Jump to content

  • Log In with Google      Sign In   
  • Create Account

We're offering banner ads on our site from just $5!

1. Details HERE. 2. GDNet+ Subscriptions HERE. 3. Ad upload HERE.


Don't forget to read Tuesday's email newsletter for your chance to win a free copy of Construct 2!


Whats a good 3d C++ class to represent a 3D mesh object ?


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
4 replies to this topic

#1 James   Members   -  Reputation: 122

Like
Likes
Like

Posted 14 October 1999 - 07:45 PM

Hi all,

I'm writing a simple geometry engine in c++ to work on top of OpenGL. As I began to lay down some code for the 3DObject class I was wondering if anyone had any experience writing one already and could give some ointers or even a sample class definition. e.g. something like the following ....

class C3DObject : CWorldObject
{
public:
C3DObject();
virtual ~C3DObject();

float* m_pfVertices;
unsigned int m_uiNumVertices;

float* m_pfNormals;
unsigned int m_uiNumNormals;

float* m_pfColours;
unsigned int m_uiNumColours;
};


Sponsor:

#2 Ake   Members   -  Reputation: 122

Like
Likes
Like

Posted 04 October 1999 - 06:36 AM

My object class looks alot like yours...
(Somebody please make the code font bigger)
code:

int m_iNumPolygons;
CPolygon *m_cPolygons;

int m_iNumVertices;
CVector *m_cVertices;
CVector *m_cVNormals;

D3DMATRIX m_tMatrix;
CVector m_cPosition;
CVector m_cAngle;
CTextureCoord *m_cTextureCoords;
CColor *m_cVertexColors;

int m_iTextureType;
int m_iShadingType;



I store texturecoords both in the polygons,
and in another array, I use the array when
I do environmentmapping.

Greetings Tobias

[This message has been edited by Ake (edited October 04, 1999).]


#3 aav   Members   -  Reputation: 122

Like
Likes
Like

Posted 04 October 1999 - 07:17 AM

I have a (for my application) more flexible approach, which is based on a "channel" system. Each Geometry object in my scene is requested every frame to return one or more PrimitiveSet objects. These objects contain various "channels" of per-vertex data:

WSG_XYZ
WSG_COLORn (0-15)
WSG_TEXCOORDn (0-15)
WSG_NORMAL

In addition, the PrimitiveSet has a few functions like ImmediatePrimitive() and
IndexedPrimitive() for specifying TRIANGLES, TRIANGLE_STRIPS, TRIANGLE_FANS etc.

Each PrimitiveSet is bound to a "shader" script, which determines which textures will be used, blending setup between texture layers and what texture coordinate channels to bind the images to. Etc etc.

I find this approach much more flexible than having a fixed class of a "3d" object, as each Geometry-based object has a more "API" based relation to the graphics engine.
YMMV.


#4 Anonymous Poster_Anonymous Poster_*   Guests   -  Reputation:

Likes

Posted 05 October 1999 - 04:03 PM

Heh, aav could have been describing the exact method I've used in my current project.

for a single stream the setup would be something like the following.(complete objects have 1 or more streams)

Surface* // specs textures/blends/procedural // functions
polytype // particles/tris/bezier patches
indices* // index array
verts* // vertex array
texverts** // pointer to texture coord arrays
// the number used is determined
// by the surface
normals* // normal array



#5 LordChaos   Members   -  Reputation: 122

Like
Likes
Like

Posted 14 October 1999 - 07:45 PM

Using C++ I've found it easier to use vectors
instead of pointer arrays - memory allocation/garbage collection is much easier...

As for the way I've implemented my class, check out my GLobs page

Basically I created an object class which contains vertexbins (ie polygons) and vertex vectors, the polygons using local referencing to get the polygon number..

That's a really bad description....check out the page for more..




Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS