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jagguy2

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About jagguy2

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  1. jagguy2

    find Y value

    how do i get scalar constant? say I am moving over this plane with normalized vec (0, .707, -.707) A(0,0,0) B(200,0,0) C(200,71,71) D(0,71,71) I start at 0,0,0 and I want to move forward 10 along z axis to 10 my x val is =0 but my Y val =?
  2. jagguy2

    find Y value

    If I have the normal vector of a rectangular surface and the coordinates of each vertex. Can I work out the Y value of the surface given x,z value? Say I have a right angled triangle shape and the surface I am, talking about is the longest side . Can I find the point on the surface given x and z so I would need to find Y somehow?
  3. jagguy2

    normals to a plane

    thanks for the help speaking of just a vector what confuses me is the concept of vector has a direction. It is just a 3D point and we are saying it also points to a direction. how do we know what direction it points at because a point on x,y,z could point in any direction theoretically
  4. jagguy2

    normals to a plane

    what has happened is that I am using away3D. z axis has positive values into the screen and negative values out of the screen. so will switching the order in which you do the cross product solve this?
  5. jagguy2

    normals to a plane

    (0,-14200,14200) is normal so normalize i get 20081 = normalize factor (0, -.707, .707) now since y value is negative the normal points down but i want it to point up dont I out of the surface?
  6. jagguy2

    normals to a plane

    let me see if i have this right i will find the suface that is on a slope for right angled triangle 3d Shape (the longest side). now the slope is at a 45 deg angle . 4 points around this rectangle surface is A(0,0,0) B(200,0,0) C(200,71,71) D(0,71,71) V1 vector1= B - A (200,0,0) V2 vector2=C - A (200,71,71) cross product vector1 X vector2 cross product x= v1.y X v2.z - v1.zX v2.y = 0X71 - 71X0= 0 cross product y= - (( v2.z X v1.x) - (v2.x X v1.z)) = - 71X200 -0= -14200 cross product z= v1.x X v2.y - v1.y X v2.x= 14200 (0,-14200,14200) is normal is this correct?
  7. jagguy2

    normals to a plane

    hi, I have a 3D shape which is a right angles triangle shape. Like a bike ramp. I have an object that moves up the ramp. What I need to know is given an x,y,z point how do i know if this point will be inside or outside this 3D object. I really need to know if this point is just touching the ramp. maybe easiest to see the mathematics
  8. jagguy2

    straight line collisions

    here is my worked example say I have 2 endpoints of a line x1(10,10,10) and x2(10,10,20) and i have a point x0(15,10,15). I want to know distance of the point x0 from the line x1 to x2 from 10) http://mathworld.wolfram.com/Point-LineDistance3-Dimensional.html d=(5,0,-5)X(5,0,-5) / (0,0,10) cross product numerator http://en.wikipedia.org/wiki/Cross_product gives (0,50,0)/(0,0,10) and now what because I need a single value?
  9. jagguy2

    straight line collisions

    It is a 3D collision but on a x/z axis the missile moves a certain amount of pixels per frame. I can collide by simply calculating the postion of the missile and object to hit. I am not sure what you mean by your 2) although it sounds interesting. basically I have 2 points in x,y,z space which is the missile line. I have a point eg middile of object to hit. I need to caculate the how close this point is to the line
  10. I have a 3D game where I shoot a missile forward about 200px at a time. some objects in the missile path are smaller than 200px wide. I can test for collisions every 50px but is there another algorithm to I could use?
  11. jagguy2

    repeating background

    I am not seeing how this works exactly. the texture could go over all the shapes and only a few parts of the trach should be displayed at once and then keep swapping? each part of the track has its own texture in place. This is what I rrad.
  12. jagguy2

    repeating background

    In 3D how do you do repeating backgrounds? The issues of displaying a road for example in a car race (just straight head track with a few curves. NOt a loop.
  13. jagguy2

    3D camera clipping

    I am using away3D and actionscript3. What are the 3D concepts where objects are clipped/not clipped when out of view. I am having problems finding this for away3D. MY issue is when I move the camera forward , objects move behind me and out of view. If an object is only partly displayed (1/3 in view) it seems to just vanish when the camera is moved forward without displaying the rest of the image.
  14. jagguy2

    3D camera

    moved beginner
  15. jagguy2

    3D collisions

    I am still confused about how ray plane intersection works for 3D objects like a missile and building or walking into a solid object. I am needed it for a computer game but i prefer to understand the mathmatics first. I think the issue is that I need an example with real coodinates.
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