How to use a DLL with WinBasicGLDownload(ImportDLL_example.zip)





In the previous tutorial we have showed how to make a DLL for WinBasicGL using the C language, now we will show 
how to import and use the new function.
First of all we must write a definition file to declare the new functions list, file syntax structure is :



[return type] "function name 1" [Number of parameters] [parameter(1) type] [parameter(2) type] ... [parameter(N) type]
[return type] "function name 2" [Number of parameters] [parameter(1) type] [parameter(2) type] ... [parameter(N) type]
[return type] "function name 3" [Number of parameters] [parameter(1) type] [parameter(2) type] ... [parameter(N) type]
....
END

accepted types are :
  VOID (to use if the command do not return values)
  INTEGER
  FLOAT
  STRING
(!) for each function the max number of supported parameters are 16







Now insert at the top of declaration section the ImportDLL istruction and use 
the new commands into the program.
The above example show how to use "Obj3D.dll".

'*************************************************'
'******    Import functions from a DLL      ******'
'*************************************************'

ImportDll "Obj3D",".\data\Obj3D.lst"

Dim texture0 As Integer
Dim texture1 As Integer
Dim xrot As Float,yrot As Float,zrot As Float

Sub SetSizeGLScene   (width As Integer, height As Integer)			' Resize And Initialize The GL Window
	If   (height=0) 							' Prevent A Divide By Zero By	
		height=1							' Making Height Equal One
	EndIf
	glViewport 0,0,width,height						' Reset The Current Viewport
	glMatrixMode GL_PROJECTION						' Select The Projection Matrix
	glLoadIdentity								' Reset The Projection Matrix
	' Calculate The Aspect Ratio Of The Window
	gluPerspective 45.0f,width/height,0.1f,100.0f
	glMatrixMode GL_MODELVIEW						' Select The Modelview Matrix
	glLoadIdentity								' Reset The Modelview Matrix
EndSub

Sub InitGL()									' All Setup For OpenGL Goes Here
	glEnable GL_TEXTURE_2D	
	glShadeModel GL_SMOOTH	 						' Enable Smooth Shading
	glClearColor 0.0f, 0.0f, 0.0f, 0.5f					' Black Background
	glClearDepth 1.0f	 						' Depth Buffer Setup
	glEnable GL_DEPTH_TEST 							' Enables Depth Testing
	glDepthFunc GL_LEQUAL							' The Type Of Depth Testing To Do
	glHint GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST 			' Really Nice Perspective Calculations
EndSub


Sub DrawGLScene()								' Here's Where We Do All The Drawing
	glClear GL_COLOR_BUFFER_BIT  						' Clear The Screen And The Depth Buffer
	glClear GL_DEPTH_BUFFER_BIT
	glLoadIdentity  							' Reset The View


        '*** here we use the dll function to draw and animate two textured cube ***

	wbGLdrawCube 1.4f,0.0f,-6.0f,xrot,0.0,zrot,1.0,texture0			
	wbGLdrawCube -1.4f,0.0f,-6.0f,0.0,yrot,0.0,1.0,texture1			

        '**************************************************************************
     
	xrot=xrot+0.03f
	yrot=yrot+0.02f
	zrot=zrot+0.04f
EndSub

SetWindowMode WINDOW,400,300
SetWindowTitle "Import commands from a DLL"
SetSizeGLScene 400,300
InitGL
texture0 = 101
LoadTexture texture0,1,".\data\portal.bmp"
texture1 = 102
LoadTexture texture1,1,".\data\affresco01.bmp"

MainLoop
 DrawGLScene
 RenderScene
 If (KEYCODE = 27) Exit
EndMainLoop