animation - Animating a Fractal Via OpenGL -
i working on animating fractal (triangle fractal) frame-by-frame. know need use call-back method this, not sure how implement it. wish working via left-mouse click have code:
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 window on right button if(button == glut_right_button && state == glut_down){ exit(0); } } this mouse click call back, doesn't re-animate triangle each time triangle drawn. how can show process of drawing each time recurse through triangle drawing?
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 @ end of recursion */ } i want redisplay once draw new triangle here, , make appear animation, guess need delay between redisplays. how can set up? want make can draw without animating everytime, i.e. click specific mouse key: 'f1' or unreserved key , display final recursive triangle.
#ifdef __apple__ //for use 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 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 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 @ 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 , y 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; } } /* do: 1. add cmd line args, (width, depth, , recursive depth) (check) 2. add color swap 3. add exit callback (check> right mouse) 4. idle callback animation */
use gluttimerfunc() callback boolean flag increment recursion depth value , post redisplays:
bool animating = false; unsigned int n = 4; void timer( int value ) { if( !animating ) return; n++; if( n > 6 ) n = 0; gluttimerfunc( 200, timer, 0 ); glutpostredisplay(); } void mouse(int button, int state, int x, int y) { if(button == glut_right_button && state == glut_down) { animating = !animating; gluttimerfunc( 0, timer, 0 ); } } all together:
#include <gl/glut.h> bool animating = false; unsigned int n = 4; void timer( int value ) { if( !animating ) return; n++; if( n > 6 ) n = 0; gluttimerfunc( 200, timer, 0 ); glutpostredisplay(); } void mouse(int button, int state, int x, int y) { if(button == glut_right_button && state == glut_down) { animating = !animating; gluttimerfunc( 0, timer, 0 ); } } typedef glfloat point2[2]; void divide_triangle(point2 a, point2 b, point2 c, int m) { /* triangle subdivision using vertex coordinates */ if(m>0) { point2 v0, v1, v2; for( int j=0; j<2; j++) v0[j]=(a[j]+b[j])/2; for( int j=0; j<2; j++) v1[j]=(a[j]+c[j])/2; for( int 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 { glvertex2fv(a); glvertex2fv(b); glvertex2fv(c); } } void display(void) { glclearcolor (0.10, 0.10, 0.10 ,1.0); glclear(gl_color_buffer_bit); glmatrixmode(gl_projection); glloadidentity(); gluortho2d(-2.0, 2.0, -2.0, 2.0); glmatrixmode(gl_modelview); glloadidentity(); float red = .25; float green = .25; float blue = .70; glcolor3f(red, green, blue); /* initial triangle – global variables */ point2 v[]={{-2.0, -1.5}, {2.0, -1.5}, {0.0, 1.5}}; glbegin(gl_triangles); divide_triangle(v[0], v[1], v[2], n); glend(); glflush(); } int main(int argc, char **argv) { glutinit(&argc, argv); glutinitdisplaymode(glut_single|glut_rgb); glutinitwindowsize(500, 500); glutcreatewindow("n-force"); glutdisplayfunc(display); glutmousefunc(mouse); glutmainloop(); } 
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