Just a quick update of this example, since the old example was not longer working with OSX 10.9:
;
; Basic OS X calls to GLUT and OpenGL
;
; Example by Stino / ByTeGeiZ
;
; compile with:
; nasm -g -f macho32 bspGLframBuff.asm
; xcrun gcc -framework GLUT -framework OpenGL -m32 -o bspGLframBuff.out bspGLframBuff.o
;
;inclut GLUT/OpenGL stuff
%include "gl.inc"
%include "glut.inc"
;glibc stuff
extern _clock, _malloc, _free, _usleep, _system
;different ways to use OpenGL (all should work)
;%define USE_TIMER_UPDATE 1
;%define USE_DEPTH_BUFFER 1
%define USE_DOUBLE_BUFFER 1
%define USE_VSYNC 1
; inside com.apple.glut.plist
; set GLUTSyncToVBLKey to true for vsync active in GLUT/OpenGL
;
; at terminal:
; defaults read com.apple.glut GLUTSyncToVBLKey
; defaults write com.apple.glut GLUTSyncToVBLKey 1
; frame buffer data
%define width 800
%define high 600
%define colordeep 4
; static data
segment .data
; enable/disable vertical retrace sync inside com.apple.glut.plist
; set GLUTSyncToVBLKey to true for vsync active in GLUT/OpenGL
;
; at terminal:
; defaults read com.apple.glut GLUTSyncToVBLKey
; defaults write com.apple.glut GLUTSyncToVBLKey 1
enable_glut_vsync_command: db "defaults write com.apple.glut GLUTSyncToVBLKey 1", 10, 0
disable_glut_vsync_command: db "defaults write com.apple.glut GLUTSyncToVBLKey 0", 10, 0
window_name: db "OpenGL frame buffer example", 10, 0
window_handle: dd 0
fl_one: dd 1.0
fl_neg_one: dd -1.0
fl_zero: dd 0.0
fl_half: dd 0.5
fl_neg_half: dd -0.5
; variables for random
seed1: dd 0
seed2: dd 0
; variables for argc/argv
argc: dd 0
argv: dd 0
; for pointer to frame buffer
fbuff: dd 0
; code
segment .text
global _main
; the main function that init OpenGL and install the gl draw function (_display_func)
_main:
lea ecx, [esp+4] ;load adress of argc in stack to ecx
lea edx, [esp+8] ;load adress of argv in stack to edx
push ebp ; setup the frame
mov ebp, esp
sub esp,24 ;add to get rid of 16-bit-alignment-problem (not 28 as normal since we allready push ebp)
%ifdef USE_VSYNC
mov [argv],edx
mov [argc],ecx
;force enable vsync support of GLUT in OSX
mov [esp],dword enable_glut_vsync_command
call _system
mov edx,[argv]
mov ecx,[argc] ;ecx=argc is not longer saved by _system and this will cause problems in _glutInit and so we need to save and restore it now
%endif
;init OpenGL with GLUT
mov [esp+4],edx ;**argv
mov [esp],ecx ;&argc
call _glutInit
;Init Random numbers
call _randomize
;get memory for the gl-frame-buffer
mov eax,width*high*colordeep
mov [esp], eax
call _malloc
; check if the malloc failed
test eax, eax
jz _fail_exit
mov [fbuff],eax
;init display mode for OpenGL window
mov eax, GLUT_RGB
%ifdef USE_DOUBLE_BUFFER
or eax, GLUT_DOUBLE
%else
or eax, GLUT_SINGLE
%endif
%ifdef USE_DEPTH_BUFFER
or eax, GLUT_DEPTH
%endif
mov [esp], eax
call _glutInitDisplayMode
;define position of OpenGL window
mov [esp+4],dword 80
mov [esp],dword 80
call _glutInitWindowPosition
;define OpenGL window size
mov [esp+4], dword high
mov [esp], dword width
call _glutInitWindowSize
;create OpenGL window
mov eax, dword window_name
mov [esp], eax
call _glutCreateWindow
mov dword [window_handle],eax
%ifdef USE_DEPTH_BUFFER
;enable depth buffer
mov [esp],dword GL_DEPTH_TEST
call _glEnable
%endif
;add own draw function as call back
mov [esp], dword _display_func
call _glutDisplayFunc
%ifdef USE_TIMER_UPDATE
;add call back that triggers draw update(timer based)
mov [esp+8], dword 0
mov [esp+4], dword _timer_func
mov [esp], dword 1
call _glutTimerFunc
%else
;add call back that triggers draw update(idle based)
mov [esp], dword _idle_func
call _glutIdleFunc
%endif
%ifdef USE_VSYNC
; disable glut vsync before main loop, since this loop will never terminate normaly
; it works if it was enabled while init of glut/OpenGL ;-)
mov [esp],dword disable_glut_vsync_command
call _system
%endif
;start OpenGL main loop
call _glutMainLoop
; free the malloc'd memory
mov eax, dword [fbuff]
mov [esp], eax
call _free
_pass_exit:
add esp,24
pop ebp
ret
_fail_exit:
%ifdef USE_VSYNC
;disable glut vsync in case we had an error
mov [esp],dword disable_glut_vsync_command
call _system
%endif
mov eax, 1
add esp,24
pop ebp
ret
;##############################################################################
; GL timer function to give GL draw function the command for redraw and also restart the timer
_timer_func:
sub esp,28
;select OpenGL window
mov eax, [window_handle]
mov [esp],eax
call _glutSetWindow
;start redraw of OpenGL
call _glutPostRedisplay
;restart timer
mov [esp+8], dword 0
mov [esp+4], dword _timer_func
mov [esp], dword 40 ;the timer
call _glutTimerFunc
add esp,28
ret
;##############################################################################
; GL idle function to give GL draw function the command for redraw
_idle_func:
sub esp,28
;just wait a few micro secs
mov [esp], dword 10
call _usleep
;select OpenGL window
mov eax,[window_handle]
mov [esp],eax
call _glutSetWindow
;start redraw of OpenGL
call _glutPostRedisplay
add esp,28
ret
;##############################################################################
; the gl draw function (here is the content of OpenGL
_display_func:
pusha ; we have to save all registers because newer versions of GLUT framework need a few registers (ebx, edx, esi ...) before and after call of our _display_func
sub esp,28 ;add to get rid of 16-bit-alignment-problem
;fill frame buffer with some content
call _draw_to_frame_buff
;defiene color for clear screen
mov eax, dword [fl_one]
mov [esp+12],eax
mov eax, dword [fl_zero]
mov [esp+8],eax
mov [esp+4],eax
mov [esp],eax
call _glClearColor
;clear screen
mov eax, dword GL_COLOR_BUFFER_BIT
%ifdef USE_DEPTH_BUFFER
or eax, dword GL_DEPTH_BUFFER_BIT
%endif
mov [esp],eax
call _glClear
;set position were _glDrawPixels will start
mov eax,dword [fl_neg_one]
mov [esp+4],eax
mov [esp],eax
call _glRasterPos2f
;draw frame buffer to screen
mov eax, dword [fbuff]
mov [esp+16],eax
mov [esp+12],dword GL_UNSIGNED_BYTE
mov [esp+8],dword GL_RGBA
mov [esp+4],dword high
mov [esp],dword width
call _glDrawPixels
%ifdef USE_DOUBLE_BUFFER
;do all actions and than change the buffer
call _glutSwapBuffers
%else
;so all actions in single buffer mode
call _glFlush
%endif
add esp,28
popa
ret
;##############################################################################
;here draw own content to frame buffer
_draw_to_frame_buff:
sub esp,28 ;add to get rid of 16-bit-alignment-problem
;get a random number
mov [esp],dword 0xFFFFFFFF
call _random ;eax has radom number
;fill complete frame buffer with a random color
mov edi,[fbuff]
mov ecx,width*high
rep stosd
add esp,28
ret
;##############################################################################
;Init the random number seeds with system time
_randomize:
;parameter:
;none
;return value:
;none
push eax
push edx
xor eax,eax
sub esp,4
call _clock ;nach eax
add esp,4
mov [seed1],eax
mov edx,eax
sub esp,4
call _clock ;nach eax
add esp,4
xor eax,edx
mul edx ;eax * edx nach edx:eax
mov [seed2],eax
pop edx
pop eax
ret
;##############################################################################
;create a new random number
_random:
;parameter:
;EAX = w, range of random number: 0 - (w-1)
;return value:
;EAX = new random number
push ebx
push edx
mov ebx,eax
mov eax,[seed1]
mov edx,[seed2]
mov [seed2],eax
add eax,edx
shld eax,edx,9
mov [seed1],eax
xor edx,edx
div ebx
mov eax,edx
pop edx
pop ebx
ret
There were two reasons:
1.) "call _system" destroys content of register ecx and so the next "call _glutInit" that needs this register as input fails with an "Segmentation fault: 11"
2.) Inside the "_display_func" where we draw our content into the GL frame buffer and that is called by GLUT framework, we need to save all registers with an "pusha" and restore them later with an "popa". In newer versions of GLUT framework the registers ebx, edx, esi and edi are used, before and after calling the users _display_func.
Furthermore with newer versions of XCode you should use the following sequence to assemble and to link the frameworks:
nasm -g -f macho32 bspGLframBuff.asm
xcrun gcc -framework GLUT -framework OpenGL -m32 -o bspGLframBuff.out bspGLframBuff.o
