Notices by Colin McMillen (colin_mcmillen@piaille.fr), page 3

A bit more work to use the usual "play each sample twice to heighten the volume and drown the carrier", Glider for Apple II sounds good now, I think?

Commit: https://github.com/colinleroy/a2tools/commit/82b659311486d843f96ab27971b3f0cd49840821

#RetroComputing #Apple2

Of course, with the cursed Apple II colour implementation, it looks like shit on a colour screen.
But to me, the Apple II experience is better with a monochrome screen, and I'm OK with that.

More info about The Curse: https://paleotronic.com/2018/10/03/apple-ii-colour-computer-graphics/

#RetroComputing #Apple2

I think it's time to work a bit on the level design. I find it hard to make things look neat on 280x192 pixels, but I'm quite happy with the result of this one hour session?

#RetroComputing #Apple2

I can barely move 3 sprites of that size in between two mouse interrupts, that's gonna have to be a simple game if I want it to work at 60hz 😄

Mmmmh, I have time to easily draw four sprites if I draw half of them on one mouse interrupt and the two others on the next one, that's cool.

Previous sprite was hand-generated from a LibreOffice Calc spreadsheet, copy-pasted to assembler sources. This was VERY painful. Those who know HGR know.

New sprite is generated by C code that take a PNG in and dump relevant .s and .inc files. It is much more satisfying.
Am I going to try and make a #Glider clone? Maybe.

#Retrocomputing #Apple2

Will I manage collision detection?
I don't know.
#Retrocomputing #Apple2

Sprite generator input / output.
The plane.s file contains 8 sprites for the same plane, as a pixel is a bit and not a byte on the Apple II : storing 8 sprites shifted by one pixel (bit), and selecting the correct one at runtime, is MUCH faster than letting the 6502 shift data.

Vents are implemented (https://github.com/colinleroy/a2tools/commit/14173b3ecd8e6601adb6dec2f6de72a2676bb7e9)

#RetroComputing #Apple2

Collision detection is in place! (https://github.com/colinleroy/a2tools/commit/e11338289ef54cec3853c92ad818cc149c3129d5)

Enough #RetroComputing for the day!

(sound on)

Obviously there were bugs in the sprite generator, (in the smoothing of the X coordinate via multiple sprites), fixed that before going to bed. (https://github.com/colinleroy/a2tools/commit/77bdc26b5b64965ac8afc487a7beabf68815b08d)
#RetroComputing #Apple2

I fixed one more bug - I divided and "moduloed" my pixels by 8 to blit my sprite at the correct HGR bytes, but I had forgotten that 1 byte = 7 pixels, not 8.

That explains why my plane refused to go to the right border of the screen.

My plane's movement and the collision detection is now pixel-perfect.

(https://github.com/colinleroy/a2tools/commit/ad2263b8b7bfc3c1f9247ac3cc10d1b30e6a5f09)

#RetroComputing #Apple2

I managed to generalize my sprite drawing code, implemented another sprite, and can now put an arbitrary number of sprites on the screen! (but 8 max in reality otherwise it's too slow).

When the plane and the moving clock collide, the background save/restore fails because the second sprite drawing saves the "background" on which the first sprite is already drawn.

That's not a real issue because once it'll be implemented, sprite collision will either trigger the plane's crash or a bonus (and the bonus sprite will disappear).

Big commit: https://github.com/colinleroy/a2tools/commit/ba551f6422d406e31fc3a37a56bab2613c5b685b

#RetroComputing #Apple2

I'm quite happy with how I will define the levels. All kind of data (vents boxes, hitboxes for obstacles, and sprites): are defined in one file.

https://github.com/colinleroy/a2tools/blob/master/src/glider/level0.s

Later these definitions will be augmented with the game logic, probably via callback functions in the sprites definitions.

#RetroComputing #Apple2

The sprites' hitboxes are now checked!
This will allow to either die (if the sprite is a malus) or get a bonus. For now they're all killers.

Commit: https://github.com/colinleroy/a2tools/commit/ffad67d7f91fb8be6ada52fd5926c686271bd703

#RetroComputing #Apple2

Correct level reset.

(Commit: https://github.com/colinleroy/a2tools/commit/d0d4c120db4033d309c87ca670a37e44515d07fe#diff-ac9b74279012ad39c638284c929dff20aae4c961e12305f7d4712384c70aa469)

#RetroComputing #Apple2

An invisible commit. Whereas the moving clock was previously moved in the main game loop, I have now set up a specific callback so that each level gets its own level logic function.

That will allow me to have specific movements, triggers etc for each level.

https://github.com/colinleroy/a2tools/commit/67c52b79d4f09704ca8cf14867bc2848284f55b4

#RetroComputing #Apple2

I would very much like to implement "level win, go to next level" now, but instead I'm babysitting the 3D printer shitting itself.

Level win & next level, done! I'm really happy how simple it turns out to add a level. The main difficulty is the art.

Commit: https://github.com/colinleroy/a2tools/commit/371acfdbbe3957c6c3cd919f3c34b2c47dc40f84

#RetroComputing #Apple2