利用Projection來學會如何使用相機
(1)windows 資料夾內打開 Projection
2. gluLookAt 紅框框為相機的位置(x,y,z)，橙框框出為看的中心點位置(x,y,z)，黃框處為相機(上)的位置(x,y,z)
gluPerspetive 為透視投影法，參數依序為fovy為y方向視野視角的意思，aspect為畫面長寬比的意思，zNear為前面的透明藍方塊，zFar為後面的灰色背景，調整數值可以調整遠近
code:#ifdef __APPLE__#include <GLUT/glut.h>#else#include <GL/glut.h>#endif
#include <stdlib.h>
static int slices = 16;static int stacks = 16;
/* GLUT callback Handlers */
static void resize(int width, int height)//今天教的 glutReshapeFunc(你的函式名字){ const float ar = (float) width / (float) height; //ar=aspect ratio glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); glFrustum(-ar, ar, -1.0, 1.0, 2.0, 100.0);
glMatrixMode(GL_MODELVIEW); glLoadIdentity() ;}
static void display(void){ const double t = glutGet(GLUT_ELAPSED_TIME) / 1000.0; const double a = t*90.0;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glColor3d(1,0,0);
glPushMatrix(); glTranslated(-2.4,1.2,-6); glRotated(60,1,0,0); glRotated(a,0,0,1); glutSolidSphere(1,slices,stacks); glPopMatrix();
glPushMatrix(); glTranslated(0,1.2,-6); glRotated(60,1,0,0); glRotated(a,0,0,1); glutSolidCone(1,1,slices,stacks); glPopMatrix();
glPushMatrix(); glTranslated(2.4,1.2,-6); glRotated(60,1,0,0); glRotated(a,0,0,1); glutSolidTorus(0.2,0.8,slices,stacks); glPopMatrix();
glPushMatrix(); glTranslated(-2.4,-1.2,-6); glRotated(60,1,0,0); glRotated(a,0,0,1); glutWireSphere(1,slices,stacks); glPopMatrix();
glPushMatrix(); glTranslated(0,-1.2,-6); glRotated(60,1,0,0); glRotated(a,0,0,1); glutWireCone(1,1,slices,stacks); glPopMatrix();
glPushMatrix(); glTranslated(2.4,-1.2,-6); glRotated(60,1,0,0); glRotated(a,0,0,1); glutWireTorus(0.2,0.8,slices,stacks); glPopMatrix();
glutSwapBuffers();}
static void key(unsigned char key, int x, int y){ switch (key) { case 27 : case 'q': exit(0); break;
case '+': slices++; stacks++; break;
case '-': if (slices>3 && stacks>3) { slices--; stacks--; } break; }
glutPostRedisplay();}
static void idle(void){ glutPostRedisplay();}
const GLfloat light_ambient[] = { 0.0f, 0.0f, 0.0f, 1.0f };const GLfloat light_diffuse[] = { 1.0f, 1.0f, 1.0f, 1.0f };const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f };
const GLfloat mat_ambient[] = { 0.7f, 0.7f, 0.7f, 1.0f };const GLfloat mat_diffuse[] = { 0.8f, 0.8f, 0.8f, 1.0f };const GLfloat mat_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };const GLfloat high_shininess[] = { 100.0f };
/* Program entry point */
int main(int argc, char *argv[]){ glutInit(&argc, argv); glutInitWindowSize(640,480); glutInitWindowPosition(10,10); glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glutCreateWindow("GLUT Shapes");
glutReshapeFunc(resize);//如果要改攝影機 投影矩陣的設定，在這裡寫 resize(int w, int h) glutDisplayFunc(display); glutKeyboardFunc(key); glutIdleFunc(idle);
glClearColor(1,1,1,1);//被景色是白色 glEnable(GL_CULL_FACE);//可以讓有些面提早決定不要畫 glCullFace(GL_BACK);//小心容易設定錯誤，可能是 GL_BACK 也可能是 GL_FRONT，要看面的頂點順序
glEnable(GL_DEPTH_TEST);//3D的深度測試 glDepthFunc(GL_LESS);
glEnable(GL_LIGHT0);//打光，Light0 開起來 glEnable(GL_NORMALIZE);//打光，裡面的法向量 長度 要讓電腦OpenGL重算成1 glEnable(GL_COLOR_MATERIAL);//打光，material 開起來 glEnable(GL_LIGHTING);//打光，lighting 開起來
glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);//打光，把光設定好 glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse); glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular); glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient);//打光，把material設定好 glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);
glutMainLoop(); //主要迴圈
return EXIT_SUCCESS;}
用滑鼠來調整運鏡的角度
1. 新增一個 glut 專案
2. 開頭的地方要記得 #include<math.h> ，因為在後面的motion函式有用到 sin()、cos() 函式，然後在主程式要記得加上 glutMotionFunc(motion);
code:
void motion(int x,int y)
{
float angle=x*3.1415926/180.0;
float cameraY=(y-300)/100.0;
glMatrixMode(GL_MODELVIEW);
glLoadIdentity() ;
gluLookAt(5*cos(angle),cameraY,5*sin(angle)-6, 0,0,-6, 0,1,0);
glutPostRedisplay();//從畫畫面
}
學會運鏡，我們就可以自己當導演！！
