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|
! This program plots a function of two variables. The function, called
! func_to_plot, is an external procedure at the end of the file.
! This begins with the same module used in the modview example, followed by
! another module for plotting the function, called function_plotter.
! You might want to change default initial settings in modules modview and
! function_plotter.
! William F. Mitchell
! william.mitchell@nist.gov
! Mathematical and Computational Sciences Division
! National Institute of Standards and Technology
! August, 1999
!---------------------------------------------------------------------------
module view_modifier
! This module provides facilities to modify the view in an OpenGL window.
! The mouse buttons and keyboard arrow keys can be used to zoom, pan,
! rotate and change the scale. A menu or submenu can be used to select which
! buttons perform which function and to reset the view to the initial settings.
! This is limited to one window.
! William F. Mitchell
! william.mitchell@nist.gov
! Mathematical and Computational Sciences Division
! National Institute of Standards and Technology
! April, 1998
! To use this module:
!
! 1) put a USE view_modifier statement in any program unit that calls a
! procedure in this module
!
! 2) set the initial operation assignments, view and scale below the
! "Initial configuration" comment below
!
! 3) call view_modifier_init after glutCreateWindow
! This is a function that returns integer(kind=glcint) menuid. The menuid
! is the ID returned by glutCreateMenu. You can either use the view_modifier
! menu as your menu by calling glutAttachMenu immediately after
! view_modifier_init, as in
! menuid = view_modifier_init()
! call glutAttachMenu(GLUT_RIGHT_BUTTON)
! or by using the menuid to attach a submenu to your own menu, as in
! call glutAddSubMenu("View Modifier",menuid)
!
! 4) in any callback functions that update the display, put
! call reset_view
! as the first executable statement
!
! Note that view_modifier_init sets the callback functions for glutMouseFunc,
! glutMotionFunc and glutSpecialFunc, so don't call these yourself
!
! The menu allows you to select what operation is attached to the left and
! middle mouse buttons and arrow keys, reset to the initial view, and quit.
! The right mouse button should be used for the menu.
use opengl_gl
use opengl_glu
use opengl_glut
implicit none
private
public :: view_modifier_init, reset_view
private :: ZOOM, PAN, ROTATE, SCALEX, SCALEY, SCALEZ, RESET, ABOVE, QUIT, &
PI, &
left_button_func, middle_button_func, arrow_key_func, &
init_lookat, init_lookfrom, &
init_xscale_factor, init_yscale_factor, init_zscale_factor, &
angle, shift, xscale_factor, yscale_factor, zscale_factor, &
moving_left, moving_middle, begin_left, begin_middle, &
cart2sphere, sphere2cart, cart3D_plus_cart3D, cart3D_minus_cart3D, &
reset_to_init, mouse, motion, arrows, &
menu_handler, set_left_button, set_middle_button, set_arrow_keys
integer(kind=glcint), parameter :: ZOOM = 1, PAN = 2, ROTATE = 3, SCALEX = 4, &
SCALEY = 5, SCALEZ = 6
integer(kind=glcint), parameter :: RESET = 10, ABOVE = 11, QUIT = 12
real(kind=gldouble), parameter :: PI = 3.141592653589793_gldouble
type, private :: cart2D ! 2D cartesian coordinates
real(kind=gldouble) :: x, y
end type cart2D
type, private :: cart3D ! 3D cartesian coordinates
real(kind=gldouble) :: x, y, z
end type cart3D
type, private :: sphere3D ! 3D spherical coordinates
real(kind=gldouble) :: theta, phi, rho
end type sphere3D
type(cart2D), save :: angle
type(cart3D), save :: shift
real(kind=gldouble), save :: xscale_factor, yscale_factor, zscale_factor
logical, save :: moving_left, moving_middle
type(cart2D), save :: begin_left, begin_middle
interface operator(+)
module procedure cart3D_plus_cart3D
end interface
interface operator(-)
module procedure cart3D_minus_cart3D
end interface
! ------- Initial configuration -------
! Set the initial operation performed by each button and the arrow keys.
! The operations are ZOOM, PAN, ROTATE, SCALEX, SCALEY, and SCALEZ
integer, save :: left_button_func = ROTATE, &
middle_button_func = ZOOM, &
arrow_key_func = PAN
! Set the initial view as the point you are looking at, the point you are
! looking from, and the scale factors
type(cart3D), parameter :: &
init_lookat = cart3D(0.5_gldouble, 0.5_gldouble, 0.0_gldouble), &
init_lookfrom = cart3D(5.0_gldouble, 10.0_gldouble, 2.5_gldouble)
real(kind=gldouble), parameter :: &
init_xscale_factor = 1.0_gldouble, &
init_yscale_factor = 1.0_gldouble, &
init_zscale_factor = 1.0_gldouble
! -------- end of Initial configuration ------
contains
! -------------
subroutine reset_to_init
! -------------
! This resets the view to the initial configuration
type(sphere3D) :: slookfrom
slookfrom = cart2sphere(init_lookfrom-init_lookat)
angle%x = -180.0_gldouble*slookfrom%theta/PI - 90.0_gldouble
angle%y = -180.0_gldouble*slookfrom%phi/PI
shift%x = 0.0_gldouble
shift%y = 0.0_gldouble
shift%z = -slookfrom%rho
xscale_factor = init_xscale_factor
yscale_factor = init_yscale_factor
zscale_factor = init_zscale_factor
call glutPostRedisplay
return
end subroutine reset_to_init
! ---------------
subroutine view_from_above
! ---------------
! This sets the view to be from straight above
type(sphere3D) :: slookfrom
slookfrom = cart2sphere(cart3D(0.0,0.0,1.0))
angle%x = -180.0_gldouble*slookfrom%theta/PI
angle%y = -180.0_gldouble*slookfrom%phi/PI
call glutPostRedisplay
return
end subroutine view_from_above
! ----------
subroutine reset_view
! ----------
! This routine resets the view to the current orientation and scale
call glMatrixMode(GL_MODELVIEW)
call glPopMatrix
call glPushMatrix
call glTranslated(shift%x, shift%y, shift%z)
call glRotated(angle%x, 0.0_gldouble, 0.0_gldouble, 1.0_gldouble)
call glRotated(angle%y, cos(PI*angle%x/180.0_gldouble), &
-sin(PI*angle%x/180.0_gldouble), 0.0_gldouble)
call glTranslated(-init_lookat%x, -init_lookat%y, -init_lookat%z)
call glScaled(xscale_factor,yscale_factor,zscale_factor)
return
end subroutine reset_view
! -----
subroutine mouse(button, state, x, y) bind(c,name="")
! -----
integer(kind=glcint), value :: button, state, x, y
! This gets called when a mouse button changes
if (button == GLUT_LEFT_BUTTON .and. state == GLUT_DOWN) then
moving_left = .true.
begin_left = cart2D(x,y)
endif
if (button == GLUT_LEFT_BUTTON .and. state == GLUT_UP) then
moving_left = .false.
endif
if (button == GLUT_MIDDLE_BUTTON .and. state == GLUT_DOWN) then
moving_middle = .true.
begin_middle = cart2D(x,y)
endif
if (button == GLUT_MIDDLE_BUTTON .and. state == GLUT_UP) then
moving_middle = .false.
endif
end subroutine mouse
! ------
subroutine motion(x, y) bind(c,name="")
! ------
integer(kind=glcint), value :: x, y
! This gets called when the mouse moves
integer :: button_function
type(cart2D) :: begin
real(kind=gldouble) :: factor
! Determine and apply the button function
if (moving_left) then
button_function = left_button_func
begin = begin_left
else if(moving_middle) then
button_function = middle_button_func
begin = begin_middle
end if
select case(button_function)
case (ZOOM)
if (y < begin%y) then
factor = 1.0_gldouble/(1.0_gldouble + .002_gldouble*(begin%y-y))
else if (y > begin%y) then
factor = 1.0_gldouble + .002_gldouble*(y-begin%y)
else
factor = 1.0_gldouble
end if
shift%z = factor*shift%z
case (PAN)
shift%x = shift%x + .01*(x - begin%x)
shift%y = shift%y - .01*(y - begin%y)
case (ROTATE)
angle%x = angle%x + (x - begin%x)
angle%y = angle%y + (y - begin%y)
case (SCALEX)
if (y < begin%y) then
factor = 1.0_gldouble + .002_gldouble*(begin%y-y)
else if (y > begin%y) then
factor = 1.0_gldouble/(1.0_gldouble + .002_gldouble*(y-begin%y))
else
factor = 1.0_gldouble
end if
xscale_factor = xscale_factor * factor
case (SCALEY)
if (y < begin%y) then
factor = 1.0_gldouble + .002_gldouble*(begin%y-y)
else if (y > begin%y) then
factor = 1.0_gldouble/(1.0_gldouble + .002_gldouble*(y-begin%y))
else
factor = 1.0_gldouble
end if
yscale_factor = yscale_factor * factor
case (SCALEZ)
if (y < begin%y) then
factor = 1.0_gldouble + .002_gldouble*(begin%y-y)
else if (y > begin%y) then
factor = 1.0_gldouble/(1.0_gldouble + .002_gldouble*(y-begin%y))
else
factor = 1.0_gldouble
end if
zscale_factor = zscale_factor * factor
end select
! update private variables and redisplay
if (moving_left) then
begin_left = cart2D(x,y)
else if(moving_middle) then
begin_middle = cart2D(x,y)
endif
if (moving_left .or. moving_middle) then
call glutPostRedisplay
endif
return
end subroutine motion
! ------
subroutine arrows(key, x, y) bind(c,name="")
! ------
integer(glcint), value :: key, x, y
! This routine handles the arrow key operations
real(kind=gldouble) :: factor
select case(arrow_key_func)
case(ZOOM)
select case(key)
case(GLUT_KEY_DOWN)
factor = 1.0_gldouble + .02_gldouble
case(GLUT_KEY_UP)
factor = 1.0_gldouble/(1.0_gldouble + .02_gldouble)
case default
factor = 1.0_gldouble
end select
shift%z = factor*shift%z
case(PAN)
select case(key)
case(GLUT_KEY_LEFT)
shift%x = shift%x - .02
case(GLUT_KEY_RIGHT)
shift%x = shift%x + .02
case(GLUT_KEY_DOWN)
shift%y = shift%y - .02
case(GLUT_KEY_UP)
shift%y = shift%y + .02
end select
case(ROTATE)
select case(key)
case(GLUT_KEY_LEFT)
angle%x = angle%x - 1.0_gldouble
case(GLUT_KEY_RIGHT)
angle%x = angle%x + 1.0_gldouble
case(GLUT_KEY_DOWN)
angle%y = angle%y + 1.0_gldouble
case(GLUT_KEY_UP)
angle%y = angle%y - 1.0_gldouble
end select
case(SCALEX)
select case(key)
case(GLUT_KEY_DOWN)
factor = 1.0_gldouble/(1.0_gldouble + .02_gldouble)
case(GLUT_KEY_UP)
factor = 1.0_gldouble + .02_gldouble
case default
factor = 1.0_gldouble
end select
xscale_factor = xscale_factor * factor
case(SCALEY)
select case(key)
case(GLUT_KEY_DOWN)
factor = 1.0_gldouble/(1.0_gldouble + .02_gldouble)
case(GLUT_KEY_UP)
factor = 1.0_gldouble + .02_gldouble
case default
factor = 1.0_gldouble
end select
yscale_factor = yscale_factor * factor
case(SCALEZ)
select case(key)
case(GLUT_KEY_DOWN)
factor = 1.0_gldouble/(1.0_gldouble + .02_gldouble)
case(GLUT_KEY_UP)
factor = 1.0_gldouble + .02_gldouble
case default
factor = 1.0_gldouble
end select
zscale_factor = zscale_factor * factor
end select
call glutPostRedisplay
return
end subroutine arrows
! ------------
subroutine menu_handler(value) bind(c,name="")
! ------------
integer(kind=glcint), value :: value
! This routine handles the first level entries in the menu
select case(value)
case(RESET)
call reset_to_init
case(ABOVE)
call view_from_above
case(QUIT)
stop
end select
return
end subroutine menu_handler
! ---------------
subroutine set_left_button(value) bind(c,name="")
! ---------------
integer(kind=glcint), value :: value
! This routine sets the function of the left button as given by menu selection
left_button_func = value
return
end subroutine set_left_button
! -----------------
subroutine set_middle_button(value) bind(c,name="")
! -----------------
integer(kind=glcint), value :: value
! This routine sets the function of the middle button as given by menu selection
middle_button_func = value
return
end subroutine set_middle_button
! --------------
subroutine set_arrow_keys(value) bind(c,name="")
! --------------
integer(kind=glcint), value :: value
! This routine sets the function of the arrow keys as given by menu selection
arrow_key_func = value
return
end subroutine set_arrow_keys
! ------------------
function view_modifier_init() result(menuid)
! ------------------
integer(kind=glcint) :: menuid
! This initializes the view modifier variables and sets initial view.
! It should be called immediately after glutCreateWindow
integer(kind=glcint) :: button_left, button_middle, arrow_keys
! set the callback functions
call glutMouseFunc(mouse)
call glutMotionFunc(motion)
call glutSpecialFunc(arrows)
! create the menu
button_left = glutCreateMenu(set_left_button)
call glutAddMenuEntry("rotate"//char(0),ROTATE)
call glutAddMenuEntry("zoom"//char(0),ZOOM)
call glutAddMenuEntry("pan"//char(0),PAN)
call glutAddMenuEntry("scale x"//char(0),SCALEX)
call glutAddMenuEntry("scale y"//char(0),SCALEY)
call glutAddMenuEntry("scale z"//char(0), SCALEZ)
button_middle = glutCreateMenu(set_middle_button)
call glutAddMenuEntry("rotate"//char(0),ROTATE)
call glutAddMenuEntry("zoom"//char(0),ZOOM)
call glutAddMenuEntry("pan"//char(0),PAN)
call glutAddMenuEntry("scale x"//char(0),SCALEX)
call glutAddMenuEntry("scale y"//char(0),SCALEY)
call glutAddMenuEntry("scale z"//char(0), SCALEZ)
arrow_keys = glutCreateMenu(set_arrow_keys)
call glutAddMenuEntry("rotate"//char(0),ROTATE)
call glutAddMenuEntry("zoom"//char(0),ZOOM)
call glutAddMenuEntry("pan"//char(0),PAN)
call glutAddMenuEntry("scale x"//char(0),SCALEX)
call glutAddMenuEntry("scale y"//char(0),SCALEY)
call glutAddMenuEntry("scale z"//char(0), SCALEZ)
menuid = glutCreateMenu(menu_handler)
call glutAddSubMenu("left mouse button"//char(0),button_left)
call glutAddSubMenu("middle mouse button"//char(0),button_middle)
call glutAddSubMenu("arrow keys"//char(0),arrow_keys)
call glutAddMenuEntry("reset to initial view"//char(0),RESET)
call glutAddMenuEntry("view from above"//char(0),ABOVE)
call glutAddMenuEntry("quit"//char(0),QUIT)
! set the perspective
call glMatrixMode(GL_PROJECTION)
call gluPerspective(10.0_gldouble, 1.0_gldouble, 0.1_gldouble, 200.0_gldouble)
! set the initial view
call glMatrixMode(GL_MODELVIEW)
call glPushMatrix
call reset_to_init
return
end function view_modifier_init
! -----------
function sphere2cart(spoint) result(cpoint)
! -----------
type(sphere3D), intent(in) :: spoint
type(cart3D) :: cpoint
! This converts a 3D point from spherical to cartesean coordinates
real(kind=gldouble) :: t,p,r
t=spoint%theta
p=spoint%phi
r=spoint%rho
cpoint%x = r*cos(t)*sin(p)
cpoint%y = r*sin(t)*sin(p)
cpoint%z = r*cos(p)
return
end function sphere2cart
! -----------
function cart2sphere(cpoint) result(spoint)
! -----------
type(cart3D), intent(in) :: cpoint
type(sphere3D) :: spoint
! This converts a 3D point from cartesean to spherical coordinates
real(kind=gldouble) :: x,y,z
x=cpoint%x
y=cpoint%y
z=cpoint%z
spoint%rho = sqrt(x*x+y*y+z*z)
if (x==0.0_gldouble .and. y==0.0_gldouble) then
spoint%theta = 0.0_gldouble
else
spoint%theta = atan2(y,x)
end if
if (spoint%rho == 0.0_gldouble) then
spoint%phi = 0.0_gldouble
else
spoint%phi = acos(z/spoint%rho)
endif
return
end function cart2sphere
! ------------------
function cart3D_plus_cart3D(cart1,cart2) result(cart3)
! ------------------
type(cart3D), intent(in) :: cart1, cart2
type(cart3D) :: cart3
! Compute the sum of two 3D cartesean points
cart3%x = cart1%x + cart2%x
cart3%y = cart1%y + cart2%y
cart3%z = cart1%z + cart2%z
return
end function cart3D_plus_cart3D
! -------------------
function cart3D_minus_cart3D(cart1,cart2) result(cart3)
! -------------------
type(cart3D), intent(in) :: cart1, cart2
type(cart3D) :: cart3
! Compute the difference of two 3D cartesean points
cart3%x = cart1%x - cart2%x
cart3%y = cart1%y - cart2%y
cart3%z = cart1%z - cart2%z
return
end function cart3D_minus_cart3D
end module view_modifier
!---------------------------------------------------------------------------
module function_plotter
use opengl_gl
use opengl_glut
use view_modifier
implicit none
private
public :: display, draw_func, menu_handler2, make_menu
! symbolic constants
integer, parameter :: surfgrid_toggle = 1, &
surfsolid_toggle = 2, &
contour_toggle = 3, &
quit_selected = 4
integer, parameter :: set_nx = 1, &
set_ny = 2, &
set_ncontour = 3, &
set_contour_val = 4, &
set_xrange = 5, &
set_yrange = 6, &
reset_params = 7
integer, parameter :: black_contour = 1, &
rainbow_contour = 2
integer, parameter :: white_surface = 1, &
red_surface = 2, &
rainbow_surface = 3
! Default initial settings
integer, parameter :: init_ngridx = 40, &
init_ngridy = 40, &
init_num_contour = 20, &
init_contour_color = black_contour, &
init_surface_color = rainbow_surface
real(GLDOUBLE), parameter :: init_minx = 0.0_GLDOUBLE, &
init_maxx = 1.0_GLDOUBLE, &
init_miny = 0.0_GLDOUBLE, &
init_maxy = 1.0_GLDOUBLE
logical, parameter :: init_draw_surface_grid = .false., &
init_draw_surface_solid = .true., &
init_draw_contour = .true.
! Current settings
integer :: ngridx = init_ngridx, &
ngridy = init_ngridy, &
num_contour = init_num_contour, &
contour_color = init_contour_color, &
surface_color = init_surface_color
real(GLDOUBLE) :: minx = init_minx, &
maxx = init_maxx, &
miny = init_miny, &
maxy = init_maxy, &
minz = 0.0_GLDOUBLE, &
maxz = 0.0_GLDOUBLE
logical :: draw_surface_grid = init_draw_surface_grid, &
draw_surface_solid = init_draw_surface_solid, &
draw_contour = init_draw_contour, &
contour_values_given = .false.
real(GLDOUBLE), allocatable :: actual_contours(:)
contains
subroutine display() bind(c)
! This gets called when the display needs to be redrawn
call reset_view
call glClear(ior(GL_COLOR_BUFFER_BIT,GL_DEPTH_BUFFER_BIT))
call glCallList(1)
call glutSwapBuffers
return
end subroutine display
subroutine draw_func
real(GLDOUBLE) :: gridx(0:ngridx),gridy(0:ngridy),zval(0:ngridy,2)
integer :: i,j,k,cont
real(GLDOUBLE) :: x1,x2,x3,xt,y1,y2,y3,yt,z1,z2,z3,zt
real(GLDOUBLE) :: frac,xcross1,xcross2,ycross1,ycross2
real(GLDOUBLE) :: contour_value(num_contour)
real(GLFLOAT) :: color(4), normal(3), &
red(4) = (/1.0,0.0,0.0,1.0/), &
black(4) = (/0.0,0.0,0.0,1.0/), &
white(4) = (/1.0,1.0,1.0,1.0/)
real(GLDOUBLE), external :: func_to_plot
! prepare to make a new display list
call reset_view
call glDeleteLists(1_gluint, 1_glsizei)
call glNewList(1_gluint, gl_compile_and_execute)
! set the grid points
gridx = (/ ((minx + i*(maxx-minx)/ngridx),i=0,ngridx) /)
gridy = (/ ((miny + i*(maxy-miny)/ngridy),i=0,ngridy) /)
! if this is the first call and either rainbow coloring of a solid surface
! or contours are being drawn, minz and maxz need to be set
if (minz == 0.0_GLDOUBLE .and. maxz == 0.0_GLDOUBLE .and. &
( (draw_surface_solid .and. surface_color == rainbow_surface) .or. &
draw_contour ) ) then
do i=0,ngridx
do j=0,ngridy
z1 = func_to_plot(gridx(i),gridy(j))
minz = min(z1,minz)
maxz = max(z1,maxz)
end do
end do
endif
! draw the solid surface
if (draw_surface_solid) then
call glPolygonMode(gl_front_and_back, gl_fill)
call glBegin(gl_triangles)
! set the color for a red or white surface. For white, set the lighting
! such that there is uniform brightness.
if (surface_color == red_surface) then
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,red)
elseif (surface_color == white_surface) then
call glDisable(gl_light0)
call glLightModelfv(gl_light_model_ambient, (/1.,1.,1.,1./))
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,white)
endif
! compute the function values for the first line of points
do j=0,ngridy
zval(j,2) = func_to_plot(gridx(0),gridy(j))
end do
! for each x grid interval...
do i=1,ngridx
! copy left side function values from the right side of the previous interval
zval(:,1) = zval(:,2)
! compute the function values for the right side of the interval
do j=0,ngridy
zval(j,2) = func_to_plot(gridx(i),gridy(j))
end do
minz = min(minz,minval(zval))
maxz = max(maxz,maxval(zval))
! for each y grid interval ...
do j=1,ngridy
! add two triangles to the display list
! Before each triangle, set the normal. Before each vertex, set the
! color if we're coloring by height
normal = normcrossprod((/gridx(i-1),gridx(i),gridx(i)/), &
(/gridy(j-1),gridy(j-1),gridy(j)/), &
(/zval(j-1,1),zval(j-1,2),zval(j,2)/))
call glNormal3fv(normal)
if (surface_color == rainbow_surface) then
call get_rainbow(zval(j-1,1),minz,maxz,color)
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,color)
endif
call glvertex3d(gridx(i-1),gridy(j-1),zval(j-1,1))
if (surface_color == rainbow_surface) then
call get_rainbow(zval(j-1,2),minz,maxz,color)
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,color)
endif
call glvertex3d(gridx(i ),gridy(j-1),zval(j-1,2))
if (surface_color == rainbow_surface) then
call get_rainbow(zval(j,2),minz,maxz,color)
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,color)
endif
call glvertex3d(gridx(i ),gridy(j ),zval(j ,2))
normal = normcrossprod((/gridx(i-1),gridx(i-1),gridx(i)/), &
(/gridy(j),gridy(j-1),gridy(j)/), &
(/zval(j,1),zval(j-1,1),zval(j,2)/))
call glNormal3fv(normal)
if (surface_color == rainbow_surface) then
call get_rainbow(zval(j,2),minz,maxz,color)
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,color)
endif
call glvertex3d(gridx(i ),gridy(j ),zval(j ,2))
if (surface_color == rainbow_surface) then
call get_rainbow(zval(j-1,1),minz,maxz,color)
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,color)
endif
call glvertex3d(gridx(i-1),gridy(j-1),zval(j-1,1))
if (surface_color == rainbow_surface) then
call get_rainbow(zval(j,1),minz,maxz,color)
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,color)
endif
call glvertex3d(gridx(i-1),gridy(j ),zval(j ,1))
end do
end do
call glEnd
! if the surface is white, reset the lighting conditions
if (surface_color == white_surface) then
call glEnable(gl_light0)
call glLightModelfv(gl_light_model_ambient, (/.5,.5,.5,1./))
endif
endif ! draw_surface_solid
! draw the surface grid
if (draw_surface_grid) then
call glPolygonMode(gl_front_and_back, gl_line)
call glBegin(gl_triangles)
! draw surface grid in black
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,black)
! compute the function values for the first line of points
do j=0,ngridy
zval(j,2) = func_to_plot(gridx(0),gridy(j))
end do
! for each x grid interval...
do i=1,ngridx
! copy left side function values from the right side of the previous interval
zval(:,1) = zval(:,2)
! compute the function values for the right side of the interval
do j=0,ngridy
zval(j,2) = func_to_plot(gridx(i),gridy(j))
end do
minz = min(minz,minval(zval))
maxz = max(maxz,maxval(zval))
! for each y grid interval ...
do j=1,ngridy
! add two triangles to the display list
call glvertex3d(gridx(i-1),gridy(j-1),zval(j-1,1))
call glvertex3d(gridx(i ),gridy(j-1),zval(j-1,2))
call glvertex3d(gridx(i ),gridy(j ),zval(j ,2))
call glvertex3d(gridx(i ),gridy(j ),zval(j ,2))
call glvertex3d(gridx(i-1),gridy(j-1),zval(j-1,1))
call glvertex3d(gridx(i-1),gridy(j ),zval(j ,1))
end do
end do
call glEnd
endif ! draw_surface_grid
! draw the contour plot
if (draw_contour) then
call glPolygonMode(gl_front_and_back, gl_line)
call glBegin(gl_lines)
call glNormal3fv((/0.0_glfloat, 0.0_glfloat, 1.0_glfloat/))
! draw the domain in black, also sets color to black for black_contour
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse,black)
call glVertex3d(minx,miny,0.0_GLDOUBLE)
call glVertex3d(maxx,miny,0.0_GLDOUBLE)
call glVertex3d(maxx,miny,0.0_GLDOUBLE)
call glVertex3d(maxx,maxy,0.0_GLDOUBLE)
call glVertex3d(maxx,maxy,0.0_GLDOUBLE)
call glVertex3d(minx,maxy,0.0_GLDOUBLE)
call glVertex3d(minx,maxy,0.0_GLDOUBLE)
call glVertex3d(minx,miny,0.0_GLDOUBLE)
! set the contour values
if (contour_values_given) then
contour_value = actual_contours
else
do i=1,num_contour
contour_value(i) = minz+(maxz-minz)*(i-1)/real(num_contour-1,GLDOUBLE)
end do
endif
! compute the function values for the first line of points
do j=0,ngridy
zval(j,2) = func_to_plot(gridx(0),gridy(j))
end do
! for each x grid interval...
do i=1,ngridx
! copy left side function values from the right side of the previous interval
zval(:,1) = zval(:,2)
! compute the function values for the right side of the interval
do j=0,ngridy
zval(j,2) = func_to_plot(gridx(i),gridy(j))
end do
minz = min(minz,minval(zval))
maxz = max(maxz,maxval(zval))
! for each y grid interval ...
do j=1,ngridy
! for two triangles
do k=1,2
! set the vertices
if (k==1) then
x1 = gridx(i-1); y1 = gridy(j-1); z1 = zval(j-1,1)
x2 = gridx(i ); y2 = gridy(j-1); z2 = zval(j-1,2)
x3 = gridx(i ); y3 = gridy(j ); z3 = zval(j ,2)
else
x1 = gridx(i-1); y1 = gridy(j-1); z1 = zval(j-1,1)
x2 = gridx(i-1); y2 = gridy(j ); z2 = zval(j ,1)
x3 = gridx(i ); y3 = gridy(j ); z3 = zval(j ,2)
endif
! order the vertices by z value
xt = x1; yt = y1; zt = z1
if (z2 < z1) then
xt = x1; yt = y1; zt = z1
if (z3 < z1) then
if (z2 < z3) then
x1 = x2; y1 = y2; z1 = z2
x2 = x3; y2 = y3; z2 = z3
else
x1 = x3; y1 = y3; z1 = z3
endif
x3 = xt; y3 = yt; z3 = zt
else
x1 = x2; y1 = y2; z1 = z2
x2 = xt; y2 = yt; z2 = zt
endif
elseif (z3 < z1) then
x1 = x3; y1 = y3; z1 = z3
x3 = x2; y3 = y2; z3 = z2
x2 = xt; y2 = yt; z2 = zt
elseif (z3 < z2) then
xt = x2; yt = y2; zt = z2
x2 = x3; y2 = y3; z2 = z3
x3 = xt; y3 = yt; z3 = zt
endif
! if z1==z3, the triangle is horizontal and no contours pass through it
if (z1==z3) cycle
! for each contour value
do cont = 1,num_contour
! see if it passes through this triangle
if (contour_value(cont) < z1) cycle
if (contour_value(cont) > z3) exit
! set the color for contours colored by solution
if (contour_color == rainbow_contour) then
call get_rainbow(contour_value(cont),minz,maxz,color)
call glMaterialfv(gl_front_and_back,gl_ambient_and_diffuse, &
color)
endif
! see where it crosses the 1-3 edge
frac = (contour_value(cont)-z1)/(z3-z1)
xcross1 = (1.0_GLDOUBLE - frac)*x1 + frac*x3
ycross1 = (1.0_GLDOUBLE - frac)*y1 + frac*y3
! see where it crosses one of the other edges
if (contour_value(cont) == z2) then
xcross2 = x2
ycross2 = y2
elseif (contour_value(cont) < z2) then
frac = (contour_value(cont)-z1)/(z2-z1)
xcross2 = (1.0_GLDOUBLE - frac)*x1 + frac*x2
ycross2 = (1.0_GLDOUBLE - frac)*y1 + frac*y2
else
frac = (contour_value(cont)-z2)/(z3-z2)
xcross2 = (1.0_GLDOUBLE - frac)*x2 + frac*x3
ycross2 = (1.0_GLDOUBLE - frac)*y2 + frac*y3
endif
! add the line segment to the display list
call glVertex3d(xcross1,ycross1,0.0_GLDOUBLE)
call glVertex3d(xcross2,ycross2,0.0_GLDOUBLE)
end do
end do
end do
end do
call glEnd
endif ! draw_contour
! finish off display list
call glEndList
call glutPostRedisplay
end subroutine draw_func
subroutine get_rainbow(val,minval,maxval,c)
real(GLDOUBLE), intent(in) :: val,maxval,minval
real(GLFLOAT), intent(out) :: c(4)
real(GLFLOAT) :: f
if (maxval > minval) then
f = (val-minval)/(maxval-minval)
else ! probably maxval==minval
f = 0.5_glfloat
endif
if (f < .25) then
c(1) = 0.0_glfloat
c(2) = 4.0_glfloat * f
c(3) = 1.0_glfloat
c(4) = 1.0_glfloat
elseif (f < .5) then
c(1) = 0.0_glfloat
c(2) = 1.0_glfloat
c(3) = 2.0_glfloat - 4.0_glfloat*f
c(4) = 1.0_glfloat
elseif (f < .75) then
c(1) = 4.0_glfloat * f - 2.0_glfloat
c(2) = 1.0_glfloat
c(3) = 0.0_glfloat
c(4) = 1.0_glfloat
else
c(1) = 1.0_glfloat
c(2) = 4.0_glfloat - 4.0_glfloat*f
c(3) = 0.0_glfloat
c(4) = 1.0_glfloat
endif
end subroutine get_rainbow
function normcrossprod(x,y,z)
real(glfloat), dimension(3) :: normcrossprod
real(gldouble), dimension(3), intent(in) :: x,y,z
real(glfloat) :: t1(3),t2(3),norm
t1(1) = x(2) - x(1)
t1(2) = y(2) - y(1)
t1(3) = z(2) - z(1)
t2(1) = x(3) - x(1)
t2(2) = y(3) - y(1)
t2(3) = z(3) - z(1)
normcrossprod(1) = t1(2)*t2(3) - t1(3)*t2(2)
normcrossprod(2) = t1(3)*t2(1) - t1(1)*t2(3)
normcrossprod(3) = t1(1)*t2(2) - t1(2)*t2(1)
norm = sqrt(dot_product(normcrossprod,normcrossprod))
if (norm /= 0._glfloat) normcrossprod = normcrossprod/norm
end function normcrossprod
subroutine menu_handler2(selection) bind(c,name="")
integer(kind=glcint), value :: selection
select case (selection)
case (surfgrid_toggle)
draw_surface_grid = .not. draw_surface_grid
call draw_func
case (surfsolid_toggle)
draw_surface_solid = .not. draw_surface_solid
call draw_func
case (contour_toggle)
draw_contour = .not. draw_contour
call draw_func
case (quit_selected)
stop
end select
return
end subroutine menu_handler2
subroutine param_handler(selection) bind(c,name="")
integer(kind=glcint), value :: selection
select case (selection)
case (set_nx)
print *,"Enter number of x subintervals:"
read *, ngridx
call draw_func
case (set_ny)
print *,"Enter number of y subintervals:"
read *, ngridy
call draw_func
case (set_ncontour)
print *,"Enter number of contour lines:"
read *, num_contour
contour_values_given = .false.
call draw_func
case (set_contour_val)
print *,"enter number of contours:"
read *, num_contour
if (allocated(actual_contours)) deallocate(actual_contours)
allocate(actual_contours(num_contour))
print *,"enter ",num_contour," contour values:"
read *,actual_contours
contour_values_given = .true.
call draw_func
case (set_xrange)
print *,"Enter minimum and maximum x values:"
read *,minx,maxx
call draw_func
case (set_yrange)
print *,"Enter minimum and maximum y values:"
read *,miny,maxy
call draw_func
case (reset_params)
ngridx = init_ngridx
ngridy = init_ngridy
num_contour = init_num_contour
contour_color = init_contour_color
surface_color = init_surface_color
minx = init_minx
maxx = init_maxx
miny = init_miny
maxy = init_maxy
draw_surface_grid = init_draw_surface_grid
draw_surface_solid = init_draw_surface_solid
draw_contour = init_draw_contour
call draw_func
end select
end subroutine param_handler
subroutine contour_color_handler(selection) bind(c,name="")
integer(kind=glcint), value :: selection
contour_color = selection
call draw_func
end subroutine contour_color_handler
subroutine surface_color_handler(selection) bind(c,name="")
integer(kind=glcint), value :: selection
surface_color = selection
call draw_func
end subroutine surface_color_handler
subroutine make_menu(submenuid)
integer, intent(in) :: submenuid
integer :: menuid, param_id, contour_color_menu, surface_color_menu
contour_color_menu = glutCreateMenu(contour_color_handler)
call glutAddMenuEntry("black"//char(0),black_contour)
call glutAddMenuEntry("contour value"//char(0),rainbow_contour)
surface_color_menu = glutCreateMenu(surface_color_handler)
call glutAddMenuEntry("red"//char(0),red_surface)
call glutAddMenuEntry("white"//char(0),white_surface)
call glutAddMenuEntry("surface height"//char(0),rainbow_surface)
param_id = glutCreateMenu(param_handler)
call glutAddMenuEntry("number of x grid intervals"//char(0),set_nx)
call glutAddMenuEntry("number of y grid intervals"//char(0),set_ny)
call glutAddMenuEntry("number of uniform contour lines"//char(0),set_ncontour)
call glutAddMenuEntry("contour values"//char(0),set_contour_val)
call glutAddMenuEntry("x range"//char(0),set_xrange)
call glutAddMenuEntry("y range"//char(0),set_yrange)
call glutAddSubMenu("contour color"//char(0),contour_color_menu)
call glutAddSubMenu("surface color"//char(0),surface_color_menu)
call glutAddMenuEntry("reset to initial parameters"//char(0),reset_params)
menuid = glutCreateMenu(menu_handler2)
call glutAddSubMenu("View Modifier"//char(0),submenuid)
call glutAddMenuEntry("toggle surface grid"//char(0),surfgrid_toggle)
call glutAddMenuEntry("toggle solid surface"//char(0),surfsolid_toggle)
call glutAddMenuEntry("toggle contour"//char(0),contour_toggle)
call glutAddSubMenu("plotting parameters"//char(0),param_id)
call glutAddMenuEntry("quit"//char(0),quit_selected)
call glutAttachMenu(GLUT_RIGHT_BUTTON)
end subroutine make_menu
end module function_plotter
!---------------------------------------------------------------------------
program plot_func
use opengl_gl
use opengl_glut
use view_modifier
use function_plotter
implicit none
integer :: winid, menuid, submenuid
! Initializations
call glutInit
call glutInitDisplayMode(ior(GLUT_DOUBLE,ior(GLUT_RGB,GLUT_DEPTH)))
call glutInitWindowSize(500_glcint,500_glcint)
! Create a window
winid = glutCreateWindow("Function plotter")
! initialize view_modifier, receiving the id for it's submenu
submenuid = view_modifier_init()
! create the menu
call make_menu(submenuid)
! Set the display callback
call glutDisplayFunc(display)
! set the lighting conditions
call glClearColor(0.9_glclampf, 0.9_glclampf, 0.9_glclampf, 1.0_glclampf)
call glLightfv(gl_light0, gl_diffuse, (/1.,1.,1.,1./))
call glLightfv(gl_light0, gl_position, (/1.5,-.5,2.,0.0/))
call glEnable(gl_lighting)
call glEnable(gl_light0)
call glLightModelfv(gl_light_model_ambient, (/.5,.5,.5,1./))
call glDepthFunc(gl_lequal)
call glEnable(gl_depth_test)
! Create the image
call draw_func
! Let glut take over
call glutMainLoop
end program plot_func
!---------------------------------------------------------------------------
! The function to plot
function func_to_plot(x,y)
use opengl_gl
real(GLDOUBLE) :: func_to_plot
real(GLDOUBLE), intent(in) :: x,y
func_to_plot = 0.5_GLDOUBLE * ( &
cos(0.3_GLDOUBLE*sqrt(80.0_GLDOUBLE*x)-16.0_GLDOUBLE*y/3.0_GLDOUBLE)* &
cos(16.0_GLDOUBLE*x/3.0_GLDOUBLE) + x-y )
end function func_to_plot
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