• 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

3D free camera

5 posts in this topic

Hi folks,


i am using a SDK which is based on OpenGL ES and provides me a LookAt(from, to, up) function to construct a view matrix for camera.

What i want to achieve is implement a camera which can be moved freely using mouse (looking left/right and up/down) and keyboard (moving foreward/backwar and strafe left/right).

I initially set up the camera matrix with the required vectors (from, to, up) and need to maintain theses vectors while changing the camera orientation (mouse look).

Moving is easy, i can easily change camera location (from), up vector doesn't change.

What i need are code/calculations how to "maintain" the up/to vectors once camera orientation is changed.


any help welcome ;)



Share this post

Link to post
Share on other sites

"What i need are code/calculations how to "maintain" the up/to vectors once camera orientation is changed."


For a flycam, my recommendation is don't "maintain" the 'up' and 'to' vectors. Maintain heading and pitch angles and use them to construct your 'up' and 'to' vector.


I think this is correct, (but it's untested):


to = from + vector3(cosf(pitch) * sinf(heading), -sinf(pitch), cosf(pitch) * cosf(heading))

up = vector3(sinf(pitch)*sinf(heading), cosf(pitch), sinf(pitch)*cosf(heading));


Share this post

Link to post
Share on other sites

The "to" vector can be calculated by adding a small value to the camera position that will always be in front of the camera. You just transform the small vector by the camera matrix so its pointing in the correct direction then add it to the camera position, that can be your lookat position. Then you can do some cross products to calculate the correct "up" and "right" vectors.


Vector to(0,0,1);
to = cameraMatrix.TransformVector(to);
Vector lookat = cameraPosition + to;
Vector up(0,1,0);
Vector right = lookat.Cross(up);
up = lookat.Cross(right);

This link may also be useful to you for creating a free camera.

Edited by Nyssa

Share this post

Link to post
Share on other sites


I picked the idea of using the 2 angles "pitch" and "roll" and reconstruct the vectors each time from these 2  and used the equations @C0lumbo gave me and it worked well.


Share this post

Link to post
Share on other sites

I've still got one problem:

using the equations and rendering a quad with an image it seems that the rotation around z-axis is not right, because the image looks like to be rotated 90° to right (around z-axis).

So instead of rendering an image with arrow on it like this







its rendered like this:







Here is my camera (view matrix) update code:



float cos_pitch = cosf(pitch);
    float sin_pitch = sinf(pitch);
    float cos_roll = cosf(roll);
    float sin_roll = sinf(roll);

    _forward.x = cos_pitch * sin_roll;
    _forward.y = -sin_pitch;
    _forward.z = cos_pitch * cos_roll;

    _up.x = sin_pitch * sin_roll;
    _up.y = cos_pitch;
    _up.z = sin_pitch * cos_roll;

    _right = _up ^ _forward;    
    if (_right.IsZero())
        _right.x = 1.0f;
    _up = _forward ^ _right;    

    _view_mat.m[0][0] =  _right.x; _view_mat.m[0][1] = _right.y; _view_mat.m[0][2] =  _right.z;
    _view_mat.m[1][0] =  _up.x; _view_mat.m[1][1] =  _up.y; _view_mat.m[1][2] =  _up.z;
    _view_mat.m[2][0] =  _forward.x; _view_mat.m[2][1] =  _forward.y; _view_mat.m[2][2] = _forward.z;



and here is my quad rendering code:

// x,y,z : top left, verts go counter-clockwise
void RenderQuad(float x, float y, float z, float w, float h)
    static CIwFVec3 verts[4];
    verts[0] = CIwFVec3(x, y, z);
    verts[1] = CIwFVec3(x, y-h, z);
    verts[2] = CIwFVec3(x+w, y-h, z);
    verts[3] = CIwFVec3(x+w, y, z);
    IwGxSetVertStreamWorldSpace(s_Verts, 4);

    // texture-atlas 512x512 , image on tex-atlas at (0,0) -> (63,63)
    static CIwFVec2 uvs[4];
    uvs[0] = CIwFVec2(0.0f, 0.0f);
    uvs[1] = CIwFVec2(0.0f, 63.0f/512.0f);
    uvs[2] = CIwFVec2(63.0f/512.0f, 63.0f/512.0f);
    uvs[3] = CIwFVec2(63.0f/512.0f, 0.0f);

    static uint16 strips[4];
    strips[0] = 0;
    strips[1] = 1;
    strips[2] = 3;
    strips[3] = 2;
    IwGxDrawPrims(IW_GX_QUAD_STRIP, strips, 4);

Share this post

Link to post
Share on other sites

to sum it up:


this is my quad in 3D-space





    |      |

    |      |





this is renderd on screen




    |      |

    |      |



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
      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