movement

games/ocean.p8

@@ -56,55 +56,135 @@ end
 function draw_ocean()
     cls(12)
     local ocean_anim = {[0]=0, 0, 1, 2, 3, 4, 0, 0, 0, 0, 0, 0, 0}
-    if ocean_wind_x != 0 or ocean_wind_y != 0 then 
+    if ocean_wind_x ~= 0 or ocean_wind_y ~= 0 then 
         for x=0,15 do
             for y=0,15 do
                 local anim = ocean_anim[(flr(time()*4) - ocean_wind_y*y - ocean_wind_x*x) % #ocean_anim]
                 local base = 0
-                if ocean_wind_y != 0 then base = 5 end
+                if ocean_wind_y ~= 0 then base = 5 end
                 if anim > 0 then
                     spr(base+anim, 8*x, 8*y, 1, 1, ocean_wind_x < 0, ocean_wind_y < 0)
                 end
             end
         end
     end
+    map(player_x-8, player_y-8, 0, 0, 16, 16)
+    -- DEBUG
+    print("player: "..player_x..", "..player_y.."  heading: "..player_heading)
     print("wind: "..ocean_wind_x..", "..ocean_wind_y)
-    draw_ship(player_ship, 64, 64)
+    draw_ship(player_ship, player_heading, 64, 64)
 end
 
 function update_ocean()
     if btn(0) then 
-        ocean_wind_x = -1
+        player_vx = -1
+        player_heading = "W"
     elseif btn(1) then
-        ocean_wind_x = 1
+        player_vx = 1
+        player_heading = "E"
     else
-        ocean_wind_x = 0
+        player_vx = 0
     end
     if btn(2) then 
-        ocean_wind_y = -1
+        player_vy = -1
+        player_heading = "N"
     elseif btn(3) then
-        ocean_wind_y = 1
+        player_vy = 1
+        player_heading = "S"
     else
-        ocean_wind_y = 0
+        player_vy = 0
+    end
+
+    if t() - last_move_time > 1 and (player_vy or player_vx) then
+        last_move_time = t()
+        player_x += player_vx
+        player_y += player_vy
     end
 end
 
 _scenes.ocean = {start=start_ocean, draw=draw_ocean, update=update_ocean}
 
-function draw_ship(ship, x, y)
-    spr(ship.n, x-ship.w*4, y-ship.h*4, 1, ship.h)
-    if ship.w > 1 then
-        spr(ship.n, x-ship.w*4+8, y-ship.h*4, 1, ship.h, true)
+function draw_ship(ship, heading, x, y)
+    local angle = false
+    if heading == "N" then
+        angle = 0
+    elseif heading == "S" then
+        angle = 180
     end
+
+    spr_r(ship.i, ship.j, x-ship.w/2, y-ship.h/2, ship.w*8, ship.h*8, false, false, ship.w*4, ship.h*4, angle, 0)
+    if ship.w > 1 then
+        spr(ship.n, x-ship.w*4+8, y-ship.h*4, 1, ship.h, true, flipy)
+    end
+    --function spr_r(i, j, x, y, w, h, flip_x, flip_y, pivot_x, pivot_y, angle, transparent_color)
 end
 
+-- globals
 ship_type = {
-    small={n=64, w=1, h=1},
-    medium={n=65, w=1, h=2},
-    large={n=66, w=2, h=2},
-    ghost={n=67, w=2, h=3}
+    small={i=0, j=32, w=8, h=8, speed=1},
+    medium={i=8, j=32, w=8, h=16, speed=0.6},
+    large={i=16, j=32, w=16, h=16, speed=0.4},
+    ghost={i=24, j=32, w=126, h=24}
 }
-player_ship = ship_type.ghost
+player_ship = ship_type.small
+player_x = 20
+player_y = 20
+player_vx = 0
+player_vy = 0
+player_heading = "N"
+last_move_time = 0
+
+-- external utils
+
+-- via https://www.lexaloffle.com/bbs/?pid=52525
+function spr_r(i, j, x, y, w, h, flip_x, flip_y, pivot_x, pivot_y, angle, transparent_color)
+    -- precompute pixel values from tile indices: sprite source top-left, sprite size
+    local sx = 8 * i
+    local sy = 8 * j
+    local sw = 8 * w
+    local sh = 8 * h
+  
+    -- precompute angle trigonometry
+    local sa = sin(angle)
+    local ca = cos(angle)
+  
+    -- in the operations below, 0.5 offsets represent pixel "inside"
+    -- we let PICO-8 functions floor coordinates at the last moment for more symmetrical results
+  
+    -- precompute "target disc": where we must draw pixels of the rotated sprite (relative to (x, y))
+    -- the target disc ratio is the distance between the pivot the farthest corner of the sprite rectangle
+    local max_dx = max(pivot_x, sw - pivot_x) - 0.5 
+    local max_dy = max(pivot_y, sh - pivot_y) - 0.5
+    local max_sqr_dist = max_dx * max_dx + max_dy * max_dy
+    local max_dist_minus_half = ceil(sqrt(max_sqr_dist)) - 0.5
+  
+    -- iterate over disc's bounding box, then check if pixel is really in disc
+    for dx = - max_dist_minus_half, max_dist_minus_half do
+      for dy = - max_dist_minus_half, max_dist_minus_half do
+        if dx * dx + dy * dy <= max_sqr_dist then
+          -- prepare flip factors
+          local sign_x = flip_x and -1 or 1
+          local sign_y = flip_y and -1 or 1
+  
+          local xx = pivot_x + sign_x * ( ca * dx + sa * dy)
+          local yy = pivot_y + sign_y * (-sa * dx + ca * dy)
+  
+          -- make sure to never draw pixels from the spritesheet
+          --  that are outside the source sprite
+          if xx >= 0 and xx < sw and yy >= 0 and yy < sh then
+            -- get source pixel
+            local c = sget(sx + xx, sy + yy)
+            -- ignore if transparent color
+            if c ~= transparent_color then
+              -- set target pixel color to source pixel color
+              pset(x + dx, y + dy, c)
+            end
+          end
+        end
+      end
+    end
+  end
+
 
 __gfx__
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