Opengl Samples - Depth

#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(); }