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Author	SHA1	Message	Date
Jeremy Rand	eb418fb1c4	Add the ability to shoot centipede segments.	2020-10-02 14:50:14 -04:00
Jeremy Rand	74a21db9e0	Change the starting position so we get a collision right away.	2020-09-24 23:19:43 -04:00
Jeremy Rand	766eaf6273	Add the code to detect segment collisions and change direction if a head is colliding with another head or body segment.	2020-09-24 23:17:39 -04:00
Jeremy Rand	a9f62257f9	Reverse the order in which segments are added in memory and add some data for tracking the tiles occupied by segments. This will allow for segment collision detection next.	2020-09-23 23:04:05 -04:00
Jeremy Rand	69efb23800	Some minor optimization to the update code and check for a mushroom in the tile we are moving into and the next tile when we need to decide to change direction. This better reproduces the real game's behaviour.	2020-09-23 22:42:02 -04:00
Jeremy Rand	1dfbe8156a	Add support for having both fast and slow centipedes in play at the same time.	2020-09-21 22:57:06 -04:00
Jeremy Rand	c4902f486b	Add some global data to have a bit mask of tiles which contain a centipede segment. This will allow the update code to figure out if centipede segments are colliding and if so, change direction. Still need to write some codegen for this global constant data rather than building it at runtime in C.	2020-09-20 22:22:58 -04:00
Jeremy Rand	a9d3b12725	Add code to poison a centipede.	2020-09-13 16:08:32 -04:00
Jeremy Rand	03466f8847	Add code to allow a centipede and all its body segments to scroll in at the top of the screen at slow speed. Need to do the same for fast speed.	2020-09-13 15:18:18 -04:00
Jeremy Rand	f99ff8e816	Add all the code to handle double speed centipede segments.	2020-09-13 14:54:18 -04:00
Jeremy Rand	dc5ab4720d	Fix bugs that cause the centipede segment to drop as if poisoned when it reaches the bottom half of the screen.	2020-09-13 13:32:25 -04:00
Jeremy Rand	ab5f5c6299	Fix bug in code that looks for the edge of the screen which was comparing by tile number, not tile offset.	2020-09-11 00:25:41 -04:00
Jeremy Rand	46567659e9	Add the code to animate the segments at slow speed. There is a bug where the centipede seems to get stuck along the left edge sometimes. But overall looks pretty good.	2020-09-11 00:01:30 -04:00
Jeremy Rand	0362b53e2c	The head segment is now animating to the right. But it needs better support for segment speed and it needs to change direction when it reaches an obstacle. And all of the other directions to write still.	2020-09-09 23:53:51 -04:00
Jeremy Rand	0d4677c397	More work towards the animation of centipede segments.	2020-09-08 23:54:44 -04:00
Jeremy Rand	36617cbf9d	Lay some more groundwork for animating centipede segments. We now have an array of 96 (97 actually) entries which describe the position of the segment now or in the past. By keeping past information, body segments which follow head segments will take no calculation to update. We just have to animate head segments and body segments will follow them 8 pixels behind automatically.	2020-09-07 22:35:32 -04:00
Jeremy Rand	3b541f8482	Fix bug leading to crash when trying to add centipede body segments. I needed to have a nop instruction after the self-modifying long jump. I am writing 4 bytes of the address into the long jump which only uses a 3 byte address and I was corrupting the next instruction. Inserting a nop ensures no corruption happens.	2020-09-06 13:39:00 -04:00
Jeremy Rand	f5d1aa9ee6	Improve the performance of the centipede segment draw function.	2020-09-06 02:05:33 -04:00
Jeremy Rand	07f8df4b4f	Draw the scorpion once we are sure the beam has past it on the screen for the previous frame. Adjust the wait for VBL look to look for less than scan line 200 rather than scan line 0. That way, we shouldn't get a frame glitch at 2.8MHz any more.	2020-09-06 01:54:47 -04:00
Jeremy Rand	92c02ded0f	Simplify the handling of the dirty tiles to just store the dirty word and not keep the array of dirty tile offsets. Have the flea use game and non-game dirty tiles to fix the problem with LHS tiles being marked dirty all the time.	2020-09-04 01:55:38 -04:00
Jeremy Rand	22a22d3533	Change the code to race the beam down the screen, redrawing the dirty game rows as it goes.	2020-09-04 00:17:19 -04:00
Jeremy Rand	b07221c363	Change from an array of structs to a series of individual arrays for the tile information. This makes it easier to index into the arrays because the tile number * 2 is the offset, rather than tile number * 16.	2020-09-02 00:15:53 -04:00
Jeremy Rand	df56cdecf1	Add the ability to display head segments of the centipede. Body segments is not working yet.	2020-08-27 23:36:16 -04:00
Jeremy Rand	3a63b2ef1b	Add code to support marking dirty tiles under head and body segments.	2020-08-27 22:36:04 -04:00
Jeremy Rand	d8e9c6863b	Add the code to draw the body and head segments in the game loop. Still need to add code to create, update and shoot segments.	2020-08-26 23:44:41 -04:00
Jeremy Rand	67e2b56dc2	Add some more code to support adding bug segments to the game.	2020-08-10 23:58:49 -04:00
Jeremy Rand	7d7afc908d	Use macros to reduce the copy/pasted code for marking tiles as dirty. Rough out the support for body and head segments.	2020-07-30 23:34:48 -04:00
Jeremy Rand	2b45813cbb	Increase the chance that a flea produces a mushroom.	2020-07-28 15:44:55 -04:00
Jeremy Rand	8bcd4fccf6	Add the code to support switching between fast and slow spiders.	2020-07-27 23:30:11 -04:00
Jeremy Rand	883d882d0e	Provide an API to set the default speed of a flea or a scorpion. This will allow the speed to be changed for different levels in the game. Need to add this API for spiders also.	2020-07-27 22:27:18 -04:00
Jeremy Rand	36be001229	Improve the randN function. Show a different colour on the border when drawing versus updating the game state.	2020-07-27 21:47:28 -04:00
Jeremy Rand	9fde825430	Add some constants for the spider score amounts.	2020-07-27 14:25:22 -04:00
Jeremy Rand	3ad311dca6	Add support for shooting the spider and displaying a score.	2020-07-27 14:22:34 -04:00
Jeremy Rand	49baa1b360	Get spider motion working in both directions.	2020-07-26 16:00:46 -04:00
Jeremy Rand	d4fbd9f14c	Almost done animating the spider.	2020-07-26 02:13:06 -04:00
Jeremy Rand	bf01c47285	Getting close to having the spider fully implemented...	2020-07-26 00:05:32 -04:00
Jeremy Rand	18d0c3a80f	Add some randomness when the spider changes direction.	2020-07-25 14:54:35 -04:00
Jeremy Rand	213686ea1d	The spider can now go down and to the right. More directions to come.	2020-07-25 14:34:44 -04:00
Jeremy Rand	184461947b	Getting closer on the spider	2020-07-25 00:01:42 -04:00
Jeremy Rand	f890200a0d	More spider work.	2020-07-24 23:50:01 -04:00
Jeremy Rand	45bc6641e6	Some more work on spider animation.	2020-07-24 23:27:33 -04:00
Jeremy Rand	aa2e5408da	Some code for adding a spider on the LHS.	2020-07-24 14:42:03 -04:00
Jeremy Rand	4f74d630b9	Start coding support for the spider. Also, try to show the performance of the main game loop in the border colour.	2020-07-23 23:41:12 -04:00
Jeremy Rand	ada774960b	Finish up work on the scorpion, adding support for shooting the scorpion. Some more cleanup of hard coded constants, moving them to globals.	2020-07-22 23:46:04 -04:00
Jeremy Rand	68ecca75df	Add support for fast moving scorpions which appear at later levels.	2020-07-22 02:31:50 -04:00
Jeremy Rand	78f439d248	Add a constant for creating a poisoned mushroom.	2020-07-22 01:47:59 -04:00
Jeremy Rand	b3da2023e4	Get the scorpion moving to the right and to the left and poisoning the mushrooms. Still need to handle exploding the scorpion and double speed scorpions.	2020-07-22 00:06:01 -04:00
Jeremy Rand	44cb944f22	More general cleanup and get rid of more magic numbers.	2020-07-21 22:30:05 -04:00
Jeremy Rand	c614164c14	Add code to get scorpions animating to the left. Lots of cleanup, adding a global data section that also has important global constants.	2020-07-21 21:47:50 -04:00
Jeremy Rand	1ccdb1d0b6	Start to get scorpion support into the game.	2020-07-20 23:04:27 -04:00