/*
* License Applicability. Except to the extent portions of this file are
* made subject to an alternative license as permitted in the SGI Free
* Software License B, Version 1.1 (the "License"), the contents of this
* file are subject only to the provisions of the License. You may not use
* this file except in compliance with the License. You may obtain a copy
* of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
* Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
*
* http://oss.sgi.com/projects/FreeB
*
* Note that, as provided in the License, the Software is distributed on an
* "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
* DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
* CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
* PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
*
* Original Code. The Original Code is: OpenGL Sample Implementation,
* Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
* Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
* Copyright in any portions created by third parties is as indicated
* elsewhere herein. All Rights Reserved.
*
* Additional Notice Provisions: The application programming interfaces
* established by SGI in conjunction with the Original Code are The
* OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
* April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
* 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
* Window System(R) (Version 1.3), released October 19, 1998. This software
* was created using the OpenGL(R) version 1.2.1 Sample Implementation
* published by SGI, but has not been independently verified as being
* compliant with the OpenGL(R) version 1.2.1 Specification.
*
*/
/*
* aaindex.c
* This program draws shows how to draw anti-aliased lines in color
* index mode. It draws two diagonal lines to form an X; when 'r'
* is typed in the window, the lines are rotated in opposite
* directions.
*/
#include <GL/glut.h>
#include "stdlib.h"
#define RAMPSIZE 16
#define RAMP1START 32
#define RAMP2START 48
static float rotAngle = 0.;
/* Initialize antialiasing for color index mode,
* including loading a green color ramp starting
* at RAMP1START, and a blue color ramp starting
* at RAMP2START. The ramps must be a multiple of 16.
*/
void init(void)
{
int i;
for (i = 0; i < RAMPSIZE; i++) {
GLfloat shade;
shade = (GLfloat) i/(GLfloat) RAMPSIZE;
glutSetColor(RAMP1START+(GLint)i, 0., shade, 0.);
glutSetColor(RAMP2START+(GLint)i, 0., 0., shade);
}
glEnable (GL_LINE_SMOOTH);
glHint (GL_LINE_SMOOTH_HINT, GL_DONT_CARE);
glLineWidth (1.5);
glClearIndex ((GLfloat) RAMP1START);
}
/* Draw 2 diagonal lines to form an X
*/
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glIndexi(RAMP1START);
glPushMatrix();
glRotatef(-rotAngle, 0.0, 0.0, 0.1);
glBegin (GL_LINES);
glVertex2f (-0.5, 0.5);
glVertex2f (0.5, -0.5);
glEnd ();
glPopMatrix();
glIndexi(RAMP2START);
glPushMatrix();
glRotatef(rotAngle, 0.0, 0.0, 0.1);
glBegin (GL_LINES);
glVertex2f (0.5, 0.5);
glVertex2f (-0.5, -0.5);
glEnd ();
glPopMatrix();
glFlush();
}
void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= h)
gluOrtho2D (-1.0, 1.0,
-1.0*(GLfloat)h/(GLfloat)w, 1.0*(GLfloat)h/(GLfloat)w);
else
gluOrtho2D (-1.0*(GLfloat)w/(GLfloat)h,
1.0*(GLfloat)w/(GLfloat)h, -1.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 'r':
case 'R':
rotAngle += 20.;
if (rotAngle >= 360.) rotAngle = 0.;
glutPostRedisplay();
break;
case 27: /* Escape Key */
exit(0);
break;
default:
break;
}
}
/* Main Loop
* Open window with initial window size, title bar,
* color index display mode, and handle input events.
*/
int main(int argc, char** argv)
{
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_INDEX);
glutInitWindowSize (200, 200);
glutCreateWindow (argv[0]);
init();
glutReshapeFunc (reshape);
glutKeyboardFunc (keyboard);
glutDisplayFunc (display);
glutMainLoop();
return 0;
}