| /* |
| * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc. |
| * |
| * Permission to use, copy, modify, distribute, and sell this software and |
| * its documentation for any purpose is hereby granted without fee, provided |
| * that (i) the above copyright notices and this permission notice appear in |
| * all copies of the software and related documentation, and (ii) the name of |
| * Silicon Graphics may not be used in any advertising or |
| * publicity relating to the software without the specific, prior written |
| * permission of Silicon Graphics. |
| * |
| * THE SOFTWARE IS PROVIDED "AS-IS" 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 BE LIABLE FOR |
| * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, |
| * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, |
| * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF |
| * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE |
| * OF THIS SOFTWARE. |
| */ |
| |
| #include <GL/glew.h> |
| #include <math.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <stdlib.h> |
| #include <GL/glut.h> |
| |
| |
| |
| GLenum doubleBuffer; |
| |
| static void Init(void) |
| { |
| fprintf(stderr, "GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER)); |
| fprintf(stderr, "GL_VERSION = %s\n", (char *) glGetString(GL_VERSION)); |
| fprintf(stderr, "GL_VENDOR = %s\n", (char *) glGetString(GL_VENDOR)); |
| fflush(stderr); |
| |
| glClearColor(0.0, 0.0, 1.0, 0.0); |
| } |
| |
| static void Reshape(int width, int height) |
| { |
| glViewport(0, 0, (GLint)width, (GLint)height); |
| |
| glMatrixMode(GL_PROJECTION); |
| glLoadIdentity(); |
| glOrtho(-1.0, 1.0, -1.0, 1.0, 0, 100.0); |
| glMatrixMode(GL_MODELVIEW); |
| } |
| |
| static void Key(unsigned char key, int x, int y) |
| { |
| switch (key) { |
| case 27: |
| exit(1); |
| default: |
| break; |
| } |
| glutPostRedisplay(); |
| } |
| |
| |
| static float |
| expected(float z, float size, const float atten[3]) |
| { |
| float dist = fabs(z); |
| const GLfloat q = atten[0] + dist * (atten[1] + dist * atten[2]); |
| const GLfloat a = sqrt(1.0 / q); |
| return size * a; |
| } |
| |
| |
| static void Draw(void) |
| { |
| static GLfloat atten[3] = { 0.0, 0.1, .01 }; |
| float size = 40.0; |
| int i; |
| |
| glClear(GL_COLOR_BUFFER_BIT); |
| |
| glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); |
| glPointSize(size); |
| glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, atten); |
| |
| glColor3f(1,0,0); |
| |
| printf("Expected point sizes:\n"); |
| glBegin(GL_POINTS); |
| for (i = 0; i < 5; i++) { |
| float x = -0.8 + i * 0.4; |
| float z = -i * 20 - 10; |
| glVertex3f( x, 0.0, z); |
| printf(" %f\n", expected(z, size, atten)); |
| } |
| glEnd(); |
| |
| glFlush(); |
| |
| if (doubleBuffer) { |
| glutSwapBuffers(); |
| } |
| } |
| |
| |
| static GLenum Args(int argc, char **argv) |
| { |
| GLint i; |
| |
| doubleBuffer = GL_FALSE; |
| |
| for (i = 1; i < argc; i++) { |
| if (strcmp(argv[i], "-sb") == 0) { |
| doubleBuffer = GL_FALSE; |
| } else if (strcmp(argv[i], "-db") == 0) { |
| doubleBuffer = GL_TRUE; |
| } else { |
| fprintf(stderr, "%s (Bad option).\n", argv[i]); |
| return GL_FALSE; |
| } |
| } |
| return GL_TRUE; |
| } |
| |
| |
| int main(int argc, char **argv) |
| { |
| GLenum type; |
| |
| glutInit(&argc, argv); |
| |
| if (Args(argc, argv) == GL_FALSE) { |
| exit(1); |
| } |
| |
| glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250); |
| |
| type = GLUT_RGB | GLUT_ALPHA; |
| type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE; |
| glutInitDisplayMode(type); |
| |
| if (glutCreateWindow(argv[0]) == GL_FALSE) { |
| exit(1); |
| } |
| |
| glewInit(); |
| |
| Init(); |
| |
| glutReshapeFunc(Reshape); |
| glutKeyboardFunc(Key); |
| glutDisplayFunc(Draw); |
| glutMainLoop(); |
| return 0; |
| } |