/* $Id: reflect.c,v 1.7 2001/04/25 15:51:32 brianp Exp $ */ /* * Demo of a reflective, texture-mapped surface with OpenGL. * Brian Paul August 14, 1995 This file is in the public domain. * * Hardware texture mapping is highly recommended! * * The basic steps are: * 1. Render the reflective object (a polygon) from the normal viewpoint, * setting the stencil planes = 1. * 2. Render the scene from a special viewpoint: the viewpoint which * is on the opposite side of the reflective plane. Only draw where * stencil = 1. This draws the objects in the reflective surface. * 3. Render the scene from the original viewpoint. This draws the * objects in the normal fashion. Use blending when drawing * the reflective, textured surface. * * This is a very crude demo. It could be much better. */ /* * Authors: * Brian Paul * Dirk Reiners (reiners@igd.fhg.de) made some modifications to this code. * Mark Kilgard (April 1997) * Brian Paul (April 2000 - added keyboard d/s options) */ #include #include #include #include "GL/glut.h" #include "../util/showbuffer.c" #include "../util/readtex.c" #define DEG2RAD (3.14159/180.0) #define TABLE_TEXTURE "../images/tile.rgb" static GLint ImgWidth, ImgHeight; static GLenum ImgFormat; static GLubyte *Image = NULL; #define MAX_OBJECTS 2 static GLint table_list; static GLint objects_list[MAX_OBJECTS]; static GLfloat xrot, yrot; static GLfloat spin; static GLint Width = 400, Height = 300; static GLenum ShowBuffer = GL_NONE; static GLboolean Anim = GL_TRUE; /* performance info */ static GLint T0 = 0; static GLint Frames = 0; static void make_table( void ) { static GLfloat table_mat[] = { 1.0, 1.0, 1.0, 0.6 }; static GLfloat gray[] = { 0.4, 0.4, 0.4, 1.0 }; table_list = glGenLists(1); glNewList( table_list, GL_COMPILE ); /* load table's texture */ glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, table_mat ); /* glMaterialfv( GL_FRONT, GL_EMISSION, gray );*/ glMaterialfv( GL_FRONT, GL_DIFFUSE, table_mat ); glMaterialfv( GL_FRONT, GL_AMBIENT, gray ); /* draw textured square for the table */ glPushMatrix(); glScalef( 4.0, 4.0, 4.0 ); glBegin( GL_POLYGON ); glNormal3f( 0.0, 1.0, 0.0 ); glTexCoord2f( 0.0, 0.0 ); glVertex3f( -1.0, 0.0, 1.0 ); glTexCoord2f( 1.0, 0.0 ); glVertex3f( 1.0, 0.0, 1.0 ); glTexCoord2f( 1.0, 1.0 ); glVertex3f( 1.0, 0.0, -1.0 ); glTexCoord2f( 0.0, 1.0 ); glVertex3f( -1.0, 0.0, -1.0 ); glEnd(); glPopMatrix(); glDisable( GL_TEXTURE_2D ); glEndList(); } static void make_objects( void ) { GLUquadricObj *q; static GLfloat cyan[] = { 0.0, 1.0, 1.0, 1.0 }; static GLfloat green[] = { 0.2, 1.0, 0.2, 1.0 }; static GLfloat black[] = { 0.0, 0.0, 0.0, 0.0 }; q = gluNewQuadric(); gluQuadricDrawStyle( q, GLU_FILL ); gluQuadricNormals( q, GLU_SMOOTH ); objects_list[0] = glGenLists(1); glNewList( objects_list[0], GL_COMPILE ); glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, cyan ); glMaterialfv( GL_FRONT, GL_EMISSION, black ); gluCylinder( q, 0.5, 0.5, 1.0, 15, 1 ); glEndList(); objects_list[1] = glGenLists(1); glNewList( objects_list[1], GL_COMPILE ); glMaterialfv( GL_FRONT, GL_AMBIENT_AND_DIFFUSE, green ); glMaterialfv( GL_FRONT, GL_EMISSION, black ); gluCylinder( q, 1.5, 0.0, 2.5, 15, 1 ); glEndList(); } static void init( void ) { make_table(); make_objects(); Image = LoadRGBImage( TABLE_TEXTURE, &ImgWidth, &ImgHeight, &ImgFormat ); if (!Image) { printf("Couldn't read %s\n", TABLE_TEXTURE); exit(0); } gluBuild2DMipmaps(GL_TEXTURE_2D, 3, ImgWidth, ImgHeight, ImgFormat, GL_UNSIGNED_BYTE, Image); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST ); glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST ); xrot = 30.0; yrot = 50.0; spin = 0.0; glShadeModel( GL_FLAT ); glEnable( GL_LIGHT0 ); glEnable( GL_LIGHTING ); glClearColor( 0.5, 0.5, 0.9, 0.0 ); glEnable( GL_NORMALIZE ); } static void reshape(int w, int h) { GLfloat yAspect = 2.5; GLfloat xAspect = yAspect * (float) w / (float) h; Width = w; Height = h; glViewport(0, 0, w, h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glFrustum( -xAspect, xAspect, -yAspect, yAspect, 10.0, 30.0 ); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } static void draw_objects( GLfloat eyex, GLfloat eyey, GLfloat eyez ) { (void) eyex; (void) eyey; (void) eyez; #ifndef USE_ZBUFFER if (eyex<0.5) { #endif glPushMatrix(); glTranslatef( 1.0, 1.5, 0.0 ); glRotatef( spin, 1.0, 0.5, 0.0 ); glRotatef( 0.5*spin, 0.0, 0.5, 1.0 ); glCallList( objects_list[0] ); glPopMatrix(); glPushMatrix(); glTranslatef( -1.0, 0.85+3.0*fabs( cos(0.01*spin) ), 0.0 ); glRotatef( 0.5*spin, 0.0, 0.5, 1.0 ); glRotatef( spin, 1.0, 0.5, 0.0 ); glScalef( 0.5, 0.5, 0.5 ); glCallList( objects_list[1] ); glPopMatrix(); #ifndef USE_ZBUFFER } else { glPushMatrix(); glTranslatef( -1.0, 0.85+3.0*fabs( cos(0.01*spin) ), 0.0 ); glRotatef( 0.5*spin, 0.0, 0.5, 1.0 ); glRotatef( spin, 1.0, 0.5, 0.0 ); glScalef( 0.5, 0.5, 0.5 ); glCallList( objects_list[1] ); glPopMatrix(); glPushMatrix(); glTranslatef( 1.0, 1.5, 0.0 ); glRotatef( spin, 1.0, 0.5, 0.0 ); glRotatef( 0.5*spin, 0.0, 0.5, 1.0 ); glCallList( objects_list[0] ); glPopMatrix(); } #endif } static void draw_table( void ) { glCallList( table_list ); } static void draw_scene( void ) { static GLfloat light_pos[] = { 0.0, 20.0, 0.0, 1.0 }; GLfloat dist = 20.0; GLfloat eyex, eyey, eyez; glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT); eyex = dist * cos(yrot*DEG2RAD) * cos(xrot*DEG2RAD); eyez = dist * sin(yrot*DEG2RAD) * cos(xrot*DEG2RAD); eyey = dist * sin(xrot*DEG2RAD); /* view from top */ glPushMatrix(); gluLookAt( eyex, eyey, eyez, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0 ); glLightfv( GL_LIGHT0, GL_POSITION, light_pos ); /* draw table into stencil planes */ glDisable( GL_DEPTH_TEST ); glEnable( GL_STENCIL_TEST ); glStencilFunc( GL_ALWAYS, 1, 0xffffffff ); glStencilOp( GL_REPLACE, GL_REPLACE, GL_REPLACE ); glColorMask( GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE ); draw_table(); glColorMask( GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE ); glEnable( GL_DEPTH_TEST ); /* render view from below (reflected viewport) */ /* only draw where stencil==1 */ if (eyey>0.0) { glPushMatrix(); glStencilFunc( GL_EQUAL, 1, 0xffffffff ); /* draw if ==1 */ glStencilOp( GL_KEEP, GL_KEEP, GL_KEEP ); glScalef( 1.0, -1.0, 1.0 ); /* Reposition light in reflected space. */ glLightfv(GL_LIGHT0, GL_POSITION, light_pos); draw_objects(eyex, eyey, eyez); glPopMatrix(); /* Restore light's original unreflected position. */ glLightfv(GL_LIGHT0, GL_POSITION, light_pos); } glDisable( GL_STENCIL_TEST ); glEnable( GL_BLEND ); glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ); glEnable( GL_TEXTURE_2D ); draw_table(); glDisable( GL_TEXTURE_2D ); glDisable( GL_BLEND ); /* view from top */ glPushMatrix(); draw_objects(eyex, eyey, eyez); glPopMatrix(); glPopMatrix(); if (ShowBuffer == GL_DEPTH) { ShowDepthBuffer(Width, Height, 1.0, 0.0); } else if (ShowBuffer == GL_STENCIL) { ShowStencilBuffer(Width, Height, 255.0, 0.0); } else if (ShowBuffer == GL_ALPHA) { ShowAlphaBuffer(Width, Height); } glutSwapBuffers(); { GLint t = glutGet(GLUT_ELAPSED_TIME); Frames++; if (t - T0 >= 5000) { GLfloat seconds = (t - T0) / 1000.0; GLfloat fps = Frames / seconds; printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps); T0 = t; Frames = 0; } } } static void idle( void ) { spin += 2.0; yrot += 3.0; glutPostRedisplay(); } static void Key( unsigned char key, int x, int y ) { (void) x; (void) y; if (key == 'd') { ShowBuffer = GL_DEPTH; } else if (key == 's') { ShowBuffer = GL_STENCIL; } else if (key == 'a') { ShowBuffer = GL_ALPHA; } else if (key == ' ') { Anim = !Anim; if (Anim) glutIdleFunc(idle); else glutIdleFunc(NULL); } else if (key==27) { exit(0); } else { ShowBuffer = GL_NONE; } glutPostRedisplay(); } static void SpecialKey( int key, int x, int y ) { (void) x; (void) y; switch (key) { case GLUT_KEY_UP: xrot += 3.0; if ( xrot > 85 ) xrot = 85; break; case GLUT_KEY_DOWN: xrot -= 3.0; if ( xrot < 5 ) xrot = 5; break; case GLUT_KEY_LEFT: yrot += 3.0; break; case GLUT_KEY_RIGHT: yrot -= 3.0; break; } glutPostRedisplay(); } int main( int argc, char *argv[] ) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH | GLUT_STENCIL); glutInitWindowPosition( 0, 0 ); glutInitWindowSize( Width, Height ); glutCreateWindow(argv[0]); glutReshapeFunc(reshape); glutDisplayFunc(draw_scene); glutKeyboardFunc(Key); glutSpecialFunc(SpecialKey); glutIdleFunc(idle); init(); glutMainLoop(); return 0; }