C++ OpenGL缩放效率
我是OpenGL的初学者,作为我的第一个应用程序,我尝试使用三角形的重心细分方法生成分形。由于不知道OpenGL在透视变化方面的功能,我对缩放和视点变化算法的第一个想法是,每次按下一个键(箭头表示相机移动,+/-表示缩放),用不同的起点坐标和比例因子简单地重绘整个分形 考虑到重心细分的6次迭代绘制了大约56000个三角形(6^0+6^1+6^2+6^3+6^4+6^5+6^6三角形),该算法效率非常低。所以我试着用gluPerspective()进行缩放,结果很不幸是一个黑屏,而不是分形。我有两个主要问题:C++ OpenGL缩放效率,c++,opengl,camera,zooming,C++,Opengl,Camera,Zooming,我是OpenGL的初学者,作为我的第一个应用程序,我尝试使用三角形的重心细分方法生成分形。由于不知道OpenGL在透视变化方面的功能,我对缩放和视点变化算法的第一个想法是,每次按下一个键(箭头表示相机移动,+/-表示缩放),用不同的起点坐标和比例因子简单地重绘整个分形 考虑到重心细分的6次迭代绘制了大约56000个三角形(6^0+6^1+6^2+6^3+6^4+6^5+6^6三角形),该算法效率非常低。所以我试着用gluPerspective()进行缩放,结果很不幸是一个黑屏,而不是分形。我有两
- 用于透视变化和视点(gluPerspective()、gluLookAt()、glFrustum()等)的OpenGL函数是否使用不同的坐标重新绘制整个图形,还是使用更有效的方法获得相同的结果?在我的情况下,它们的使用会更有效吗
- 我在代码中做错了什么。为什么我会有黑屏
#include <GL/glfw.h> #include <iostream> #include <math.h> using namespace std; struct punct{ GLdouble x, y;}; //"punct" means "point" in my native language punct A, B, C; int n=0, mode=1; double l=1.6, ox=0, oy=0, scale=1; punct mid (punct A, punct B); void initiate (); void line (punct A, punct B); void triangle (punct A, punct B, punct C); void divide (punct A, punct B, punct C,int i); int main () { int width, height; bool running = true; char input=NULL; glfwInit(); if( !glfwOpenWindow( 800, 800, 0, 0, 0, 0, 0, 0, GLFW_FULLSCREEN ) ) { glfwTerminate(); return 0; } glfwSetWindowTitle("Baricentric"); while(running) { glfwGetWindowSize( &width, &height ); height = height > 0 ? height : 1; glViewport( 0, 0, width, height ); glClearColor( 0.0f, 0.0f, 0.0f, 0.0f ); glClear( GL_COLOR_BUFFER_BIT ); //This functions make my screen black //glMatrixMode(GL_MODELVIEW); //glLoadIdentity(); //gluPerspective (50*scale, width/height, 10.0, 100.0); initiate (); if(glfwGetKey(GLFW_KEY_KP_ADD) && glfwGetKey(GLFW_KEY_LCTRL)) input='+'; if(!glfwGetKey(GLFW_KEY_KP_ADD) && input=='+') { if(n<7) n++; input='\n'; } if(glfwGetKey(GLFW_KEY_KP_SUBTRACT) && glfwGetKey(GLFW_KEY_LCTRL)) input='-'; if(!glfwGetKey(GLFW_KEY_KP_SUBTRACT) && input=='-') { if(n>0)n--; input='\n'; } if(glfwGetKey(GLFW_KEY_KP_1)||glfwGetKey('1')) input='1'; if(!glfwGetKey(GLFW_KEY_KP_1) && input=='1') { mode=1; input='\n'; } if(glfwGetKey(GLFW_KEY_KP_0)||glfwGetKey('0')) input='0'; if(!glfwGetKey(GLFW_KEY_KP_0) && input=='0') { mode=0; input='\n'; } if(glfwGetKey(GLFW_KEY_KP_ADD) && !glfwGetKey(GLFW_KEY_LCTRL)) l+=0.002*(n+0.5); //'l' is replaced with 'scale' when using gluPerspective() if(glfwGetKey(GLFW_KEY_KP_SUBTRACT) && !glfwGetKey(GLFW_KEY_LCTRL)) l-=0.002*(n+0.5); //'l' is replaced with 'scale' when using gluPerspective() if(glfwGetKey(GLFW_KEY_UP)) oy-=0.002*(n+0.5); if(glfwGetKey(GLFW_KEY_DOWN)) oy+=0.002*(n+0.5); if(glfwGetKey(GLFW_KEY_RIGHT)) ox+=0.002*(n+0.5); if(glfwGetKey(GLFW_KEY_LEFT)) ox-=0.002*(n+0.5); if (n) divide (A,B,C,1); glfwSwapBuffers(); running = !glfwGetKey(GLFW_KEY_ESC) && glfwGetWindowParam( GLFW_OPENED); } glfwTerminate(); return 0; } punct mid (punct A, punct B) { punct C; C.x=(A.x+B.x)/2; C.y=(A.y+B.y)/2; return C; } void initiate () { A.x = -(l/2)+ox; A.y = -(l*sqrt(3)/4)+oy; B.x = l/2+ox; B.y = A.y; C.x = 0+ox; C.y = (l*sqrt(3)/4)+oy; glBegin (GL_QUADS); glColor3f(0.93,0.84,0.82); glVertex3d(-1, 1, 0); glColor3f(0.01,0.95,0.83); glVertex3d(-1, -1, 0); glColor3f(0.80,0.71,0.80); glVertex3d(1, -1, 0); glColor3f(0.8,1,0.8); glVertex3d(1, 1, 0); glEnd (); glBegin (GL_TRIANGLES); glColor3f(0,0.6,0.88); glVertex3d(C.x, C.y, 0); glColor3f(0,0.77,0.73); glVertex3d(B.x, B.y, 0); glColor3f(0.01,0.66,0.62); glVertex3d(A.x, A.y, 0); glEnd (); if (mode==0) { glLineWidth (0.1); glColor3f(0,0,0.36); glBegin (GL_LINE_LOOP); glVertex3d(C.x, C.y, 0); glVertex3d(B.x, B.y, 0); glVertex3d(A.x, A.y, 0); glEnd (); } } void divide (punct A, punct B, punct C, int i) { if(i<=n) { punct a, b, c, G; c=mid(A,B); b=mid(A,C); a=mid(B,C); G.x=(A.x+B.x+C.x)/3; G.y=(A.y+B.y+C.y)/3; if(mode==1) { triangle(G,a,C); triangle(G,b,C); triangle(G,a,B); triangle(G,c,B); triangle(G,c,A); triangle(G,b,A); } line(c,C); line(a,A); line(b,B); divide(G,a,C,i+1); divide(G,b,C,i+1); divide(G,a,B,i+1); divide(G,c,B,i+1); divide(G,c,A,i+1); divide(G,b,A,i+1); } } void line (punct A, punct B) { glBegin (GL_LINE_STRIP); glVertex3d(A.x,A.y,0); glVertex3d(B.x,B.y,0); glEnd (); } void triangle (punct A, punct B, punct C) { glBegin (GL_TRIANGLES); glColor3f(0,0.6,0.88); glVertex3d(C.x, C.y, 0); glColor3f(0,0.77,0.73); glVertex3d(B.x, B.y, 0); glColor3f(0.01,0.66,0.62); glVertex3d(A.x, A.y, 0); glEnd (); }
#包括 #包括 #包括 使用名称空间std; 结构点{glx,y;}//在我的母语中,“点”的意思是“点” 点A、B、C; int n=0,mode=1; 双l=1.6,ox=0,oy=0,刻度=1; 中点(A点、B点); 无效初始化(); 空隙线(点A、点B); 空心三角形(点A、点B、点C); 空隙分割(点A、点B、点C、点i); int main() { int宽度、高度; bool running=true; 字符输入=NULL; glfwInit(); 如果(!glfwOpenWindow(800,800,0,0,0,0,0,GLFW_全屏)) { glfwTerminate(); 返回0; } glfwSetWindowTitle(“Barictric”); (跑步时) { GLFWGetWindowsSize(宽度和高度); 高度=高度>0?高度:1; glViewport(0,0,宽度,高度); glClearColor(0.0f、0.0f、0.0f、0.0f); glClear(GLU颜色缓冲位); //这些功能使我的屏幕变黑 //glMatrixMode(GLU模型视图); //glLoadIdentity(); //透视图(50*比例,宽度/高度,10.0,100.0); 发起(); if(glfwGetKey(GLFW_KEY_KP_ADD)和&glfwGetKey(GLFW_KEY_LCTRL))输入=“+”; 如果(!glfwGetKey(GLFW_KEY_KP_ADD)&&input='+')){ 如果(n0)n--; 输入='\n'; } if(glfwGetKey(GLFW_KEY_KP_1)| | glfwGetKey('1'))input='1'; 如果(!glfwGetKey(GLFW_KEY_KP_1)&&input='1'){ 模式=1; 输入='\n'; } if(glfwGetKey(GLFW_KEY_KP_0)| | glfwGetKey('0'))input='0'; 如果(!glfwGetKey(GLFW_KEY_KP_0)&&input='0'){ 模式=0; 输入='\n'; } 如果使用gluPerspective()时,(glfwGetKey(GLFW_KEY_KP_ADD)和&!glfwGetKey(GLFW_KEY_LCTRL))l+=0.002*(n+0.5);//“l”替换为“比例” 如果(glfwGetKey(GLFW_KEY_KP_SUBTRACT)和&!glfwGetKey(GLFW_KEY_LCTRL))l-=0.002*(n+0.5);//'l'在使用GLUPperspective()时替换为'scale' 如果(glfwGetKey(GLFW_KEY_UP))oy-=0.002*(n+0.5); 如果(glfwGetKey(GLFW_KEY_DOWN))oy+=0.002*(n+0.5); 如果(glfwGetKey(GLFW_KEY_RIGHT))ox+=0.002*(n+0.5); 如果(glfwGetKey(GLFW_KEY_LEFT))ox-=0.002*(n+0.5); 如果(n)除以(A,B,C,1); glfwSwapBuffers(); 运行=!glfwGetKey(GLFW_KEY_ESC)和&glfwGetWindowParam(GLFW_打开); } glfwTerminate(); 返回0; } 中点(A点、B点){ C点; C.x=(A.x+B.x)/2; C.y=(A.y+B.y)/2; 返回C; } 无效启动(){ A.x=-(l/2)+ox;A.y=-(l*sqrt(3)/4)+oy; B.x=l/2+ox;B.y=A.y; C.x=0+ox;C.y=(l*sqrt(3)/4)+oy; glBegin(GL_QUADS); glColor3f(0.93,0.84,0.82);glVertex3d(-1,1,0); glColor3f(0.01,0.95,0.83);glVertex3d(-1,-1,0); glColor3f(0.80,0.71,0.80);glVertex3d(1,-1,0); glColor3f(0.8,1,0.8);glVertex3d(1,1,0); 格伦德(); glBegin(GL_三角形); glColor3f(0,0.6,0.88);glVertex3d(C.x,C.y,0); glColor3f(0,0.77,0.73);glVertex3d(B.x,B.y,0); glColor3f(0.01,0.66,0.62);glVertex3d(A.x,A.y,0); 格伦德(); 如果(模式==0){ glLineWidth(0.1); gl3f(0,0,0.36); glBegin(GL_线_环); glVertex3d(C.x,C.y,0); glVertex3d(B.x,B.y,0); glVertex3d(A.x,A.y,0); 格伦德(); } } 空分(点A、点B、点C、点i){
如果(我像以前很多人一样,你已经陷入了一种错误的观念,认为OpenGL是一个场景图。事实并非如此 OpenGL是一个绘图API。您的操作系统提供一个画布(窗口、PBuffer、Pixmap等),OpenGL提供点、线或三角形形式的绘图工具 OpenGL的透视变化函数和视点(gluPerspective()、gluLookAt()、glFrustum()等)是否用不同的坐标重新绘制了整个图形
他们所做的只是改变一些矩阵的值。屏幕上的任何内容都不会因此而改变。你必须重新绘制整个内容以进行可见的更改。像以前很多人一样,你已经陷入了一种错误的观念,认为OpenGL是一个场景图。事实并非如此 OpenGL是一个绘图API。您的操作系统提供一个画布(窗口、PBuffer、Pixmap等),OpenGL提供点、线或三角形形式的绘图工具 OpenGL的透视变化函数和视点(gluPerspective()、gluLookAt()、glFrustum()等)是否用不同的坐标重新绘制了整个图形 他们所做的只是更改一些矩阵的值。屏幕上的任何内容都不会因此而改变。你必须重新绘制整个内容,以进行可见的更改