Collision early elimination method - Revision history

Aoineko: /* Method */

2024-04-07T21:41:18Z

‎Method

2024-04-07T20:45:58Z

2024-04-07T20:45:39Z

2024-04-07T20:42:54Z

2024-04-07T20:33:28Z

2024-04-07T20:33:11Z

2024-04-07T20:31:33Z

2024-04-07T20:29:29Z

2024-04-07T20:29:16Z

2024-04-07T20:28:32Z

@@ Line 25: / Line 25: @@
 ** Divide Y coordinate + object height by 32 (value between 0 and 7) and set corresponding bit to 1.
 <syntaxhighlight lang="c">
 u8 o.maskX = bit[o.posX / 32] | bit[(o.posX + o.width) / 32];
 u8 o.maskY = bit[o.posY / 32] | bit[(o.posY + o.height) / 32];

@@ Line 49: / Line 49: @@
 └──┴──┴──┴────────────── Y coordinate mask (0-15)
 </syntaxhighlight>
 <syntaxhighlight lang="c">
 u8 o.mask = bit[o.posX / 64] | bit[(o.posX + o.width) / 64] | (bit[o.posY / 64] | bit[(o.posY + o.height) / 64]) << 4;
 </syntaxhighlight>
 <syntaxhighlight lang="c">
 bool TestCollision(const object* o1, const object* o2)

@@ Line 32: / Line 32: @@
 bool TestCollision(const object* o1, const object* o2)
+{
-   if((o1->maskX & o2->maskX) == 0)
+   if((o1->maskX & o2->maskX) == 0) // Test X coordinates
      return FALSE;
-   if((o1->maskY & o2->maskY) == 0)
+   if((o1->maskY & o2->maskY) == 0) // Test Y coordinates
      return FALSE;
    /* do more advanced collision code here... */
@@ Line 48: / Line 48: @@
 │  │  │  │  └──┴──┴──┴── X coordinate mask (0-15)
 └──┴──┴──┴────────────── Y coordinate mask (0-15)
 </syntaxhighlight>

← Older revision		Revision as of 20:42, 7 April 2024
Line 44:		Line 44:
	This method uses 4-bit X coordinates and 4-bit Y coordinates.		This method uses 4-bit X coordinates and 4-bit Y coordinates.
	The screen chinks are then 64x64 pixels.		The screen chinks are then 64x64 pixels.
		+	<syntaxhighlight lang="txt">
		+	7 6 5 4 3 2 1 0
		+	│ │ │ │ └──┴──┴──┴── X coordinate mask (0-15)
		+	└──┴──┴──┴────────────── Y coordinate mask (0-15)
		+	</syntaxhighlight>

@@ Line 43: / Line 43: @@
 == 8-bit mask ==
 This method uses 4-bit X coordinates and 4-bit Y coordinates.
-The screen bits are then 64x64 pixels.
+The screen chinks are then 64x64 pixels.

← Older revision		Revision as of 20:33, 7 April 2024
Line 42:		Line 42:

	== 8-bit mask ==		== 8-bit mask ==
		+	This method uses 4-bit X coordinates and 4-bit Y coordinates.
		+	The screen bits are then 64x64 pixels.

← Older revision		Revision as of 20:31, 7 April 2024
Line 2:		Line 2:

	The idea is to create masks that represent the parts of the screen that the object occupies.		The idea is to create masks that represent the parts of the screen that the object occupies.
		+	In the mask, all parts where the object is located will be set to 1 and the others to 0.
	Then simply compare the masks to eliminate any objects that are not in the same part of the screen.		Then simply compare the masks to eliminate any objects that are not in the same part of the screen.

@@ Line 31: / Line 31: @@
 bool TestCollision(const object* o1, const object* o2)
+{
-   if((o1.maskX && o2.maskX) == 0)
+   if((o1->maskX && o2->maskX) == 0)
      return FALSE;
-   if((o1.maskY && o2.maskY) == 0)
+   if((o1->maskY && o2->maskY) == 0)
      return FALSE;
    /* do more advanced collision code here... */