Pixel-Composer/scripts/blurSurface/blurSurface.gml

function surface_blur_init() {
	__blur_hori = surface_create(1, 1);
	__blur_vert = surface_create(1, 1);
}

function surface_apply_gaussian(surface, size, bg = false, bg_c = c_white, sampleMode = 0, overColor = noone) {
	static uni_bor = shader_get_uniform(sh_blur_gaussian, "sampleMode");
	static uni_dim = shader_get_uniform(sh_blur_gaussian, "dimension");
	static uni_hor = shader_get_uniform(sh_blur_gaussian, "horizontal");
	static uni_wei = shader_get_uniform(sh_blur_gaussian, "weight");
	static uni_sze = shader_get_uniform(sh_blur_gaussian, "size");
	static uni_ovr = shader_get_uniform(sh_blur_gaussian, "overrideColor");
	static uni_ovc = shader_get_uniform(sh_blur_gaussian, "overColor");
	
	__blur_hori = surface_verify(__blur_hori, surface_get_width(surface), surface_get_height(surface));	
	__blur_vert = surface_verify(__blur_vert, surface_get_width(surface), surface_get_height(surface));	
	
	#region kernel generation
		size = max(1, round(size));
		var gau_array = array_create(size);
		var we = 0;
		var b  = 0.3 * ((size - 1) * 0.5 - 1) + 0.8;
		for(var i = 0; i < size; i++) {
			var _x = i * .5;
		
			gau_array[i] = (1 / sqrt(2 * pi * b)) * exp( -sqr(_x) / (2 * sqr(b)) );
			we += i? gau_array[i] * 2 : gau_array[i];
		}
		for(var i = 0; i < size; i++) {
			gau_array[i] /= we;
		}
	#endregion
	
	BLEND_OVERRIDE;
	surface_set_target(__blur_hori);
		draw_clear_alpha(bg_c, bg);
		
		shader_set(sh_blur_gaussian);
		shader_set_uniform_f_array_safe(uni_dim, [ surface_get_width(surface), surface_get_height(surface) ]);
		shader_set_uniform_f_array_safe(uni_wei, gau_array);
		
		shader_set_uniform_i(uni_bor, sampleMode);
		shader_set_uniform_i(uni_sze, size);
		shader_set_uniform_i(uni_hor, 1);
		
		shader_set_uniform_i(uni_ovr, overColor != noone);
		shader_set_uniform_f_array_safe(uni_ovc, colToVec4(overColor));
		
		draw_surface_safe(surface, 0, 0);
		shader_reset();
	surface_reset_target();
	
	surface_set_target(__blur_vert);
		draw_clear_alpha(bg_c, bg);
		
		shader_set(sh_blur_gaussian);
		shader_set_uniform_i(uni_hor, 0);
		
		draw_surface_safe(__blur_hori, 0, 0);
		shader_reset();
	surface_reset_target();
	BLEND_NORMAL;
	
	return __blur_vert;
}