單擊此處編輯母版標題樣式,,單擊此處編輯母版文本樣式,,第二級,,第三級,,第四級,,第五級,,,*,計算機圖形圖像繪制技術(shù),,第二講,,,主要內(nèi)容,,顯示三維坐標的程序（1）,,幾何對象的變換,,變換矩陣,,平移glTranslatef,,旋轉(zhuǎn)glRotatef,,縮放glScalef,,三維實體,,顯示三維坐標的程序（2）,,顏色,,點與線的屬性,,面的顯示,,隱藏面與深度緩沖,,多邊形面的方向,,顯示模式,,練習,,,,顯示三維坐標的程序（1）,,,,變換矩陣,,在OpenGL中使用矩陣進行渲染三維場景所需要的數(shù)據(jù)計算,,為簡化操作，OpenGL提供一個矩陣棧，每次用棧頂?shù)木仃噷o定的物體或場景進行渲染,,用glPushMatrix和glPopMatrix函數(shù)來將矩陣壓棧和出棧，還可以用glScalef和glRotatef等函數(shù)對棧頂?shù)木仃囘M行縮放和旋轉(zhuǎn)等修改,,Push / Pop Matrix,,void,glPushMatrix,(void);,,,Push Matrix,,Push / Pop Matrix,,Pop Matrix,void,glPopMatrix,(void);,,,,Example,,glPushMatrix();,,glTranslatef(...);,,glRotatef(...);,,glScalef(...);,,glutSolidCylinder(...);,,glPopMatrix();,,,平移glTranslatef,,void glTranslated (GLdouble x, GLdouble y, GLdouble z);,,void glTranslatef (GLfloat x, GLfloat y, GLfloat z);,,,演示,,,旋轉(zhuǎn)glRotatef,,void glRotated (GLdouble angle, GLdouble x, GLdouble y, GLdouble z);,,void glRotatef (GLfloat angle, GLfloat x, GLfloat y, GLfloat z);,,,演示,,縮放glScalef,,void glScaled (GLdouble x, GLdouble y, GLdouble z);,,void glScalef (GLfloat x, GLfloat y, GLfloat z);,,,演示,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,,Example,,glLoadIdentity();,,glPushMatrix();,,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,Translate,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,Translate,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,Translate,,Identity,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,Translate,,Identity,,Translate,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,Translate,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,Translate,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,Translate,,Rotate,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,,glPopMatrix();,,glPopMatrix();,,Identity,,Translate,,,Example,,glLoadIdentity();,,glPushMatrix();,,glTranslatef (…);,,glPushMatrix();,,glLoadIdentity();,,glTranslate (…);,,glPopMatrix();,,glPushMatrix();,,glRotatef (…);,,glPopMatrix();,,glPopMatrix();,,Identity,,,平移與旋轉(zhuǎn)的次序很重要,,glLoadIdentity(),,,,glRotated(45, 0, 0, 1),,,,glTranslated(5, 0, 0),OpenGL commands successively define new “l(fā)ocal” coordinate spaces in terms of the “current” or previous local space.,,三維實體對象,,Glaux.lib庫,,void auxWireSphere(GLdouble);,,void auxSolidSphere(GLdouble);,,void auxWireCube(GLdouble);,,void auxSolidCube(GLdouble);,,void auxWireBox(GLdouble, GLdouble, GLdouble);,,void auxSolidBox(GLdouble, GLdouble, GLdouble);,,void auxWireTorus(GLdouble, GLdouble);,,void auxSolidTorus(GLdouble, GLdouble);,,void auxWireCylinder(GLdouble, GLdouble);,,void auxSolidCylinder(GLdouble, GLdouble);,,void auxWireIcosahedron(GLdouble);,,void auxSolidIcosahedron(GLdouble);,,void auxWireOctahedron(GLdouble);,,void auxSolidOctahedron(GLdouble);,,void auxWireTetrahedron(GLdouble);,,void auxSolidTetrahedron(GLdouble);,,void auxWireDodecahedron(GLdouble);,,void auxSolidDodecahedron(GLdouble);,,void auxWireCone(GLdouble, GLdouble);,,void auxSolidCone(GLdouble, GLdouble);,,void auxWireTeapot(GLdouble);,,void auxSolidTeapot(GLdouble);,球,,立方體,,長方體,,圓環(huán),,圓柱,,二十面體,,八面體,,四面體,,十二面體,,圓錐,,茶壺,,,Glut庫,,void glutWireSphere(GLdouble radius, GLint slices, GLint stacks);,,void glutSolidSphere(GLdouble radius, GLint slices, GLint stacks);,,void glutWireCone(GLdouble base, GLdouble height, GLint slices, GLint stacks);,,void glutSolidCone(GLdouble base, GLdouble height, GLint slices, GLint stacks);,,void glutWireCube(GLdouble size);,,void glutSolidCube(GLdouble size);,,void glutWireTorus(GLdouble innerRadius, GLdouble outerRadius, GLint sides, GLint rings);,,void glutSolidTorus(GLdouble innerRadius, GLdouble outerRadius, GLint sides, GLint rings);,,void glutWireDodecahedron(void);,,void glutSolidDodecahedron(void);,,void glutWireTeapot(GLdouble size);,,void glutSolidTeapot(GLdouble size);,,void glutWireOctahedron(void);,,void glutSolidOctahedron(void);,,void glutWireTetrahedron(void);,,void glutSolidTetrahedron(void);,,void glutWireIcosahedron(void);,,void glutSolidIcosahedron(void);,,顯示三維坐標的程序(2),,（演示）,,顏色,,glColor3fv(face color),,render_face(),,glColor3fv(eye color),,render_eyes(),,glColor3fv(hair color),,render_hair(),,glColor3fv(teeth color),,render_teeth(),,Colors,顏色其有四個分量:,,,,R - 紅 Red.,,G - 綠 Green.,,B - 藍 Blue.,,A - 透明度 Transparent.,關(guān)于透明處理…,在后面講,!,,glShadeModel(GL_FLAT);,,glBegin(GL_QUADS);,,glColor3f (1.0,0.0,0.0);,,glVertex3f(0.0,0.0,0.0);,,glColor3f (0.0,1.0,0.0);,,glVertex3f(1.0,0.0,0.0);,,glColor3f (0.0,0.0,1.0);,,glVertex3f(1.0,1.0,0.0);,,glColor3f (1.0,1.0,0.0);,,glVertex3f(0.0,1.0,0.0);,,glEnd();,Shading Models,,,glShadeModel(GL_SMOOTH);,,glBegin(GL_QUADS);,,glColor3f (1.0,0.0,0.0);,,glVertex3f(0.0,0.0,0.0);,,glColor3f (0.0,1.0,0.0);,,glVertex3f(1.0,0.0,0.0);,,glColor3f (0.0,0.0,1.0);,,glVertex3f(1.0,1.0,0.0);,,glColor3f (1.0,1.0,0.0);,,glVertex3f(0.0,1.0,0.0);,,glEnd();,Shading Models,,,演示,,,,點與線的屬性,,,void,glPointSize(GLfloat,size);,,void,glLineWidth(GLfloat,width);,,glLineStipple(1, 0x3F07);,glEnable(GL_LINE_STIPPLE);,,void,glLineStipple(GLint,factor,,Glushort,pattern);,,演示,,,,深度緩沖區(qū),,當我們從某處看景物時，接近于視點的物體遮擋了離視點較遠的物體。,,深度緩沖區(qū)為每個像素保存一個距離或深度值，以便讓OpenGL通過簡單方法做隱藏面計算。,,只有當新像素的深度值小于舊像素的深度值時，才允許像素的覆蓋。,,,,,畫家算法與深度排序,,,,畫家算法的局限性,,解決辦法：分割成兩個,,演示,,,,多邊形面的方向,,,,,back-face,normal pointing inside,,法線方向的指定方法一,,v,0,v,1,v,2,v,3,v,0,v,1,v,2,v,3,根據(jù)頂點順序確定,,法線方向的指定方法二,,指定法線,,面的可見性,,void glCullFace (GLenum mode);,,GLenum取值：GL_FRONT、GL_BACK、GL_FRONT_AND_BACK,,多邊形顯示模式,,glPolygonMode(GLenum face, GLenum mode);,GL_FILL, GL_LINE, GL_POINT,GL_FRONT, GL_BACK, GL_FRONT_AND_BACK,GL_FILL,GL_LINE,GL_POINT,,演示,,,,練習,,1. 簡單的城市模型,,,2 三維飛機模型,,,3,,,4 作三維成績統(tǒng)計餅圖或條形圖,,第二次課和第三次課練習作為一次大作業(yè);,,可任選題目;,,第一次大作業(yè)在第四次課,上課之前交.,,作業(yè)發(fā)email至:liuzhongtu@,,