opengl,OpenGL建模疯狂代码！

此次讲解OPENGL复杂建模方式，将分几个部分完成，这篇先介绍图原扩展：如何利用专用函数精确绘制平面图形。下次会讲解如何利用法向量生成曲面。 1.点和线 void glPointSize(GLfloat size); 设置点的宽度，size必须>0，缺省1 void glLineWidth(GLfoat width); 设置线宽，width>0，缺省为1 void glLineStipple(GLint factor,GLushort pattern); 设置线的模式，factor用于对模式进行拉伸的比例因子，pattern是线的模式例如11001100是虚线（1绘制，0不绘制）必须要启用glEnable(GL_LINE_STIPPLE)才能使用以上函数，不再使用时调用 glDisable(GL_LINE_STIPPLE)关闭，这与以前的glEnable();glDisable();的用法都是类似的。请看下面例子： #include <windows.h> #include <gl/gl.h> #include <gl/glu.h> #include <gl/glaux.h> #pragma comment(lib, "OpenGl32.lib") #pragma comment(lib, "glu32.lib") #pragma comment(lib, "glaux.lib") #pragma warning(disable : 4244) // MIPS #pragma warning(disable : 4136) // X86 #pragma warning(disable : 4051) // ALPHA ////////////////////////////////////////////////////////////////// //sample.cpp /////////////////////////////////////////////////////////////////// //sample.cpp void myinit(void); void CALLBACK display(void); void CALLBACK reshape(GLsizei w,GLsizei h); void myinit(void) { auxInitDisplayMode(AUX_SINGLE|AUX_RGBA); auxInitPosition(0,0,600,500); auxInitWindow("sample1"); glClearColor(0.0,0.0,0.0,0.0); glClear(GL_COLOR_BUFFER_BIT); glShadeModel(GL_FLAT); } /* void CALLBACK reshape(GLsizei w,GLsizei h) { glViewport(0,0,w,h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); if(w<=h) glOrtho(-4.0,4.0,-4.0*(GLfloat)h/(GLfloat)w, 4.0*(GLfloat)h/(GLfloat)w,-4.0,4.0); else glOrtho(-4.0*(GLfloat)h/(GLfloat)w, 4.0*(GLfloat)h/(GLfloat)w,-4.0,4.0,-4.0,4.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } */ //自定义的绘制直线的函数，参数为起始点和终止点坐标 void line2i(GLint x1,GLint y1,GLint x2,GLint y2) { glBegin(GL_LINES); glVertex2f(x1,y1); glVertex2f(x2,y2); glEnd(); } void CALLBACK display(void) { glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); //首先绘制一系列点，点的大小不断增加 int i; glColor3f(0.8,0.6,0.4); for(i=1;i<=10;i++) { glPointSize(i*2); glBegin(GL_POINTS); glVertex2f(30.0+((GLfloat)i*50.0),330.0); glEnd(); } //再绘制两条虚线，第二条比第一条松散一些，由pattern参数即可看出 glEnable(GL_LINE_STIPPLE); glLineStipple(1,0x0101);//间隔1位 glColor3f(1.0,0.0,0.0); line2i(20,250,250,250); glLineStipple(1,0x00ff);//间隔2位 glColor3f(0.0,0.0,1.0); line2i(300,250,550,250); //改变线的绘制宽度的效果--加宽 //重新画出上面两条虚线 glLineWidth(5.0); glEnable(GL_LINE_STIPPLE); glLineStipple(1,0x0101); glColor3f(1.0,0.0,0.0); line2i(50,150,250,150); glLineStipple(1,0x00ff); glColor3f(0.0,0.0,1.0); line2i(300,150,550,150); glFlush(); } void main(void) { myinit(); // auxReshapeFunc(reshape); auxMainLoop(display); } //end of sample ////////////////////////////////////////////// 2.多边形 void glPolygonMode(GLenum face,GLenum mode); 控制多边形指定面的绘图模式， face为：GL_FRONT GL_BACK或GL_FRONT_AND BACK mode为：GL_POINT GL_LINE或GL_FILL表示多边型的轮廓点、轮廓线和填充模式的绘制方式。缺省是填充方式。 void glPolygonStipple(const GLubyte *mask); 其中mask必须是指向32*32的位图指针，1是绘制、0不绘制使用上述函数也要调用： glEnable(GL_POLYGON-STIPPLE); glDisable(GL_POLYGON_STIPPLE); 请看下面例子： #include <windows.h> #include <gl/gl.h> #include <gl/glu.h> #include <gl/glaux.h> #pragma comment(lib, "OpenGl32.lib") #pragma comment(lib, "glu32.lib") #pragma comment(lib, "glaux.lib") #pragma warning(disable : 4244) // MIPS #pragma warning(disable : 4136) // X86 #pragma warning(disable : 4051) // ALPHA ///////////////////////////////////////////// //sample.cpp void myinit(void); void CALLBACK display(void); void CALLBACK reshape(GLsizei w,GLsizei h); //定义填充模式32*32点阵 GLubyte pattern[]={ 0x00,0x01,0x80,0x00, 0x00,0x03,0xc0,0x00, 0x00,0x07,0xe0,0x00, 0x00,0x0f,0xf0,0x00, 0x00,0x1f,0xf8,0x00, 0x00,0x3f,0xfc,0x00, 0x00,0x7f,0xfe,0x00, 0x00,0xff,0xff,0x00, 0x01,0xff,0xff,0x80, 0x03,0xff,0xff,0xc0, 0x07,0xff,0xff,0xe0, 0x0f,0xff,0xff,0xf0, 0x1f,0xff,0xff,0xf8, 0x3f,0xff,0xff,0xfc, 0x7f,0xff,0xff,0xfe, 0xff,0xff,0xff,0xff, 0xff,0xff,0xff,0xff, 0x7f,0xff,0xff,0xfe, 0x3f,0xff,0xff,0xfc, 0x1f,0xff,0xff,0xf8, 0x0f,0xff,0xff,0xf0, 0x07,0xff,0xff,0xe0, 0x03,0xff,0xff,0xc0, 0x01,0xff,0xff,0x80, 0x00,0xff,0xff,0x00, 0x00,0x7f,0xfe,0x00, 0x00,0x3f,0xfc,0x00, 0x00,0x1f,0xf8,0x00, 0x00,0x0f,0xf0,0x00, 0x00,0x07,0xe0,0x00, 0x00,0x03,0xc0,0x00, 0x00,0x01,0x80,0x00 }; void myinit(void) { auxInitDisplayMode(AUX_SINGLE|AUX_RGBA); auxInitPosition(0,0,400,400); auxInitWindow("sample1"); glClearColor(0.0,0.0,0.0,0.0); glClear(GL_COLOR_BUFFER_BIT); glShadeModel(GL_FLAT); } /* void CALLBACK reshape(GLsizei w,GLsizei h) { glViewport(0,0,w,h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); if(w<=h) glOrtho(-4.0,4.0,-4.0*(GLfloat)h/(GLfloat)w, 4.0*(GLfloat)h/(GLfloat)w,-4.0,4.0); else glOrtho(-4.0*(GLfloat)h/(GLfloat)w, 4.0*(GLfloat)h/(GLfloat)w,-4.0,4.0,-4.0,4.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } */ void CALLBACK display(void) { glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); //选用兰色作为填充色 glColor3f(0.0,0.0,1.0); //启用多边形绘制模式 glEnable(GL_POLYGON_STIPPLE); //利用定义好的填充模式绘制多边形 glPolygonStipple(pattern); //绘制长方形 glRectf(48.0,80.0,210.0,305.0); glFlush(); } void main(void) { myinit(); // auxReshapeFunc(reshape); auxMainLoop(display); } //end of sample 例子中的运行结果是给出一个表面有定义图样的长方形

opengl,OpenGL建模

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