karma/flying-balls
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Merge branch 'cairo' into faces

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This commit is contained in:
Antonio Carzaniga 2019-07-29 18:41:23 +02:00
commit 32cd25bd56
1 changed files with 29 additions and 14 deletions
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27
balls.c
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@ -39,6 +39,8 @@ unsigned int n_balls = 50;
static double g_y = 20;
static double g_x = 0;
static double clear_alpha = 1.0;
void random_velocity(struct ball * p) {
double r2;
do {
@ -142,7 +144,11 @@ const char * face_filename = 0;
cairo_surface_t * face_surface = 0;
int face_x_offset, face_y_offset;
static int gravity_vector_countdown = 0;
static int gravity_vector_init = 300;
static void draw_gravity_vector() {
if (gravity_vector_countdown != 0) {
cairo_new_path(cr);
cairo_move_to(cr, width/2, height/2);
cairo_line_to(cr, width/2 + g_x, height/2 + g_y);
@ -151,6 +157,9 @@ static void draw_gravity_vector() {
cairo_stroke(cr);
cairo_arc(cr, width/2 + g_x, height/2 + g_y, 3, 0, 2*M_PI);
cairo_fill(cr);
if (gravity_vector_countdown > 0)
--gravity_vector_countdown;
}
}
static void draw_balls_onto_window () {
@ -158,7 +167,7 @@ static void draw_balls_onto_window () {
cr = gdk_cairo_create(window->window);
/* clear pixmap */
cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0);
cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, clear_alpha);
cairo_paint(cr);
draw_gravity_vector();
@ -212,20 +221,23 @@ static gint keyboard_input (GtkWidget *widget, GdkEventKey *event) {
switch(event->keyval) {
case GDK_KEY_Up:
g_y -= 10;
gravity_vector_countdown = gravity_vector_init;
break;
case GDK_KEY_Down:
g_y += 10;
gravity_vector_countdown = gravity_vector_init;
break;
case GDK_KEY_Left:
g_x -= 10;
gravity_vector_countdown = gravity_vector_init;
break;
case GDK_KEY_Right:
g_x += 10;
gravity_vector_countdown = gravity_vector_init;
break;
case GDK_KEY_F:
case GDK_KEY_f:
g_x = rand() % 201 - 100;
g_y = rand() % 201 - 100;
case GDK_KEY_G:
case GDK_KEY_g:
gravity_vector_countdown = gravity_vector_init;
break;
case GDK_KEY_Q:
case GDK_KEY_q:
@ -259,7 +271,8 @@ void print_usage (const char * progname) {
"\tfy=<y-force>\n"
"\tradius=<min-radius>-<max-radius>\n"
"\tv=<min-velocity>-<max-velocity>\n"
"\tdelta=<frame-delta-time>\n",
"\tdelta=<frame-delta-time>\n"
"\tclear=<clear-alpha>\n",
progname);
}
@ -321,6 +334,8 @@ int main (int argc, const char *argv[]) {
define_face_surface(argv[i] + 5);
continue;
}
if (sscanf(argv[i], "clear=%lf", &clear_alpha) == 1)
continue;
print_usage(argv[0]);
return 1;
}