[英]draw in animated opengl scene
單擊鼠標按鈕時,在動畫場景中繪制煙火效果時出現問題。 為什么不畫圖?
我的代碼:
#include<GL/glut.h>
struct Point {
GLint x;
GLint y;
};
Point p1, p2;
int ww=600,wh=400;
int xi,yi,xf,yf,y1b,x1b,y2b,x2b;
float px, py, t;
float x=0.,y=0.,x1=5.;
void update()
{
x+=0.01;
x1 -= 0.02;
if (x>6)
{
x -= 6;
x1 = 4;
}
}
我在那里創建了一個根據貝塞爾曲線繪制煙花效果的函數。 如果我在靜態窗口上繪制,它將為Okey。
// Bezier curve firework
void bezier(int xi, int yi, int xf, int yf)
{
// Coordinates for additional points of bezier curve
x1b = xi + rand()%15;
y1b = yi + rand()%5;
x2b = xf + rand()%15;
y2b = xf + rand()%5;
calculate and draw the curves
for (t=0.;t<=1.;t+=0.001)
{
px=(1-t)*(1-t)*(1-t)*xi+3*t*(1-t)*(1-t)*x1b+3*t*t*(1-t)*x2b+t*t*t*xf;
py=(1-t)*(1-t)*(1-t)*yi+3*t*(1-t)*(1-t)*y1b+3*t*t*(1-t)*y2b+t*t*t*yf;
glPointSize(2);
glBegin(GL_POINTS);
//glColor3f(1,0,0);
glVertex2d(px,py);
glEnd();
glFlush();
}
}
void initRendering()
{
glEnable(GL_DEPTH_TEST);
}
void reshaped(int w , int h)
{
glViewport(0,0,w,h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45, (double)w/(double)h,1,200);
}
// If pressed ESC -> exit
void keyPressed(unsigned char k, int x, int y)
{
if(k==27)
{
exit(0);
}
}
然后,如果我按下鼠標按鈕,它應該調用上面的函數並繪制我需要的東西。 但是沒有(
// If pressed mouse button -> draw firework effect
void mousePressed(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON && state == GLUT_UP)
{
xi=x;
yi=wh-y;
xf=x + 5.;
p1.x = xi; p1.y = yi;
p2.x = xf; p2.y = yi;
//drawLine(xi,yi,xf,yi);
bezier(xi, yi,xf, yi);
}
glutPostRedisplay();
}
在那里,我創建了動畫窗口。 兩朵雲在准波中移動。
// Display a two moving clouds and the earth
void display()
{
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glPushMatrix();
glTranslatef(x1,y,-5.0);
glBegin(GL_POLYGON);
glColor3f(1.,0.,0.5);
glVertex3f(-1.,1.,-5.);
glVertex3f(0.,2.,-5.);
glVertex3f(-2.,2.,-5.);
glVertex3f(1.,1.,-5.);
glEnd();
glPopMatrix();
glPushMatrix();
glTranslatef(x,y,-5.);
glBegin(GL_POLYGON);
glColor3f(0.,0.5,0.5);
glVertex3f(1.,0.7,-5.);
glVertex3f(1.5,1.0,-5.0);
glVertex3f(0.7,1.5,-5.0);
glVertex3f(0.0,2.0,-5.0);
glVertex3f(-0.7,1.5,-5.0);
glVertex3f(-1.4,1.6,-5.0);
glVertex3f(-1.7,1.0,-5.0);
glVertex3f(-1.5,0.7,-5.0);
glVertex3f(-1.0,0.5,-5.0);
glEnd();
glPopMatrix();
glBegin(GL_POLYGON);
glColor3f(1.,1.,1.5);
glVertex3f(-2.,-2.,-5.);
glVertex3f(-2.0,-2.0,-5.0);
glVertex3f(-1.0,-1.5,-5.0);
//glVertex3f(0.0,0.0,-5.0);
glVertex3f(2.0,-2.0,-5.0);
glVertex3f(1.2,-1.5,-5.0);
glEnd();
update();
glutSwapBuffers();
glFlush();
}
void myinit()
{
glViewport(0,0,ww,wh);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluOrtho2D(0.0,(GLdouble)ww,0.0,(GLdouble)wh);
glMatrixMode(GL_MODELVIEW);
}
int main(int argc,char **argv)
{
// Initialization
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB|GLUT_DEPTH);
glutInitWindowPosition(100,100);
glutInitWindowSize(400,400);
glutCreateWindow("Salute | Clouds");
initRendering();
// Registration
glutDisplayFunc(display);
glutIdleFunc(display);
glutReshapeFunc(reshaped);
// Handler of
myinit();
glutKeyboardFunc(keyPressed);
glutMouseFunc(mousePressed);
// Main Loop
glutMainLoop();
return(0);
}
我認為問題如下:我試圖在更新的動畫窗口中繪制煙花。 每次我單擊屏幕時,它都會更新。 最后,什么也看不見。 實際上是一個問題:如何使glutMoseFunk函數在更新的窗口中向我致敬?
當您的場景以透視投影繪制時, bezier
函數可與正交投影一起使用。 這意味着在調用bezier
之前必須更改投影矩陣。
此外,在主循環中進行所有渲染( display
功能)。 事件mousePressed
僅應用於更改參數(設置xi
, yi
,...)。
顯示功能可能如下所示:
int ww=400, wh=400;
void display()
{
// clear the frame buffer
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
// setup perspective projection
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45, (double)ww/(double)wh,1,200);
// set model view matrix (identity matrix)
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// draw scene
.....
// setup ortihgraphic projection
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(0.0,(GLdouble)ww,0.0,(GLdouble)wh);
bezier(xi, yi,xf, yi);
update();
glutSwapBuffers();
glutPostRedisplay();
}
reshaped
函數應設置視口並僅注意窗口大小:
void reshaped(int w , int h)
{
ww = w;
wh = h;
glViewport(0, 0, ww, wh);
}
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