{=============================================================================}
{= Copyright (c) Mark J. Kilgard, 1994.                                      =}
{=============================================================================}

{=============================================================================}
{= (c) Copyright 1993, 1994, Silicon Graphics, Inc.                          =}
{= ALL RIGHTS RESERVED                                                       =}
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{= any purpose and without fee is hereby granted, provided that the above    =}
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{= and this permission notice appear in supporting documentation, and that   =}
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{= or publicity pertaining to distribution of the software without specific, =}
{= written prior permission.                                                 =}
{=                                                                           =}
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{= AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,          =}
{= INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR          =}
{= FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON              =}
{= GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,           =}
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{=                                                                           =}
{= US Government Users Restricted Rights                                     =}
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{= clauses in the FAR or the DOD or NASA FAR Supplement.                     =}
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{=                                                                           =}
{= OpenGL(TM) is a trademark of Silicon Graphics, Inc.                       =}
{=============================================================================}
unit BezMesh;

interface

implementation

uses
    MGLTypes,
    DemoList,
    CmdLine,
    MGLGlut,
    MGLGl;

const
    ctrlpoints: array[0..3,0..3,0..2] of GLfloat =
        (
            (
                (-1.5, -1.5,  4.0),
                (-0.5, -1.5,  2.0),
                ( 0.5, -1.5, -1.0),
                ( 1.5, -1.5,  2.0)
            ),
            (
                (-1.5, -0.5,  1.0),
                (-0.5, -0.5,  3.0),
                ( 0.5, -0.5,  0.0),
                ( 1.5, -0.5, -1.0)
            ),
            (
                (-1.5, 0.5, 4.0),
                (-0.5, 0.5, 0.0),
                ( 0.5, 0.5, 3.0),
                ( 1.5, 0.5, 4.0)
            ),
            (
                (-1.5, 1.5, -2.0),
                (-0.5, 1.5, -2.0),
                ( 0.5, 1.5,  0.0),
                ( 1.5, 1.5, -1.0)
            )
        );

procedure   InitLights;
const
    ambient         : array[0..3] of GLfloat = (0.2, 0.2, 0.2, 1.0);
    position        : array[0..3] of GLfloat = (0.0, 0.0, 2.0, 1.0);
    mat_diffuse     : array[0..3] of GLfloat = (0.6, 0.6, 0.6, 1.0);
    mat_specular    : array[0..3] of GLfloat = (1.0, 1.0, 1.0, 1.0);
    mat_shininess   : array[0..0] of GLfloat = (50.0);
begin
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);

    glLightfv(GL_LIGHT0, GL_AMBIENT, @ambient);
    glLightfv(GL_LIGHT0, GL_POSITION, @position);

    glMaterialfv(GL_FRONT, GL_DIFFUSE, @mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR, @mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, @mat_shininess);
end;

procedure   Display; cdecl;
begin
    glClear(GL_COLOR_BUFFER_BIT or GL_DEPTH_BUFFER_BIT);
    glPushMatrix();
    glRotatef(85.0, 1.0, 1.0, 1.0);
    glEvalMesh2(GL_FILL, 0, 20, 0, 20);
    glPopMatrix();
    glFlush();
end;

procedure   MyInit;
begin
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glEnable(GL_DEPTH_TEST);
    glMap2f(GL_MAP2_VERTEX_3, 0, 1, 3, 4,
        0, 1, 12, 4, @ctrlpoints[0][0][0]);
    glEnable(GL_MAP2_VERTEX_3);
    glEnable(GL_AUTO_NORMAL);
    glEnable(GL_NORMALIZE);
    glMapGrid2f(20, 0.0, 1.0, 20, 0.0, 1.0);
    InitLights();   // for lighted version only
end;

procedure   MyReshape(w, h: int); cdecl;
begin
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    if w <= h then
        glOrtho(-4.0, 4.0, -4.0 * h / w, 4.0 * h / w, -4.0, 4.0)
    else
        glOrtho(-4.0 * w / h, 4.0 * w / h, -4.0, 4.0, -4.0, 4.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
end;

procedure   Demo;
begin
    InitGLUT;
    glutInitDisplayMode(GLUT_SINGLE or GLUT_RGB or GLUT_DEPTH);
    glutCreateWindow('BezMesh');
    MyInit();
    glutReshapeFunc(MyReshape);
    glutDisplayFunc(Display);
    glutMainLoop();
end;

initialization
    RegisterDemo(
                'Book',
                'BezMesh',
                'Renders a lighted, filled Bezier surface, using two-dimensional evaluators',
                 Demo
                );
end.
