#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <GL/glut.h>
#define CI_OFFSET_1 16
#define CI_OFFSET_2 32
GLenum rgb, doubleBuffer;
GLenum antiAlias, stipple;
GLubyte stippleBits[32*4] = {
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
0xAA, 0xAA, 0xAA, 0xAA, 0x55, 0x55, 0x55, 0x55,
};
static void Init(void)
{
GLint i;
if (!rgb) {
for (i = 0; i < 16; i++) {
glutSetColor(i+CI_OFFSET_1, 0.0, 0.0, i/15.0);
glutSetColor(i+CI_OFFSET_2, 0.0, i/15.0, 0.0);
}
}
glClearColor(0.0, 0.0, 0.0, 0.0);
glClearIndex(0.0);
glPolygonStipple(stippleBits);
antiAlias = GL_FALSE;
stipple = GL_FALSE;
}
static void Reshape(int width, int height)
{
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
glMatrixMode(GL_MODELVIEW);
}
static void Key(unsigned char key, int x, int y)
{
switch (key) {
case '1':
antiAlias = !antiAlias;
glutPostRedisplay();
break;
case '2':
stipple = !stipple;
glutPostRedisplay();
break;
case 27:
exit(0);
}
}
static void Draw(void)
{
GLint ci1, ci2;
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
if (antiAlias) {
ci1 = CI_OFFSET_1;
ci2 = CI_OFFSET_2;
glBlendFunc(GL_SRC_ALPHA, GL_ONE);
glEnable(GL_BLEND);
glEnable(GL_POLYGON_SMOOTH);
glDisable(GL_DEPTH_TEST);
} else {
ci1 = 4;
ci2 = 2;
glDisable(GL_BLEND);
glDisable(GL_POLYGON_SMOOTH);
glEnable(GL_DEPTH_TEST);
}
if (stipple) {
glEnable(GL_POLYGON_STIPPLE);
} else {
glDisable(GL_POLYGON_STIPPLE);
}
glBegin(GL_TRIANGLES);
(rgb) ? glColor3f(0.0, 0.0, 1.0) : glIndexi(ci1);
glVertex3f( 0.9, -0.9, -30.0);
glVertex3f( 0.9, 0.9, -30.0);
glVertex3f(-0.9, 0.0, -30.0);
(rgb) ? glColor3f(0.0, 1.0, 0.0) : glIndexi(ci2);
glVertex3f(-0.9, -0.9, -40.0);
glVertex3f(-0.9, 0.9, -40.0);
glVertex3f( 0.9, 0.0, -25.0);
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 = GLUT_DEPTH;
type |= (rgb) ? GLUT_RGB : GLUT_INDEX;
type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
glutInitDisplayMode(type);
glutInitWindowSize(300, 300);
glutCreateWindow("Depth Test");
Init();
glutReshapeFunc(Reshape);
glutKeyboardFunc(Key);
glutDisplayFunc(Draw);
glutMainLoop();
}