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{
GL units for Free Pascal - GLUT demo
1999 Sebastian Guenther, sguenther@gmx.de
2008 Jonas Maebe (converted to use vertex arrays)
You may use this source as starting point for your own programs; consider it
as Public Domain.
}
{$mode objfpc}
program GLUTDemoVA;
uses
GL, GLU, GLUT;
const
FPCImg: array[0..4, 0..10] of Byte =
((1, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1),
(1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0),
(1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0),
(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0),
(1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1));
var
counter: Integer;
(*
3 __ 2
/| |
7/0|_ |1
|/ /
+--+
4 5
back plane: 0-3-2-1
*)
const
colors: array[0..7, 0..2] of Single =
((0, 0, 0), (0, 0, 1), (0, 1, 0), (0, 1, 1),
(1, 0, 0), (1, 0, 1), (1, 1, 0), (1, 1, 1));
corners: array[0..7, 0..2] of Single =
((-1, -1, -1), (+1, -1, -1), (+1, +1, -1), (-1, +1, -1),
(-1, -1, +1), (+1, -1, +1), (+1, +1, +1), (-1, +1, +1));
indices: array[0..5] of array[0..3] of GLubyte =
(
{ all vertices must be in ccw order }
(0,3,1,2), // back
(4,5,7,6), // front
(3,0,7,4), // left
(1,2,5,6), // right
(3,7,2,6), // top
(5,4,1,0) // bottom
);
procedure DrawCube;
begin
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glVertexPointer(3,GL_FLOAT,0,@corners);
glColorPointer(3,GL_FLOAT,0,@colors);
// this will also draw a bunch of triangles inside the cube, but
// may still be faster than the commented-out sequence below due
// to less calls into the renderer
glDrawElements(GL_TRIANGLE_STRIP,24,GL_UNSIGNED_BYTE,@indices[0]);
(*
glDrawElements(GL_TRIANGLE_STRIP,4,GL_UNSIGNED_BYTE,@indices[0]);
glDrawElements(GL_TRIANGLE_STRIP,4,GL_UNSIGNED_BYTE,@indices[1]);
glDrawElements(GL_TRIANGLE_STRIP,4,GL_UNSIGNED_BYTE,@indices[2]);
glDrawElements(GL_TRIANGLE_STRIP,4,GL_UNSIGNED_BYTE,@indices[3]);
glDrawElements(GL_TRIANGLE_STRIP,4,GL_UNSIGNED_BYTE,@indices[4]);
glDrawElements(GL_TRIANGLE_STRIP,4,GL_UNSIGNED_BYTE,@indices[5]);
*)
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_COLOR_ARRAY);
end;
procedure DisplayWindow; cdecl;
var
x, y: Integer;
begin
Inc(counter);
// counter:=145;
glClearColor(0, 0, 0.2, 1);
glClear(GL_COLOR_BUFFER_BIT+GL_DEPTH_BUFFER_BIT);
glPushMatrix;
glTranslatef(0, 0, Sin(Single(counter) / 20.0) * 5.0 - 5.0);
glRotatef(Sin(Single(counter) / 200.0) * 720.0, 0, 1, 0);
glRotatef(counter, 0, 0, 1);
for y := 0 to 4 do
for x := 0 to 10 do
if FPCImg[y, x] > 0 then begin
glPushMatrix;
glRotatef(x * Sin(Single(counter) / 5.0), 0, 1, 0);
glRotatef(y * Sin(Single(counter) / 12.0) * 4.0, 0, 0, 1);
glTranslatef((x - 5) * 1, (2 - y) * 1, 0);
glScalef(0.4, 0.4, 0.4);
glRotatef(counter, 0.5, 1, 0);
DrawCube;
glPopMatrix;
end;
glPopMatrix;
// Inc(counter);
glutSwapBuffers;
end;
procedure OnTimer(value: Integer); cdecl;
begin
glutPostRedisplay;
glutTimerFunc(20, @OnTimer, 0);
end;
begin
glutInit(@argc, argv);
glutInitDisplayMode(GLUT_RGB or GLUT_DOUBLE or GLUT_DEPTH);
glutCreateWindow('Free Pascal GLUT demo');
glutDisplayFunc(@DisplayWindow);
glutTimerFunc(20, @OnTimer, 0);
WriteLn;
WriteLn('GL info:');
WriteLn(' Vendor: ', PChar(glGetString(GL_VENDOR)));
WriteLn(' Renderer: ', PChar(glGetString(GL_RENDERER)));
WriteLn(' Version: ', PChar(glGetString(GL_VERSION)));
WriteLn(' Extensions: ', PChar(glGetString(GL_EXTENSIONS)));
// Enable backface culling
glEnable(GL_CULL_FACE);
// Set up depth buffer
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
// Set up projection matrix
glMatrixMode(GL_PROJECTION);
glLoadIdentity;
gluPerspective(90, 1.3, 0.1, 100);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity;
glTranslatef(0, 0, -5.5);
WriteLn('Starting...');
glutMainLoop;
end.
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