tmp

zaki-yama · Jul 20, 2021 · bd9c48f · bd9c48f
1 parent f6ecf36
commit bd9c48f
Show file tree

Hide file tree

Showing 2 changed files with 104 additions and 0 deletions.
diff --git a/the-art-of-webassembly/ch08/README.md b/the-art-of-webassembly/ch08/README.md
@@ -18,6 +18,7 @@
     - [Setting a Pixel Color](#setting-a-pixel-color)
     - [Drawing the Object](#drawing-the-object)
     - [Setting and Getting Object Attributes](#setting-and-getting-object-attributes)
+    - [The $main Function](#the-main-function)
 
 <!-- /TOC -->
 
@@ -75,3 +76,9 @@
 - attribute の get と set でアドレスの計算は共通化できる (DRY) けど、しばしばパフォーマンス低下につながることがあるのでやらない
   - また、この後の Chapter でさらに DRY をやめることになる
 - 他のアセンブリ言語においては、マクロは DRY 原則とパフォーマンスを両立させるためのすばらしい方法だが、wat2wasm は現在マクロをサポートしていない
+
+### The $main Function
+
+- 毎フレーム JS から呼ばれる処理
+- オブジェクトを velocity に基づいて動かし、衝突判定し、色を塗る
+  Defining Local Variables
diff --git a/the-art-of-webassembly/ch08/collide.wat b/the-art-of-webassembly/ch08/collide.wat
@@ -188,4 +188,101 @@
     i32.load ;; load the pointer above
     ;; returns the attribute
   )
+
+  ;; move and detect collisions between all of the objects in our app
+  (func $main (export "main")
+    (local $i i32) ;; outer loop index
+    (local $j i32) ;; inner loop index
+    (local $outer_ptr i32) ;; pointer to outer loop object
+    (local $inner_ptr i32) ;; pointer to inner loop object
+
+    (local $x1 i32) ;; outer loop object x coordinate
+    (local $x2 i32) ;; inner loop object x coordinate
+    (local $y1 i32) ;; outer loop object y coordinate
+    (local $y2 i32) ;; inner loop object y coordinate
+
+    (local $xdist i32) ;; distance between objects on x axis
+    (local $ydist i32) ;; distance between objects on y axis
+
+    (local $i_hit i32) ;; i object hit boolean flag
+    (local $xv i32) ;; x velocity
+    (local $vy i32) ;; y velocity
+
+    (loop $move_loop
+      ;; get x attribute
+      (call $get_obj_attr (local.get $i) (global.get $x_offset))
+      local.set $x1
+
+      ;; get y attribute
+      (call $get_obj_attr (local.get $i) (global.get $y_offset))
+      local.set $y1
+
+      ;; get x velocity attribute
+      (call $get_obj_attr (local.get $i) (global.get $xv_offset))
+      local.set $xv
+
+      ;; get y velocity attribute
+      (call $get_obj_attr (local.get $i) (global.get $yv_offset))
+      local.set $yv
+
+      ;; add velocity to x and force it to stay in the canvas bounds
+      (i32.add (local.get $xv) (local.get $x1))
+      i32.const 0x1ff ;; 511 decimal
+      i32.and ;; clear high-order 23 bits
+      local.set $x1
+
+      ;; add velocity to y and force it to stay in the canvas bounds
+      (i32.add (local.get $yv) (local.get $y1))
+      i32.const 0x1ff ;; 511 decimal
+      i32.and ;; clear high-order 23 bits
+      local.set $y1
+
+      ;; set the x attribute in linear memory
+      (call $set_obj_attr
+        (local.get $i)
+        (global.get $x_offset)
+        (local.get $x1)
+      )
+
+      ;; set the y attribute in linear memory
+      (call $set_obj_attr
+        (local.get $i)
+        (global.get $y_offset)
+        (local.get $y1)
+      )
+
+      local.get $i
+      i32.const 1
+      i32.add
+      local.tee $i ;; increment $i
+
+      global.get $obj_cnt
+      i32.lt_u ;; $i < $obj_cnt
+
+      if ;; if $i < $obj_cnt branch back to top of $move_loop
+        br $move_loop
+      end
+    )
+
+    i32.const 0
+    local.set $i
+
+    (loop $outer_loop (block $outer_break
+      i32.const 0
+      local.tee $j ;; setting j to 0
+
+      ;; $i_hit is a boolean value. 0 for false, 1 for true
+      local.set $i_hit ;; setting i_hit to 0
+
+      ;; get x attribute for object $i
+      (call $get_obj_attr (local.get $i) (global.get $x_offset))
+      local.set $xi
+
+      ;; get y attribute for object $i
+      (call $get_obj_attr (local.get $i) (global.get $y_offset))
+      local.set $yi
+
+
+
+
 )