TheGameCreators - CodeBase - draw curved road function

Category: Basic 3D

Version: 1.0

Information

Uploaded: 26th Mar 2007 03:15

Modified: 1st Jan 1970 01:00

Author: Visigoth

Summary

simple function to create curved road segments by using triangle objects. You can set radius of turn, angle of turn, width of road, and segments per section (resolution)

Full Description

by just typing in this:<br /> drawroad(1,xcenter,ycenter,300,400,16,180,prevangle,trianglecount)<br /> would create a 180 degree curved section of road with a width of 10 units (the difference between the inside radius and the outside radius), using 16 segments, each segment is 2 triangles, so 32 triangles total. The more segments, the smoother the turn. 8 segments per 90 degrees seems to work good. You can play with the z values inside the function where the triangles are drawn. They are all set to zero, but it is totally possible to change them and make banked turns or dips and hills.

DarkBASIC Professional Source Code

` This code was downloaded from The Game Creators

` It is reproduced here with full permission

` http://www.thegamecreators.com

REM Project: Curved Roads Function

REM Created: 3/7/2007 8:15:47 PM

REM Created by Mike Shihrer

REM ***** Main Source File *****

REM

REM demonstrates function to draw curved roads.

REM at this time, turns must alternate between right and left

REM for simplicity sake for me, the z coordinate is actually the height value

REM feel free to use this code, a credit to me would be cool though, thanks

autocam off

rem load your own road texture here, and uncomment out the texture command inside the drawroad function

rem load image "E:\Dev\Projects\STRider\media\road.jpg",1

rem load image "E:\Dev\Projects\STRider\media\road1.jpg",2

REM array stores x,y coords for triangles to be drawn

dim coordinatearray#(4,36)

Global trianglecount rem keeps track of number of triangles

Global xcenter as float rem center of radius of turn x position

Global ycenter as float rem center of radius of turn y position

Global prevangle as float rem the angle of the end of the last curve section

Global lastradius as float rem the outside radius of the last curve section

Global cameraflag as integer

xcenter = 15000 rem pick somewhere way out in space to avoid negative numbers

ycenter = 15000 rem pick somewhere way out in space to avoid negative numbers

prevangle = 180 rem start angle of first turn

trianglecount = 0 rem initialize triangle object numbers here, it increments as you draw more triangles

lastradius = 0 rem should start at zero here

rem parameters are : drawroad(direction 0 for left, 1 for right,x pos of radius center, y pos of radius center, inside radius, outside radius, segments per curve, angle of turn, last turn ending angle, triangle object number)

drawroad(1,xcenter,ycenter,300,400,16,180,prevangle,trianglecount)

drawroad(0,xcenter,ycenter,300,400,8,90,prevangle,trianglecount)

drawroad(1,xcenter,ycenter,1000,1100,2,5,prevangle,trianglecount)

drawroad(0,xcenter,ycenter,200,300,4,90,prevangle,trianglecount)

drawroad(1,xcenter,ycenter,300,400,16,180,prevangle,trianglecount)

drawroad(0,xcenter,ycenter,300,400,8,90,prevangle,trianglecount)

drawroad(1,xcenter,ycenter,1000,1100,2,5,prevangle,trianglecount)

drawroad(0,xcenter,ycenter,200,300,4,90,prevangle,trianglecount)

position camera xcenter,ycenter,-15

xrotate camera -90 rem comment this out for a top down view of the road

movecamera()

Loop

function drawroad(direction as integer,centerx as float, centerY as float, insideradius as float, outsideradius as float, segments as integer, angle as float,lastangle as float,triangles as integer)

xpi as float

ypi as float

xpo as float

ypo as float

a as float

calcangle as float

calcangle = angle / segments

if direction = 0 rem this is for laft turns

rem Calculate radius centerx and centery between turns

xcenter = centerx + (insideradius + lastradius) * cos(prevangle)

ycenter = centery + (insideradius + lastradius) * sin(prevangle)

a = lastangle - 180 rem keep the angle in a clock wise orientation

rem plot the x and y positions on the curves

for b = 1 to (segments + 1)

xpi = xcenter + insideradius * cos(a)

ypi = ycenter + insideradius * sin(a)

xpo = xcenter + outsideradius * cos(a)

ypo = ycenter + outsideradius * sin(a)

REM store the segment coordinate positions in an array so we can have the positions for the triangles

coordinatearray#(1,b) = xpi

coordinatearray#(2,b) = ypi

coordinatearray#(3,b) = xpo

coordinatearray#(4,b) = ypo

a = a + calcangle

next b

rem update prevangle with ending angle of curve, update lastradius so can calculate next radius centerx and centery

prevangle = a - calcangle

lastradius = outsideradius

endif

if direction = 1 rem this is for right turns

xcenter = centerx + (insideradius + lastradius) * cos(prevangle)

ycenter = centery + (insideradius + lastradius) * sin(prevangle)

a = lastangle + 180

for b = 1 to (segments + 1)

xpi = xcenter + insideradius * cos(a)

ypi = ycenter + insideradius  * sin(a)

xpo = xcenter + outsideradius * cos(a)

ypo = ycenter + outsideradius * sin(a)

REM store the segment coordinate positions in an array so we can have the positions for the triangles

coordinatearray#(1,b) = xpi

coordinatearray#(2,b) = ypi

coordinatearray#(3,b) = xpo

coordinatearray#(4,b) = ypo

a = a - calcangle

next b

prevangle = a + calcangle

lastradius = outsideradius

endif

rem loop through the coordinatearray and draw the triangles

for i = 1 to segments

make object triangle triangles + i,coordinatearray#(1,i),coordinatearray#(2,i),0,coordinatearray#(3,i),coordinatearray#(4,i),0,coordinatearray#(3,(i+1)),coordinatearray#(4,(i+1)),0

rem texture object triangles + i,1

next i

triangles = triangles + i

for ii = 1 to segments

make object triangle triangles + ii,coordinatearray#(1,ii),coordinatearray#(2,ii),0,coordinatearray#(3,ii+1),coordinatearray#(4,ii+1),0,coordinatearray#(1,(ii+1)),coordinatearray#(2,(ii+1)),0

rem texture object triangles + ii,2

next ii

triangles = triangles + ii

trianglecount = triangles + 1

endfunction

function movecamera()

if upkey() then move camera .50

if downkey() then move camera -.5

if leftkey() then turn camera left .2

if rightkey() then turn camera right .2

endfunction

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Author Name:	Visigoth
CodeBase Entries:	18

CodeBase - draw curved road function