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[leszpol]

I was helped by John Horspool to solve my problem:
"save bitmap from my OpenGL Window to file on my hard disk".

I prepared a small program witch draws red sphere
on yello background. The program should save conten
of window to disk as a bitmap file called Junk_BMP.bmp.
I have bitmap but there is only black square nothing more.
There is something wrong! Are there anybody who would
correct the program to achieve the goal (saving bitmap to file).

Leszek Flis


PROGRAM STENCIL
include <clearwin.ins>,nolist
include <opengl.ins> ,nolist

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! parameters for opengl window
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
parameter (kw_ogl=400,kh_ogl=400)

integer i,koff,kount,k,j
integer opengl_proc
external opengl_proc

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! Coded by JohnHorspool to is needed to save bitmap file
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
CHARACTER*1 ImageData(3*(kw_ogl+3)*kh_ogl),ImageDib(3,kw_ogl,kh_ogl)

i=winio@('%es%ca[Saving BITMAP]%sp%ww[no_border]%pv%^og[depth32,stencil]',0,0,kw_ogl,kh_ogl,opengl_proc)

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! MAIN part Coded by JohnHorspool - is needed to save bitmap file
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
ImageData=' '
ImageDib =' '

call glReadPixels(0,0,kw_ogl,kh_ogl,GL_RGB,GL_UNSIGNED_BYTE,ImageData)

koff=mod(kw_ogl,4)
kount=0
do j=1,kh_ogl
do i=1,kw_ogl
do k=1,3
kount=kount+1
ImageDib(k,i,kh_ogl-j+1)=ImageData(kount)
end do
end do
kount=kount+koff
end do

call put_dib_block@('Junk_bmp.bmp',ImageDib,kw_ogl,kh_ogl,0,0,kw_ogl,kh_ogl,24,ierr)

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
! MAIN part Coded by JohnHorspool - is needed to save bitmap file
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

CALL glutMainLoop

END

! Subroutines
! Draw a sphere
subroutine display()
include <opengl.ins>,nolist

call glClearColor(1.0,1.0,0.0,1.0)
call glClear(OR(GL_COLOR_BUFFER_BIT,GL_DEPTH_BUFFER_BIT))
call glColor3f(1.0,0.0,0.0)
call auxSolidSphere (1.0d0)
call glFlush()
end

! Whenever the window is reshaped, redefine the
! coordinate system and redraw the stencil area.
subroutine myReshape(width,height)

INCLUDE <opengl.ins>,nolist
INTEGER width,height
REAL*8 r

r=1.0
IF (height==0) height=1
CALL glViewport(0, 0, width, height)
CALL glMatrixMode(GL_PROJECTION)
CALL glLoadIdentity()
IF(width<=height) then
CALL glOrtho(-r,r,-r*height/width,r*height/width,-r,r)
ELSE
CALL glOrtho(-r*width/height,r*width/height,-r,r,-r,r)
ENDIF

CALL glMatrixMode(GL_MODELVIEW)
CALL glLoadIdentity()

end

integer function opengl_proc()
include <clearwin.ins>,nolist
include <opengl.ins>,nolist
integer w,h
character*256 reason
reason=clearwin_string@('CALL_BACK_REASON')
if(reason.eq.'SETUP')then
call glEnable(GL_DEPTH_TEST)
else if(reason.eq.'RESIZE')then
w=clearwin_info@('OPENGL_WIDTH')
h=clearwin_info@('OPENGL_DEPTH')
call myReshape(w,h)
else if(reason.eq.'DIRTY')then
call display()
end if
opengl_proc=2
end

[JohnHorspool]

Leszek,

Here is the stencil example supplied with the installation, I have modified it to include a save to bitmap routine. I have done very little to the original code, just put the width and height variables (w,h) into common, put in a menu and added the bit map creation routine, you can resize the window and create multiple bitmaps.

cheers
John

[code:1:fa1d6ad15a]

* stencil.c
* This program draws two rotated tori in a window.
* A diamond in the center of the window masks out part
* of the scene. Within this mask, a different model
* (a sphere) is drawn in a different color.
*
subroutine myinit()
include <opengl.ins>,nolist
real yellow_diffuse(4)
real yellow_specular(4)

real blue_diffuse(4)
real blue_specular(4)

real position_one(4)

integer YELLOWMAT
integer BLUEMAT
parameter(YELLOWMAT = 1)
parameter(BLUEMAT = 2)

data yellow_diffuse / 0.7, 0.7, 0.0, 1.0 /
data yellow_specular / 1.0, 1.0, 1.0, 1.0 /

data blue_diffuse / 0.1, 0.1, 0.7, 1.0 /
data blue_specular / 0.1, 1.0, 1.0, 1.0 /

data position_one / 1.0, 1.0, 1.0, 0.0 /


call glNewList(YELLOWMAT, GL_COMPILE)
call glMaterialfv(GL_FRONT, GL_DIFFUSE, yellow_diffuse)
call glMaterialfv(GL_FRONT, GL_SPECULAR, yellow_specular)
call glMaterialf(GL_FRONT, GL_SHININESS, 64.0)
call glEndList()

call glNewList(BLUEMAT, GL_COMPILE)
call glMaterialfv(GL_FRONT, GL_DIFFUSE, blue_diffuse)
call glMaterialfv(GL_FRONT, GL_SPECULAR, blue_specular)
call glMaterialf(GL_FRONT, GL_SHININESS, 45.0)
call glEndList()

call glLightfv(GL_LIGHT0, GL_POSITION, position_one)

call glEnable(GL_LIGHT0)
call glEnable(GL_LIGHTING)
call glDepthFunc(GL_LESS)
call glEnable(GL_DEPTH_TEST)

call glClearStencil(z'0')
call glEnable(GL_STENCIL_TEST)

end

* Draw a sphere in a diamond-shaped section in the
* middle of a window with 2 tori.
*
subroutine display()
include <opengl.ins>,nolist

integer YELLOWMAT
integer BLUEMAT
parameter(YELLOWMAT = 1)
parameter(BLUEMAT = 2)

call glClear(OR(GL_COLOR_BUFFER_BIT,GL_DEPTH_BUFFER_BIT))

* draw blue sphere where the stencil is 1 */
call glStencilFunc (GL_EQUAL, z'1', z'1')
call glCallList (BLUEMAT)
call auxSolidSphere (0.5d0)

* draw the tori where the stencil is not 1 */
call glStencilFunc (GL_NOTEQUAL, z'1', z'1')
call glStencilOp (GL_KEEP, GL_KEEP, GL_KEEP)
call glPushMatrix()
call glRotatef (45.0, 0.0, 0.0, 1.0)
call glRotatef (45.0, 0.0, 1.0, 0.0)
call glCallList (YELLOWMAT)
call auxSolidTorus (0.275d0, 0.85d0)
call glPushMatrix()
call glRotatef (90.0, 1.0, 0.0, 0.0)
call auxSolidTorus (0.275d0, 0.85d0)
call glPopMatrix()
call glPopMatrix()
call glFlush()
end

* Whenever the window is reshaped, redefine the
* coordinate system and redraw the stencil area.
*
subroutine myReshape()
include <opengl.ins>,nolist

integer w,h
double precision aspect_ratio

common /size/w,h

if (h.ne.0) then
aspect_ratio=dble(w)/h
call glViewport(0, 0, w, h)

call glClear(GL_STENCIL_BUFFER_BIT)
* create a diamond shaped stencil area *
call glMatrixMode(GL_PROJECTION)
call glLoadIdentity()
call glOrtho(-3d0, 3d0, -3d0, 3d0, -1d0, 1d0)

[JohnHorspool]

and the rest (I hope!)