How about 3D drawing procedures
lazarus / 7-LCL

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Danail · 2006-07-03 10:12

It would be nice to develope a component or an unit with calculations
for making 3D graphics. If it is an unit it will be the procedures
that will calculate the x, y and z coordinates of a point, and their x
and y coordinates on the screen, which can be applied for all pixels
needed in futura projects, and if it is a component maybe to be
something like an image component that to have build in procedures for
drawing 3d lines and 3d pixels, maybe its name can be 3d canvas for
example... I think that the idea is nice and even though I don't
understand much from 3D graphics, I am agree even to take part of the
creating the unit or component if noone else wants and when I have
time to do this. I know how to make an unit that to be used in the
uses section later, however I don't know how to make components and I
don't much understand from 3d graphics. My email is:
Danail_Angelov@Yahoo.com if you have any idea how such component to be
made, or how exactly are these calculated, and how I can start it here
in lazarus project so on anyone to be able to develope it please email
me or answer here. Thanks in regards. Danail.

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CCRDude · 2006-07-03 10:50

I would make a unit, not a component. Components are mostly for use in
combination with forms, but this would be something more abstract in
the first place. Maybe later a display component as an example...

Making a unit isn't that complicated... just fill in the maths:

Code: [Select]unit Unit1;

{$IFDEF FPC}
{$mode objfpc}{$H+}
{$ENDIF FPC}

interface

uses
  Classes, SysUtils;

type
   T3DPoint = record
      X, Y, Z: integer;
   end;

   { TCoordCalc }

   TCoordCalc = class
   private
     FCameraPos: T3DPoint;
     FViewPoint: T3DPoint;
   public
      procedure Coords3Dto2D(AX, AY, AZ: integer; var BX, BY:
integer);
      property CameraPos: T3DPoint read FCameraPos write FCameraPos;
      property ViewPoint: T3DPoint read FViewPoint write FViewPoint;
   end;


procedure SimpleCoords3Dto2D(AX, AY, AZ: integer; var BX, BY:
integer);

implementation

procedure SimpleCoords3Dto2D(AX, AY, AZ: integer; var BX, BY:
integer);
begin
   BX := somethingdependingon(AX, AY, AZ);
   BY := somethingdependingon(AX, AY, AZ);
end;

{ TCoordCalc }

procedure TCoordCalc.Coords3Dto2D(AX, AY, AZ: integer; var BX, BY:
integer);
begin
   BX := somethingdependingon(AX, AY, AZ, FCameraPos);
   BY := somethingdependingon(AX, AY, AZ, FViewPoint);
end;

end.

Well, that's still very basic of course, just something to get started
with the unit

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Danail · 2006-07-03 11:39

Thanks CCRDude. Well, lets start together to do the unit. Maybe lated
there will be and others who will join us. I managed to understand
some things about the 3d points and their coordinates. They are being
calculated with the use of matrixces. I have some of them - for the
rotation and the converting of 3d point with x, y and z coordinate to
2d coordinate with x and y positions for the screen. I think that we
are ready to start and create an Unit with the first sample procedure
for converting the x, y and z coordinates into x and y coordinates.
How to make our unit possible for all volunteers to develope it?

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CCRDude · 2006-07-03 14:09

Well, I just gave you the frame, I don't really have time for this
with half a dozen other more important things to write

Complete the basic function, write a small demo showing it, and post
it on the Wiki as an example would be my suggestion.