karma/flying-balls
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modularized init/destroy functions for graphics system.

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This commit is contained in:
Antonio Carzaniga 2019-07-29 19:25:45 +02:00
parent 32cd25bd56
commit d715b99e32
1 changed files with 26 additions and 14 deletions
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40
balls.c
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@ -41,7 +41,7 @@ static double g_x = 0;
static double clear_alpha = 1.0;
void random_velocity(struct ball * p) {
static void random_velocity(struct ball * p) {
double r2;
do {
p->v_x = v_min + rand() % (v_max + 1 - v_min);
@ -137,6 +137,9 @@ static void update_state () {
ball_update_state(balls + i);
}
/* Graphics System
*/
static GtkWidget * window;
static cairo_t * cr = 0;
@ -162,10 +165,20 @@ static void draw_gravity_vector() {
}
}
static void draw_balls_onto_window () {
if (!cr)
cr = gdk_cairo_create(window->window);
static void init_graphics() {
if (cr)
cairo_destroy(cr);
cr = gdk_cairo_create(window->window);
}
static void destroy_graphics() {
if (cr) {
cairo_destroy(cr);
cr = 0;
}
}
static void draw_balls_onto_window () {
/* clear pixmap */
cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, clear_alpha);
cairo_paint(cr);
@ -206,10 +219,7 @@ static gint resize_event (GtkWidget *widget, GdkEventConfigure * event) {
width = widget->allocation.width;
height = widget->allocation.height;
if (cr) {
cairo_destroy(cr);
cr = gdk_cairo_create(window->window);
}
init_graphics();
draw_balls_onto_window();
return TRUE;
@ -249,16 +259,17 @@ static gint keyboard_input (GtkWidget *widget, GdkEventKey *event) {
return TRUE;
}
static void show_event (GtkWidget *widget, gpointer data) {
init_graphics();
}
static gboolean expose_event (GtkWidget *widget, GdkEventExpose *event, gpointer data) {
return TRUE;
}
static void destroy_window (void) {
gtk_main_quit();
if (cr) {
cairo_destroy(cr);
cr = 0;
}
destroy_graphics();
}
void print_usage (const char * progname) {
@ -355,8 +366,9 @@ int main (int argc, const char *argv[]) {
g_signal_connect(window, "destroy", G_CALLBACK(destroy_window), NULL);
g_signal_connect(window, "expose-event", G_CALLBACK(expose_event), NULL);
g_signal_connect(window, "configure_event", G_CALLBACK(resize_event), NULL);
g_signal_connect(window, "key_press_event", G_CALLBACK(keyboard_input), NULL);
g_signal_connect(window, "configure-event", G_CALLBACK(resize_event), NULL);
g_signal_connect(window, "show", G_CALLBACK(show_event), NULL);
g_signal_connect(window, "key-press-event", G_CALLBACK(keyboard_input), NULL);
gtk_widget_set_events (window, GDK_EXPOSURE_MASK | GDK_BUTTON_PRESS_MASK | GDK_KEY_PRESS_MASK);