• 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.

Archived

This topic is now archived and is closed to further replies.

Dwarf with Axe

OpenGL
Last post about 2D in OpenGL (so please stop!)

34 posts in this topic

Are you guys just lazy!? There have been thousands of posts along the lines of "How do I do 2d in OpenGL" to "Duuuhde, I wunt too maek a two dee gaem in ohpun jee el; how do eye set uhp two dee???!?" I have developed a simple, nice, pretty way for all of you to have your 2D fun.
  
void glEnable2D()
{
	int vPort[4];

   glGetIntegerv(GL_VIEWPORT, vPort);

   glMatrixMode(GL_PROJECTION);
   glPushMatrix();
   glLoadIdentity();

   glOrtho(0, vPort[2], 0, vPort[3], -1, 1);
   glMatrixMode(GL_MODELVIEW);
   glPushMatrix();
   glLoadIdentity();
}

void glDisable2D()
{
   glMatrixMode(GL_PROJECTION);
   glPopMatrix();   
   glMatrixMode(GL_MODELVIEW);
   glPopMatrix();	
}

  
To use these two functions, simply call glEnable2D(), draw whatever you want to have 2D''d, then call glDisable2D(). Here''s an example:
  
void RenderScene()
{
  glClear(GL_COLOR_BUFFER_BIT| GL_DEPTH_BUFFER_BIT);
  glLoadIdentity();
  
  glEnable2D();
    glBegin(GL_TRIANGLES);
      glColor3ub(255, 0, 0);
        glVertex2d(0, 0);
      glColor3ub(0, 255, 0);
        glVertex2d(100,0);
      glColor3ub(0, 0, 255);
        glVertex2D(50, 50);
    glEnd();
  glDisable2D();
}
  
See? Nice and small; Nice and simple. So please friends, don''t ask how to setup OpenGL in 2D mode... Because now you know. ~Jesse Lawson
2

Share this post


Link to post
Share on other sites
This was just a way for me to simply say that there is an alternative to asking a question that someone else has already asked. So happy happy joy joy man!

Yeah baby, yeahhhh..
~ Jesse
0

Share this post


Link to post
Share on other sites
The best thing to do is store this message URL for further reference.

And then cut and paste.


ZoomBoy
Developing a iso-tile 2D RPG with skills, weapons, and adventure. See my old Hex-Tile RPG GAME, character editor, diary, 3D Art resources at Check out my web-site
0

Share this post


Link to post
Share on other sites
Lol! Dwarf, this is a legendary thread dude.

Im actually about to start a 2D game in OGL, but Im not up to doing the graphics (actually still in design ATM), but your post means I don''t have to look up MSDN.

I''ve bookmarked this thread and I''ll recommend it for anyone else who posts asking how to do 2D in OpenGL.

Henrym
My Site
0

Share this post


Link to post
Share on other sites
Well thanks everyone. I''m glad this can help BTW! My new project (as of last month really) is gl2d, a site dedicated to 2D Game Development in OpenGL.

You can check it out at http://www.jesse.luethy.net, or click here

I hope many can benefit from it, and have fun!
~ Jesse

OpenGL_2D Project
0

Share this post


Link to post
Share on other sites
Great functions man. Thanks ALOT, now I don''t have to spend weeks working out how to do this.
0

Share this post


Link to post
Share on other sites
quote:
Original post by Khawk
I added it to the forum FAQ. Now you just have to point people there.




People actually read that? The link to the FAQ should be half the size of the screen and say: "Read the FAQ or i will come to your house and eat your children." that should make it more effective.


Oh and Dwarf with Axe: how about some code for quad and rendering arbitrary sized bitmaps?
1

Share this post


Link to post
Share on other sites
People need to ask about this kind of thing?! wow... My opinion of humanity just dropped down a notch.
0

Share this post


Link to post
Share on other sites
something (probably very easy) i couldn''t figure out is how to draw things in ortho using the default (float) cartesian space instead of using pixels...

Does somebody knows how to do it?
0

Share this post


Link to post
Share on other sites
quote:
Original post by Ilici
The link to the FAQ should be half the size of the screen and say: "Read the FAQ or i will come to your house and eat your children." that should make it more effective.


Probably wouldn''t work so well. People who can''t find the FAQ are usually newbies. Newbies tend to be kids. Kids don''t have children.

How about "Read the FAQ or i will send a hideous winged deamon to haunt you and scare away the chicks, so that you''ll NEVER lose you virginity. MUHAHAHAH!"? Hmmm, not very catchy either
0

Share this post


Link to post
Share on other sites
quote:
Original post by owl
something (probably very easy) i couldn''t figure out is how to draw things in ortho using the default (float) cartesian space instead of using pixels...

Does somebody knows how to do it?


Use gluOrtho2D(0,1,0,1); to set up the proj matrix.

--------------------------------------------------------
Life would be so much easier if we could just get the source code.
0

Share this post


Link to post
Share on other sites
OpenGL can just be annoying with 2D stuff. Things being a pixel off; it being a pixel off in various implementations, etc. is just irritating and is one reason I put my engine on hold. Also, the OpenGL PixelCopy functions are ridiculously slow.

I get the impression that things like that are more of a problem than setting up a window (although that can confuse people too)...
0

Share this post


Link to post
Share on other sites
Thanks from the bottom of my heart for making this thread sticky ...

If I ever see one more "how do I place a font/bitmap/jpg/HUD/tilebased/whateva on the screen in 2D" thread I''m leaving for Vegas
0

Share this post


Link to post
Share on other sites
The thing is sometimes stuff is a pixel off if you use a textured quad and if you use PixelCopy, you get HORRIBLE performance. So actually, sometimes questiuons can be reasonable.
0

Share this post


Link to post
Share on other sites
quote:
Original post by Puzzler183
Also, the OpenGL PixelCopy functions are ridiculously slow.



You mean glReadPixels? Yes, it''s slow, but it''s not necesseraly OpenGL''s fault. The AGP bus is optimized for writing to the Video memory, not retrieving data from it so reading back pixels, which requires the driver to lock the framebuffer in video memory and send data back on the bus to system memory is slow. If you want software rendering, i think MesaGL is what you are looking for.

0

Share this post


Link to post
Share on other sites
lol, i have almost the same exact functions in my game for drawing 2D UI stuff

- Voxelz
0

Share this post


Link to post
Share on other sites
Great Job on the sticky.

One thing though - On the implementation example, can you change the last "glVertex2D(50, 50);" to "glVertex2d(50, 50);" so newbies like me won''t have to use their brains.
0

Share this post


Link to post
Share on other sites
The same, essentially, except in lwjgl/java.

Haven''t tested it yet, but it compiles, so here it is. Licenced the same as the original.

(I was working on my snippet library and wanted to add this back to where it came from)


import org.lwjgl.opengl.GL11;

public final class OpenGL2D extends java.lang.Object {
public static void glEnable2D() {
java.nio.IntBuffer vPort = java.nio.IntBuffer.allocate(4);
GL11.glGetInteger(GL11.GL_VIEWPORT, vPort);
GL11.glMatrixMode(GL11.GL_PROJECTION);
GL11.glPushMatrix();
GL11.glLoadIdentity();
GL11.glOrtho(0, vPort.get(2), 0, vPort.get(3), -1, 1);
GL11.glMatrixMode(GL11.GL_MODELVIEW);
GL11.glPushMatrix();
GL11.glLoadIdentity();
}
public static void glDisable2D() {
GL11.glMatrixMode(GL11.GL_PROJECTION);
GL11.glPopMatrix();
GL11.glMatrixMode(GL11.GL_MODELVIEW);
GL11.glPopMatrix();
}
}
0

Share this post


Link to post
Share on other sites
Also, if you want to be able to access the screen in floating-point with the left side being -1.0 and the top being -1.0 (bottom and right still 1.0), you can do:

gluOrtho2D( 0.0, 0.0, 1.0, 1.0 );

[Edited by - fyhuang on August 31, 2005 11:25:03 AM]
0

Share this post


Link to post
Share on other sites

  • Similar Content

    • By Toastmastern
      So it's been a while since I took a break from my whole creating a planet in DX11. Last time around I got stuck on fixing a nice LOD.
      A week back or so I got help to find this:
      https://github.com/sp4cerat/Planet-LOD
      In general this is what I'm trying to recreate in DX11, he that made that planet LOD uses OpenGL but that is a minor issue and something I can solve. But I have a question regarding the code
      He gets the position using this row
      vec4d pos = b.var.vec4d["position"]; Which is then used further down when he sends the variable "center" into the drawing function:
      if (pos.len() < 1) pos.norm(); world::draw(vec3d(pos.x, pos.y, pos.z));  
      Inside the draw function this happens:
      draw_recursive(p3[0], p3[1], p3[2], center); Basically the 3 vertices of the triangle and the center of details that he sent as a parameter earlier: vec3d(pos.x, pos.y, pos.z)
      Now onto my real question, he does vec3d edge_center[3] = { (p1 + p2) / 2, (p2 + p3) / 2, (p3 + p1) / 2 }; to get the edge center of each edge, nothing weird there.
      But this is used later on with:
      vec3d d = center + edge_center[i]; edge_test[i] = d.len() > ratio_size; edge_test is then used to evaluate if there should be a triangle drawn or if it should be split up into 3 new triangles instead. Why is it working for him? shouldn't it be like center - edge_center or something like that? Why adding them togheter? I asume here that the center is the center of details for the LOD. the position of the camera if stood on the ground of the planet and not up int he air like it is now.

      Full code can be seen here:
      https://github.com/sp4cerat/Planet-LOD/blob/master/src.simple/Main.cpp
      If anyone would like to take a look and try to help me understand this code I would love this person. I'm running out of ideas on how to solve this in my own head, most likely twisted it one time to many up in my head
      Thanks in advance
      Toastmastern
       
       
    • By fllwr0491
      I googled around but are unable to find source code or details of implementation.
      What keywords should I search for this topic?
      Things I would like to know:
      A. How to ensure that partially covered pixels are rasterized?
         Apparently by expanding each triangle by 1 pixel or so, rasterization problem is almost solved.
         But it will result in an unindexable triangle list without tons of overlaps. Will it incur a large performance penalty?
      B. A-buffer like bitmask needs a read-modiry-write operation.
         How to ensure proper synchronizations in GLSL?
         GLSL seems to only allow int32 atomics on image.
      C. Is there some simple ways to estimate coverage on-the-fly?
         In case I am to draw 2D shapes onto an exisitng target:
         1. A multi-pass whatever-buffer seems overkill.
         2. Multisampling could cost a lot memory though all I need is better coverage.
            Besides, I have to blit twice, if draw target is not multisampled.
       
    • 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));  
  • Popular Now