effet distorsion

//draw_lens(x, y, r, deformation, precision)
//deformation entre 0 et 1.0 rend un effet de lentille qui zoom
//deformation plus grand que 1.0 fait le contraire
//deformation = 0 fait rien
//
//precision est le nombre d'itération pour le rendu de
//la lentille

var xx; xx = argument0;
var yy; yy = argument1;
var r; r = argument2;
var d; d = argument3;
var p; p = argument4;

var dim; dim = (2*r);

var u; u = (dim/p);//Cellule
var c; c = (p/2);//Centre

var src; src = sprite_create_from_screen(xx - r, yy - r, dim, dim, false, false, 0, 0);
var tex; tex = sprite_get_texture(src, 0);

var oc; oc = draw_get_color();
var oa; oa = draw_get_alpha();

draw_set_color(c_white);
draw_set_alpha(1.0);

d3d_transform_add_translation(xx - r, yy - r, 0);

d3d_primitive_begin_texture(pr_trianglelist, tex);
for(h = 0; h < p; h += 1)
{
for(w = 0; w < p; w +=1)
{
var x1; x1 = w*u;
var y1; y1 = h*u;
var x2; x2 = (w+1)*u;
var y2; y2 = h*u;
var x3; x3 = (w+1)*u;
var y3; y3 = (h+1)*u;
var x4; x4 = w*u;
var y4; y4 = (h+1)*u;

var cu; cu = c*u;

var tx1; tx1 = w/p;
var ty1; ty1 = h/p;
var tx2; tx2 = (w+1)/p;
var ty2; ty2 = (h+1)/p;

if (point_distance(x1, y1, cu, cu) <= r){
x1 = lengthdir_x((power(point_distance(x1, y1, cu, cu)/r, d))*r, point_direction(cu, cu, x1, y1)) + cu;
y1 = lengthdir_y((power(point_distance(x1, y1, cu, cu)/r, d))*r, point_direction(cu, cu, x1, y1)) + cu;
}
if (point_distance(x2, y2, cu, cu) <= r){
x2 = lengthdir_x((power(point_distance(x2, y2, cu, cu)/r, d))*r, point_direction(cu, cu, x2, y2)) + cu;
y2 = lengthdir_y((power(point_distance(x2, y2, cu, cu)/r, d))*r, point_direction(cu, cu, x2, y2)) + cu;
}
if (point_distance(x3, y3, cu, cu) <= r){
x3 = lengthdir_x((power(point_distance(x3, y3, cu, cu)/r, d))*r, point_direction(cu, cu, x3, y3)) + cu;
y3 = lengthdir_y((power(point_distance(x3, y3, cu, cu)/r, d))*r, point_direction(cu, cu, x3, y3)) + cu;
}
if (point_distance(x4, y4, cu, cu) <= r){
x4 = lengthdir_x((power(point_distance(x4, y4, cu, cu)/r, d))*r, point_direction(cu, cu, x4, y4)) + cu;
y4 = lengthdir_y((power(point_distance(x4, y4, cu, cu)/r, d))*r, point_direction(cu, cu, x4, y4)) + cu;
}

d3d_vertex_texture(x1, y1, 0, tx1, ty1);
d3d_vertex_texture(x2, y2, 0, tx2, ty1);
d3d_vertex_texture(x4, y4, 0, tx1, ty2);

d3d_vertex_texture(x2, y2, 0, tx2, ty1);
d3d_vertex_texture(x4, y4, 0, tx1, ty2);
d3d_vertex_texture(x3, y3, 0, tx2, ty2);

}
}
d3d_primitive_end();

d3d_transform_set_identity();

draw_set_alpha(oa);
draw_set_color(oc);

sprite_delete(src);