; ----------------------------------------------------------------------------
; triangle.asm
;
; A very simple *Linux* opengl application using the glut library.  it
; draws a nicely colored triangle in a top-level application window.
; Version of numit_or: numit_or@cantv.net
;
; Compile with:
;    nasm -felf triangle.asm -o triangle.o
;    gcc triangle.o -o triangle -L/usr/X11R6/lib -lGL -lglut -lglu
;
; you can find nasm in:
;   http://nasm.sourceforge.net/
;
; ----------------------------------------------------------------------------
;
; libGL is in
;    libMesaGL1 pack (Mandrake)
;   mesag3 - mesag-dev - mesa-common-dev packs (Debian)
; libglut and libGLU are in:
;    libMesaglut pack (Mandrake)
;   freeglut3 - freeglut3-dev - libglut3 - libglut3-dev (Debian)
;
; ----------------------------------------------------------------------------
   global   main
   extern   glClear
   extern   glBegin
   extern   glEnd
   extern   glColor3f
   extern   glVertex3f
   extern   glFlush
   extern   glutInit
   extern   glutInitDisplayMode
   extern   glutInitWindowPosition
   extern   glutInitWindowSize
   extern   glutCreateWindow
   extern   glutDisplayFunc
   extern   glutMainLoop

GL_COLOR_BUFFER_BIT   equ    16384
GL_POLYGON      equ   9

section   .data
title   db   'A Simple Triangle', 0
zero   dd   0.0
one   dd   1.0
half   dd   0.5
neghalf dd   -0.5

section .text
display:
   mov   rdi, GL_COLOR_BUFFER_BIT
   call   glClear         ; glClear(GL_COLOR_BUFFER_BIT)
   mov   rdi, GL_POLYGON
   call   glBegin         ; glBegin(GL_POLYGON)
   movss   xmm0, [zero]
   movss   xmm1, [zero]
   movss   xmm2, [one]
   call   glColor3f      ; glColor3f(1, 0, 0)
   movss   xmm0, [zero]
   movss   xmm1, [neghalf]
   movss   xmm2, [neghalf]
   call   glVertex3f      ; glVertex(-.5, -.5, 0)
   movss   xmm0, [zero]
   movss   xmm1, [one]
   movss   xmm2, [zero]
   call   glColor3f      ; glColor3f(0, 1, 0)
   movss   xmm0, [zero]
   movss   xmm1, [neghalf]
   movss   xmm2, [half]
   call   glVertex3f      ; glVertex(.5, -.5, 0)
   movss   xmm0, [one]
   movss   xmm1, [zero]
   movss   xmm2, [zero]
   call   glColor3f      ; glColor3f(0, 0, 1)
   movss   xmm0, [zero]
   movss   xmm1, [half]
   movss   xmm2, [zero]
   call   glVertex3f      ; glVertex(0, .5, 0)
   call   glEnd         ; glEnd()
   call   glFlush         ; glFlush()
   ret

main:
   mov   rsi, rcx
   call   glutInit
   mov   rsi, 0
   call   glutInitDisplayMode
   mov   rsi, 100
   mov   rdi, 100
   call   glutInitWindowPosition
   mov   rdi, 400
   mov   rsi, 300
   call   glutInitWindowSize
   mov   rdi, title
   call   glutCreateWindow
   mov   rdi, display
   call   glutDisplayFunc
   call   glutMainLoop
   leave
   ret