( This code can be found at .\tutorial\Lesson6\Triangle.bas )
'----------------------------
'- Declare global variables -
'----------------------------
CONST SCREENWIDTH = 800 ' width of screen
CONST SCREENHEIGHT = 600 ' height of screen
DIM Leg% ' the length of the triangle base leg in pixels
DIM Height% ' the height of the triangle
'----------------
'- Main program -
'----------------
SCREEN _NEWIMAGE(SCREENWIDTH, SCREENHEIGHT, 32) ' initiate graphics screen
CLS ' clear the screen
PRINT ' get user input
INPUT " Enter the height of the triangle > ", Height%
INPUT " Enter the length of the base leg > ", Leg%
DrawTriangle Height%, Leg% ' draw the triangle to the screen
PRINT
PRINT " Triangle complete. Press any key to exit."
SLEEP ' wait for a key press
SYSTEM ' return control to OS
'------------------------------------------------------------------------------------------------------------
SUB DrawTriangle (h%, l%) '------------------------------------------------------------------------------------------------------------
'- Draws a tringle given the height and base leg length. -
'- -
'- h% - the height of the triangle -
'- l% - the base leg lenth of the triangle -
'---------------------------------------------------------
'---------------------------
'- Declare local variables -
'---------------------------
DIM x1%, y1% ' top x,y location of triangle
DIM x2%, y2% ' lower left x,y location of triangle
DIM x3%, y3% ' lower right x,y location of triangle
'------------------------
'- Subroutine main code -
'------------------------
x1% = SCREENWIDTH / 2 - 1 ' calculate three x,y points for triangle
x2% = SCREENWIDTH / 2 - l% / 2 - 1
x3% = x2% + l%
y1% = SCREENHEIGHT / 2 - h% / 2 - 1
y2% = y1% + h%
y3% = y2%
LINE (x1%, y1%)-(x2%, y2%), _RGB32(255, 255, 0) ' draw the triangle
LINE -(x3%, y2%), _RGB32(255, 0, 0)
LINE -(x1%, y1%), _RGB32(255, 255, 0)
LINE -(x1%, y2%), _RGB32(255, 0, 0)
END SUB