• 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
blueshogun96

OpenGL
glOrtho not working?

7 posts in this topic

I started writing a totally new OpenGL  game for iOS a few days ago, and I cannot get 2D working to save my life.  3D works fine (using a customized implementation of gluPerspective), but 2D just won't.  I've done a 2D game for iOS before, and I didn't have any problems.  Now, no matter what I do, nothing renders.

 

My code:

 

Initialization:

// 2. Create a Context
    EAGLContext *context = [[[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1] autorelease];
    [EAGLContext setCurrentContext:context];
    
    // 3. Create a View
    GLView *glView = [[[GLView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)] autorelease];
    [self.view addSubview:glView];
    
    // 4. Create a Renderbuffer
    GLuint renderbuffer;
    glGenRenderbuffers(1, &renderbuffer);
    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
    [context renderbufferStorage:GL_RENDERBUFFER fromDrawable:(CAEAGLLayer*)glView.layer];
    
    // 5. Create a Framebuffer
    GLuint framebuffer;
    glGenFramebuffers(1, &framebuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8_OES, 320, 480 );
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffer);
    
    GLuint depthBuffer;
    glGenRenderbuffers( 1, &depthBuffer );
    glBindRenderbuffer( GL_RENDERBUFFER, depthBuffer );
    glRenderbufferStorage( GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, 320, 480 );
    glFramebufferRenderbuffer( GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthBuffer );
    
    glBindRenderbuffer( GL_RENDERBUFFER, renderbuffer );
    
    GLenum status = glCheckFramebufferStatus( GL_FRAMEBUFFER );
    if( status != GL_FRAMEBUFFER_COMPLETE )
    {
        NSLog( @"Error completing FBO! %x", status );
    }
    
    glEnable( GL_DEPTH_TEST );
    glDepthFunc( GL_LEQUAL );
    glClearDepthf( 1.0f );
    
    glDisable( GL_CULL_FACE );
    glDisable( GL_LIGHT0 );

 

 

Rendering:

-(void) drawView:(id)sender
{
    glViewport( 0, 0, 320, 480 );
    glMatrixMode( GL_PROJECTION );
    glOrthof( 0, 320, 0, 480, -1, 1);
    
    glClearColor( 0.0f, 0.5f, 0.0f, 1.0f );
    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
    glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();
  
    draw_quad( 0, 50, 50, 300, 300 );
    
    [[EAGLContext currentContext] presentRenderbuffer:GL_RENDERBUFFER];
}

void draw_quad( GLuint texture, float x, float y, float w, float h )
{
	float vertices[] = { x, y, x+w, y, x+w, y+h, x, y+h };
	float tex[] = { 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f };

	glBindTexture( GL_TEXTURE_2D, texture );

	glTexCoordPointer( 2, GL_FLOAT, 0, tex );
	glVertexPointer( 2, GL_FLOAT, sizeof(float)*2, vertices );
	glDrawArrays( GL_TRIANGLE_FAN, 0, 4 );

	spf++;
}

 

Majority of this code I'm reusing, but I don't see what the problem is.  Arrgh, iOS is a complete NIGHTMARE to work with (problems at every corner for me).  I hate to say it, but PS2 was more straight forward than iOS.  This really sucks.  Any ideas?  Thanks.

0

Share this post


Link to post
Share on other sites

OpenGL/OpenGL ES are the pain, not iOS.  Bind-to-modify is a design flaw from the early 90’s that they have refused to fix for compatibility reasons.

Your own headaches are compounded by the fact that you are using OpenGL ES 1.0 instead of OpenGL ES 2.0.  Learning how to handle OpenGL’s quirks, such as modifying your lighting system to deal with the fact that they modify the lights you set by the current model-view matrix, and only once (sigh), is a lot harder than learning shaders.  No joke.

 

Anyway, firstly you need to disable lighting.  You didn’t call ::glDisable( GL_LIGHTING ).

 

Secondly, you should be glad you are on iOS because there is a large toolset to help you debug this.

Firstly, only code using a real device.  This is a simple fact of life.

Secondly, once you are on a real device, you can take a screenshot and step through to see what is happening.

 

 

L. Spiro

0

Share this post


Link to post
Share on other sites

OpenGL/OpenGL ES are the pain, not iOS.  Bind-to-modify is a design flaw from the early 90’s that they have refused to fix for compatibility reasons.

Your own headaches are compounded by the fact that you are using OpenGL ES 1.0 instead of OpenGL ES 2.0.  Learning how to handle OpenGL’s quirks, such as modifying your lighting system to deal with the fact that they modify the lights you set by the current model-view matrix, and only once (sigh), is a lot harder than learning shaders.  No joke.

 

Anyway, firstly you need to disable lighting.  You didn’t call ::glDisable( GL_LIGHTING ).

 

Secondly, you should be glad you are on iOS because there is a large toolset to help you debug this.

Firstly, only code using a real device.  This is a simple fact of life.

Secondly, once you are on a real device, you can take a screenshot and step through to see what is happening.

 

 

L. Spiro

I beg to differ.  I've never had any serious problems out of OpenGL until I started on iOS.  I'm using OpenGL ES 1.1 simply because I don't have an OpenGL ES 2.0 compatible iOS device (can't afford one atm).  I tried disabling lighting with glDisable( GL_LIGHTING ); still doesn't work.  Even when I got 3D working, it didn't make a difference.  And whether I use a real device or the simulator, I get the same results.  I still don't see what I'm doing wrong here.

0

Share this post


Link to post
Share on other sites

The same code on any other device will yield the same results.  The problem is your code, not iOS.

And I told you to use a real device for debugging purposes.

I told you to Capture an OpenGL ES Frame.

As in, run the project on a real device, go to Xcode, select Product->Debug->Capture OpenGL ES Frame.

Now you can single-step through every OpenGL ES call, or just the render calls, and see everything about the context and look for what could be wrong.

 

Look:

frame_capture.png

 

You should count your blessings that you are on iOS.  There is no such feature on Android™.

If you can’t figure it out on your own after doing this, go to the draw call that you think should be drawing a quad and post a screenshot.

 

 

L. Spiro

Edited by L. Spiro
1

Share this post


Link to post
Share on other sites

Here's your problem:

 

    glMatrixMode( GL_PROJECTION );
    glOrthof( 0, 320, 0, 480, -1, 1);

 

glOrtho doesn't load the generated ortho matrix onto the stack; what it does is take the current matrix and multiplies it by the generated ortho matrix (http://www.khronos.org/opengles/sdk/1.1/docs/man/).  So instead you do:

 

    glMatrixMode( GL_PROJECTION );
    glLoadIdentity ()
    glOrthof( 0, 320, 0, 480, -1, 1);

 

And it works!

Edited by mhagain
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 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