• 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
DaveDavis

OpenGL
Simple GLSL Image Processing

19 posts in this topic

I've been working on my first game in OpenGL and C++ for a little while now, and I'm trying my hand at GLSL for some simple image processing effects. Specifically, I'm trying to implement a simple gaussian blur. However, I'm having difficulty understanding conceptually how this is supposed to work. Here's how I think it's supposed to go from reading various forum entries/tutorials online:

Setup (one time at the beginning of my game init code):
[list=1][*]Enable texturing (glEnable(GL_TEXTURE_2D), glGenTextures(...), glBindTexture(...), etc.)[*]Load vertex/frag shaders (I'm loading from a file)[*]Compile shaders[*]Create shader program[*]Link Shaders[*]Check glGetInfoLogARB for errors[/list]
So far, so good (at least I see no output from the info log, so I'm assuming that's good).

Then, to render each frame:
[list=1][*]glUseProgram(my_shader_program_id)[*]Render my frame normally[*]glFlush() (?)[*]glUseProgam(0) (stop using my shader?)[*]glCopyTexImage2d(...) (Capture rendered output to a texture)[*]Calculate texture offsets based on window size[*]Pass texture offsets to shader using glUniform2fv(...) (I think that this isn't totally necessary if my window size is always the same, then I could have the same texture offsets, but not sure, I've seen a ton of different shader code for the fragment shader that does this in seemingly different ways)[*]Render full screen quad (optionally changing projection matrix to make this easier...) with texture coords[*]glFlush()[/list]
Does that sound about right? I think this is what I'm doing, but I'm getting really strange output. If this general approach looks correct, I'll post some more specific code, but I wanted to make sure I wasn't wasting anybody's time if I didn't have the concept correctly.
0

Share this post


Link to post
Share on other sites
You're probably close, but theres a couple changes I would make:

#1) I don't think you ever need to call glFlush. The driver should keep track of what is dependent on what else, so you won't be able to pull from a texture or framebuffer until its ready.

#2) Instead of rendering your scene normally and then copying the texels to a texture, you can render directly into a texture via framebuffers. Look into the commands:
glGenFramebuffers
glBindFramebuffer
glFramebufferTexture

This should be a lot more efficient.

#3) When you render the fullscreen quad, you definately don't want to use the same projection matrix. The easiest is to just use no matrix at all (define input coordinates in normalized device coordinates). Just draw your quad with vertices (+/-1, +/-1, 0) and that will align with the fullscreen without any transform required.
1

Share this post


Link to post
Share on other sites
[quote name='karwosts' timestamp='1302577753' post='4797364']You're probably close, but theres a couple changes I would make:

#1) I don't think you ever need to call glFlush. The driver should keep track of what is dependent on what else, so you won't be able to pull from a texture or framebuffer until its ready.

#2) Instead of rendering your scene normally and then copying the texels to a texture, you can render directly into a texture via framebuffers. Look into the commands:
glGenFramebuffers
glBindFramebuffer
glFramebufferTexture

This should be a lot more efficient.

#3) When you render the fullscreen quad, you definately don't want to use the same projection matrix. The easiest is to just use no matrix at all (define input coordinates in normalized device coordinates). Just draw your quad with vertices (+/-1, +/-1, 0) and that will align with the fullscreen without any transform required.
[/quote]

Ok, I'll give [s]that[/s] framebuffers a shot at some point, but I'm not very concerned with efficiency at this point, just want to get it working :) I've read about framebuffers though and it does seem like they are often used for this purpose, and if it makes it easier I'm all for it.

As I was re-reading my post this morning, I think I either made a mistake in my explanation above (and probably my implementation, but I'm at work so can't check my code right now), or I REALLY don't understand how the OpenGL pipeline works.

I think I need to swap steps 1 and 4 of the render portion, i.e. I need to render my normal frame WITHOUT my shaders first, then capture the screen as a texture, enable my blur shader and re-render, then map that to a quad. Otherwise, it doesn't seem to make sense to me (i.e., it seems like the only reason we need the texture is to pass the data in to the shader, since a blur shader needs to know about surrounding pixel data, and the fragment shader otherwise doesn't know about surrounding fragments...please correct me if I'm wrong about this though).

Also, I'm currently using an Orthographic projection (I'm building a Geometry Wars clone just to learn game programming so it's 2D), so would I still need to alter my projection matrix? I think I should easily be able to use my current projection matrix, but I could be wrong about this as well (all the example code for 3D does this by setting it back to normal I believe and using 0,1 (or -1,1, can never keep it straight...), but I was thinking I could skip this step since I already have an orthographic projection.

Thanks for your reply! I'll try swapping steps 1 and 4 of the render piece later when I get back, and if that doesn't work I'll try to come up with some example code to show the problem I'm having.
0

Share this post


Link to post
Share on other sites
[quote]
As I was re-reading my post this morning, I think I either made a mistake in my explanation above (and probably my implementation, but I'm at work so can't check my code right now), or I REALLY don't understand how the OpenGL pipeline works.

I think I need to swap steps 1 and 4 of the render portion, i.e. I need to render my normal frame WITHOUT my shaders first, then capture the screen as a texture, enable my blur shader and re-render, then map that to a quad. Otherwise, it doesn't seem to make sense to me (i.e., it seems like the only reason we need the texture is to pass the data in to the shader, since a blur shader needs to know about surrounding pixel data, and the fragment shader otherwise doesn't know about surrounding fragments...please correct me if I'm wrong about this though).
[/quote]

Yeah, this sounds right. I'm used to using a shader for everything, so it looked right to me to have a shader bound to render your scene. If thats your blur shader you want it active during step 8.

[quote]
Also, I'm currently using an Orthographic projection (I'm building a Geometry Wars clone just to learn game programming so it's 2D), so would I still need to alter my projection matrix? I think I should easily be able to use my current projection matrix, but I could be wrong about this as well (all the example code for 3D does this by setting it back to normal I believe and using 0,1 (or -1,1, can never keep it straight...), but I was thinking I could skip this step since I already have an orthographic projection.
[/quote]
You could make it work with an orthographic projection matrix, but my point was that you don't have to use a matrix at all. If you define your quad's input coordinates in NDC, than you can just let this be your vertex shader:

[code]
in vec2 vertex;
out vec2 texcoord;

main () {
gl_Position = vec4(vertex,0,1); //no matrix multiplies necessary
texcoord = vertex*0.5 + 0.5; //scale -1/1 range to 0/1;
}

[/code]
0

Share this post


Link to post
Share on other sites
[quote name='karwosts' timestamp='1302624380' post='4797540']
You could make it work with an orthographic projection matrix, but my point was that you don't have to use a matrix at all. If you define your quad's input coordinates in NDC, than you can just let this be your vertex shader:

[code]
in vec2 vertex;
out vec2 texcoord;

main () {
gl_Position = vec4(vertex,0,1); //no matrix multiplies necessary
texcoord = vertex*0.5 + 0.5; //scale -1/1 range to 0/1;
}

[/code]
[/quote]

Awesome, yeah that would be ideal. I think I'll take your suggestions and try to implement them in a simple example (FBO + your simple vertex shader above) and then see if I can port it over to my game code. I need to move away from using glBegin()/glEnd() eventually anyway and move to vertex arrays or VBO's at some point too, but want to avoid a total re-write :)




0

Share this post


Link to post
Share on other sites
Ok, I took a quick shot at using an FBO instead of drawing and then copying it to a texture. I must be doing something wrong, because all I get is a white screen, but I don't get any errors, so I feel like I'm close. I haven't implemented shader stuff yet, but that's next.

Here's the code:

[url="https://gist.github.com/916742"]https://gist.github.com/916742[/url]

You can comment out the FBO binding in the draw method as well as the "drawTexturedQuad" function call, and you'll see the normal frame.
0

Share this post


Link to post
Share on other sites
There may be other issues as well, but for one thing you're not allowed to have a texture bound to a sampler at the same time you are writing to it, you'll get undefined behaviour. Unbind the texture from the sampler when you're writing to the framebuffer, and unbind the framebuffer when you're reading from the texture.

Once you start working with offscreen rendertargets, it's probably a good idea to go pick up a free copy of gdebugger, it will make your life a lot easier.

EDIT:

Also you have to bind the framebuffer to attach a texture to it:
[code]
glGenFramebuffers(1, &fbo_id);
glBindFramebuffer(GL_FRAMEBUFFER,fbo_id); //NEW
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex_id, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0); //NEW
[/code]
0

Share this post


Link to post
Share on other sites
[quote name='karwosts' timestamp='1302655344' post='4797728']
There may be other issues as well, but for one thing you're not allowed to have a texture bound to a sampler at the same time you are writing to it, you'll get undefined behaviour. Unbind the texture from the sampler when you're writing to the framebuffer, and unbind the framebuffer when you're reading from the texture.

Once you start working with offscreen rendertargets, it's probably a good idea to go pick up a free copy of gdebugger, it will make your life a lot easier.

EDIT:

Also you have to bind the framebuffer to attach a texture to it:
[code]
glGenFramebuffers(1, &fbo_id);
glBindFramebuffer(GL_FRAMEBUFFER,fbo_id); //NEW
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex_id, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0); //NEW
[/code]
[/quote]

Hmmm, I added that code, and added two lines to the draw method (to try not to have texture/fbo bound at the same time per your suggestion), but still same all-white screen. Perhaps I'm not doing it correctly though? I updated the gist with the new code in the draw method.
0

Share this post


Link to post
Share on other sites
For reference, I'm reading this article on FBO's:

[url="http://www.gamedev.net/page/resources/_//feature/fprogramming/opengl-frame-buffer-object-101-r2331"]http://www.gamedev.net/page/resources/_//feature/fprogramming/opengl-frame-buffer-object-101-r2331[/url]

The first thing they do in the article is create a renderbuffer for use as a depth buffer. Is this something I need to do as well? I would think I don't need depth information considering I'm doing everything in 2d...but then again I don't fully understand FBO's yet so...
0

Share this post


Link to post
Share on other sites
I'm pretty sure you don't need a depth attachment if you don't want one, you should be able to render fine to just a color attachment. Be sure to disable depth test and depth write though when drawing to the FB.
0

Share this post


Link to post
Share on other sites
[quote name='karwosts' timestamp='1302657944' post='4797741']
I'm pretty sure you don't need a depth attachment if you don't want one, you should be able to render fine to just a color attachment. Be sure to disable depth test and depth write though when drawing to the FB.
[/quote]


Is depth test enabled by default? I thought I would have to explicitly enable it with glEnable(GL_DEPTH_TEST). If I'm not doing that, should I have to worry about it?
0

Share this post


Link to post
Share on other sites
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);

This is a problem if you don't build mipmaps. If you're not using them, you have to set the minfilter to not use mipmapping (GL_LINEAR for example), otherwise it won't sample the texture.

[url="http://www.opengl.org/wiki/Common_Mistakes#Creating_a_Texture"]http://www.opengl.org/wiki/Common_Mistakes#Creating_a_Texture[/url]


Also this:
glGenFramebuffers(1, &fbo_id);
glBindFramebuffer(GL_FRAMEBUFFER, 1);

You probably meant to bind fbo_id, not "1". It may work but it is prone to breaking.

[quote]
Is depth test enabled by default? I thought I would have to explicitly enable it with glEnable(GL_DEPTH_TEST). If I'm not doing that, should I have to worry about it?
[/quote]

You're right, its disabled by default. You should be fine.
1

Share this post


Link to post
Share on other sites
Ok cool, I figured it out. It was partially the GL_MIN_TEXTURE_FILTER I was using as you mentioned, and partially the way I was binding/unbinding textures and FBO, etc.

This stackoverflow question helped a bit: [url="http://stackoverflow.com/questions/3466736/render-to-fbo-not-working-gdebugger-says-otherwise"]http://stackoverflow.com/questions/3466736/render-to-fbo-not-working-gdebugger-says-otherwise[/url]

And I've updated the gist new code: [url="https://gist.github.com/916742"]https://gist.github.com/916742[/url]

On to implementing my blur shader... :)
0

Share this post


Link to post
Share on other sites
Alright, I've tried to implement a blur shader with some gaussian blur code I found, but no luck.

I've updated the gist at [url="https://gist.github.com/916742"]https://gist.github.com/916742[/url], but the main problem is at line 274. The program always fails here with the message "linking with uncompiled shader". I can't seem to find much helpful online about this error, so if anyone has any ideas I'm all ears. I've included the shader source files at the bottom of the gist as well for reference.
0

Share this post


Link to post
Share on other sites
I'm still learning and using copy-pasted code from tutorials, so I have no idea if this is your problem, but here's the code I'm using to accomplish something similar:


[code]
myShader = glCreateProgramObjectARB();

myFragShader = glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
glShaderSourceARB(myFragShader,1,&myFragShaderSource,0);
glCompileShaderARB(myFragShader);
glAttachObjectARB(myShader, myFragShader);

glLinkProgramARB(myShader);[/code]


I notice that you create your vert and frag shaders using glCreateShader, whereas I use glCreateShader[b]Object[/b], and then attach that to the main shader program... Maybe this is it?
0

Share this post


Link to post
Share on other sites
I'm pretty sure glCreateShader is the right code. I've never even heard of glCreateShaderObject, and I can't find any documentation on it except for a couple blurbs from some powerpoint presentations from like 2002.

I'm going to guess that that's some extension that was around in the very early days of shading languages, but glCreateShader should be the correct way.
0

Share this post


Link to post
Share on other sites
[quote name='karwosts' timestamp='1302809812' post='4798523']
I'm pretty sure glCreateShader is the right code. I've never even heard of glCreateShaderObject, and I can't find any documentation on it except for a couple blurbs from some powerpoint presentations from like 2002.

I'm going to guess that that's some extension that was around in the very early days of shading languages, but glCreateShader should be the correct way.
[/quote]

I think you're right, a quick google for glCreateShaderObject doesn't seem to return anything useful. I'm still trying to figure out when to use the "*ARB" methods; it seems like you have to use some of them still, but most of the time I'm using the non-ARB methods.

I have a feeling it has something to do with the shader code, since I don't get that method if I change the fragment shader to a simple pass-through frag shader, but the results from the compile log for the gauss2.fs shader don't report anything wrong, so I'm kind of lost at this point.


0

Share this post


Link to post
Share on other sites
Oh yeah, should have tested... glCreateShaderObject isn't even defined in my environment.

glCreateShaderObjectARB is provided by GLEW I believe, and there's no glCreateShaderARB.

Replacing the call with plain "glCreateShader" produces the exact same result.
0

Share this post


Link to post
Share on other sites
Ok, so I've updated my gist with the working code: [url="https://gist.github.com/916742"]https://gist.github.com/916742[/url]

The main thing to notice is that the fragment shader has changed quite a bit: no more use of the "const" keyword, and no more initializing the offsets and gaussian kernel weights during the declaration (or even in loops). I'm not sure why I can't do that, but I'm guessing it's because my laptop is using an intel integrated graphics chip that doesn't support the most current GLSL language. That's the only thing I can guess, I've yet to test the old frag shader code on my desktop (which is nvidia).

Anyway, hopefully this helps someone else in the future.
0

Share this post


Link to post
Share on other sites
Just updated the [url="https://gist.github.com/916742#comments"]gist[/url] so that the texture offsets and kernel weights are calculated in the main program and then passed into the shader, since we should only have to calculate those once at the beginning of the program.
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 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
    • By afraidofdark
      I have just noticed that, in quake 3 and half - life, dynamic models are effected from light map. For example in dark areas, gun that player holds seems darker. How did they achieve this effect ? I can use image based lighting techniques however (Like placing an environment probe and using it for reflections and ambient lighting), this tech wasn't used in games back then, so there must be a simpler method to do this.
      Here is a link that shows how modern engines does it. Indirect Lighting Cache It would be nice if you know a paper that explains this technique. Can I apply this to quake 3' s light map generator and bsp format ?
  • Popular Now