R Type clone

[Coppis]

I started development of a R Type clone for A1200 AGA using Blitz Basic 2.1.
The graphics have been ripped from original Amiga version of R Type using MapTapper.
The game uses dual playfield mode with two playfields of 4 bitplanes each: one playfield is used for background and the other playfield for the bobs, in order to use the most efficient QBlit mode.
Link to a video:

[ Show youtube player ]

[nikosidis]

We all love R-Type What is your plan with this? Make if arcade perfect or do your own game?

[saimon69]

If you are looking for ideas take also a peek at the Rayxamber series on FM Towns and PC Engine (did inspire me at the time for Powder too) - and as usual i offer my help for assets, mostly music but also some pixel art

Rayxanber
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Rayxanber II
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Rayxanber III
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[Coppis]

Originally Posted by nikosidis

We all love R-Type What is your plan with this? Make if arcade perfect or do your own game?

I don't like the excessive difficulty of the arcade version, so I plan to make the game easier, but leaving the fundamental mechanics such as: beam, force and weapons.

[Havie]

Looks good already.

[lmimmfn]

looks excellent, great job!

I'm not sure if dual playfield is the correct method though(unless used with parallax)?
As far as i know in RType other than bullets there's very little/no overlap with the scenery. Its only stars in the background, those can be handled with the CPU. Collisions also shouldn't have any overlap.
Maybe sprites can be used for enemy bullets making sure to not exceed max number of sprites per line?

[Coppis]

15/04/2021 Collisions between player ship and enemies

Today I will implement collisions between player ship and enemies. Both player ship and enemies are Blobs (Blitter Objects). Blitz Basic 2 (BB2) provides the following function:

ShapesHit(shape#,x,y,shape#,x,y)

This function will calculate whether the rectangular areas occupied by 2 shapes overlap.
ShapesHit will automatically take the shape handles into account. If the 2 shapes overlap,
ShapesHit will return true (-1),otherwise ShapesHit will return false (0).

This pseudo code snippet shows the logic for the collision check:

CheckCollisionsShipAliens:

loops through all the aliens
     if alien is active AND player ship collides with the current alien
        if ship state is not "hit"
            change player ship state to "hit"
            decrease lives number

Player ship states

In the following picture is shown a diagram of the player ship states:



In "Active" state the player can control the ship using the joystick, moving around the screen and firing. When there is a collision between the ship and an enemy or a bullet, the ship switches to the "Hit" state. In this state, the player can not control the ship and the ship explodes. When the explosion animation ends, the ship goes into "Invulnerable" state, in which the player can control the ship, but the ship can not collide with enemies and bullets and the ship is flashing. After a given amount of time (i.e. 5 seconds), the ship returns in the Active state.

Player ship explosion

The player ship explosion animation uses the following 7 frames:




Each frame size is 32x30 pixels, 4 bitplanes.
Here is a preview of the animation:



Planning future work:

• Collisions between player ship and background
• Information panel
• Show score and number of lives
• Beam bar and beam fire
• Pick ups
• Force satellite
• Fire power ups
• End level boss
• Sound effects
• Music
• Game over
• Intro screen
• Optimizations

In the following video you can see the ship explosion:

[ Show youtube player ]

[Adrian Browne]

Might be cooler with new graphics and gameplay?

[jotd]

A1200? maybe use the original arcade graphics instead?

[malko]

@Coppis : Really nice result so far
Wish you all the best with your project

[Tigerskunk]

I wish you a lot of strength for a project that might easily take a few years to realize for one guy...

Keep us updated, mate.

[Coppis]

Originally Posted by jotd

A1200? maybe use the original arcade graphics instead?

The reason I chose to use the Amiga version graphics is that I was able to rip the graphics easily using Maptapper.
To rip the graphics of the arcade version you need to find some tools for the MAME. Can anyone point me to some tools or tutorials for ripping graphics from MAME?

[roondar]

I'm not 100% sure on this, but I seem to recall that the original Arcade GFX used more than 16 colours per layer. So if you do go the Arcade GFX route, be aware you might need to colour reduce them. You may also run into resolution issues as the original R-Type used a very wide screen.

Regardless, good luck with the game. Always nice to see new Amiga games

[Tigerskunk]

Thinking about it, may I ask what the ambition here is, seems a bit unclear to me.

I mean, there is already the old version of the game with those graphics assets you are using now running quite well on A500s.

An arcade quality conversion running on AGA machines would be a cool thing, though.

[jotd]

color reduced arcade graphics on AGA (32 colors in dual PF? more with sprites?) will probably look much nicer than original OCS amiga graphics

[nikosidis]

I agree with Steril707. I seen you plan to do a more easy version but if you go with AGA you should try to rip the arcade GFX.
If you do that there will be much more interest. Even if the original port to Amiga was good it is first of all the GFX that is not on par with the arcade. That said, the Amiga version at the time was by far the best arcade port

[Retro-Nerd]

That said, the Amiga version at the time was by far the best arcade port.

You mean on a home computer (the good Sharp X68000 was released in 1989 too). The PC-Engine version was much better though.

[Coppis]

16/04/2021: Player ship "invulnerable" state

After the ship is hit and the explosion animation ends, the ship is returned to its original position. It may happen that in this position there are enemies and then the ship is hit again. Losing a life like this is frustrating for the player. To avoid this I have introduced the "invulnerable" state, where the ship is controllable but cannot be destroyed by enemies. The ship enters this state immediately after the explosion animation ends. The permanence in this state is regulated by a timer, currently set at 5 seconds. To give the player visual feedback that the ship is invulnerable, we let the ship flashing.


The following code snippet shows how I implemented flashing durign "invulnerable" state:

#SHIP_FLASH_DELAY = 5  ; flashing duration (in frames)


; if the state is invulnerable, makes the ship flash making it disappear and reappear
If myShip\state = #SHIP_STATE_INVULNERABLE
    shipFlashingDelay = shipFlashingDelay + 1
    ; if the flashing time has elapsed
    If shipFlashingDelay = #SHIP_FLASH_DELAY
        ; reset the flashing timer
        shipFlashingDelay = 0
        ; toggle ship visibility
        shipVisible = 1- shipVisible
    EndIf
EndIf

If shipVisible = 1
    QBlit #QUEUE_ID+db,shapeID,myShip\x,myShip\y
EndIf

The duration of the "invulnerable" state is checked in the MoveShip function, shown in the following code snippet:

; move and update the player ship
Statement MoveShip{}
   Shared myShip,shipInvulnerabilityTimer

    ; if ship is in invulnerable state
   If myShip\state = #SHIP_STATE_INVULNERABLE
       shipInvulnerabilityTimer = shipInvulnerabilityTimer+1
       ; if the time period for invulnerability has elapsed
       If shipInvulnerabilityTimer = #SHIP_INVULNERABLE_STATE_DURATION
           ; reset invulnerability timer
           shipInvulnerabilityTimer = 0
           ; change state to active
           myShip\state = #SHIP_STATE_ACTIVE
       EndIf
   EndIf

The following video shows the player ship flashing after a collision with the enemies.


[ Show youtube player ]

[saimon69]

Hey, if you hit a wall on performance ask advice to mcGeezer and Earok!

[BippyM]

This looks good. Can you speed it up at all?