basic prototype

diff --git a/main.py b/main.py
index 2bc367daf828050215559b82031127666a4ee7eb..fc0d85b4ab9dd2d49ad6df6fcb8a8cbbef72d3af 100644 (file)
--- a/main.py
+++ b/main.py
@@ -1,5 +1,7 @@
 import pygame
 
+pygame.init()
+
 from particle import PointParticle
 
 SCREEN_WIDTH, SCREEN_HEIGHT = 800, 600
@@ -10,7 +12,8 @@ is_running = True
 clock = pygame.Clock()
 delta = 0
 
-particles = [PointParticle((SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2))]
+particles = [PointParticle((SCREEN_WIDTH / 3, SCREEN_HEIGHT / 2)),
+             PointParticle((SCREEN_WIDTH * 2 / 3, SCREEN_HEIGHT / 2), -1.6e-19)]
 
 while is_running:
     for event in pygame.event.get():
@@ -18,7 +21,7 @@ while is_running:
             is_running = False
 
     for particle in particles:
-        particle.update(delta)
+        particle.update(delta, particles)
 
     screen.fill((255, 255, 255))
     for particle in particles:

diff --git a/particle.py b/particle.py
index f4dfa35cddf7712c6198aa85ca753d4f2e8d2e25..0f2209bcbac1c8986b97f9674466b71d2d90408e 100644 (file)
--- a/particle.py
+++ b/particle.py
@@ -1,26 +1,74 @@
 import pygame
+import math
 
 
 class PointParticle:
+    font = pygame.font.SysFont("arial", 75)
+    signs = {'+': font.render("+", True, (0, 0, 0)),
+             '−': font.render('−', True, (0, 0, 0))}
+
+    BLUE = (0, 153, 255)
+    RED = (255, 43, 0)
+
+    line_step = pygame.Vector2(10, 0)
 
     def __init__(self, position, charge=1.6e-19):
         self.position = pygame.Vector2(position)
         self.mouse_offset = pygame.Vector2(0, 0)
         self.charge = charge
-        self.radius = 50
+        self.radius = 25
         self.dragging = False
-        self.colour = (255, 0, 0) if self.charge < 0 else (0, 0, 255)
-
-    def update(self, delta):
-        if pygame.mouse.get_pressed(3)[0]:
-            if not self.dragging and self.position.distance_to(pygame.mouse.get_pos()) < self.radius:
-                self.mouse_offset = pygame.Vector2(pygame.mouse.get_pos()) - self.position
-                self.dragging = True
-            if self.dragging:
-                self.position = pygame.Vector2(pygame.mouse.get_pos()) - self.mouse_offset
-        elif self.dragging:
-            self.dragging = False
+        self.colour = self.RED if self.charge < 0 else self.BLUE
+        self.sign = self.signs['−' if self.charge < 0 else '+']
+
+        self.num_field_lines = int(self.charge / 1.6e-19 * 8)  # default will be 8 lines
+        self.field_line_angles = list(range(0, 360, int(360 / self.num_field_lines)))  # List of angles
+        self.field_lines = [[] for _ in range(self.num_field_lines)]
+
+    def update(self, delta, particles):
+        if self.dragging or not (True in [p.dragging for p in particles]):
+            if pygame.mouse.get_pressed(3)[0]:
+                if not self.dragging and self.position.distance_to(pygame.mouse.get_pos()) < self.radius:
+                    self.mouse_offset = pygame.Vector2(pygame.mouse.get_pos()) - self.position
+                    self.dragging = True
+                if self.dragging:
+                    self.position = pygame.Vector2(pygame.mouse.get_pos()) - self.mouse_offset
+            elif self.dragging:
+                self.dragging = False
+
+        particle_positions = {tuple(p.position) for p in particles}
+
+        for field_line_index, angle in enumerate(self.field_line_angles):
+            self.field_lines[field_line_index].clear()
+            position = self.position.copy()
+            direction = angle
+            end = False
+            for i in range(250):
+                position += self.line_step.copy().rotate(math.degrees(direction))
+
+                electric_field_x_net = 0
+                electric_field_y_net = 0
+                for particle in particles:
+                    diff = position - particle.position
+                    if diff.length() < particle.radius and particle is not self:
+                        end = True
+                        break
+                    angle = math.atan2(diff.y, diff.x)  # radians
+                    electric_field = 8.99e9 * particle.charge / pow(diff.length(), 2)
+                    electric_field_x_net += electric_field * math.cos(angle)
+                    electric_field_y_net += electric_field * math.sin(angle)
+
+                direction = math.atan2(electric_field_y_net, electric_field_x_net)
+                self.field_lines[field_line_index].append(position.copy())
+
+                if end == True:
+                    break
 
     def draw(self, surf):
         pygame.draw.circle(surf, self.colour, self.position, self.radius)
         pygame.draw.circle(surf, (0, 0, 0), self.position, self.radius, 3)
+        surf.blit(self.sign, self.sign.get_rect(center=self.position))
+
+
+        for line in self.field_lines:
+            pygame.draw.lines(surf, (0, 255, 0), False, line, 5)