【发布时间】：2015-10-07 04:02:03
【问题描述】：
我正在逐帧制作分形（三角形分形）动画。我知道我需要使用回调方法来执行此操作，但我不确定如何实现它。我希望通过鼠标左键单击使其工作，因此我有以下代码：
void mouse(int button, int state, int x, int y){
if(button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN){
glClear(GL_COLOR_BUFFER_BIT);
divide_triangle(v[0], v[1], v[2], n);
}
//Closes the window on right button
if(button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN){
exit(0);
}
}
这是我的鼠标点击回调，但这不会在每次绘制三角形时重新为三角形设置动画。每次递归绘制三角形的时候，怎么显示绘制的过程呢？
void divide_triangle(point2 a, point2 b, point2 c, int m)
{
/* triangle subdivision using vertex coordinates */
point2 v0, v1, v2;
int j;
if(m>0){
for(j=0; j<2; j++) v0[j]=(a[j]+b[j])/2;
for(j=0; j<2; j++) v1[j]=(a[j]+c[j])/2;
for(j=0; j<2; j++) v2[j]=(b[j]+c[j])/2;
divide_triangle(a, v0, v1, m-1);
divide_triangle(c, v1, v2, m-1);
divide_triangle(b, v2, v0, m-1);
}
else(triangle(a,b,c));
glutPostRedisplay();
/* draw triangle at end of recursion */
}
我想在这里绘制新三角形后重新显示，让它看起来像一个动画，所以我想我需要在重新显示之间有一个延迟。我该如何设置？但我也想让它在我可以绘制它而不是每次都动画的地方，即我单击一个特定的鼠标键：说“F1”或一些未保留的键，它只会显示最终的递归三角形。
Here is my full code for your viewing:
#ifdef __APPLE__ //For use with OS X
#include <GLUT/glut.h>
#else //Linux
#include <GL/glut.h>
#endif
#include <stdlib.h>
#include <GL/glut.h>
typedef GLfloat point2[2];
/* initial triangle – global variables */
point2 v[]={{-2.0, -1.5}, {2.0, -1.5},
{0.0, 1.5}};
int n; /* number of recursive steps */
int windowX, windowY; //Window size parameters.
float red = .25;
float green = .25;
float blue = .70;
bool color_state = true;
void mouse(int button, int state, int x, int y);
void triangle( point2 a, point2 b, point2 c);
void divide_triangle(point2 a, point2 b, point2 c, int m);
void swap_colors();
void display(void){
glClear(GL_COLOR_BUFFER_BIT);
divide_triangle(v[0], v[1], v[2], n);
glFlush();
}
void init(){
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluOrtho2D(-2.0, 2.0, -2.0, 2.0);
glMatrixMode(GL_MODELVIEW);
glClearColor (0.10, 0.10, 0.10 ,1.0);
glColor3f(red, green, blue);
}
int main(int argc, char **argv){
if(argc <= 1){
windowX = 500;
windowY = 500;
n = 4;
}
else if(argc > 1){
windowX = atoi(argv[1]); //atoi converts char to int
windowY = atoi(argv[2]);
n = atoi(argv[3]);
}
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_SINGLE|GLUT_RGB);
glutInitWindowSize(windowX, windowY);
glutCreateWindow("N-Force");
glutDisplayFunc(display);
glutTimerFunc(30, recurse, -1)
glutMouseFunc(mouse);
init();
glutMainLoop();
}
void mouse(int button, int state, int x, int y){
if(button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN){ //Swap colors
glClear(GL_COLOR_BUFFER_BIT);
divide_triangle(v[0], v[1], v[2], n);
}
//Closes the window on right button
if(button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN){
exit(0);
}
}
void divide_triangle(point2 a, point2 b, point2 c, int m)
{
/* triangle subdivision using vertex coordinates */
point2 v0, v1, v2;
int j;
if(m>0){
for(j=0; j<2; j++) v0[j]=(a[j]+b[j])/2;
for(j=0; j<2; j++) v1[j]=(a[j]+c[j])/2;
for(j=0; j<2; j++) v2[j]=(b[j]+c[j])/2;
divide_triangle(a, v0, v1, m-1);
divide_triangle(c, v1, v2, m-1);
divide_triangle(b, v2, v0, m-1);
}
else(triangle(a,b,c));
glutPostRedisplay();
/* draw triangle at end of recursion */
}
void triangle( point2 a, point2 b, point2 c){
glBegin(GL_TRIANGLES);
glVertex2fv(a);
glVertex2fv(b);
glVertex2fv(c);
glEnd();
}
void swap_colors(){ //maybe add parameters x and y to change colors based on coordinates
if(color_state == true){
red = blue = green = .1;
color_state = false;
}
else{
red = 0.25;
green = .25;
blue = 0.70;
color_state = true;
}
}
/* TO DO:
1. add cmd line args, (width, depth, and recursive depth) (CHECK)
2. add color swap
3. add exit callback (check> right mouse)
4. Idle callback for animation
*/
【问题讨论】：
标签： opengl animation recursion callback