//Mouse listener
void mouse_callback(GLFWwindow* window, int btn, int action, int mods){
if (action == GLFW_RELEASE && btn == GLFW_MOUSE_BUTTON_LEFT){
//Create a snow shape, if none exist
if (snow_shapes.empty())
create_new_shape();
//Add vertex to the shape
double x, y;
glfwGetCursorPos(window, &x, &y);
//Convert screen coordinates to world
y = (1-y/WIN_SIZE)*WIN_METERS;
x = x/WIN_SIZE*WIN_METERS;
//Regular point
switch (circle_draw_state){
//Regular point
case 0:
snow_shapes.back()->addPoint(x, y);
break;
//Circle origin
case 1:
circle_origin.setData(x, y);
circle_draw_state = 2;
break;
//Circle radius
case 2:
const int segments = 18;
//Cool circle algorithm: http://slabode.exofire.net/circle_draw.shtml
float x_dif = circle_origin[0] - x,
y_dif = circle_origin[1] - y,
radius = sqrt(x_dif*x_dif + y_dif*y_dif),
theta = 6.283185307 / (float) segments,
tan_fac = tan(theta),
cos_fac = cos(theta),
x = radius,
y = 0;
for (int i=0; i<segments; i++){
snow_shapes.back()->addPoint(x+circle_origin[0], y+circle_origin[1]);
float flip_x = -y, flip_y = x;
x += flip_x*tan_fac;
y += flip_y*tan_fac;
x *= cos_fac;
y *= cos_fac;
}
circle_draw_state = 0;
break;
}
dirty_buffer = true;
}
}
