// Laplacian Filter
//@param1:scale 'scale' 1 0.1 10 5 0.1

src = 0;
input_info(src, w, h) ? ( project_w = w; project_h = h; );

// clear frame-buffer
gfx_fillrect(0, 0, w, h);

colorspace = 'RGBA';

// accum-buffer
img = gfx_img_alloc(w, h, 1);
gfx_dest = img;
gfx_r = gfx_g = gfx_b = 0;
gfx_fillrect(0, 0, w, h);

// Laplacian Filtering (4-dir)
ofs = 1;
mode_bkup = gfx_mode;
gfx_mode = 1; // blend: add

gfx_a = 1/4; // depth scaling 1 -> 1/4
x = -ofs; y = 0;
gfx_blit(src, 1, x, y, w, h);
x =  ofs; y = 0;
gfx_blit(src, 1, x, y, w, h);
x =  0; y = -ofs;
gfx_blit(src, 1, x, y, w, h);
x =  0; y = ofs;
gfx_blit(src, 1, x, y, w, h);
gfx_a = -1; // sub
x = y = 0;
gfx_blit(src, 1, x, y, w, h);

// Value Scaling
gfx_mode = 1;
gfx_dest = -1;     // dest: frame-buffer
gfx_a = 4 * scale; // scaling 1/4 -> 1 -> amp
gfx_blit(img);

// cleanup
gfx_mode = mode_bkup;
gfx_img_free(img);