karma/flying-balls
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added optional face (image) for balls

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This commit is contained in:
Antonio Carzaniga 2019-07-29 14:21:55 +02:00
parent b2c96f75c1
commit f7706865fe
2 changed files with 47 additions and 6 deletions
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3
Makefile
View File

@ -8,6 +8,9 @@ LIBS=$(GTK_LIBS)
PROGS=balls
.PHONY: default
default: all
.PHONY: run
run: balls
./balls

50
balls.c
View File

@ -138,6 +138,10 @@ static void update_state () {
static GtkWidget * window;
static cairo_t * cr = 0;
const char * face_filename = 0;
cairo_surface_t * face_surface = 0;
int face_x_offset, face_y_offset;
static void draw_gravity_vector() {
cairo_new_path(cr);
cairo_move_to(cr, width/2, height/2);
@ -161,12 +165,28 @@ static void draw_balls_onto_window () {
/* draw balls */
for(int i = 0; i < n_balls; ++i) {
cairo_set_source_rgb(cr,
1.0*balls[i].rgb_channels[0]/255,
1.0*balls[i].rgb_channels[1]/255,
1.0*balls[i].rgb_channels[2]/255);
cairo_arc(cr, balls[i].x, balls[i].y, balls[i].radius, 0, 2 * M_PI);
cairo_fill(cr);
if (face_surface) {
cairo_save(cr);
cairo_translate(cr, balls[i].x, balls[i].y);
cairo_arc(cr, 0.0, 0.0, balls[i].radius, 0, 2 * M_PI);
cairo_clip(cr);
cairo_set_source_rgb(cr,
1.0*balls[i].rgb_channels[0]/255,
1.0*balls[i].rgb_channels[1]/255,
1.0*balls[i].rgb_channels[2]/255);
cairo_paint(cr);
cairo_scale (cr, 1.0 * balls[i].radius / face_x_offset, 1.0 * balls[i].radius / face_y_offset);
cairo_set_source_surface(cr, face_surface, -face_x_offset, -face_y_offset);
cairo_paint(cr);
cairo_restore(cr);
} else {
cairo_set_source_rgb(cr,
1.0*balls[i].rgb_channels[0]/255,
1.0*balls[i].rgb_channels[1]/255,
1.0*balls[i].rgb_channels[2]/255);
cairo_arc(cr, balls[i].x, balls[i].y, balls[i].radius, 0, 2 * M_PI);
cairo_fill(cr);
}
}
}
@ -264,6 +284,20 @@ gboolean timeout (gpointer user_data) {
return TRUE;
}
void define_face_surface(const char * filename) {
face_surface = cairo_image_surface_create_from_png (filename);
switch (cairo_surface_status(face_surface)) {
case CAIRO_STATUS_SUCCESS:
face_x_offset = cairo_image_surface_get_width (face_surface) / 2;
face_y_offset = cairo_image_surface_get_height (face_surface) / 2;
break;
default:
cairo_surface_destroy (face_surface);
face_surface = 0;
fprintf(stderr, "could not create sorfece from PNG file %s\n", filename);
}
}
int main (int argc, const char *argv[]) {
int w = DEFAULT_WIDTH;
int h = DEFAULT_HEIGHT;
@ -283,6 +317,10 @@ int main (int argc, const char *argv[]) {
continue;
if (sscanf(argv[i], "delta=%lf", &delta) == 1)
continue;
if (strncmp(argv[i], "face=", 5) == 0) {
define_face_surface(argv[i] + 5);
continue;
}
print_usage(argv[0]);
return 1;
}