conclusion that, like Spiro said, truly "smooth" streaming isn't possible. Then again on a more modern card it would most likely be less of a pain.

 

I still wonder though, old games like GTA on a PS2 did the same thing (I think). Of course those textures were really low-res, but so was that hardware 10 years ago. Though you could clearly see the scene getting loaded step by step when traveling too fast sometimes, it didn't noticably hurt the performance. And more recent games such as GTA IV are doing it with more (and more detailed) textures on "dating" hardware such as the XBox or PS3. Are they doing something really different, am I just fooled by low-res textures, or is their whole memory architecture different anyway? Just curious.

 

Cheers

0

Share this post


Link to post
Share on other sites

Are they doing something really different, am I just fooled by low-res textures, or is their whole memory architecture different anyway? Just curious.

Both. Basically this problem is specific to most versions of OpenGL (any that do not allow sharing resources between contexts). PC and Xbox * have always used DirectX and so resources can be fully processed on a second thread, and other modern architectures may implement wrappers for OpenGL (well, the really modern ones are just DirectX 11) but still have an underlying architecture that does not enforce a state-machine-driven way of handling things. Mobile devices don’t have this problem either because they can share resources across contexts which means it can be fully loaded on one thread and then used on the other.


L. Spiro

Edited by L. Spiro
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0

  • Similar Content

    • By Solid_Spy
      Hello, I have been working on SH Irradiance map rendering, and I have been using a GLSL pixel shader to render SH irradiance to 2D irradiance maps for my static objects. I already have it working with 9 3D textures so far for the first 9 SH functions.
      In my GLSL shader, I have to send in 9 SH Coefficient 3D Texures that use RGBA8 as a pixel format. RGB being used for the coefficients for red, green, and blue, and the A for checking if the voxel is in use (for the 3D texture solidification shader to prevent bleeding).
      My problem is, I want to knock this number of textures down to something like 4 or 5. Getting even lower would be a godsend. This is because I eventually plan on adding more SH Coefficient 3D Textures for other parts of the game map (such as inside rooms, as opposed to the outside), to circumvent irradiance probe bleeding between rooms separated by walls. I don't want to reach the 32 texture limit too soon. Also, I figure that it would be a LOT faster.
      Is there a way I could, say, store 2 sets of SH Coefficients for 2 SH functions inside a texture with RGBA16 pixels? If so, how would I extract them from inside GLSL? Let me know if you have any suggestions ^^.
    • By DaniDesu
      #include "MyEngine.h" int main() { MyEngine myEngine; myEngine.run(); return 0; } MyEngine.h
      #pragma once #include "MyWindow.h" #include "MyShaders.h" #include "MyShapes.h" class MyEngine { private: GLFWwindow * myWindowHandle; MyWindow * myWindow; public: MyEngine(); ~MyEngine(); void run(); }; MyEngine.cpp
      #include "MyEngine.h" MyEngine::MyEngine() { MyWindow myWindow(800, 600, "My Game Engine"); this->myWindow = &myWindow; myWindow.createWindow(); this->myWindowHandle = myWindow.getWindowHandle(); // Load all OpenGL function pointers for use gladLoadGLLoader((GLADloadproc)glfwGetProcAddress); } MyEngine::~MyEngine() { this->myWindow->destroyWindow(); } void MyEngine::run() { MyShaders myShaders("VertexShader.glsl", "FragmentShader.glsl"); MyShapes myShapes; GLuint vertexArrayObjectHandle; float coordinates[] = { 0.5f, 0.5f, 0.0f, 0.5f, -0.5f, 0.0f, -0.5f, 0.5f, 0.0f }; vertexArrayObjectHandle = myShapes.drawTriangle(coordinates); while (!glfwWindowShouldClose(this->myWindowHandle)) { glClearColor(0.5f, 0.5f, 0.5f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Draw something glUseProgram(myShaders.getShaderProgram()); glBindVertexArray(vertexArrayObjectHandle); glDrawArrays(GL_TRIANGLES, 0, 3); glfwSwapBuffers(this->myWindowHandle); glfwPollEvents(); } } MyShaders.h
      #pragma once #include <glad\glad.h> #include <GLFW\glfw3.h> #include "MyFileHandler.h" class MyShaders { private: const char * vertexShaderFileName; const char * fragmentShaderFileName; const char * vertexShaderCode; const char * fragmentShaderCode; GLuint vertexShaderHandle; GLuint fragmentShaderHandle; GLuint shaderProgram; void compileShaders(); public: MyShaders(const char * vertexShaderFileName, const char * fragmentShaderFileName); ~MyShaders(); GLuint getShaderProgram(); const char * getVertexShaderCode(); const char * getFragmentShaderCode(); }; MyShaders.cpp
      #include "MyShaders.h" MyShaders::MyShaders(const char * vertexShaderFileName, const char * fragmentShaderFileName) { this->vertexShaderFileName = vertexShaderFileName; this->fragmentShaderFileName = fragmentShaderFileName; // Load shaders from files MyFileHandler myVertexShaderFileHandler(this->vertexShaderFileName); this->vertexShaderCode = myVertexShaderFileHandler.readFile(); MyFileHandler myFragmentShaderFileHandler(this->fragmentShaderFileName); this->fragmentShaderCode = myFragmentShaderFileHandler.readFile(); // Compile shaders this->compileShaders(); } MyShaders::~MyShaders() { } void MyShaders::compileShaders() { this->vertexShaderHandle = glCreateShader(GL_VERTEX_SHADER); this->fragmentShaderHandle = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(this->vertexShaderHandle, 1, &(this->vertexShaderCode), NULL); glShaderSource(this->fragmentShaderHandle, 1, &(this->fragmentShaderCode), NULL); glCompileShader(this->vertexShaderHandle); glCompileShader(this->fragmentShaderHandle); this->shaderProgram = glCreateProgram(); glAttachShader(this->shaderProgram, this->vertexShaderHandle); glAttachShader(this->shaderProgram, this->fragmentShaderHandle); glLinkProgram(this->shaderProgram); return; } GLuint MyShaders::getShaderProgram() { return this->shaderProgram; } const char * MyShaders::getVertexShaderCode() { return this->vertexShaderCode; } const char * MyShaders::getFragmentShaderCode() { return this->fragmentShaderCode; } MyWindow.h
      #pragma once #include <glad\glad.h> #include <GLFW\glfw3.h> class MyWindow { private: GLFWwindow * windowHandle; int windowWidth; int windowHeight; const char * windowTitle; public: MyWindow(int windowWidth, int windowHeight, const char * windowTitle); ~MyWindow(); GLFWwindow * getWindowHandle(); void createWindow(); void MyWindow::destroyWindow(); }; MyWindow.cpp
      #include "MyWindow.h" MyWindow::MyWindow(int windowWidth, int windowHeight, const char * windowTitle) { this->windowHandle = NULL; this->windowWidth = windowWidth; this->windowWidth = windowWidth; this->windowHeight = windowHeight; this->windowTitle = windowTitle; glfwInit(); } MyWindow::~MyWindow() { } GLFWwindow * MyWindow::getWindowHandle() { return this->windowHandle; } void MyWindow::createWindow() { // Use OpenGL 3.3 and GLSL 3.3 glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // Limit backwards compatibility glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // Prevent resizing window glfwWindowHint(GLFW_RESIZABLE, GL_FALSE); // Create window this->windowHandle = glfwCreateWindow(this->windowWidth, this->windowHeight, this->windowTitle, NULL, NULL); glfwMakeContextCurrent(this->windowHandle); } void MyWindow::destroyWindow() { glfwTerminate(); } MyShapes.h
      #pragma once #include <glad\glad.h> #include <GLFW\glfw3.h> class MyShapes { public: MyShapes(); ~MyShapes(); GLuint & drawTriangle(float coordinates[]); }; MyShapes.cpp
      #include "MyShapes.h" MyShapes::MyShapes() { } MyShapes::~MyShapes() { } GLuint & MyShapes::drawTriangle(float coordinates[]) { GLuint vertexBufferObject{}; GLuint vertexArrayObject{}; // Create a VAO glGenVertexArrays(1, &vertexArrayObject); glBindVertexArray(vertexArrayObject); // Send vertices to the GPU glGenBuffers(1, &vertexBufferObject); glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObject); glBufferData(GL_ARRAY_BUFFER, sizeof(coordinates), coordinates, GL_STATIC_DRAW); // Dertermine the interpretation of the array buffer glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3*sizeof(float), (void *)0); glEnableVertexAttribArray(0); // Unbind the buffers glBindBuffer(GL_ARRAY_BUFFER, 0); glBindVertexArray(0); return vertexArrayObject; } MyFileHandler.h
      #pragma once #include <cstdio> #include <cstdlib> class MyFileHandler { private: const char * fileName; unsigned long fileSize; void setFileSize(); public: MyFileHandler(const char * fileName); ~MyFileHandler(); unsigned long getFileSize(); const char * readFile(); }; MyFileHandler.cpp
      #include "MyFileHandler.h" MyFileHandler::MyFileHandler(const char * fileName) { this->fileName = fileName; this->setFileSize(); } MyFileHandler::~MyFileHandler() { } void MyFileHandler::setFileSize() { FILE * fileHandle = NULL; fopen_s(&fileHandle, this->fileName, "rb"); fseek(fileHandle, 0L, SEEK_END); this->fileSize = ftell(fileHandle); rewind(fileHandle); fclose(fileHandle); return; } unsigned long MyFileHandler::getFileSize() { return (this->fileSize); } const char * MyFileHandler::readFile() { char * buffer = (char *)malloc((this->fileSize)+1); FILE * fileHandle = NULL; fopen_s(&fileHandle, this->fileName, "rb"); fread(buffer, this->fileSize, sizeof(char), fileHandle); fclose(fileHandle); buffer[this->fileSize] = '\0'; return buffer; } VertexShader.glsl
      #version 330 core layout (location = 0) vec3 VertexPositions; void main() { gl_Position = vec4(VertexPositions, 1.0f); } FragmentShader.glsl
      #version 330 core out vec4 FragmentColor; void main() { FragmentColor = vec4(1.0f, 0.0f, 0.0f, 1.0f); } I am attempting to create a simple engine/graphics utility using some object-oriented paradigms. My first goal is to get some output from my engine, namely, a simple red triangle.
      For this goal, the MyShapes class will be responsible for defining shapes such as triangles, polygons etc. Currently, there is only a drawTriangle() method implemented, because I first wanted to see whether it works or not before attempting to code other shape drawing methods.
      The constructor of the MyEngine class creates a GLFW window (GLAD is also initialized here to load all OpenGL functionality), and the myEngine.run() method in Main.cpp is responsible for firing up the engine. In this run() method, the shaders get loaded from files via the help of my FileHandler class. The vertices for the triangle are processed by the myShapes.drawTriangle() method where a vertex array object, a vertex buffer object and vertrex attributes are set for this purpose.
      The while loop in the run() method should be outputting me the desired red triangle, but all I get is a grey window area. Why?
      Note: The shaders are compiling and linking without any errors.
      (Note: I am aware that this code is not using any good software engineering practices (e.g. exceptions, error handling). I am planning to implement them later, once I get the hang of OpenGL.)

       
    • By KarimIO
      EDIT: I thought this was restricted to Attribute-Created GL contexts, but it isn't, so I rewrote the post.
      Hey guys, whenever I call SwapBuffers(hDC), I get a crash, and I get a "Too many posts were made to a semaphore." from Windows as I call SwapBuffers. What could be the cause of this?
      Update: No crash occurs if I don't draw, just clear and swap.
      static PIXELFORMATDESCRIPTOR pfd = // pfd Tells Windows How We Want Things To Be { sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor 1, // Version Number PFD_DRAW_TO_WINDOW | // Format Must Support Window PFD_SUPPORT_OPENGL | // Format Must Support OpenGL PFD_DOUBLEBUFFER, // Must Support Double Buffering PFD_TYPE_RGBA, // Request An RGBA Format 32, // Select Our Color Depth 0, 0, 0, 0, 0, 0, // Color Bits Ignored 0, // No Alpha Buffer 0, // Shift Bit Ignored 0, // No Accumulation Buffer 0, 0, 0, 0, // Accumulation Bits Ignored 24, // 24Bit Z-Buffer (Depth Buffer) 0, // No Stencil Buffer 0, // No Auxiliary Buffer PFD_MAIN_PLANE, // Main Drawing Layer 0, // Reserved 0, 0, 0 // Layer Masks Ignored }; if (!(hDC = GetDC(windowHandle))) return false; unsigned int PixelFormat; if (!(PixelFormat = ChoosePixelFormat(hDC, &pfd))) return false; if (!SetPixelFormat(hDC, PixelFormat, &pfd)) return false; hRC = wglCreateContext(hDC); if (!hRC) { std::cout << "wglCreateContext Failed!\n"; return false; } if (wglMakeCurrent(hDC, hRC) == NULL) { std::cout << "Make Context Current Second Failed!\n"; return false; } ... // OGL Buffer Initialization glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT); glBindVertexArray(vao); glUseProgram(myprogram); glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_SHORT, (void *)indexStart); SwapBuffers(GetDC(window_handle));  
    • By Tchom
      Hey devs!
       
      I've been working on a OpenGL ES 2.0 android engine and I have begun implementing some simple (point) lighting. I had something fairly simple working, so I tried to get fancy and added color-tinting light. And it works great... with only one or two lights. Any more than that, the application drops about 15 frames per light added (my ideal is at least 4 or 5). I know implementing lighting is expensive, I just didn't think it was that expensive. I'm fairly new to the world of OpenGL and GLSL, so there is a good chance I've written some crappy shader code. If anyone had any feedback or tips on how I can optimize this code, please let me know.
       
      Vertex Shader
      uniform mat4 u_MVPMatrix; uniform mat4 u_MVMatrix; attribute vec4 a_Position; attribute vec3 a_Normal; attribute vec2 a_TexCoordinate; varying vec3 v_Position; varying vec3 v_Normal; varying vec2 v_TexCoordinate; void main() { v_Position = vec3(u_MVMatrix * a_Position); v_TexCoordinate = a_TexCoordinate; v_Normal = vec3(u_MVMatrix * vec4(a_Normal, 0.0)); gl_Position = u_MVPMatrix * a_Position; } Fragment Shader
      precision mediump float; uniform vec4 u_LightPos["+numLights+"]; uniform vec4 u_LightColours["+numLights+"]; uniform float u_LightPower["+numLights+"]; uniform sampler2D u_Texture; varying vec3 v_Position; varying vec3 v_Normal; varying vec2 v_TexCoordinate; void main() { gl_FragColor = (texture2D(u_Texture, v_TexCoordinate)); float diffuse = 0.0; vec4 colourSum = vec4(1.0); for (int i = 0; i < "+numLights+"; i++) { vec3 toPointLight = vec3(u_LightPos[i]); float distance = length(toPointLight - v_Position); vec3 lightVector = normalize(toPointLight - v_Position); float diffuseDiff = 0.0; // The diffuse difference contributed from current light diffuseDiff = max(dot(v_Normal, lightVector), 0.0); diffuseDiff = diffuseDiff * (1.0 / (1.0 + ((1.0-u_LightPower[i])* distance * distance))); //Determine attenuatio diffuse += diffuseDiff; gl_FragColor.rgb *= vec3(1.0) / ((vec3(1.0) + ((vec3(1.0) - vec3(u_LightColours[i]))*diffuseDiff))); //The expensive part } diffuse += 0.1; //Add ambient light gl_FragColor.rgb *= diffuse; } Am I making any rookie mistakes? Or am I just being unrealistic about what I can do? Thanks in advance
    • By yahiko00
      Hi,
      Not sure to post at the right place, if not, please forgive me...
      For a game project I am working on, I would like to implement a 2D starfield as a background.
      I do not want to deal with static tiles, since I plan to slowly animate the starfield. So, I am trying to figure out how to generate a random starfield for the entire map.
      I feel that using a uniform distribution for the stars will not do the trick. Instead I would like something similar to the screenshot below, taken from the game Star Wars: Empire At War (all credits to Lucasfilm, Disney, and so on...).

      Is there someone who could have an idea of a distribution which could result in such a starfield?
      Any insight would be appreciated
  • Popular Now