384 lines
9.4 KiB
C
384 lines
9.4 KiB
C
/*
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* lumiere.c
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*
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* OpenGL light
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*/
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#include <stdlib.h>
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#include <stdio.h>
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// for mac osx
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#ifdef __APPLE__
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#include <OpenGL/gl.h>
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#include <OpenGL/glu.h>
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#include <GLUT/glut.h>
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#else
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// only for windows
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#ifdef _WIN32
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#include <windows.h>
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#endif
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// for windows and linux
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#include <GL/gl.h>
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#include <GL/glu.h>
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#include <GL/freeglut.h>
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#endif
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int angle_x = 45, angle_y = -45;
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float distance = 8.f;
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float shininess = 25.f;
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int directional = 0;
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int infinite_view = 0;
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// the room: it's a cube with inverted normals, ie pointing inwards
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void glRoom(GLfloat size)
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{
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GLfloat v = size / 2;
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glBegin(GL_QUADS);
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glNormal3f(0, 0, 1);
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glVertex3f(-v, -v, -v);
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glVertex3f(v, -v, -v);
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glVertex3f(v, v, -v);
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glVertex3f(-v, v, -v);
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glNormal3f(0, 0, -1);
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glVertex3f(v, -v, v);
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glVertex3f(-v, -v, v);
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glVertex3f(-v, v, v);
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glVertex3f(v, v, v);
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glNormal3f(-1, 0, 0);
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glVertex3f(v, -v, -v);
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glVertex3f(v, -v, v);
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glVertex3f(v, v, v);
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glVertex3f(v, v, -v);
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glNormal3f(1, 0, 0);
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glVertex3f(-v, -v, v);
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glVertex3f(-v, -v, -v);
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glVertex3f(-v, v, -v);
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glVertex3f(-v, v, v);
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glNormal3f(0, -1, 0);
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glVertex3f(-v, v, -v);
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glVertex3f(v, v, -v);
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glVertex3f(v, v, v);
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glVertex3f(-v, v, v);
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glNormal3f(0, 1, 0);
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glVertex3f(-v, -v, -v);
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glVertex3f(-v, -v, v);
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glVertex3f(v, -v, v);
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glVertex3f(v, -v, -v);
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glEnd();
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}
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// place the camera, make the scene turn around the scene origin
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void place_camera()
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{
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glTranslatef(0.f, 0.f, -distance);
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glRotatef(angle_x, 1.f, 0.f, 0.f);
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glRotatef(angle_y, 0.f, 1.f, 0.f);
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}
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// place the light in x,y,z
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void place_light(GLfloat x, GLfloat y, GLfloat z)
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{
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//**********************************
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// set the light components: ambient (0.2 grey),
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// diffuse and specular (both white)
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//**********************************
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GLfloat light_ambient[] = {0.2, 0.2, 0.2, 1.0}; // the ambient component
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// GLfloat light_diffuse[] = {1.0, 1.0, 1.0, 1.0}; // the diffuse component
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// GLfloat light_specular[] = {1.0, 1.0, 1.0, 1.0}; // the specular component
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glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
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// glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
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// glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
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//**********************************
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// set the light position (directional or positional)
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//**********************************
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GLfloat light_position[] = {x, y, z, directional}; // the light position
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glLightfv(GL_LIGHT0, GL_POSITION, light_position);
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//**********************************
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// draw a yellow point to visually represent the light
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//**********************************
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glDisable(GL_LIGHT0);
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glDisable(GL_LIGHTING);
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glPushMatrix();
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glColor3f(1, 1, 0);
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glTranslatef(x, y, z);
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glutSolidSphere(0.1, 100, 100); // a yellow sphere
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glPopMatrix();
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glEnable(GL_LIGHT0);
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glEnable(GL_LIGHTING);
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//**********************************
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// turn the light and the lighting on
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//**********************************
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glEnable(GL_LIGHT0); // turn light on
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glEnable(GL_LIGHTING); // turn lighting on
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}
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// define a material in terms of its components
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void define_material(GLfloat ar, GLfloat ag, GLfloat ab, // ambient
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GLfloat dr, GLfloat dg, GLfloat db, // diffuse
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GLfloat sr, GLfloat sg, GLfloat sb, // specular
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GLfloat sh // shininess
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)
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{
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GLfloat mat_ambient[4];
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GLfloat mat_diffuse[4];
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GLfloat mat_specular[4];
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//**********************************
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// set the ambient property
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//**********************************
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mat_ambient[0] = ar;
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mat_ambient[1] = ag;
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mat_ambient[2] = ab;
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mat_ambient[3] = 1.f;
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glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);
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//**********************************
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// set the diffuse property
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//**********************************
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mat_diffuse[0] = dr;
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mat_diffuse[1] = dg;
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mat_diffuse[2] = db;
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mat_diffuse[3] = 1.f;
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glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);
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//**********************************
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// set the specular property
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//**********************************
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mat_specular[0] = sr;
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mat_specular[1] = sg;
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mat_specular[2] = sb;
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mat_specular[3] = 1.f;
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glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
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//**********************************
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// set the shininess property
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//**********************************
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glMaterialf(GL_FRONT, GL_SHININESS, sh);
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}
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// draw the room
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void place_background()
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{
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glPushMatrix();
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glScalef(15.f, 15.f, 15.f);
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glRoom(1.f);
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glPopMatrix();
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}
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/*
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* OpenGL Initialization
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*/
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void init()
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{
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glClearColor(0.f, 0.f, 0.f, 0.f);
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//**********************************
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// activate the Gouraud shading instead of the flat one
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//**********************************
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glShadeModel(GL_FLAT);
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//**********************************
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// enable face culling
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//**********************************
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glEnable(GL_CULL_FACE);
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//**********************************
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// enable the depth test
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//**********************************
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glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH);
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glEnable(GL_DEPTH_TEST);
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//**********************************
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// set the ambient light with glLightModelfv to a 50% grey
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//**********************************
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GLfloat light_ambient[] = {0.5, 0.5, 0.5, 1.0};
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glLightModelfv(GL_LIGHT_MODEL_AMBIENT, light_ambient);
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glEnable(GL_NORMALIZE);
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}
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void display()
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{
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glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, infinite_view);
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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glMatrixMode(GL_MODELVIEW);
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glLoadIdentity();
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// place the camera
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place_camera();
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//**********************************
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// place the light in the scene using place_light
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//**********************************
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place_light(7.4, 4, -7.4);
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//**********************************
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// define the material for the room (instead of color)
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//**********************************
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// glColor3f(1.f, 1.f, 1.f);
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define_material(1, 1, 1,
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0.5, 0.5, 0.5,
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0, 0, 0,
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0);
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place_background();
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// the 2 objects
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// red shining sphere
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glPushMatrix();
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glTranslatef(-2.f, 0.f, 0.f);
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//**********************************
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// define the material for the sphere (instead of color)
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//**********************************
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// glColor3f(1.f, 0.f, 0.f);
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define_material(0.2, 0, 0,
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0.8, 0, 0,
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0.8, 0.8, 0.8,
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shininess);
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glutSolidSphere(1.0, 240, 120);
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glPopMatrix();
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// green cube
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glPushMatrix();
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glTranslatef(2.f, 0.f, 0.f);
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//**********************************
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// define the material for the cube (instead of color)
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//**********************************
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// glColor3f(0.f, 1.f, 0.f);
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define_material(0, 0.8, 0,
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0, 0.5, 0,
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0, 0, 0,
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0);
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glutSolidCube(2.0);
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glPopMatrix();
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glutSwapBuffers();
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}
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/*
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* @brief Callback for window size change
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* @param[in] w new width of the window
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* @param[in] h new height of the window
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*/
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void reshape(int w, int h)
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{
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glViewport(0, 0, (GLsizei)w, (GLsizei)h);
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glMatrixMode(GL_PROJECTION);
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glLoadIdentity();
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gluPerspective(60, (GLfloat)w / (GLfloat)h, 0.1, 50);
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}
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/*
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* Callback for special keys
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*/
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#define DELTA_ANGLE_X 5
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#define DELTA_ANGLE_Y 5
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#define DELTA_DISTANCE 0.3f
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#define DISTANCE_MIN 0.0
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void special(int key, int x, int y)
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{
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switch (key)
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{
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case GLUT_KEY_UP:
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angle_x = (angle_x + DELTA_ANGLE_X) % 360;
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break;
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case GLUT_KEY_DOWN:
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angle_x = (angle_x - DELTA_ANGLE_X) % 360;
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break;
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case GLUT_KEY_LEFT:
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angle_y = (angle_y + DELTA_ANGLE_Y) % 360;
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break;
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case GLUT_KEY_RIGHT:
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angle_y = (angle_y - DELTA_ANGLE_Y) % 360;
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break;
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case GLUT_KEY_PAGE_DOWN:
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distance += DELTA_DISTANCE;
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break;
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case GLUT_KEY_PAGE_UP:
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distance -= (distance > DISTANCE_MIN) ? DELTA_DISTANCE : 0.f;
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break;
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default:
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break;
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}
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glutPostRedisplay();
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}
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void keyboard(unsigned char key, int x, int y)
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{
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switch (key)
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{
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//**********************************
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// directional light, use global variable directional
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//**********************************
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case 'd':
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directional = (directional + 1) % 2;
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break;
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//**********************************
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// infinite_view
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//**********************************
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case 'f':
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infinite_view = (infinite_view + 1) % 2;
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break;
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//**********************************
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// Shininess: 's' to decrement, 'S' to increment
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//**********************************
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case 'S':
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shininess += 1;
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break;
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case 's':
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shininess -= 1;
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break;
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case 'q':
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case 27: // [ESC]
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exit(0);
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break;
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default:
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break;
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}
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glutPostRedisplay();
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}
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int main(int argc, char **argv)
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{
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glutInit(&argc, argv);
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// enable the double buffer and the depth buffer
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glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
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// main window
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glutInitWindowSize(640, 480);
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glutInitWindowPosition(50, 50);
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glutCreateWindow("Testing OpenGL light");
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// callbacks
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glutDisplayFunc(display);
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glutReshapeFunc(reshape);
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glutKeyboardFunc(keyboard);
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glutSpecialFunc(special);
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init();
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glutMainLoop();
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exit(0);
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}
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