from __future__ import division import pygame, math, vect, ui, random, physics, simobject, constants def sphere_collide(object1, object2): if sphere_test(object1, object2): """ assumes hard bodies that mostly conserve energy and momentum""" relative_velocity = vect.add(1,object1.velocity,-1,object2.velocity) rel_speed = vect.length(relative_velocity) if rel_speed > 0: direction_to = vect.direction_to(object2.location, object1.location) projection = vect.dot(direction_to,relative_velocity) if projection > 0: angle = vect.angle_to(object2.location, object1.location) restitution = object1.attrs['physics']['elasticity']*object2.attrs['physics']['elasticity'] mass_factor = object2.attrs['physics']['mass']*object1.attrs['physics']['mass']/(object1.attrs['physics']['mass']+object2.attrs['physics']['mass']) damping = 0.5 momentum_transfer = (1+restitution)*mass_factor*projection*damping impulse1 = momentum_transfer/object1.physics_dt impulse2 = momentum_transfer/object2.physics_dt """we apply forces to both objects in case object1 moves quickly and object2 never gets to affect object1""" physics.temp_force(object1,impulse1/2,angle+math.pi) physics.temp_force(object2,impulse2/2,angle) def sphere_test(object1, object2): collision_distance = object1.radius+object2.radius dist = vect.distance_to(object1.location, object2.location) if dist < collision_distance: return True else: return False def square_test(object1, object2, radius = None): # test for collision between round object1 and square object2 # yes, i realise that this is actually between two square objects currently bool = False if radius == None: r = object1.radius else: r = radius dx,dy = object2.lengthx/2, object2.lengthy/2 if math.fabs(object1.location[0]-object2.location[0]) < r+dx: if math.fabs(object1.location[1]-object2.location[1]) < r+dy: bool = True return bool def square_projection(object1, object2, radius = None): """method to back track to find point of entry and can move sim there""" if square_test(object1, object2): vx,vy = object1.velocity lx,ly = object1.location if radius == None: r = object1.radius else: r = radius dx,dy = object2.lengthx/2, object2.lengthy/2 x,y = object2.location time = {} Time = None """setup time/direction dictionary""" if not vx: time[(1,0)] = 0 time[(-1,0)] = 0 else: time[(1,0)] = (x-dx-r-lx)/vx time[(-1,0)] = (x+dx+r-lx)/vx if not vy: time[(0,1)] = 0 time[(0,-1)] = 0 else: time[(0,1)] = (y-dy-r-ly)/vy time[(0,-1)] = (y+dy+r-ly)/vy """ find the shortest historical intersection with a square boundary """ for key, val in time.items(): if Time: if val < 0 and val > Time: Time = val dir = key else: if val < 0: Time = val dir = key """ if vx = vy = 0 have a problem """ if not Time: Time = 0 dir = (0,0) """ reset object1 location at the edge""" if object1.penetrating: # if it is penetrating, we might not want to reset its position, so we store the potential position for later usage # we remove its latest position so that it doesnt draw itself inside the solid object if len(object1.physics_locations)>0: object1.physics_locations.pop(-1) object1.physics_locations.append((lx+Time*vx , ly+Time*vy )) else: object1.location = lx+Time*vx , ly+Time*vy return dir def repulse(object1, object2): ''' keeps objects from occupying the same space''' collision_distance = 1.1*(object1.radius+object2.radius) distance = vect.distance_to(object1.location, object2.location) penetration = collision_distance-distance if penetration>0: angle = vect.angle_to(object1.location, object2.location) ##repulse1 = 4*(penetration+1)/(distance+0.01)*object1.attrs['physics']['mass']/object1.world.dt repulse1 = max(object1.acc+0.1,object1.attrs['physics']['friction_0'])*(object1.attrs['physics']['mass']+0.001) if object2.mobile: frac = 1.2 else: frac = 2 ##fraction =(max(frac,collision_distance/max(distance,0.001))-frac)*object2.attrs['physics']['mass']/object1.attrs['physics']['mass'] ##object1.health -= fraction/object1.max_health*1000 physics.temp_force(object1,repulse1,angle) def circle_projection(object1, object2): ''' keeps objects from occupying the same space''' collision_distance = (object1.radius+1*object2.radius) distance = vect.distance_to(object1.location, object2.location) penetration = max(collision_distance-distance,0) if penetration>0: if len(object2.physics_locations)==0: prev_location = object2.location else: prev_location = object2.physics_locations[-1] direction_to = vect.direction_to(prev_location, object1.location) angle = vect.angle_to(object1.location, prev_location) object2.location = vect.add(1,object2.location, 1.01*penetration+0.01,direction_to) object2.world.grid.moveSim(object2) def bullet_strike(object1, object2): ''' bullet collisions with objects ''' debug_color = False direction_to = None if object2.attrs['physics']['shape'] == "square": if square_test(object1, object2, 0): direction_to = square_projection(object1, object2,0) elif object2.attrs['physics']['shape'] == "circle": if sphere_test(object1, object2): direction_to = vect.direction_to(object2.location, object1.location) if direction_to: relative_velocity = vect.add(1,object1.velocity,-1,object2.velocity) projection = vect.dot(direction_to,relative_velocity) if projection > 0: # we draw some blood if (object2.sim_cat is "biped") or (object2.sim_type is "zombie_hive"): object1.world.blood = object1.world.add_sim("blood", object1.location, object1.direction, sim_cat = "effect") ##pygame.draw.circle(object1.world.screen, (0,0,0), ui.screen_pos(object1.world, object1.location),10) # we let zombies know they've been shot. might use this for others. might change this to ref ai. if (object2.sim_cat is "biped"): object2.hit = True object2.hit_direction = object1.direction+math.pi # we calculate how the bullet interacts with target directed_energy = 1/2*object1.attrs['physics']['mass']*projection**2 embed_bullet = False ##print directed_energy/object1.attrs['physics']['reference_area'] if (directed_energy > object1.attrs['physics']['reference_area']*object2.attrs['physics']['hardness']):# or (object2.block and object1.currently_penetrating): #object1 mostly penetrates if object1.attrs['physics']['elasticity'] < random.random()*random.random(): """ bullet gets stuck in target """ angle = object1.vel_dir mass_factor = object2.attrs['physics']['mass']*object1.attrs['physics']['mass']/(object1.attrs['physics']['mass']+object2.attrs['physics']['mass']) embed_bullet = True energy = 0.5*(projection*mass_factor)**2/object1.attrs['physics']['mass'] object2.damage(energy, "kinetic") momentum_transfer = mass_factor*projection #physics.temp_force(object1,momentum_transfer/object1.physics_dt,angle+math.pi) physics.temp_force(object2,momentum_transfer/object2.physics_dt,angle) object1.velocity = object2.velocity physics.get_polar_speed(object1) object1.health = -1 object1.physics_time_remaining = 0 if debug_color: object1.color = (0,0,255) else: ## bullet squarely hits target and passes cleanly through mass_factor = 0 #angle = object1.vel_dir if debug_color: object1.color = (0,255,0) object2.damage(object1.attrs['physics']['mass']*projection**2/2, "kinetic") ## we do not want the bullet to reflect off blocks for a while, or else ## it can bounce between two adjacent blocks, which is quite computationally slow if object2.block: object1.currently_penetrating = True else: ## object1 mostly reflects if debug_color: object1.color = (255,0,0) if len(object1.physics_locations)>0: ## restore object1 location to exterior of object2 object1.location = object1.physics_locations[-1] ## draw a ricochet if object2.block: object1.world.ricochet = object1.world.add_sim("ricochet", object1.location, object1.direction, sim_cat = "effect") ##calculate physics restitution = object1.attrs['physics']['elasticity']*object2.attrs['physics']['elasticity'] mass_factor = (1+restitution)*object2.attrs['physics']['mass']*object1.attrs['physics']['mass']/(object1.attrs['physics']['mass']+object2.attrs['physics']['mass']) angle = vect.angle_to(direction_to) momentum_transfer = mass_factor*projection ## enact physics physics.temp_force(object1,momentum_transfer/object1.physics_dt,angle+math.pi) physics.temp_force(object2,momentum_transfer/object2.physics_dt,angle) object1.direction = object1.vel_dir ## cause some damage energy = 0.5*(projection*mass_factor)**2/object1.attrs['physics']['mass'] object2.damage(energy, "kinetic") def laser_strike(object1, object2): ''' laser collisions wih objects''' collision_distance = 0.9*(object1.radius+object2.radius) if vect.distance_to(object1.location, object2.location) < collision_distance: direction_to = vect.direction_to(object2.location, object1.location) relative_velocity = vect.add(1,object1.velocity,-1,object2.velocity) projection = vect.dot(direction_to,relative_velocity) if projection >= 0: object1.velocity = object2.velocity physics.get_polar_speed(object1) object1.health = -1 object1.physics_time_remaining = 0 object1.world.Heat.add_cell(object2.grid_location, constants.LASER_PULSE_TEMP) object2.damage(constants.LASER_PULSE_DAMAGE, "burn")