TheGameCreators - CodeBase - 3D world using 2D commands

Category: Complete Applications

Version: 1.0

Information

Uploaded: 20th Jul 2007 17:16

Modified: 29th Jul 2007 18:53

Author: Libervurto

Summary

This program uses perspective to simulate three dimensions while only using 2D commands. WARNING: THIS IS NOT ACCURATE 3D, IT IS MERELY IMITATING PERSPECTIVE. CONTROLS LEFT/RIGHT - Moves the cube along the X-Axis UP/DOWN - Moves the cube along the Y-Axis SHIFT/CONTROL - Moves the cube along the Z-Axis

Full Description

DarkBASIC Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

remstart

--------------------------------

THREE DIMENSIONS IN A 2D WORLD

--------------------------------

The main obstacle for creating a 3D world on a 2D screen is obvious; the screen is 2D! There is no depth.

So how do we create a third dimension? We need to add perspective. Perspective can be at any angle but for this

example I am using the most simple, 1:1 (X:Y). To understand what this means, think of the classic 2D drawing

of a cube. The cube is made up of 2 offset squares and four diagonal connecting lines.

{image}

Because this is a cube, we know that all lines MUST be equal in length, but in the drawing the connecting lines

are half the length of the others. This is because of perspective (1:1), half of the cube's depth was added

to the X axis, and the other half added to the Y axis, resulting in a perfectly diagonal line.

Now let's take this on another step. Lets use our cube as the boundaries to our 3D world, and lets now try and

imagine how another 3D object would be displayed in this world.

Firstly, it would be positioned according to its X and Y position, and then these would both be increased by

half its Z position. So by moving the object towards and away from us, its really travelling along a diagonal

line, left/down and right/up.

remend

`--------------------------------

` SETUP

`--------------------------------

`world Boundaries

Wx1 = 15 : Wx2 = 320

Wy1 = 200 : Wy2 = 30

Wz1 = 0 : Wz2 = 160

`Cube position

Cx = 0+Wx1

Cy = 0+Wy1

Cz = 0+Wz1

`Cube volume

Cvx = 10

Cvy = 10

Cvz = 5 : `half actual size for simplicity (no need to divide by 2)

`--------------------------------

` MAIN LOOP

`--------------------------------

sync on

cls

gosub Axis

gosub Cube

gosub control

gosub bind_cube

sync

LOOP

`--------------------------------

` GOSUBS

`--------------------------------

axis:

`x-line

ink rgb(255,0,0),0

line 15,200,320,200

`y-line

ink rgb(0,255,0),0

line 15,200,15,20

`z-line (X+Y/2)

ink rgb(0,0,255),0

line 15,200,160,55

RETURN

`------

cube:

ink rgb(255,255,255),0

`* FG Square

`Fore Bottom Horizontal

line (Cx+Cz),(Cy-Cz), (Cx+Cz)+Cvx,(Cy-Cz)

`Fore Top Horizontal

line (Cx+Cz),(Cy-Cz)-Cvy, (Cx+Cz)+Cvx,(Cy-Cz)-Cvy

`Fore Left Vert

line (Cx+Cz),(Cy-Cz), (Cx+Cz),(Cy-Cz)-Cvy

`Fore Right Vert

line (Cx+Cz)+Cvx,(Cy-Cz), (Cx+Cz)+Cvx,(Cy-Cz)-Cvy

`* BG Square

`Fore Bottom Horizontal

line (Cx+Cz)+Cvz,(Cy-Cz)-Cvz, (Cx+Cz)+Cvx+Cvz,(Cy-Cz)-Cvz

`Fore Top Horizontal

line (Cx+Cz)+Cvz,(Cy-Cz)-Cvy-Cvz, (Cx+Cz)+Cvx+Cvz,(Cy-Cz)-Cvy-Cvz

`Fore Left Vert

line (Cx+Cz)+Cvz,(Cy-Cz)-Cvz, (Cx+Cz)+Cvz,(Cy-Cz)-Cvy-Cvz

`Fore Right Vert

line (Cx+Cz)+Cvx+Cvz,(Cy-Cz)-Cvz, (Cx+Cz)+Cvx+Cvz,(Cy-Cz)-Cvy-Cvz

`* Connectors

`LB

line (Cx+Cz),(Cy-Cz), (Cx+Cz)+Cvz,(Cy-Cz)-Cvz

`RB

line (Cx+Cz)+Cvx,(Cy-Cz), (Cx+Cz)+Cvx+Cvz,(Cy-Cz)-Cvz

`LT

line (Cx+Cz),(Cy-Cz)-Cvy, (Cx+Cz)+Cvz,(Cy-Cz)-Cvy-Cvz

`RT

line (Cx+Cz)+Cvx,(Cy-Cz)-Cvy, (Cx+Cz)+Cvx+Cvz,(Cy-Cz)-Cvy-Cvz

`* Y height line (ground up)

ink rgb(0,255,0),0

line (Cx+Cz)+(Cvx/1.6),(Wy1-Cz)-(Cvy/1.6), (Cx+Cz)+(Cvx/1.6),(Cy-Cz)-(Cvy/1.6)

RETURN

`------

control:

if rightkey() = 1 then inc Cx,2

if leftkey() = 1 then dec Cx,2

if upkey() = 1 then dec Cy,2

if downkey() = 1 then inc Cy,2

if shiftkey() = 1 then inc Cz,1

if controlkey() = 1 then dec Cz,1

RETURN

`------

bind_cube:

if Cx < Wx1 then Cx = Wx1

if Cx > Wx2 then Cx = Wx2

if Cy > Wy1 then Cy = Wy1

if Cy < Wy2 then Cy = Wy2

if Cz < Wz1 then Cz = Wz1

if Cz > Wz2 then Cz = Wz2

RETURN

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Author Name:	Libervurto
CodeBase Entries:	11

CodeBase - 3D world using 2D commands

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DarkBASIC Source Code

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