R Type clone

[Amiga1992]

Why not go ahead and make something that isn't on Amiga, like R-Type 3? Pretty sure ripping SNES graphics would be easy.

You got a nice thing going here.

[LeCaravage]

Love reading game's WIP threads.
Nice job.

[Coppis]

19/04/2021: Player ship collision with background

We define 4 test points: T1, T2, T3, T4 as in the following figure.




To check if the ship collides with the background, just determine the tile underlying each test point. If the tile is solid, there is a collision.


The calculation of the underlying tile to a point Ti is simple as we used a tile map:

convert Ti in world coordinates xw,yw
calculate the indices of the underlying tile on the map:
    i = xw/16
    j = yw/16
underlying tile index = map(i,j)
if underlying tile is solid
    change ship state to hit, because there is a ship-background collision

The following video shows the ship-background collision in action:


[ Show youtube player ]

[saimon69]

Originally Posted by Akira

Why not go ahead and make something that isn't on Amiga, like R-Type 3? Pretty sure ripping SNES graphics would be easy.

You got a nice thing going here.

Even R-type LEO arcade

[Konrad]

Please not. Regarding R-type LEO:

Originally Posted by Wikipedia

The game was initially conceived as an original shoot 'em up by Nanao before being retooled into an R-Type project by Irem.

You clearly feel it. It doesn't feal anything like R-Type. R-Type III for SNES is another story, that's a good game !

I would vote for not remaking R-Type, as it's already a good port. When the game engine is finished, perhaps use the assets from R-Type 1 and/or 2 and create a new R-Type from there ?

But in the end it's Coppis decision what he does. If he wants to do an easier R-Type 1, then so be it. I would still follow this thread with interest .

[saimon69]

R-type for SNES has somewhere mode 7 that i doubt he can replicate - or am getting confused with Super R-type?
He could even do completely different levels if he has a pixel artist (one could be me in example)

[Coagulus]

Regarding the collision have you thought of using a hardware sprite for the ship and using the built in collision commands? In JetHunters I draw the tiles then the enemies and bullets then I check if the sprite has hit anything. After that check I then draw the player bullets, stars and powerups.

[Nightshft]

Very interesting Coppis, carry on please!

[Coppis]

Originally Posted by Coagulus

Regarding the collision have you thought of using a hardware sprite for the ship and using the built in collision commands? In JetHunters I draw the tiles then the enemies and bullets then I check if the sprite has hit anything. After that check I then draw the player bullets, stars and powerups.

Thank you for the suggestion, i will try to optimize the game using hardware sprite for the ship and hardware collision detection between sprite and playfield.

[Coppis]

21/04/2021 - Information Panel

We want to create an information panel, at the bottom of the screen, to show the score, the number of lives etc ... To do this we will take advantage of an Amiga feature that allows you to have different video modes simultaneously on the same screen.
The following picture shows the screen layout:




We have a game window, with a 320x192 pixel size, which starts at raster line 44. The game window uses dual playfield mode with 4 bitplanes for each playfield, so has 16 colors. Then we have an information panel, with a 320x64 pixel size, which starts at raster line 237. In fact we need to leave a 1 raster line gap between two different video modes. The panel uses 3 bitplanes, so has only 8 colors.

The following code snippet initalizes the information panel:

    ; create bitmap for panel and load graphics
    BitMap #BITMAP_PANEL,#PANEL_WIDTH,#PANEL_HEIGHT,#PANEL_BPP
    LoadBitMap #BITMAP_PANEL,"panel.iff",#PALETTE_PANEL

    ; panel copperlist settings:
    panelCopperList.l = $3              ; 3 bitplanes

    ; initialize copperlist used for panel, starting at y=44+192+1=237, height 64 px, 8 colors
    ; we need to divide the two copperlists at least by 1 scanline
    InitCopList #COPPERLIST_PANEL,237,64,panelCopperList,0,8,0
    
    ; copy color data from palette to copperlist
    DisplayPalette #COPPERLIST_PANEL,#PALETTE_PANEL

    BLITZ 

    ; setup the screen display with the copperlists
    CreateDisplay #COPPERLIST_MAIN,#COPPERLIST_PANEL

In the main loop, we must add the DisplayBitmap command to show the panel:

Repeat
    VWait
   
    DisplayBitMap #COPPERLIST_PANEL,#BITMAP_PANEL

Drawing score
To draw the current score, we need to draw numbers using a bitmap font. So we create a numeric font, in which each digit is 8x8 pixel and save these tiles into an iff file, like the following:





To display the score, which is a numeric variable, we will convert it into a string. Then we will extract each character from the string, calculate the index into the tilesheet and then blit the tile to the screen. For the blitting we use BBlit command, which saves and restores the background. The background is stored into a dedicated buffer.

This code snippet displays the score:

Statement DisplayScore{}
    Shared score

    Use BitMap #BITMAP_PANEL
    
    ; restore the background
    UnBuffer #BUFFER_SCORE

    ; convert score into a string
    text$ = Str$(score)
    
    offset=0
    ; loop for each character of the score string
    For i=0 To 5
        ; extract one character from the string
        c$ = Mid$(text$,i+1,1)
        ; get the ascii code of the current character
        ascii = Asc(c$)
        ; calculate shapeID from the ascii code
        shapeID = ascii - Asc("0")
        ; display the current character
        BBlit #BUFFER_SCORE,#SHAPE_NUMFONT+shapeID,56+offset,9
        
        ; space for the next character
        offset = offset + 8
    Next
    
End Statement

Drawing number of lives

The number of lives is displayed using icons. These icons are stored into a spritesheet. When the number of lives decreases, we blit a new frame on the panel, showing the new icons number.
The following code snippet displays the lives on the panel:

Statement DisplayLives{}
    Shared lives

    Use BitMap #BITMAP_PANEL

    ; restore the lives blob background
    UnBuffer #BUFFER_LIVES

    If lives >0
        ; calculate the offset for frame number
        offset = 3 - lives

        ; display a blob with number of lives
        BBlit #BUFFER_LIVES,#SHAPE_LIVES+offset,1,2
    EndIf
End Statement

In the following video the final panel is shown:


[ Show youtube player ]

[Dunny]

Originally Posted by saimon69

R-type for SNES has somewhere mode 7 that i doubt he can replicate - or am getting confused with Super R-type?

If you're talking about R-Type III (Third Lightning) then no, that can't be done on a stock Amiga. Not even the first level.

[Tigerskunk]

Originally Posted by Dunny

If you're talking about R-Type III (Third Lightning) then no, that can't be done on a stock Amiga. Not even the first level.

Pssshhht. Let him try...

[Adrian Browne]

If it were an original game I could help out on graphics too as best as I could. Saimon 69 is a good artist too.

[E-Penguin]

Originally Posted by Coppis

21/04/2021 - Information Panel

To display the score, which is a numeric variable, we will convert it into a string. Then we will extract each character from the string, calculate the index into the tilesheet and then blit the tile to the screen. For the blitting we use BBlit command, which saves and restores the background. The background is stored into a dedicated buffer.

If you're only adding or subtracting values to the score, you could do this more easily using BCD (binary-coded decimal), where each nibble represents one decimal digit. The Amiga's 68000 processor has hardware commands for adding (ABCD) and subtracting (SBCD).

I'll post some example code later. Beware, there's a bug in the Blitz2 compiler when generating the BCD instructions. Search on this forum for a macro work-around.

This would be much faster than converting to a string and doing string manipulations.

[Coppis]

23/04/2021 - Beam bar and beam fire

I implemented beam bar as an animated blob, using 11 frames. There are 2 versions of beam fire: small and big. The first is shooted when beam bar is greater than 50% while the second only when beam bar is full.


Look this video:

[ Show youtube player ]

[saimon69]

Originally Posted by Dunny

If you're talking about R-Type III (Third Lightning) then no, that can't be done on a stock Amiga. Not even the first level.

Strictly speaking of stage 1 AND of amiga capabilities (not blitz ones), The twisting structure @4:50 seem straight out of a demoscene intro, so that could be somehow done in a similar fashion, same for the station scaffoldings tunnel @1:01 (sprites), but the remaining stuff (rotating segments) fugghettaboutit :/

[ Show youtube player ]

[Retro1234]

you can just use block or whatever it is in blitz for the score you you don't need to restore anything.

[Retro1234]

maybe you can help with this, not sure this is the correct thread

https://eab.abime.net/showthread.php...ht=bullet+hell

question raised by Shatterhand you are firing Several bullets at several enemies, what is the quickest way to do your collision?

Originally Posted by Dunny

If you're talking about R-Type III (Third Lightning) then no, that can't be done on a stock Amiga. Not even the first level.

That could easily be pre-rendered if the SNES version isn't already, how many frames would it be?

[Dunny]

Originally Posted by Retro1234

That could easily be pre-rendered if the SNES version isn't already, how many frames would it be?

That effect could be done easily enough (assuming you could use a demo effect and then somehow get a playable game on top of it), but I'm more concerned about where the whole level is rotated several times over several seconds through a full 360 degrees prior to that... Yeah you're talking hundreds of frames.

Edit: That was in agreement with Saimon69's post.

[Coppis]

26/04/2021: Implemented different damage level for enemies



Different damage level for each type of enemy: to hit the enemy in the video below with the basic fire, you need to hit the enemy 3 times.


[ Show youtube player ]