本文使用QGLWidget來繪制各種三維基本圖形，包括立方體、圓柱體、圓錐、球體、圓環等等，涉及包括基本繪制以及上色、紋理、旋轉等操作。
使用的軟件版本：QT5.12 + QT Creater4.8.0
GLWidget.h
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#ifndef
GLWIDGET_H #define GLWIDGET_H #include <QGLWidget> class GLWidget : public QGLWidget { Q_OBJECT public : GLWidget(QWidget *parent = 0 ); ~GLWidget(); protected : // 設置渲染環境 void initializeGL(); // 繪制窗口 void paintGL(); // 響應窗口的大小變化 void resizeGL( int width, int height); private : // 場景渲染 void renderScene(); // 場景渲染-基本圖形 void renderBasicShape(); // 場景渲染-立方體紋理 void renderTextureCube(); // 場景渲染-圓柱體紋理 void renderTextureCylinder(); // 繪制立方體 void drawCube(); // 繪制圓形 void drawCircle(); // 繪制圓柱體 void drawCylinder(); // 繪制圓錐體 void drawCone(); // 繪制四面體 void drawTetrahedron(); // 繪制球體 void drawSphere(GLfloat xx = 0 . 0 , GLfloat yy = 0 . 0 , GLfloat zz = 0 . 0 , GLfloat radius = 1 . 0 , GLfloat M = 100 . 0 , GLfloat N = 100 . 0 ); // 繪制圓環 void DrawTorus( double Radius = 1 , double TubeRadius = 0 . 2 , int Sides = 20 , int Rings = 30 ); // 加載紋理 void loadGLTextures(); private : // 旋轉角度 GLfloat xRot; GLfloat yRot; GLfloat zRot; // 存儲紋理 GLuint texture[ 2 ]; }; #endif // GLWIDGET_H |
GLWidget.cpp
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#include
"GLWidget.h"
#include <qmath.h> #define PI 3 . 14 #define ROT_DELTA 0 .5f void qgluPerspective(GLdouble fovy, GLdouble aspect, GLdouble zNear, GLdouble zFar) { const GLdouble ymax = zNear * tan(qDegreesToRadians(fovy) / 2 . 0 ); const GLdouble ymin = -ymax; const GLdouble xmin = ymin * aspect; const GLdouble xmax = ymax * aspect; glFrustum(xmin, xmax, ymin, ymax, zNear, zFar); } GLWidget::GLWidget(QWidget *parent) : QGLWidget(parent) , xRot( 0 .0f) , yRot( 0 .0f) , zRot( 0 .0f) { // 設置畫面的雙緩沖和深度緩存 setFormat(QGLFormat(QGL::DoubleBuffer | QGL::DepthBuffer)); } GLWidget::~GLWidget() { } void GLWidget::initializeGL() { // 啟用陰影平滑 glShadeModel(GL_SMOOTH); // 白色背景 glClearColor( 1 . 0 , 1 . 0 , 1 . 0 , 1 . 0 ); // 設置深度緩存 glClearDepth( 1 . 0 ); // 啟用深度測試 glEnable(GL_DEPTH_TEST); // 所作深度測試的類型 glDepthFunc(GL_LEQUAL); // 告訴系統對透視進行修正 glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST); // 啟用2D紋理映射 glEnable(GL_TEXTURE_2D); // 加載紋理 loadGLTextures(); } void GLWidget::paintGL() { renderScene(); update(); } void GLWidget::resizeGL( int width, int height) { // 防止窗口大小變為0 if ( height == 0 ) { height = 1 ; } // 重置當前的視口 glViewport( 0 , 0 , (GLint)width, (GLint)height); // 選擇投影矩陣 glMatrixMode(GL_PROJECTION); // 重置投影矩陣 glLoadIdentity(); // 設置視口的大小 qgluPerspective( 45 . 0 , (GLdouble)width / (GLdouble)height, 0 . 1 , 100 . 0 ); // 選擇模型觀察矩陣 glMatrixMode(GL_MODELVIEW); // 重置投影矩陣 glLoadIdentity(); } // 繪制立方體 void GLWidget::drawCube() { glBegin(GL_QUAD_STRIP); //填充凸多邊形 glColor3f( 1 , 0 , 0 ); glVertex3f( 0 .0f, 0 .0f, 0 .0f); glColor3f( 1 , 1 , 0 ); glVertex3f( 0 .0f, 1 .0f, 0 .0f); glColor3f( 0 , 1 , 0 ); glVertex3f( 1 .0f, 0 .0f, 0 .0f); glColor3f( 0 , 1 , 1 ); glVertex3f( 1 .0f, 1 .0f, 0 .0f); glColor3f( 1 , 0 , 0 ); glVertex3f( 1 .0f, 0 .0f, - 1 .0f); glColor3f( 1 , 1 , 0 ); glVertex3f( 1 .0f, 1 .0f, - 1 .0f); glColor3f( 0 , 1 , 0 ); glVertex3f( 0 .0f, 0 .0f, - 1 .0f); glColor3f( 0 , 1 , 1 ); glVertex3f( 0 .0f, 1 .0f, - 1 .0f); glColor3f( 1 , 0 , 0 ); glVertex3f( 0 .0f, 0 .0f, 0 .0f); glColor3f( 1 , 1 , 0 ); glVertex3f( 0 .0f, 1 .0f, 0 .0f); glEnd(); glBegin(GL_QUAD_STRIP); glColor3f( 0 , 0 , 1 ); glVertex3f( 0 .0f, 0 .0f, 0 .0f); glColor3f( 1 , 0 , 1 ); glVertex3f( 1 .0f, 0 .0f, 0 .0f); glColor3f( 0 , 1 , 0 ); glVertex3f( 0 .0f, 0 .0f, - 1 .0f); glColor3f( 1 , 0 , 0 ); glVertex3f( 1 .0f, 0 .0f, - 1 .0f); glColor3f( 1 , 1 , 0 ); glVertex3f( 0 .0f, 1 .0f, 0 .0f); glColor3f( 1 , 0 , 1 ); glVertex3f( 1 .0f, 1 .0f, 0 .0f); glColor3f( 0 , 0 , 1 ); glVertex3f( 0 .0f, 1 .0f, - 1 .0f); glColor3f( 1 , 0 , 0 ); glVertex3f( 1 .0f, 1 .0f, - 1 .0f); glEnd(); } // 繪制圓形 void GLWidget::drawCircle() { glBegin(GL_TRIANGLE_FAN); //扇形連續填充三角形串 glVertex3f( 0 .0f, 0 .0f, 0 .0f); int i = 0 ; for (i = 0 ; i <= 360 ; i += 15 ) { float p = i * 3 . 14 / 180 ; glColor3f(sin(p), cos(p), tan(p)); glVertex3f(sin(p), cos(p), 0 .0f); } glEnd(); } // 繪制圓柱體 void GLWidget::drawCylinder() { // 利用三角形和四邊形等基本圖元繪制底面圓圓心在坐標原點， 半徑為 r，高為 h，方向沿 z 軸方向的圓柱； // 側面用多個四邊形,底面用多個三角形來表示 glBegin(GL_QUAD_STRIP); //連續填充四邊形串 int i = 0 ; for (i = 0 ; i <= 360 ; i += 15 ) { float p = i * 3 . 14 / 180 ; glVertex3f(sin(p), cos(p), 1 .0f); glVertex3f(sin(p), cos(p), 0 .0f); } glEnd(); //bottom circle glColor3f( 1 , 0 , 0 ); drawCircle(); glTranslatef( 0 , 0 , 1 ); //top circle glColor3f( 0 , 0 , 1 ); drawCircle(); glColor3f( 0 , 1 , 0 ); } // 繪制圓錐體 void GLWidget::drawCone() { glBegin(GL_QUAD_STRIP); //連續填充四邊形串 int i = 0 ; for (i = 0 ; i <= 360 ; i += 15 ) { float p = i * 3 . 14 / 180 ; glColor3f(sin(p), cos(p), 1 .0f); glVertex3f( 0 , 0 , 1 .0f); glVertex3f(sin(p), cos(p), 0 .0f); } glEnd(); //bottom circle glColor3f( 0 , 1 , 1 ); drawCircle(); } // 繪制四面體等 void GLWidget::drawTetrahedron() { glBegin(GL_QUADS); glNormal3f( 0 , 0 , - 1 ); glColor3f( 1 . 0 , 0 . 0 , 0 . 0 ); glVertex3f(- 1 , - 1 , 0 ); glColor3f( 0 . 0 , 1 . 0 , 0 . 0 ); glVertex3f(- 1 , 1 , 0 ); glColor3f( 0 . 0 , 0 . 0 , 1 . 0 ); glVertex3f( 1 , 1 , 0 ); glColor3f( 1 . 0 , 1 . 0 , 0 . 0 ); glVertex3f( 1 , - 1 , 0 ); glEnd(); glBegin(GL_TRIANGLES); glNormal3f( 0 , - 1 , 0 . 707 ); glColor3f( 0 . 0 , 1 . 0 , 1 . 0 ); glVertex3f(- 1 , - 1 , 0 ); glColor3f( 1 . 0 , 0 . 0 , 1 . 0 ); glVertex3f( 1 , - 1 , 0 ); glColor3f( 1 . 0 , 0 . 0 , 1 . 0 ); glVertex3f( 0 , 0 , 1 . 2 ); glEnd(); glBegin(GL_TRIANGLES); glNormal3f( 1 , 0 , 0 . 707 ); glColor3f( 0 . 0 , 1 . 0 , 1 . 0 ); glVertex3f( 1 , - 1 , 0 ); glColor3f( 1 . 0 , 0 . 0 , 1 . 0 ); glVertex3f( 1 , 1 , 0 ); glColor3f( 1 . 0 , 0 . 0 , 1 . 0 ); glVertex3f( 0 , 0 , 1 . 2 ); glEnd(); glBegin(GL_TRIANGLES); glNormal3f( 0 , 1 , 0 . 707 ); glColor3f( 0 . 0 , 1 . 0 , 1 . 0 ); glVertex3f( 1 , 1 , 0 ); glColor3f( 1 . 0 , 0 . 0 , 1 . 0 ); glVertex3f(- 1 , 1 , 0 ); glColor3f( 1 . 0 , 0 . 0 , 1 . 0 ); glVertex3f( 0 , 0 , 1 . 2 ); glEnd(); glBegin(GL_TRIANGLES); glNormal3f(- 1 , 0 , 0 . 707 ); glColor3f( 1 . 0 , 0 . 0 , 1 . 0 ); glVertex3f(- 1 , 1 , 0 ); glColor3f( 0 . 0 , 1 . 0 , 1 . 0 ); glVertex3f(- 1 , - 1 , 0 ); glColor3f( 1 . 0 , 0 . 0 , 0 . 0 ); glVertex3f( 0 , 0 , 1 . 2 ); glEnd(); } // 繪制球體 // 球心坐標為（x，y，z），球的半徑為radius，M，N分別表示球體的橫縱向被分成多少份 void GLWidget::drawSphere(GLfloat xx, GLfloat yy, GLfloat zz, GLfloat radius, GLfloat M, GLfloat N) { // 選擇使用的紋理 glBindTexture(GL_TEXTURE_2D, texture[ 0 ]); float step_z = PI / M; float step_xy = 2 * PI / N; float x[ 4 ], y[ 4 ], z[ 4 ]; float angle_z = 0 . 0 ; float angle_xy = 0 . 0 ; int i = 0 , j = 0 ; glBegin(GL_QUADS); for (i = 0 ; i < M; i++) { angle_z = i * step_z; for (j = 0 ; j < N; j++) { angle_xy = j * step_xy; x[ 0 ] = radius * sin(angle_z) * cos(angle_xy); y[ 0 ] = radius * sin(angle_z) * sin(angle_xy); z[ 0 ] = radius * cos(angle_z); x[ 1 ] = radius * sin(angle_z + step_z) * cos(angle_xy); y[ 1 ] = radius * sin(angle_z + step_z) * sin(angle_xy); z[ 1 ] = radius * cos(angle_z + step_z); x[ 2 ] = radius * sin(angle_z + step_z) * cos(angle_xy + step_xy); y[ 2 ] = radius * sin(angle_z + step_z) * sin(angle_xy + step_xy); z[ 2 ] = radius * cos(angle_z + step_z); x[ 3 ] = radius * sin(angle_z) * cos(angle_xy + step_xy); y[ 3 ] = radius * sin(angle_z) * sin(angle_xy + step_xy); z[ 3 ] = radius * cos(angle_z); for ( int k = 0 ; k < 4 ; k++) { glColor3f(sin(angle_z), cos(angle_z), tan(angle_z)); //glTexCoord2f(0.1f, 0.1f); glVertex3f(xx + x[k], yy + y[k], zz + z[k]); } } } glEnd(); } // 繪制圓環 // 大半徑Radius，小半徑TubeRadius，邊數Sides， 環數Rings void GLWidget::DrawTorus( double Radius, double TubeRadius, int Sides, int Rings) { double sideDelta = 2 . 0 * PI / Sides; double ringDelta = 2 . 0 * PI / Rings; double theta = 0 ; double cosTheta = 1 . 0 ; double sinTheta = 0 . 0 ; double phi, sinPhi, cosPhi; double dist; glColor3f( 1 , 0 , 0 ); for ( int i = 0 ; i < Rings; i++) { double theta1 = theta + ringDelta; double cosTheta1 = cos(theta1); double sinTheta1 = sin(theta1); glBegin(GL_QUAD_STRIP); phi = 0 ; for ( int j = 0 ; j <= Sides; j++) { phi = phi + sideDelta; cosPhi = cos(phi); sinPhi = sin(phi); dist = Radius + (TubeRadius * cosPhi); glNormal3f(cosTheta * cosPhi, sinTheta * cosPhi, sinPhi); glColor3f(cosTheta, sinTheta, sinPhi); glVertex3f(cosTheta * dist, sinTheta * dist, TubeRadius * sinPhi); glNormal3f(cosTheta1 * cosPhi, sinTheta1 * cosPhi, sinPhi); glColor3f(cosTheta1, sinTheta1, sinPhi); glVertex3f(cosTheta1 * dist, sinTheta1 * dist, TubeRadius * sinPhi); } glEnd(); theta = theta1; cosTheta = cosTheta1; sinTheta = sinTheta1; } } // 加載紋理 void GLWidget::loadGLTextures() { QImage tex1, buf1; QImage tex2, buf2; if (!buf1.load( ":/data/qt-logo.jpg" )) { // 如果載入不成功，自動生成一個128*128的32位色的綠色圖片。 qWarning( "Could not read image file!" ); QImage dummy( 128 , 128 , QImage::Format_RGB32); dummy.fill(Qt::green); buf1 = dummy; } if (!buf2.load( ":/data/qt-wood.jpg" )) { // 如果載入不成功，自動生成一個128*128的32位色的綠色圖片。 qWarning( "Could not read image file!" ); QImage dummy( 128 , 128 , QImage::Format_RGB32); dummy.fill(Qt::green); buf2 = dummy; } //***********************************************// // 紋理0：qt-logo //***********************************************// //轉換成紋理類型 tex1 = QGLWidget::convertToGLFormat(buf1); // 創建紋理 glGenTextures( 1 , &texture[ 0 ]); // 使用來自位圖數據生成的典型紋理,將紋理名字texture[0]綁定到紋理目標上 glBindTexture(GL_TEXTURE_2D, texture[ 0 ]); // WRAP參數：紋理坐標超出[0,0]到[1,1]的范圍該怎么處理呢？ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP); // Filter參數：紋理坐標映射到紋素位置(127.34,255.14)該怎么辦? glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // 紋理環境 glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); // 將紋素數組從CPU傳至GPU並且設置為當前紋理。 // 在處理單一紋理時，你可以用，負責效率非常低。 // 多紋理時可以參見紋理綁定。 glTexImage2D(GL_TEXTURE_2D, 0 , 3 , tex1.width(), tex1.height(), 0 , GL_RGBA, GL_UNSIGNED_BYTE, tex1.bits()); //***********************************************// // 紋理0：qt-logo //***********************************************// tex2 = QGLWidget::convertToGLFormat(buf2); glGenTextures( 1 , &texture[ 1 ]); glBindTexture(GL_TEXTURE_2D, texture[ 1 ]); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glTexImage2D(GL_TEXTURE_2D, 0 , 3 , tex2.width(), tex2.height(), 0 , GL_RGBA, GL_UNSIGNED_BYTE, tex2.bits()); // 使用紋理 // 首先調用glEnable( GL_TEXTURE_2D )，來啟用2D紋理; // 然后繪制圖形，並且為每個頂點指定ST坐標; // 最后調用glDisable( GL_TEXTURE_2D ). } // 場景渲染 void GLWidget::renderScene( void ) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glPushMatrix(); renderBasicShape(); glPopMatrix(); glPushMatrix(); glTranslatef(- 3 , 0 , 0 ); renderTextureCube(); glPopMatrix(); glPushMatrix(); glTranslatef( 3 , 0 , 0 ); renderTextureCylinder(); glPopMatrix(); } // 渲染基本圖形 void GLWidget::renderBasicShape() { static float fRotAngle = 0 .0f; fRotAngle += ROT_DELTA; if (fRotAngle > 360 ) fRotAngle = 0 ; glPushMatrix(); glColor3f( 0 , 1 , 0 ); glTranslatef(- 3 , 3 , - 12 ); glRotatef(fRotAngle, 1 , 1 , 1 ); drawCylinder(); glPopMatrix(); glPushMatrix(); glColor3f( 1 , 0 , 0 ); glTranslatef( 0 , 3 , - 12 ); glRotatef(fRotAngle, 1 , 1 , 1 ); drawTetrahedron(); glPopMatrix(); glPushMatrix(); glColor3f( 1 , 0 , 0 ); glTranslatef( 3 , 3 , - 12 ); glRotatef(fRotAngle, 1 , 1 , 1 ); drawCircle(); glPopMatrix(); glPushMatrix(); glColor3f( 1 , 0 , 0 ); glTranslatef( 0 , 0 , - 15 ); glRotatef(fRotAngle, 0 , 1 , 0 ); drawSphere(); glPopMatrix(); glPushMatrix(); glColor3f( 0 , 1 , 1 ); glTranslatef(- 3 , - 3 , - 12 ); glRotatef(fRotAngle, 1 , 1 , 1 ); drawCube(); glPopMatrix(); glPushMatrix(); glColor3f( 1 , 0 , 1 ); glTranslatef( 0 , - 3 , - 12 ); glRotatef(fRotAngle, 1 , 1 , 1 ); DrawTorus(); glPopMatrix(); glPushMatrix(); glColor3f( 1 , 1 , 0 ); glTranslatef( 3 , - 3 , - 12 ); glRotatef(fRotAngle, 1 , 1 , 1 ); drawCone(); glPopMatrix(); } // 渲染紋理 void GLWidget::renderTextureCube() { // 紋理映射 glColor3f( 1 . 0 , 1 . 0 , 1 . 0 ); glTranslatef( 0 .0f, 0 .0f, - 12 .0f); glRotatef(xRot, 1 . 0 , 0 . 0 , 0 . 0 ); glRotatef(yRot, 0 . 0 , 1 . 0 , 0 . 0 ); glRotatef(zRot, 0 . 0 , 0 . 0 , 1 . 0 ); // 使用來自位圖數據生成的典型紋理,將紋理名字texture[0]綁定到紋理目標上 glBindTexture(GL_TEXTURE_2D, texture[ 0 ]); glBegin( GL_QUADS ); glTexCoord2f( 0 . 0 , 0 . 0 ); glVertex3f( - 1 . 0 , - 1 . 0 , 1 . 0 ); glTexCoord2f( 1 . 0 , 0 . 0 ); glVertex3f( 1 . 0 , - 1 . 0 , 1 . 0 ); glTexCoord2f( 1 . 0 , 1 . 0 ); glVertex3f( 1 . 0 , 1 . 0 , 1 . 0 ); glTexCoord2f( 0 . 0 , 1 . 0 ); glVertex3f( - 1 . 0 , 1 . 0 , 1 . 0 ); glTexCoord2f( 1 . 0 , 0 . 0 ); glVertex3f( - 1 . 0 , - 1 . 0 , - 1 . 0 ); glTexCoord2f( 1 . 0 , 1 . 0 ); glVertex3f( - 1 . 0 , 1 . 0 , - 1 . 0 ); glTexCoord2f( 0 . 0 , 1 . 0 ); glVertex3f( 1 . 0 , 1 . 0 , - 1 . 0 ); glTexCoord2f( 0 . 0 , 0 . 0 ); glVertex3f( 1 . 0 , - 1 . 0 , - 1 . 0 ); glTexCoord2f( 0 . 0 , 1 . 0 ); glVertex3f( - 1 . 0 , 1 . 0 , - 1 . 0 ); glTexCoord2f( 0 . 0 , 0 . 0 ); glVertex3f( - 1 . 0 , 1 . 0 , 1 . 0 ); glTexCoord2f( 1 . 0 , 0 . 0 ); glVertex3f( 1 . 0 , 1 . 0 , 1 . 0 ); glTexCoord2f( 1 . 0 , 1 . 0 ); glVertex3f( 1 . 0 , 1 . 0 , - 1 . 0 ); glTexCoord2f( 1 . 0 , 1 . 0 ); glVertex3f( - 1 . 0 , - 1 . 0 , - 1 . 0 ); glTexCoord2f( 0 . 0 , 1 . 0 ); glVertex3f( 1 . 0 , - 1 . 0 , - 1 . 0 ); glTexCoord2f( 0 . 0 , 0 . 0 ); glVertex3f( 1 . 0 , - 1 . 0 , 1 . 0 ); glTexCoord2f( 1 . 0 , 0 . 0 ); glVertex3f( - 1 . 0 , - 1 . 0 , 1 . 0 ); glTexCoord2f( 1 . 0 , 0 . 0 ); glVertex3f( 1 . 0 , - 1 . 0 , - 1 . 0 ); glTexCoord2f( 1 . 0 , 1 . 0 ); glVertex3f( 1 . 0 , 1 . 0 , - 1 . 0 ); glTexCoord2f( 0 . 0 , 1 . 0 ); glVertex3f( 1 . 0 , 1 . 0 , 1 . 0 ); glTexCoord2f( 0 . 0 , 0 . 0 ); glVertex3f( 1 . 0 , - 1 . 0 , 1 . 0 ); glTexCoord2f( 0 . 0 , 0 . 0 ); glVertex3f( - 1 . 0 , - 1 . 0 , - 1 . 0 ); glTexCoord2f( 1 . 0 , 0 . 0 ); glVertex3f( - 1 . 0 , - 1 . 0 , 1 . 0 ); glTexCoord2f( 1 . 0 , 1 . 0 ); glVertex3f( - 1 . 0 , 1 . 0 , 1 . 0 ); glTexCoord2f( 0 . 0 , 1 . 0 ); glVertex3f( - 1 . 0 , 1 . 0 , - 1 . 0 ); glEnd(); xRot += ROT_DELTA; if (xRot > 360 ) xRot = 0 ; yRot += ROT_DELTA; if (yRot > 360 ) yRot = 0 ; zRot += ROT_DELTA; if (zRot > 360 ) zRot = 0 ; } void GLWidget::renderTextureCylinder() { // 紋理映射 glTranslatef( 0 .0f, 0 .0f, - 12 .0f); glRotatef(xRot, 1 . 0 , 0 . 0 , 0 . 0 ); //glRotatef(yRot, 0.0, 1.0, 0.0); //glRotatef(zRot, 0.0, 0.0, 1.0); // 選擇使用的紋理 glBindTexture(GL_TEXTURE_2D, texture[ 1 ]); // 利用三角形和四邊形等基本圖元繪制底面圓圓心在坐標原點， 半徑為 r，高為 h，方向沿 z 軸方向的圓柱； // 側面用多個四邊形,底面用多個三角形來表示 glBegin(GL_QUAD_STRIP); //連續填充四邊形串 int i = 0 ; for (i = 0 ; i <= 360 ; i += 15 ) { float p = i * 3 . 14 / 180 ; //p和圓周是相對應的， 這里讓紋理的橫坐標隨圓周掃過的角度一起改變，就能夠將紋理圖“刷”上去了， //而縱坐標設置為圖像的高度和紋理高度的對應，這里合適的參數是根據實際測試得到的 glTexCoord2f(p / 10 , 0 .1f); glVertex3f(sin(p), cos(p), 1 .0f); //這個 1.0f指定的是高度h glTexCoord2f(p / 10 , 0 .0f); glVertex3f(sin(p), cos(p), 0 .0f); } glEnd(); //bottom circle glBegin(GL_TRIANGLE_FAN); //扇形連續填充三角形串 glTexCoord2f( 0 .0f, 0 .0f); //將紋理圖(0, 0)映射到圓心 glVertex3f( 0 .0f, 0 .0f, 0 .0f); for (i = 0 ; i <= 360 ; i += 15 ) { float p = i * 3 . 14 / 180 ; glTexCoord2f( 1 .0f, 0 .0f); //將紋理圖(1, 0)映射到圓周 glVertex3f(sin(p), cos(p), 0 .0f); } glEnd(); glTranslatef( 0 , 0 , 1 ); //設定高度為1，畫上底面 //top circle glBegin(GL_TRIANGLE_FAN); //扇形連續填充三角形串 glTexCoord2f( 0 .0f, 0 .0f); //將紋理圖(0, 0)映射到圓心 glVertex3f( 0 .0f, 0 .0f, 0 .0f); for (i = 0 ; i <= 360 ; i += 15 ) { float p = i * 3 . 14 / 180 ; glTexCoord2f( 1 .0f, 0 .0f); //將紋理圖(1, 0)映射到圓周 glVertex3f(sin(p), cos(p), 0 .0f); } glEnd(); xRot += ROT_DELTA; if (xRot > 360 ) xRot = 0 ; yRot += ROT_DELTA; if (yRot > 360 ) yRot = 0 ; zRot += ROT_DELTA; if (zRot > 360 ) zRot = 0 ; } |
主函數調用
main.cpp
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#include
"GLWidget.h"
#include <QApplication> #include <QObject> int main( int argc, char *argv[]) { QApplication a(argc, argv); GLWidget w; w.resize( 600 , 600 ); w.setWindowTitle(QObject::tr( "Michael's OpenGL Framework" )); w.show(); return a.exec(); } |
運行效果
