• 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
irreversible

OpenGL
Picking a target GL/GLSL version

5 posts in this topic

My requirements currently are:

- OpenGL 2.0/GLSL 1.10 for core components, which also have to be blackboxed and portable, and have mostly to do with GUI drawing
- OpenGL 3.0 as the minimum version for some application components, but already have much of CPU emulation code written

Although both versions are quite old and wide-spread by now, there might be some people in my target audience who don't have 3.0 enabled cards. Since I do have CPU fallbacks for critical 3.0-dependent components (eg particle transform, bone animation, etc), the question boils down to deciding the minimum GLSL version - whether it can be 3.0 across the board or if it's worth keeping any blackboxed code using an older GLSL version.

Basically, I'm trying to [i]not [/i]assume there's a speed benefit for doing something in a newer version that can just as easily be done in an older version of GLSL, which kinds of begs the question - is there a compelling reason to force already encapsulated core components up a couple of version if the feature set doesn't really require it?

In short, the question is - is there a penalty to using GLSL 1.10 when a newer version is available (things like deprecated and sloppier compiler, direct speed disadvantages due to deprecation on driver level, possible [i]removal[/i] of older shader language versions by the Khronos group in the future, etc)?
0

Share this post


Link to post
Share on other sites
If the shader code is the same then in theory things should perform the same too. Newer GLSL versions [i]may[/i] be able to pull some optimizations in the shader compiler by e.g. compiling to new and (hopefully) more efficient instructions that weren't available in the old version, but that's a fairly low-level detail that you probably shouldn't worry about until your final optimization passes.

I find it slightly amusing that on the one hand you're trying not to assume something but yet on the other you're making a huge assumption, specifically: "[i]there might be some people in my target audience who don't have 3.0 enabled cards[/i]". That's not intended as a personal criticism, but is intended to call it out as an assumption; I'd strongly advise that you research and profile your target audience before committing to anything based on that assumption.
1

Share this post


Link to post
Share on other sites
[quote name='mhagain' timestamp='1354616535' post='5007027']
I find it slightly amusing that on the one hand you're trying not to assume something but yet on the other you're making a huge assumption, specifically: "[i]there might be some people in my target audience who don't have 3.0 enabled cards[/i]". That's not intended as a personal criticism, but is intended to call it out as an assumption; I'd strongly advise that you research and profile your target audience before committing to anything based on that assumption.
[/quote]
Yet, [i]"there might be some people in my target audience who don't have 3.0 enabled cards"[/i] is not really an assumption, is it?
I'd say it's actually very open-minded to consider that something might be true.

... But aside from that, I use as old a version as possible, test on more machines, different cards,
and then static link to GL and the extensions I use, to avoid referring to deprecated, later maybe even gone OpenGL functionality in an external binary. Edited by SuperVGA
0

Share this post


Link to post
Share on other sites
[quote name='SuperVGA' timestamp='1354618993' post='5007037']
I'd say it's actually very open-minded to consider that something might be true.
[/quote]

It's open-minded to consider it for sure, but that should be followed by research and a decision made based on actual facts, not suppositions.
0

Share this post


Link to post
Share on other sites
[quote name='mhagain' timestamp='1354621299' post='5007041']
[quote name='SuperVGA' timestamp='1354618993' post='5007037']
I'd say it's actually very open-minded to consider that something might be true.
[/quote]

It's open-minded to consider it for sure, but that should be followed by research and a decision made based on actual facts, not suppositions.
[/quote]
Ah, ok. I see what you meant now; it's because even the thought was taken out of the blue, and a choice should be founded on something regardless of whether it's open-minded or not.
For instance, he should have found that ok, only 2‰ of my audience lacks 3.0 enabled cards, and that amount is declining, -then made a decision.
Alright, back to the topic. Pardon my stray into assumption/nonassumptions. Edited by SuperVGA
0

Share this post


Link to post
Share on other sites
True, I'm basing my assumptions on a few things that I don't even know how to profile. In my case I can't really look at something like the Steam hardware statistics report, because I want to target older systems that are there (which in itself would be a kind of an answer to my question): in particular, desktop systems. So I'm basing my assumptions on a very limited dataset of people that I know. While a valid criticism, this is somewhat moot, though - in particular, because my question was actually worded the other way around: instead of "will upgrading my GL requirements limit my audience" I was asking "whether not upgrading could bite me in the butt at a later date" :)

A lot of stuff in GLSL 1.1 and 1.2 were deprecated with the introduction on 1.3, most (or all?) of which is now available in compatibility mode. I'm trying to leverage between two paradigms here: a valid justification of adhering to a new standard and my admittedly poor assumption that doing so will affect my target audience.
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 mapra99
      Hello

      I am working on a recent project and I have been learning how to code in C# using OpenGL libraries for some graphics. I have achieved some quite interesting things using TAO Framework writing in Console Applications, creating a GLUT Window. But my problem now is that I need to incorporate the Graphics in a Windows Form so I can relate the objects that I render with some .NET Controls.

      To deal with this problem, I have seen in some forums that it's better to use OpenTK instead of TAO Framework, so I can use the glControl that OpenTK libraries offer. However, I haven't found complete articles, tutorials or source codes that help using the glControl or that may insert me into de OpenTK functions. Would somebody please share in this forum some links or files where I can find good documentation about this topic? Or may I use another library different of OpenTK?

      Thanks!
    • 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
  • Popular Now