#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <GL/glut.h>
#define CI_RED GLUT_RED
#define CI_ANTI_ALIAS_GREEN 16
#define CI_ANTI_ALIAS_YELLOW 32
#define CI_ANTI_ALIAS_RED 48
GLenum rgb, doubleBuffer;
GLint windW = 300, windH = 300;
GLenum mode;
GLint size;
float point[3] = {
1.0, 1.0, 0.0
};
static void Init(void)
{
GLint i;
if (!rgb) {
for (i = 0; i < 16; i++) {
glutSetColor(i+CI_ANTI_ALIAS_RED, i/15.0, 0.0, 0.0);
glutSetColor(i+CI_ANTI_ALIAS_YELLOW, i/15.0, i/15.0, 0.0);
glutSetColor(i+CI_ANTI_ALIAS_GREEN, 0.0, i/15.0, 0.0);
}
}
glClearColor(0.0, 0.0, 0.0, 0.0);
glBlendFunc(GL_SRC_ALPHA, GL_ZERO);
mode = GL_FALSE;
size = 1;
}
static void Reshape(int width, int height)
{
windW = width;
windH = height;
glViewport(0, 0, windW, windH);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(-windW/2, windW/2, -windH/2, windH/2);
glMatrixMode(GL_MODELVIEW);
}
static void Key(unsigned char key, int x, int y)
{
switch (key) {
case '1':
mode = !mode;
glutPostRedisplay();
break;
case 'W':
size++;
glutPostRedisplay();
break;
case 'w':
size--;
if (size < 1) {
size = 1;
}
glutPostRedisplay();
break;
case 27:
exit(0);
}
}
static void SpecialKey(int key, int x, int y)
{
switch (key) {
case GLUT_KEY_LEFT:
point[0] -= 0.25;
glutPostRedisplay();
break;
case GLUT_KEY_RIGHT:
point[0] += 0.25;
glutPostRedisplay();
break;
case GLUT_KEY_UP:
point[1] += 0.25;
glutPostRedisplay();
break;
case GLUT_KEY_DOWN:
point[1] -= 0.25;
glutPostRedisplay();
break;
}
}
static void Draw(void)
{
glClear(GL_COLOR_BUFFER_BIT);
(rgb) ? glColor3f(1.0, 1.0, 0.0) : glIndexi(3);
glBegin(GL_LINE_STRIP);
glVertex2f(-windW/2, 0);
glVertex2f(windW/2, 0);
glEnd();
glBegin(GL_LINE_STRIP);
glVertex2f(0, -windH/2);
glVertex2f(0, windH/2);
glEnd();
if (mode) {
glEnable(GL_BLEND);
glEnable(GL_POINT_SMOOTH);
} else {
glDisable(GL_BLEND);
glDisable(GL_POINT_SMOOTH);
}
glPointSize(size);
if (mode) {
(rgb) ? glColor3f(1.0, 0.0, 0.0) : glIndexi(CI_ANTI_ALIAS_RED);
} else {
(rgb) ? glColor3f(1.0, 0.0, 0.0) : glIndexi(CI_RED);
}
glBegin(GL_POINTS);
glVertex3fv(point);
glEnd();
glDisable(GL_POINT_SMOOTH);
glPointSize(1);
(rgb) ? glColor3f(0.0, 1.0, 0.0) : glIndexi(2);
glBegin(GL_POINTS);
glVertex3fv(point);
glEnd();
if (doubleBuffer) {
glutSwapBuffers();
} else {
glFlush();
}
}
static void Args(int argc, char **argv)
{
GLint i;
rgb = GL_TRUE;
doubleBuffer = GL_FALSE;
for (i = 1; i < argc; i++) {
if (strcmp(argv[i], "-ci") == 0) {
rgb = GL_FALSE;
} else if (strcmp(argv[i], "-rgb") == 0) {
rgb = GL_TRUE;
} else if (strcmp(argv[i], "-sb") == 0) {
doubleBuffer = GL_FALSE;
} else if (strcmp(argv[i], "-db") == 0) {
doubleBuffer = GL_TRUE;
}
}
}
int main(int argc, char **argv)
{
GLenum type;
glutInit(&argc, argv);
Args(argc, argv);
type = (rgb) ? GLUT_RGB : GLUT_INDEX;
type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
glutInitDisplayMode(type);
glutInitWindowSize(windW, windH);
glutCreateWindow("Point Test");
Init();
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutSpecialFunc(SpecialKey);
glutDisplayFunc(Draw);
glutMainLoop();
}