Pixel-Composer/scripts/gradients_function/gradients_function.gml

enum GRADIENT_INTER {
	smooth,
	none,
	hue
}

function draw_gradient(_x, _y, _w, _h, _grad, _int = GRADIENT_INTER.smooth) {
	static RES = 48;
	var _step  = _w / RES;
	var _ox, _oc;
	
	var uniform_grad_blend = shader_get_uniform(sh_gradient_display, "gradient_blend");
	var uniform_grad = shader_get_uniform(sh_gradient_display, "gradient_color");
	var uniform_grad_time = shader_get_uniform(sh_gradient_display, "gradient_time");
	var uniform_grad_key = shader_get_uniform(sh_gradient_display, "gradient_keys");
	
	var _grad_color = [];
	var _grad_time  = [];
		
	for(var i = 0; i < ds_list_size(_grad); i++) {
		_grad_color[i * 4 + 0] = color_get_red(_grad[| i].value) / 255;
		_grad_color[i * 4 + 1] = color_get_green(_grad[| i].value) / 255;
		_grad_color[i * 4 + 2] = color_get_blue(_grad[| i].value) / 255;
		_grad_color[i * 4 + 3] = 1;
		_grad_time[i]  = _grad[| i].time;
	}
	
	if(ds_list_empty(_grad)) {
		draw_sprite_stretched(s_fx_pixel, 0, _x, _y, _w, _h)
	} else {
		shader_set(sh_gradient_display);
		shader_set_uniform_i(uniform_grad_blend, _int);
		shader_set_uniform_f_array(uniform_grad, _grad_color);
		shader_set_uniform_f_array(uniform_grad_time, _grad_time);
		shader_set_uniform_i(uniform_grad_key, ds_list_size(_grad));
			
		draw_sprite_stretched(s_fx_pixel, 0, _x, _y, _w, _h)
		shader_reset();
	}
}

function gradient_eval(_gradient, _time, _int = GRADIENT_INTER.smooth) {
	if(ds_list_size(_gradient) == 0) return c_white;
	if(ds_list_size(_gradient) == 1) return _gradient[| 0].value;
	
	for(var i = 0; i < ds_list_size(_gradient); i++) {
		var _key = _gradient[| i];
		if(_key.time >= _time) {
			if(i == 0) 
				return _gradient[| 0].value;
			else {
				var c0 = _gradient[| i - 1].value;
				if(_int == GRADIENT_INTER.smooth) {
					var rat = (_time - _gradient[| i - 1].time) / (_gradient[| i].time - _gradient[| i - 1].time);
					var c1 = _gradient[| i].value;
					return merge_color(c0, c1, rat);
				} else if(_int == GRADIENT_INTER.none) {
					return c0;
				}
			}
		}
	}
	
	return _gradient[| ds_list_size(_gradient) - 1].value;
}

function gradient_add(_gradient, _addkey, _deleteDup) {
	if(ds_list_size(_gradient) == 0) {
		ds_list_add(_gradient, _addkey);
		return;
	}
		
	for(var i = 0; i < ds_list_size(_gradient); i++) {
		var _key = _gradient[| i];
		if(_key.time == _addkey.time) {
			if(_deleteDup)
				_key.value = _addkey.value;
			return;
		} else if(_key.time > _addkey.time) {
			ds_list_insert(_gradient, i, _addkey);
			return;
		}
	}
		
	ds_list_add(_gradient, _addkey);
}