bouncy fpga game
www.youtube.com/watch?v=IiLWF3GbV7w
feat: tune the slam and jump force
+38
-11
+24
-5
physics_engine.vhd
+24
-5
physics_engine.vhd
···
52
52
-- Physics tuning
53
53
constant GRAVITY : std_logic_vector(9 downto 0) := CONV_STD_LOGIC_VECTOR(1, 10);
54
54
constant IMPULSE : std_logic_vector(9 downto 0) := CONV_STD_LOGIC_VECTOR(3, 10);
55
-
constant SLAM_FORCE : std_logic_vector(9 downto 0) := CONV_STD_LOGIC_VECTOR(8, 10);
56
-
constant JUMP_FORCE : std_logic_vector(9 downto 0) := CONV_STD_LOGIC_VECTOR(13, 10);
55
+
constant SLAM_FORCE : std_logic_vector(9 downto 0) := CONV_STD_LOGIC_VECTOR(4, 10);
56
+
-- Jump: base force at zero velocity, tapers off as |vel_y| rises.
57
+
-- Piecewise lookup approximates: max(JUMP_MIN, JUMP_BASE*JUMP_SCALE/(JUMP_SCALE+|vy|))
58
+
constant JUMP_BASE : integer := 6; -- force at zero velocity
59
+
constant JUMP_VEL_THR1 : integer := 3; -- |vy| <= 3 → force 6
60
+
constant JUMP_VEL_THR2 : integer := 8; -- |vy| <= 8 → force 4
61
+
constant JUMP_VEL_THR3 : integer := 16; -- |vy| <= 16 → force 3
62
+
constant JUMP_MIN_FORCE : integer := 2; -- floor at high velocity
57
63
constant MAX_VEL_X : std_logic_vector(9 downto 0) := CONV_STD_LOGIC_VECTOR(32, 10);
58
64
59
65
-- World bounds (11-bit)
···
128
134
else SIZE + ("000000" & squish);
129
135
130
136
physics : process
131
-
variable vx, vy : std_logic_vector(9 downto 0);
137
+
variable vx, vy : std_logic_vector(9 downto 0);
132
138
variable px, py : std_logic_vector(10 downto 0);
133
139
variable bounced : std_logic;
134
140
variable bounce_wall : std_logic;
···
137
143
variable c_left, c_right, c_top, c_bot : std_logic_vector(10 downto 0);
138
144
variable c_prev_top, c_prev_bot, c_prev_left, c_prev_right : std_logic_vector(10 downto 0);
139
145
variable tcx, tcy, dcx, dcy : std_logic_vector(10 downto 0);
146
+
variable abs_vy_int : integer;
147
+
variable jforce_int : integer;
148
+
variable jforce_slv : std_logic_vector(9 downto 0);
140
149
begin
141
150
wait until vert_sync'event and vert_sync = '1';
142
151
···
148
157
-- == INPUT ==
149
158
if key_w = '0' then jump_pressed <= '0'; end if;
150
159
160
+
-- Scaled jump: full force at low velocity, tapers as |vy| increases
161
+
if vy(9) = '1' then abs_vy_int := CONV_INTEGER((not vy) + 1);
162
+
else abs_vy_int := CONV_INTEGER(vy); end if;
163
+
if abs_vy_int <= JUMP_VEL_THR1 then jforce_int := JUMP_BASE;
164
+
elsif abs_vy_int <= JUMP_VEL_THR2 then jforce_int := 4;
165
+
elsif abs_vy_int <= JUMP_VEL_THR3 then jforce_int := 3;
166
+
else jforce_int := JUMP_MIN_FORCE;
167
+
end if;
168
+
jforce_slv := CONV_STD_LOGIC_VECTOR(jforce_int, 10);
169
+
151
170
if key_w = '1' and jump_pressed = '0' and on_ground = '1' then
152
171
vy := (others => '0');
153
-
vy := vy - JUMP_FORCE;
172
+
vy := vy - jforce_slv;
154
173
jump_pressed <= '1';
155
174
end if;
156
175
157
176
if key_w = '1' and jump_pressed = '1' and on_ground = '1' then
158
-
vy := vy - JUMP_FORCE;
177
+
vy := vy - jforce_slv;
159
178
end if;
160
179
161
180
if key_s = '1' and on_ground = '0' then vy := vy + SLAM_FORCE; end if;
+14
-6
visualizer.py
+14
-6
visualizer.py
···
23
23
# --- Physics constants (match VHDL exactly) ---
24
24
GRAVITY = 1
25
25
IMPULSE = 3
26
-
SLAM_FORCE = 8
26
+
SLAM_FORCE = 4
27
27
AIR_CONTROL = 2
28
-
JUMP_FORCE = 13
28
+
JUMP_FORCE = 6 # base jump force at zero velocity
29
+
JUMP_VEL_SCALE = 12 # velocity magnitude at which jump force is halved
30
+
JUMP_MIN_FORCE = 2 # floor: minimum jump force regardless of velocity
29
31
MAX_VEL_X = 32
30
32
SIZE = 7
31
33
BOUNCE_SHIFT = 3 # energy loss = vel >> 3 (keep 87.5%)
···
126
128
if not keys_held['w']:
127
129
jump_pressed = False
128
130
131
+
# Compute scaled jump force: full force at zero velocity, tapers off as speed rises
132
+
def scaled_jump():
133
+
speed = abs(to_signed(vel_y))
134
+
force = JUMP_FORCE * JUMP_VEL_SCALE / (JUMP_VEL_SCALE + speed)
135
+
return max(int(force), JUMP_MIN_FORCE)
136
+
129
137
# First press on ground: full jump (elif prevents double-apply on same frame)
130
138
if keys_held['w'] and not jump_pressed and on_ground:
131
139
vy = to_unsigned(0)
132
-
vy = (vy - JUMP_FORCE) & MASK
140
+
vy = (vy - scaled_jump()) & MASK
133
141
jump_pressed = True
134
142
elif keys_held['w'] and jump_pressed and on_ground:
135
143
# Holding W while bouncing: boost each ground contact
136
-
vy = (vy - JUMP_FORCE) & MASK
144
+
vy = (vy - scaled_jump()) & MASK
137
145
138
146
# S: slam (air only)
139
147
if keys_held['s'] and not on_ground:
···
352
360
if show_trail and len(trail) > 1:
353
361
for i, (tx, ty) in enumerate(trail):
354
362
alpha = int(80 * i / len(trail))
355
-
s = pygame.Surface((3, 3))
363
+
s = pygame.Surface((1, 1))
356
364
s.set_alpha(alpha)
357
365
s.fill((255, 100, 100))
358
-
screen.blit(s, (tx - 1, ty - 1))
366
+
screen.blit(s, (tx, ty))
359
367
360
368
# Character with squish
361
369
# Vertical squish (floor/ceil): wider + shorter