Delphi下的OpenGL开发入门

unit Unit1;

interface

uses
  OpenGL,Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls;

type
  TForm1 = class(TForm)
    Timer1: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
  private
    { Private declarations }
    angle:single;
    procedure Draw; //Draws an OpenGL scene on request
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}
function getNormal(p1,p2,p3:TGLArrayf3):TGLArrayf3;
var a,b:TGLArrayf3;
begin
//make two vectors
a[]:=p2[]-p1[]; a[]:=p2[]-p1[]; a[]:=p2[]-p1[];
b[]:=p3[]-p1[]; b[]:=p3[]-p1[]; b[]:=p3[]-p1[];
//calculate cross-product
result[]:=a[]*b[]-a[]*b[];
result[]:=a[]*b[]-a[]*b[];
result[]:=a[]*b[]-a[]*b[];
end; 

procedure setupPixelFormat(DC:HDC);
const
pfd:TPIXELFORMATDESCRIPTOR = (
  nSize:sizeof(TPIXELFORMATDESCRIPTOR); // size
  nVersion:;                           // version
  dwFlags:PFD_SUPPORT_OPENGL or PFD_DRAW_TO_WINDOW or
    PFD_DOUBLEBUFFER;                   // support double-buffering
  iPixelType:PFD_TYPE_RGBA;             // color type
  cColorBits:;                        // preferred color depth
  cRedBits:; cRedShift:;              // color bits (ignored)
  cGreenBits:; cGreenShift:;
  cBlueBits:; cBlueShift:;
  cAlphaBits:; cAlphaShift:;          // no alpha buffer
  cAccumBits: ;
  cAccumRedBits: ;                     // no accumulation buffer,
  cAccumGreenBits: ;                   // accum bits (ignored)
  cAccumBlueBits: ;
  cAccumAlphaBits: ;
  cDepthBits:;                        // depth buffer
  cStencilBits:;                       // no stencil buffer
  cAuxBuffers:;                        // no auxiliary buffers
  iLayerType:PFD_MAIN_PLANE;            // main layer
  bReserved: ;
  dwLayerMask: ;
  dwVisibleMask: ;
  dwDamageMask: ;                      // no layer, visible, damage masks
);
var pixelFormat:integer;
begin
pixelFormat := ChoosePixelFormat(DC, @pfd);
if (pixelFormat = ) then
exit;
if (SetPixelFormat(DC, pixelFormat, @pfd) <> TRUE) then
exit;
end; 

procedure GLInit;
const
light0_position:TGLArrayf4=( -8.0, 8.0, -16.0, 0.0);
ambient: TGLArrayf4=( 0.3, 0.3, 0.3, 0.3);
begin
// set viewing projection
glMatrixMode(GL_PROJECTION);
glFrustum(-0.1, 0.1, -0.1, 0.1, 0.3, 25.0);
// position viewer */
glMatrixMode(GL_MODELVIEW);
glEnable(GL_DEPTH_TEST); 

// set lights
glEnable(GL_LIGHTING);
glLightfv(GL_LIGHT0, GL_POSITION, @light0_position);
glLightfv(GL_LIGHT0, GL_AMBIENT, @ambient);
glEnable(GL_LIGHT0);
end; 

procedure TForm1.Draw;
const D=1.5;
H1=D/1.732;
H2=D*1.732-H1; // D/H = tg() = /sqrt()
HY=3.0;
const //vertexes
a1:TGLArrayf3=(-D, , -H1);
a2:TGLArrayf3=(D, , -H1);
a3:TGLArrayf3=(, , H2);
a4:TGLArrayf3=(, HY, );
var n1, n2, n3, n4: TGLArrayf3; //normals
begin
n1 := getNormal(a1,a3,a2);
n2 := getNormal(a1,a2,a4);
n3 := getNormal(a2,a3,a4);
n4 := getNormal(a3,a1,a4);
glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
glEnable(GL_NORMALIZE);
glShadeModel(GL_FLAT);
glCullFace(GL_BACK);
glLoadIdentity;
glTranslatef(0.0, 0.0, -12.0);
glBegin(GL_TRIANGLES);

glNormal3fv(@n1);

glVertex3fv(@a1); glVertex3fv(@a2); glVertex3fv(@a3);

glNormal3fv(@n2);
glVertex3fv(@a1); glVertex3fv(@a2); glVertex3fv(@a4);

glNormal3fv(@n3);

glVertex3fv(@a2); glVertex3fv(@a3); glVertex3fv(@a4);
glNormal3fv(@n4);

glVertex3fv(@a3); glVertex3fv(@a1); glVertex3fv(@a4);
glEnd;
SwapBuffers(wglGetCurrentDC);
end; 

procedure TForm1.FormCreate(Sender: TObject);
var DC:HDC;
RC:HGLRC;
i:integer;
begin
DC:=GetDC(Handle); //Actually, you can use any windowed control here
SetupPixelFormat(DC);
RC:=wglCreateContext(DC); //makes OpenGL window out of DC
wglMakeCurrent(DC, RC); //makes OpenGL window active
GLInit; //initialize OpenGL
end; 

procedure TForm1.FormPaint(Sender: TObject);
begin
  Draw;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
angle:=angle+1.0;
Draw;
end;
end.