/* Program to display a cube that moves around in space. Sample for description of events in OpenGL (c) 1999, Steve Cunningham */ #include "glut.h" #include #include #include #define MAXHITS 200 // size of array to hold hit records for selection GLint cubeColor1 = 1; GLint cubeColor2 = 2; GLint windW = 500, windH = 500, hit = -1; GLint vp[4]; GLuint selectBuf[MAXHITS]; // set up overall light data, including specular=ambient=light colors GLfloat light_position[]={ 10.0, 10.0, -10.0, 1.0 }; GLfloat light_color[]={ 1.0, 1.0, 1.0, 1.0 }; GLfloat ambient_color[]={ 0.2, 0.2, 0.2, 1.0 }; GLfloat mat_specular[]={ 1.0, 1.0, 1.0, 1.0 }; // prototypes for functions GLint DoSelect(GLint x, GLint y); void myinit(void); void Mouse(int button, int state, int mouseX, int mouseY); void cube(int i); void render( GLenum mode ); void display( void ); void reshape(int w,int h); void myinit(void) { glClearColor( 0.0, 0.0, 1.0, 0.0 ); glShadeModel(GL_SMOOTH); glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, mat_specular ); glLightfv(GL_LIGHT0, GL_POSITION, light_position ); glLightfv(GL_LIGHT0, GL_AMBIENT, ambient_color ); glLightfv(GL_LIGHT0, GL_SPECULAR, light_color ); glLightfv(GL_LIGHT0, GL_DIFFUSE, light_color ); // standard attributes glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_DEPTH_TEST); } // mouse callback void Mouse(int button, int state, int mouseX, int mouseY) { if (state == GLUT_DOWN) { /* find which object was selected */ hit = DoSelect((GLint) mouseX, (GLint) mouseY); } glutPostRedisplay(); } void cube(int i) { /* define a point data type */ typedef GLfloat point3[3]; point3 vertices[8]={{-1.0, -1.0, -1.0}, {-1.0, -1.0, 1.0}, {-1.0, 1.0, -1.0}, {-1.0, 1.0, 1.0}, { 1.0, -1.0, -1.0}, { 1.0, -1.0, 1.0}, { 1.0, 1.0, -1.0}, { 1.0, 1.0, 1.0} }; point3 normals[6]={{ 0.0, 0.0, 1.0}, {-1.0, 0.0, 0.0}, { 0.0, 0.0,-1.0}, { 1.0, 0.0, 0.0}, { 0.0,-1.0, 0.0}, { 0.0, 1.0, 0.0} }; GLfloat color1[]={1.0, 0.0, 0.0,1.0}, color2[]={0.0,1.0,0.0,1.0}; GLfloat mat_shininess[]={ 50.0 }; // draw our cube if (i==1){ glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, color1 ); glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, color1 ); } if (i==2){ glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, color2 ); glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, color2 ); } glMaterialfv(GL_FRONT_AND_BACK, GL_SHININESS, mat_shininess ); glBegin(GL_QUADS); glNormal3fv(normals[0]); // first quad: positive Z face glVertex3fv(vertices[1]); glNormal3fv(normals[0]); glVertex3fv(vertices[5]); glNormal3fv(normals[0]); glVertex3fv(vertices[7]); glNormal3fv(normals[0]); glVertex3fv(vertices[3]); glNormal3fv(normals[5]); // second quad: positive Y face glVertex3fv(vertices[7]); glNormal3fv(normals[5]); glVertex3fv(vertices[6]); glNormal3fv(normals[5]); glVertex3fv(vertices[2]); glNormal3fv(normals[5]); glVertex3fv(vertices[3]); glNormal3fv(normals[2]); // third quad: negative Z face glVertex3fv(vertices[2]); glNormal3fv(normals[2]); glVertex3fv(vertices[6]); glNormal3fv(normals[2]); glVertex3fv(vertices[4]); glNormal3fv(normals[2]); glVertex3fv(vertices[0]); glNormal3fv(normals[3]); // fourth quad: positive X face glVertex3fv(vertices[5]); glNormal3fv(normals[3]); glVertex3fv(vertices[4]); glNormal3fv(normals[3]); glVertex3fv(vertices[6]); glNormal3fv(normals[3]); glVertex3fv(vertices[7]); glNormal3fv(normals[4]); // fifth quad: negative Y face glVertex3fv(vertices[4]); glNormal3fv(normals[4]); glVertex3fv(vertices[5]); glNormal3fv(normals[4]); glVertex3fv(vertices[1]); glNormal3fv(normals[4]); glVertex3fv(vertices[0]); glNormal3fv(normals[1]); // sixth quad: negative X face glVertex3fv(vertices[0]); glNormal3fv(normals[1]); glVertex3fv(vertices[1]); glNormal3fv(normals[1]); glVertex3fv(vertices[3]); glNormal3fv(normals[1]); glVertex3fv(vertices[2]); glEnd(); } GLint DoSelect(GLint x, GLint y) { GLint hits, temp; glSelectBuffer(MAXHITS, selectBuf); glRenderMode(GL_SELECT); glInitNames(); glPushName(0); // set up the viewing model glPushMatrix(); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPickMatrix(x, windH - y, 4, 4, vp); glClearColor(0.0, 0.0, 1.0, 0.0); glClear(GL_COLOR_BUFFER_BIT); gluPerspective(60.0,1.0,1.0,30.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); // eye point center of view up */ gluLookAt(10.0, 10.0, 10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); render(GL_SELECT); /* draw the scene for selection */ glPopMatrix(); // find the number of hits recorded and reset mode of render hits = glRenderMode(GL_RENDER); // reset viewing model glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(60.0,1.0,1.0,30.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); // eye point center of view up */ gluLookAt(10.0, 10.0, 10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); // return the label of the object selected, if any if (hits <= 0) { return -1; } temp = cubeColor1; cubeColor1 = cubeColor2; cubeColor2 = temp; return selectBuf[3]; } void render( GLenum mode ) { // Always draw the two cubes, even if we are in GL_SELECT mode, // because an object is selectable iff it is identified in the name // list and is drawn in GL_SELECT mode if (mode == GL_SELECT) glLoadName(0); glPushMatrix(); glTranslatef( 1.0, 1.0, -2.0 ); // if (mode == GL_RENDER) cube(cubeColor2); glPopMatrix(); if (mode == GL_SELECT) glLoadName(1); glPushMatrix(); glTranslatef( -1.0, -2.0, 1.0 ); // if (mode == GL_RENDER) cube(cubeColor1); glPopMatrix(); glFlush(); glutSwapBuffers(); } void display( void ) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); render(GL_RENDER); glutSwapBuffers(); } void reshape(int w,int h) { glViewport(0,0,(GLsizei)w,(GLsizei)h); glGetIntegerv(GL_VIEWPORT, vp); // get viewport data; needed by gluPickMatrix glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(60.0,1.0,1.0,30.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); // eye point center of view up gluLookAt(10.0, 10.0, 10.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); } void main(int argc, char** argv) { // Standard GLUT initialization glutInit(&argc,argv); // initialize for double buffering, RGB color, and depth tests glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH); glutInitWindowSize(windW,windH); glutInitWindowPosition(70,70); glutCreateWindow("choosing cubes"); glutDisplayFunc(display); glutReshapeFunc(reshape); glutMouseFunc(Mouse); myinit(); glutMainLoop(); }