GLunit.pas

unit GLunit;

interface

const
  l_xyz=1;     // list for draw coordinate system
  l_text=1000; // list for text

procedure gl_create_form();    // here all commands, that must run on form create
procedure gl_destroy_form();   // here all commands, that must run on form destroy
procedure start_draw();        // procedure for drawing all
procedure start_form_resize(width,height : integer); // procedure, that set new size of drawing area
procedure draw_function();

implementation
uses OpenGL, tools;
//------------------------------------------------------------------------------
procedure glText(Lit : PChar);
begin
glPushMatrix();
  glPushAttrib(GL_LIST_BIT);
  glListBase(l_text);
  glCallLists(Length(Lit),GL_UNSIGNED_BYTE,Lit);
  glPopAttrib();
glPopMatrix();
end;
//------------------------------------------------------------------------------
procedure draw_function();
var
  n,k : integer;
begin
if (need_rotate=1) then Exit; // if we need rotate, we draw from other place (see rotate unit)
glColor3d(1,1,1);
for n:=0 to v_size-1 do
  begin
    if (vx[n]>5.5) or (vy[n]>5.5) or (vx[n]<-5.5) or (vy[n]<-5.5) then continue;
    glBegin(GL_POINTS); glVertex2d(vx[n],vy[n]); glEnd();
  end;
end;
//------------------------------------------------------------------------------
procedure start_draw;
begin
glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
//========
glCallList(l_xyz);
if (v_size<>0) then draw_function();
end;
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
procedure gl_create_form;
var
pos : array[0..3] of real; {3,3,3,0.5}
dir : array[0..2] of real; {-1,-1,-1}
mat_sp : array[0..3] of real; {1,1,1,1}
begin
pos[0]:=6; pos[1]:=6; pos[2]:=6; pos[3]:=0.5;
dir[0]:=-7; dir[1]:=-7; dir[2]:=-7;
mat_sp[0]:=1; mat_sp[1]:=1; mat_sp[2]:=1; mat_sp[3]:=1;

glClearColor(0,0,0,1);
glEnable(GL_DEPTH_TEST);
glEnable(GL_POINT_SMOOTH);
//glShadeModel(GL_SMOOTH);
glEnable(GL_COLOR_MATERIAL);
//glEnable(GL_NORMALIZE);
// Lighting
glEnable(GL_LIGHT0);
glMaterialfv(GL_FRONT_AND_BACK,GL_DIFFUSE,@mat_sp);
glMaterialf(GL_FRONT_AND_BACK,GL_SHININESS,128);

glLightfv(GL_LIGHT0,GL_POSITION,@pos);
glLightfv(GL_LIGHT0,GL_SPOT_DIRECTION,@dir);

glLighti(GL_LIGHT0,GL_SPOT_EXPONENT,0);
glLighti(GL_LIGHT0,GL_SPOT_CUTOFF,90);
// create OpenGL list for late using
glNewList(l_xyz,GL_COMPILE);
// start draw coordinate system
  glBegin(GL_LINES);
    glColor3d(1,0,0); glVertex3d(-6,0,0); glVertex3d(6,0,0); // x
    glColor3d(0,1,0); glVertex3d(0,-6,0); glVertex3d(0,6,0); // y
    glColor3d(0,0,1); glVertex3d(0,0,-6); glVertex3d(0,0,6); // z
  glEnd;
// start drawing text (x,y,z)
  glColor3d(1,0,0); glPushMatrix(); glTranslated(5.7,-0.5,0); glText('x'); glPopMatrix();
  glColor3d(0,1,0); glPushMatrix(); glTranslated(0.2,5.7,0); glText('y'); glPopMatrix();
  glColor3d(0,0,1); glPushMatrix(); glTranslated(0.2,0,5.7); glText('z'); glPopMatrix();
glEndList();
end;
//------------------------------------------------------------------------------
procedure gl_destroy_form();
begin
glDeleteLists(l_xyz,1);
glDeleteLists(l_text,256);
end;
//------------------------------------------------------------------------------
procedure start_form_resize(width,height : integer);
begin
glViewport(0,-25,width,height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-7,7,-7,7,-7,7);
glMatrixMode(GL_MODELVIEW);
end;
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------

end.