Module noddybox.glflag

ModuleInfo "Framework: Simple Open GL Backdrop flag"
ModuleInfo "Copyright: Public Domain"
ModuleInfo "Author: Ian Cowburn"
ModuleInfo "Version: $Revision$"

' $Id$

Import brl.Basic
Import pub.OpenGL

Strict

Type TGLFlag

	' These are public and can be used to modify the flag
	'
	Field xpos:Float
	Field ypos:Float
	Field zpos:Float
	Field xrot:Float
	Field yrot:Float
	Field zrot:Float
	
	' These are considered private
	'
	Global static:Int=False
	Global si:Float[]=Null
	Field v:TGLFlagVertex[,]
	Field cell:Int
	Field move:Int
	Field width:Int
	Field height:Int
	Field txt:Int

	' Creates a new flag
	'	
	' texture		- Flag texture
	' horiz		- Number of horizontal vertices
	' vert		- Number of vertical vertices
	' size		- Size of each square
	' tile		- Whether the texture is tiled or not
	' z			- Distance of flag (flags always created in the XY plane)
	'
	' Returns null for invalid parameters.
	'
	Function Create:TGLFlag(texture:Int, horiz:Int, vert:Int, size:Float, tile:Int, z:Float)
		Local o:TGLFlag
		
		If (horiz<2 Or vert<2)
			Return Null
		EndIf
		
		o=New TGLFlag
		
		If (Not o.static)
			o.si=New Float[3600]
			For Local a:Float=0 Until 3600
				o.si[a]=Sin(a/10)
			Next
			o.static=True
		EndIf
		
		o.xpos=0
		o.ypos=0
		o.zpos=z
		o.xrot=0
		o.yrot=0
		o.zrot=0
		
		o.txt=texture
		o.width=horiz
		o.height=vert
		o.cell=size
		o.move=size/2
		o.v=New TGLFlagVertex[horiz,vert]
		
		Local ox:Float
		Local oy:Float
		
		ox=-(size*horiz)/2
		oy=-(size*horiz)/2
		
		For Local x=0 Until horiz
			For Local y=0 Until vert
				Local v:TGLFlagVertex=New TGLFlagVertex
				v.x=ox+x*size
				v.y=oy+y*size
				v.z=0
				
				If (tile)
					v.u=(x&1)
					v.v=(y&1)
				Else
					v.u=1.0/(horiz-1)*x
					v.v=1.0/(vert-1)*(vert-1-y)
				EndIf

				o.v[x,y]=v
			Next
		Next
		
		Return o
	End Function

	' Call to render the flag
	'	
	Method Render()
		glPushMatrix()
		glTranslatef(xpos,ypos,zpos)
		glRotatef(xrot,1,0,0)
		glRotatef(yrot,0,1,0)
		glRotatef(zrot,0,0,1)
		glBindTexture(GL_TEXTURE_2D,txt)
		
		For Local vert:TGLFlagVertex=EachIn v
			vert.ax=(vert.ax+vert.aix) Mod 3600
			vert.ay=(vert.ay+vert.aiy) Mod 3600
			vert.az=(vert.az+vert.aiz) Mod 3600
			vert.cx=vert.x+si[vert.ax]*move
			vert.cy=vert.y+si[vert.ay]*move
			vert.cz=vert.z+si[vert.az]*move
		Next

		For Local x:Int=0 Until width-1
			glBegin(GL_TRIANGLE_STRIP)
			For Local y:Int=0 Until height
				glTexCoord2f(v[x,y].u,v[x,y].v)
				glVertex3f(v[x,y].cx,v[x,y].cy,v[x,y].cz)
				glTexCoord2f(v[x+1,y].u,v[x+1,y].v)
				glVertex3f(v[x+1,y].cx,v[x+1,y].cy,v[x+1,y].cz)
			Next
			glEnd()
		Next
		glPopMatrix()
	End Method
	
	' Sets the amount of movement for vertex movement (defaults to half the cell size)
	'
	Method SetMove(m:Int)
		move=m
	End Method
	
	' Sets the movements for a vertex
	'
	' x			- The X co-ord of the vertex
	' y			- The Y co-ord of the vertex
	' angz		- The initial angle (movement is done on a sine wave with 3600 positions) for the Z co-ord
	' angiz		- The angle increment for the Z co-ord
	' angx		- Ditto for X
	' angix		- Ditto for X
	' angy		- And Y
	' angiy		- And Y
	'
	' Note increments must be positive - to simulate negative ones pass a large increment (eg. 3599 for -1)
	'
	Method Nudge(x:Int, y:Int, angz:Float, angiz:Float=10, angx:Float=0, angix:Float=0, angy:Float=0, angiy:Float=0)
		v[x,y].ax=angx
		v[x,y].ay=angy
		v[x,y].az=angz
		v[x,y].aix=angix
		v[x,y].aiy=angiy
		v[x,y].aiz=angiz
	End Method
	
End Type

Type TGLFlagVertex
	Field x#,y#,z#
	Field cx#,cy#,cz#
	Field u#,v#
	Field ax#,ay#,az#
	Field aix#,aiy#,aiz#
	
	Method New()
		x=0
		y=0
		z=0
		cx=0
		cy=0
		cz=0
		ax=0
		ay=0
		az=0
		aix=0
		aiy=0
		aiz=0
	End Method
End Type