/***********************************************************************/ /***********************************************************************/ /* FreeVR OpenGL tutorial example 4: ex4_buttons.c */ /* FreeVR OpenGL tutorial example 5: ex5_joystick.c */ /* Last tested with: FreeVR version 0.6a */ /* Last tested with: FreeVR version 0.6a */ /* Last Modified: January 11, 2007 */ /* Last Modified: January 11, 2007 */ /* URL: http://freevr.org */ /* URL: http://freevr.org */ /***********************************************************************/ /***********************************************************************/ /* This example code demonstrates a VR application program that */ /* This example code demonstrates a VR application program that */ /* polls interface input buttons and alters the virtual world based */ /* examines the two valuator inputs that comprise the joystick */ /* on their states. Specifically the green pyramid can be raised, */ /* motion and use these values to fly the green pyramid around the */ /* lowered, or reset to it's initial state. */ /* X-Z plane. */ /* */ /* */ /* */ /* */ /* The new features of this example include: */ /* The new features of this example include: */ /* - FreeVR Library functions, variables, and macros: */ /* - FreeVR Library functions, variables, and macros: */ /* * vrGet2switchDelta() [used for button interaction] */ /* * vrGetValuatorValue() [used for joystick interaction] */ /* */ /* */ /* */ /* */ /* Considerations: */ /* Considerations: */ /* - User modifications affect the virtual world state, and are */ /* - User modifications that are based on constant polling of an */ /* performed in the simulation process, not the rendering process*/ /* input (in this case joystick valuators), should be adjusted */ /* to compensate for the speed of the machine. This is done */ /* by calculating the amount of time that passes between */ /* simulation frames (a time-delta). */ /* - Interactions from some valuators can greatly benefit from the */ /* use of an epsilon that creates a "null region" around the zero */ /* point to ensure the input is intended. Subtracting that same */ /* epsilon value from the operation is also generally a good thing*/ /* */ /* */ /* This application uses the files: */ /* This application uses the files: */ /* - shapes.c (Bill Sherman's simple OpenGL shapes) */ /* - shapes.c (Bill Sherman's simple OpenGL shapes) */ /* */ /* */ /* Copyright 2010, William R. Sherman, All Rights Reserved. */ /* Copyright 2010, William R. Sherman, All Rights Reserved. */ /* In particular, the right to republish this file in whole or in */ /* In particular, the right to republish this file in whole or in */ /* part, in any form (including electronic forms) is prohibited */ /* part, in any form (including electronic forms) is prohibited */ /* without written consent of the copyright holder. */ /* without written consent of the copyright holder. */ /***********************************************************************/ /***********************************************************************/ #include <stdio.h> /* needed for printf(), etc. */ #include <stdio.h> /* needed for printf(), etc. */ #include <stdlib.h> /* needed for exit() */ #include <stdlib.h> /* needed for exit() */ #include <signal.h> /* needed for signal() and its arguments */ #include <signal.h> /* needed for signal() and its arguments */ #include <unistd.h> /* not sure why/whether this is needed */ #include <unistd.h> /* not sure why/whether this is needed */ #include <math.h> /* needed for sin() & cos() */ #include <math.h> /* needed for sin(), cos(), fabs() & copysign() */ #include <GL/gl.h> /* needed for all OpenGL functions & values */ #include <GL/gl.h> /* needed for all OpenGL functions & values */ #include "freevr.h" /* needed for FreeVR functions & values */ #include "freevr.h" /* needed for FreeVR functions & values */ /* Define a structure for holding a database of the virtual world. */ /* Define a structure for holding a database of the virtual world. */ typedef struct { typedef struct { float obj1_x, obj1_y, obj1_z; /* location o float obj1_x, obj1_y, obj1_z; /* location o float obj2_x, obj2_y, obj2_z; /* location o float obj2_x, obj2_y, obj2_z; /* location o float obj3_x, obj3_y, obj3_z; /* location o float obj3_x, obj3_y, obj3_z; /* location o } WorldDataType; } WorldDataType; /**************************************************************************** /**************************************************************************** /* These function declarations are very important -- they will be used as arg /* These function declarations are very important -- they will be used as arg void exit_application(int signal); /* cleanly close down operati void exit_application(int signal); /* cleanly close down operati void init_gfx(void); /* initialize the graphics void init_gfx(void); /* initialize the graphics void draw_world(WorldDataType *wd); /* graphically render the wor void draw_world(WorldDataType *wd); /* graphically render the wor void init_world(WorldDataType *wd); /* initialize the world param void init_world(WorldDataType *wd); /* initialize the world param void update_world(WorldDataType *wd); /* perform the world simulati void update_world(WorldDataType *wd); /* perform the world simulati /***********************************************************************/ /***********************************************************************/ main(int argc, char* argv[]) main(int argc, char* argv[]) { { WorldDataType *wd; WorldDataType *wd; /**********************************/ /**********************************/ /*** initialize FreeVR routines ***/ /*** initialize FreeVR routines ***/ /**********************************/ /**********************************/ signal(SIGINT, SIG_IGN); signal(SIGINT, SIG_IGN); vrConfigure(&argc, argv, NULL); /* allow CLAs to affect confi vrConfigure(&argc, argv, NULL); /* allow CLAs to affect confi vrStart(); vrStart(); signal(SIGINT, exit_application); signal(SIGINT, exit_application); /********************/ /********************/ /* create the world */ /* create the world */ wd = (WorldDataType *)vrShmemAlloc0(sizeof(WorldDataType)); wd = (WorldDataType *)vrShmemAlloc0(sizeof(WorldDataType)); init_world(wd); init_world(wd); /***************************************/ /***************************************/ /* set up the FreeVR library functions */ /* set up the FreeVR library functions */ vrFunctionSetCallback(VRFUNC_DISPLAY_INIT, vrCallbackCreate(init_gfx, vrFunctionSetCallback(VRFUNC_DISPLAY_INIT, vrCallbackCreate(init_gfx, vrFunctionSetCallback(VRFUNC_DISPLAY, vrCallbackCreate(draw_world, 1, vrFunctionSetCallback(VRFUNC_DISPLAY, vrCallbackCreate(draw_world, 1, /********************************************************/ /********************************************************/ /* define the application name, authors, controls, etc. */ /* define the application name, authors, controls, etc. */ vrSystemSetName("FreeVR tutorial: example 4 -- buttons"); vrSystemSetName("FreeVR tutorial: example 5 -- joystick"); vrSystemSetAuthors("Bill Sherman"); vrSystemSetAuthors("Bill Sherman"); vrSystemSetExtraInfo("An example to show basic button inputs"); vrSystemSetExtraInfo("An example to show basic joystick input"); vrSystemSetStatusDescription("Application running fine"); vrSystemSetStatusDescription("Application running fine"); vrInputSet2switchDescription(0, "Terminate the application"); vrInputSet2switchDescription(0, "Terminate the application"); vrInputSet2switchDescription(1, "Raise the green pyramid"); vrInputSet2switchDescription(1, "Raise the green pyramid"); vrInputSet2switchDescription(2, "Reset the green pyramid"); vrInputSet2switchDescription(2, "Reset the green pyramid"); vrInputSet2switchDescription(3, "Lower the green pyramid"); vrInputSet2switchDescription(3, "Lower the green pyramid"); vrInputSetValuatorDescription(0, "Move the green pyramid in the Z-pla vrInputSetValuatorDescription(1, "Move the green pyramid in the X-pla /***************************/ /***************************/ /*** do world simulation ***/ /*** do world simulation ***/ /***************************/ /***************************/ /* run until terminate key is pressed (Escape by default) */ /* run until terminate key is pressed (Escape by default) */ while(!vrGet2switchValue(0)) { while(!vrGet2switchValue(0)) { vrFrame(); vrFrame(); update_world(wd); update_world(wd); } } /*********************/ /*********************/ /*** close up shop ***/ /*** close up shop ***/ /*********************/ /*********************/ exit_application(0); exit_application(0); } } /********************************************************************/ /********************************************************************/ /* exit_application(): clean up anything started by the application */ /* exit_application(): clean up anything started by the application */ /* (forked processes, open files, open sockets, etc.) */ /* (forked processes, open files, open sockets, etc.) */ /********************************************************************/ /********************************************************************/ void exit_application(int signal) void exit_application(int signal) { { vrExit(); vrExit(); exit(0); exit(0); } } /* ----------------8<-----------------8<-----------------8<----------------*/ /* ----------------8<-----------------8<-----------------8<----------------*/ /* In a non-example applicatation, the following would be a separate file. */ /* In a non-example applicatation, the following would be a separate file. */ /**********************************/ /**********************************/ /**********************************/ /**********************************/ /** The World Simulation section **/ /** The World Simulation section **/ /**********************************/ /**********************************/ /**********************************/ /**********************************/ /**************************************************************/ /**************************************************************/ /* init_world(): create the initial conditions of the dynamic */ /* init_world(): create the initial conditions of the dynamic */ /* simulation. */ /* simulation. */ /**************************************************************/ /**************************************************************/ void init_world(WorldDataType *wd) void init_world(WorldDataType *wd) { { /* initial location of object 1 - a blue cube */ /* initial location of object 1 - a blue cube */ wd->obj1_x = -2.0; wd->obj1_x = -2.0; wd->obj1_y = 5.0; wd->obj1_y = 5.0; wd->obj1_z = -5.0; wd->obj1_z = -5.0; /* initial location of object 2 - a red pyramid */ /* initial location of object 2 - a red pyramid */ wd->obj2_x = 2.0; wd->obj2_x = 2.0; wd->obj2_y = 5.0; wd->obj2_y = 5.0; wd->obj2_z = -5.0; wd->obj2_z = -5.0; /* initial location of object 3 - an upside-down green pyramid */ /* initial location of object 3 - an upside-down green pyramid */ wd->obj3_x = 0.0; wd->obj3_x = 0.0; wd->obj3_y = 5.0; wd->obj3_y = 5.0; wd->obj3_z = -5.0; wd->obj3_z = -5.0; } } /*********************************************************************/ /*********************************************************************/ /* update_world(): This version still has a little action, plus it */ /* update_world(): This version still has a little action, and a */ /* introduces some very simple interactivity. */ /* little more interactivity. */ /*********************************************************************/ /*********************************************************************/ void update_world(WorldDataType *wd) void update_world(WorldDataType *wd) { { #define JS_EPSILON 0.125 /* the dead-zone befo #define MOVE_FACTOR 2.5 /* a movement scale f static vrTime last_time = -1.0; /* initially set to a vrTime sim_time = vrCurrentSimTime(); /* the current time o vrTime sim_time = vrCurrentSimTime(); /* the current time o double delta_time; /* time since last up double joy_x, joy_y; /* Joystick values */ /*****************************************************/ /** Determine delta time from last simulation frame **/ /*****************************************************/ if (last_time == -1.0) delta_time = 0.0; else delta_time = sim_time - last_time; last_time = sim_time; /* now that delta_tim /* skip the update if the delta isn't big enough */ if (delta_time <= 0.0) /* can also choose a non-zero epsilon */ return; /****************************************/ /****************************************/ /* Move the objects with constant speed */ /* Move the objects with constant speed */ /* object 1 travels in a horizontal circle at a fixed speed */ /* object 1 travels in a horizontal circle at a fixed speed */ wd->obj1_x = 3*sin(sim_time * 2.0); wd->obj1_x = 3*sin(sim_time * 2.0); wd->obj1_z = 3*cos(sim_time * 2.0) - 5.0; wd->obj1_z = 3*cos(sim_time * 2.0) - 5.0; /* object 2 travels in a verticle circle at a fixed speed */ /* object 2 travels in a verticle circle at a fixed speed */ wd->obj2_x = 3*cos(sim_time * 2.0); wd->obj2_x = 3*cos(sim_time * 2.0); wd->obj2_y = 3*sin(sim_time * 2.0) + 5.0; wd->obj2_y = 3*sin(sim_time * 2.0) + 5.0; /**************************/ /**************************/ /* User interface section */ /* User interface section */ /* the first button moves the object up, when initially pressed */ /* the first button moves the object up, when initially pressed */ if (vrGet2switchDelta(1) == 1) { if (vrGet2switchDelta(1) == 1) { wd->obj3_y += 1.0; wd->obj3_y += 1.0; } } /* the second button resets the object's location, when initially pre /* the second button resets the object's location, when initially pre if (vrGet2switchDelta(2) == 1) { if (vrGet2switchDelta(2) == 1) { wd->obj3_x = 0.0; wd->obj3_y = 5.0; wd->obj3_y = 5.0; wd->obj3_z = -5.0; } } /* the third button moves the object down, when initially pressed */ /* the third button moves the object down, when initially pressed */ if (vrGet2switchDelta(3) == 1) { if (vrGet2switchDelta(3) == 1) { wd->obj3_y -= 1.0; wd->obj3_y -= 1.0; } } /* store input values so they are consistent throughout update routin joy_x = vrGetValuatorValue(0); joy_y = vrGetValuatorValue(1); /* now use those values to move the object */ if (fabs(joy_x) > JS_EPSILON) wd->obj3_x += joy_x * delta_time * MOVE_FACTOR; if (fabs(joy_y) > JS_EPSILON) wd->obj3_z -= (joy_y-copysign(JS_EPSILON,joy_y)) * delta_time /****************************************************/ /****************************************************/ /* yield to allow other processes access to the CPU */ /* yield to allow other processes access to the CPU */ vrSleep(0); vrSleep(0); } } /* ----------------8<-----------------8<-----------------8<----------------*/ /* ----------------8<-----------------8<-----------------8<----------------*/ /* In a non-example applicatation, the following would be a separate file. */ /* In a non-example applicatation, the following would be a separate file. */ /**************************/ /**************************/ /**************************/ /**************************/ /** The Graphics section **/ /** The Graphics section **/ /**************************/ /**************************/ /**************************/ /**************************/ /* functions from shapes.c */ /* functions from shapes.c */ void draw_cube(); void draw_cube(); void draw_pyramid(); void draw_pyramid(); /*********************************************************************/ /*********************************************************************/ /* init_gfx(): initialize general graphics properties (eg. lighting) */ /* init_gfx(): initialize general graphics properties (eg. lighting) */ /*********************************************************************/ /*********************************************************************/ void init_gfx(void) void init_gfx(void) { { GLfloat location_0[4] = { 0.0, 10.0, 10.0, 1.0 /* 0 = directional, 1 GLfloat location_0[4] = { 0.0, 10.0, 10.0, 1.0 /* 0 = directional, 1 ambient_0[4] = { 0.2, 0.2, 0.2, 1.0 }, ambient_0[4] = { 0.2, 0.2, 0.2, 1.0 }, diffuse_0[4] = { 0.8, 0.8, 0.8, 1.0 }, diffuse_0[4] = { 0.8, 0.8, 0.8, 1.0 }, specular_0[4] = { 0.2, 0.2, 0.2, 1.0 }; specular_0[4] = { 0.2, 0.2, 0.2, 1.0 }; /****************************************/ /****************************************/ /* set the render initialization values */ /* set the render initialization values */ glClearColor(0.0, 0.0, 0.0, 0.0); glClearColor(0.0, 0.0, 0.0, 0.0); glClearDepth(1.0); glClearDepth(1.0); /********************************************************/ /********************************************************/ /* set the polygon shading/lighting/material parameters */ /* set the polygon shading/lighting/material parameters */ glShadeModel(GL_SMOOTH); glShadeModel(GL_SMOOTH); glEnable(GL_LIGHTING); glEnable(GL_LIGHTING); glLightfv(GL_LIGHT0, GL_POSITION, location_0); glLightfv(GL_LIGHT0, GL_POSITION, location_0); glLightfv(GL_LIGHT0, GL_AMBIENT, ambient_0); glLightfv(GL_LIGHT0, GL_AMBIENT, ambient_0); glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse_0); glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse_0); glLightfv(GL_LIGHT0, GL_SPECULAR, specular_0); glLightfv(GL_LIGHT0, GL_SPECULAR, specular_0); glEnable(GL_LIGHT0); glEnable(GL_LIGHT0); /* These two lines cause the vertex colors to be used (otherwise all /* These two lines cause the vertex colors to be used (otherwise all glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE); glColorMaterial(GL_FRONT, GL_AMBIENT_AND_DIFFUSE); glEnable(GL_COLOR_MATERIAL); glEnable(GL_COLOR_MATERIAL); glEnable(GL_NORMALIZE); /* this is required when calling glScalef() w glEnable(GL_NORMALIZE); /* this is required when calling glScalef() w } } /*************************************************************/ /*************************************************************/ /* draw_world(): Render the three objects in the world. */ /* draw_world(): Render the three objects in the world. */ /* Note that two of the objects (the blue cube, and red */ /* Note that two of the objects (the blue cube, and red */ /* pyramid) get their locations from the world database */ /* pyramid) get their locations from the world database */ /*************************************************************/ /*************************************************************/ void draw_world(WorldDataType *wd) void draw_world(WorldDataType *wd) { { static GLfloat location_0[4] = { 0.0, 10.0, 0.0, 1.0 /* 0 = directio static GLfloat location_0[4] = { 0.0, 10.0, 0.0, 1.0 /* 0 = directio /**************************************/ /**************************************/ /* clear the screen -- very important */ /* clear the screen -- very important */ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); /******************************************************************** /******************************************************************** /* update the light's location -- must be done independently for each /* update the light's location -- must be done independently for each glLightfv(GL_LIGHT0, GL_POSITION, location_0); glLightfv(GL_LIGHT0, GL_POSITION, location_0); /************************/ /************************/ /* draw all the objects */ /* draw all the objects */ /* a blue cube */ /* a blue cube */ glColor3ub(100, 100, 255); glColor3ub(100, 100, 255); glPushMatrix(); glPushMatrix(); glTranslatef(wd->obj1_x, wd->obj1_y, wd->obj1_z); glTranslatef(wd->obj1_x, wd->obj1_y, wd->obj1_z); draw_cube(); draw_cube(); glPopMatrix(); glPopMatrix(); /* a red pyramid */ /* a red pyramid */ glColor3ub(255, 100, 100); glColor3ub(255, 100, 100); glPushMatrix(); glPushMatrix(); glTranslatef(wd->obj2_x, wd->obj2_y, wd->obj2_z); glTranslatef(wd->obj2_x, wd->obj2_y, wd->obj2_z); draw_pyramid(); draw_pyramid(); glPopMatrix(); glPopMatrix(); /* the green upside-down pyramid */ /* the green upside-down pyramid */ glColor3ub(100, 255, 100); glColor3ub(100, 255, 100); glTranslatef(wd->obj3_x, wd->obj3_y, wd->obj3_z); glTranslatef(wd->obj3_x, wd->obj3_y, wd->obj3_z); glScalef(1.0, -1.0, 1.0); glScalef(1.0, -1.0, 1.0); draw_pyramid(); draw_pyramid(); } }