opengl 地球-鼠标旋转 缩放

// sample.cpp // sample program demonstrating use of the arcball. // see arcball.h for an explanation of what the // arcball_*** functions do. // // must be compiled with glut // // -- Bradley Smith, 5/05/2008 #include <stdio.h> #include <GL/glut.h> #include <GL/glaux.h> #include <cstdlib> #include <cmath> #include "arcball.h" // ================= // Drawing the Scene // ================= static float aspect_ratio = 1.0f; static int width, height; // scene parameters const vec eye( 0.0f, 0.0f, -20.0f ); const vec centre( 0.0f, 0.0f, 0.0f ); const vec up( 0.0f, 1.0f, 0.0f ); float SPHERE_RADIUS = 5.0f; const int SPHERE_LAT_SLICES = 12; const int SPHERE_LONG_SLICES = 24; const int NUM_STARS = 256; static vec star[NUM_STARS]; vec coord; GLuint texture[1]; GLUquadricObj *quadratic; const float PI = 3.141592654f; AUX_RGBImageRec *LoadBMP(char *Filename) // Loads A Bitmap Image { FILE *File=NULL; // File Handle if (!Filename) // Make Sure A Filename Was Given { return NULL; // If Not Return NULL } File=fopen(Filename,"r"); // Check To See If The File Exists if (File) // Does The File Exist? { fclose(File); // Close The Handle return auxDIBImageLoad(Filename); // Load The Bitmap And Return A Pointer } return NULL; // If Load Failed Return NULL } int LoadGLTextures() // Load Bitmaps And Convert To Textures { int Status=FALSE; // Status Indicator AUX_RGBImageRec *TextureImage[1]; // Create Storage Space For The Texture memset(TextureImage,0,sizeof(void *)*1); // Set The Pointer To NULL // Load The Bitmap, Check For Errors, If Bitmap's Not Found Quit if (TextureImage[0]=LoadBMP("Data/earth.bmp")) { Status=TRUE; // Set The Status To TRUE glGenTextures(1, &texture[0]); // Create The Texture // Typical Texture Generation Using Data From The Bitmap glBindTexture(GL_TEXTURE_2D, texture[0]); glTexImage2D(GL_TEXTURE_2D, 0, 3, TextureImage[0]->sizeX, TextureImage[0]->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[0]->data); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); } if (TextureImage[0]) // If Texture Exists { if (TextureImage[0]->data) // If Texture Image Exists { free(TextureImage[0]->data); // Free The Texture Image Memory } free(TextureImage[0]); // Free The Image Structure } return Status; // Return The Status } static void reset_view(int w, int h) { width = w; height = h; aspect_ratio = (float) width / (float) height; glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective( 50.0f, aspect_ratio, 1.0f, 50.0f ); gluLookAt( eye.x, eye.y, eye.z, centre.x, centre.y, centre.z, up.x, up.y, up.z ); // set up the arcball using the current projection matrix arcball_setzoom( SPHERE_RADIUS, eye, up ); glMatrixMode(GL_MODELVIEW); glLoadIdentity() ; } inline float randf() { return ((1.0f / 127.f) * (((float)(rand() & 255)) - 128.0f)) ; } static void startup_scene() { // generate random starfield for ( int i=0; i < NUM_STARS; ++i ) { star[i] = vec( randf(), randf(), randf() ).unit() * 2.0f; } } static void shutdown_scene() { // nothing to be done here } static void draw_stars() { glBegin( GL_POINTS ); glColor3f( 1.0f, 1.0f, 1.0f ); for ( int i=0; i < NUM_STARS; ++i ) { glVertex3f( star[i].x, star[i].y, star[i].z ); } glEnd(); } inline vec rotate_x( vec v, float sin_ang, float cos_ang ) { return vec( v.x, (v.y * cos_ang) + (v.z * sin_ang), (v.z * cos_ang) - (v.y * sin_ang) ); } inline vec rotate_y( vec v, float sin_ang, float cos_ang ) { return vec( (v.x * cos_ang) + (v.z * sin_ang), v.y, (v.z * cos_ang) - (v.x * sin_ang) ); } static void draw_sphere() {/* const int NUM_FACE_COLOURS = 4; vec FACE_COLOURS[NUM_FACE_COLOURS] = { vec( 1.0f, 0.0f, 0.0f ), vec( 0.0f, 1.0f, 0.0f ), vec( 0.0f, 0.0f, 1.0f ), vec( 1.0f, 1.0f, 0.0f ) }; const float lat_angle = PI / (float)SPHERE_LAT_SLICES; const float long_angle = 2.0f * PI / (float)SPHERE_LONG_SLICES; const float sin_lat = sin( lat_angle ); const float cos_lat = cos( lat_angle ); const float sin_long = sin( long_angle ); const float cos_long = cos( long_angle ); glBegin( GL_QUADS ); vec lat_0( 0.0f, SPHERE_RADIUS, 0.0 ); for ( int y = 0; y < SPHERE_LAT_SLICES; ++y ) { vec lat_1 = rotate_x( lat_0, sin_lat, cos_lat ); vec long_0_0 = lat_0; vec long_1_0 = lat_1; for ( int x = 0; x < SPHERE_LONG_SLICES; ++x ) { vec long_0_1 = rotate_y( long_0_0, sin_long, cos_long ); vec long_1_1 = rotate_y( long_1_0, sin_long, cos_long ); vec colour = FACE_COLOURS[(x+y)%NUM_FACE_COLOURS]; glColor4f( colour.x, colour.y, colour.z, 1.0f ); glVertex3f( long_0_0.x, long_0_0.y, long_0_0.z ); glVertex3f( long_1_0.x, long_1_0.y, long_1_0.z ); glVertex3f( long_1_1.x, long_1_1.y, long_1_1.z ); glVertex3f( long_0_1.x, long_0_1.y, long_0_1.z ); long_0_0 = long_0_1; long_1_0 = long_1_1; } lat_0 = lat_1; } glEnd();*/ quadratic=gluNewQuadric(); //绘制类型 //画图 // 创建二次几何体 gluQuadricNormals(quadratic, GLU_SMOOTH); // 使用平滑法线 gluQuadricTexture(quadratic, GL_TRUE); glEnable(GL_TEXTURE_2D); // 启用纹理映射 glBindTexture(GL_TEXTURE_2D, texture[0]); gluSphere(quadratic,SPHERE_RADIUS,48,48); gluQuadricTexture(quadratic,GLU_TRUE); //建立纹理坐标 gluQuadricDrawStyle(quadratic,GLU_FILL); //用面填充 glDisable(GL_TEXTURE_2D); } static void click_scene(int x, int y) { int invert_y = (height - y) - 1; // OpenGL viewport coordinates are Cartesian arcball_start(x,invert_y); } static void drag_scene(int x, int y) { int invert_y = (height - y) - 1; arcball_move(x,invert_y,(5/SPHERE_RADIUS)); } static void draw_scene() { // stars: to simulate infinite distance, // translate the sphere of stars to the eye // and perform the arcball rotation around the eye // (also disable depth test so they become the background) glPushMatrix(); glDrawBuffer(GL_BACK); //指定在后台缓存中绘制图形 glLoadIdentity(); //初始化变换矩阵 glClearColor(0.0,0.0,0.0,0.0); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); glShadeModel(GL_SMOOTH); glDepthFunc(GL_LESS); glEnable(GL_DEPTH_TEST); //glDisable( GL_DEPTH_TEST ); glTranslatef( eye.x, eye.y, eye.z ); arcball_rotate(); //draw_stars(); glEnable( GL_DEPTH_TEST ); glPopMatrix(); // now render the regular scene under the arcball rotation about 0,0,0 // (generally you would want to render everything here) arcball_rotate(); draw_sphere(); } // ============== // GLUT Callbacks // ============== static void resize(int w, int h) { reset_view(w,h); } static void display() { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); draw_scene(); glutSwapBuffers(); } static void key(unsigned char key, int x, int y) { switch (key) { case 27 : case 'q': shutdown_scene(); exit(0); break; case '+': SPHERE_RADIUS = SPHERE_RADIUS+1; arcball_setzoom( SPHERE_RADIUS, eye, up ); break; case '-': if(SPHERE_RADIUS>1) { SPHERE_RADIUS = SPHERE_RADIUS-1; arcball_setzoom( SPHERE_RADIUS, eye, up ); } break; default : break; } glutPostRedisplay(); } static