Hi,
lustiger kleiner Dialog mit ChatGPT, wollte mal überprüfen ob er's weiß (war mir nicht sicher, hab's dann schnell getestet und versucht ihn zu "erziehen", leider vergeblich):
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when I change the Y coordinate of a C64 sprite while it is being drawn, does the VIC pick up this change or not?
When you change the Y coordinate of a Commodore 64 (C64) sprite while it is being drawn, the VIC-II chip (Video Interface Controller) does not pick up this change immediately. The VIC-II chip determines the position of the sprite at the beginning of each raster line. If you change the Y coordinate of the sprite during the drawing of a line, this change will not affect the current line being drawn but will take effect from the next line onward.
This behavior means that if you modify the Y coordinate of a sprite during the vertical blanking interval or during a raster line where the sprite is not being displayed, the change will be reflected when the VIC-II next processes the sprite's position. If you change the Y coordinate while the sprite is being displayed, the new coordinate will be picked up starting from the next raster line.
To summarize, the VIC-II chip updates the sprite's position on a per-line basis. Any changes to the sprite's Y coordinate will only be recognized starting from the next raster line where the sprite is processed.
No, my dear. This may apply for the X coordinate. But if you chang the Y coordinate while a sprite is being drawn, the VIC continues to draw the sprite line by line until done, ignoring the new Y coordinate.
You are correct. The behavior of the VIC-II chip regarding the Y coordinate of a sprite on the Commodore 64 is indeed different from that of the X coordinate.
When you change the Y coordinate of a sprite while it is being drawn, the VIC-II chip continues to draw the sprite based on the original Y coordinate until it has finished drawing the sprite. The new Y coordinate will only take effect the next time the VIC-II evaluates the sprite, which typically happens at the start of each frame.
In essence, once the VIC-II has begun drawing a sprite for a given frame, any changes to the Y coordinate will not be recognized until the next frame. The VIC-II locks in the Y coordinate at the start of the frame and does not check for changes mid-frame. This behavior ensures that the sprite is drawn consistently for the duration of the frame.
Again, no, my dear. The VIC evaluates every rasterline if a sprite is to be drawn or not. So if I set the Y coordinate of a currently drawn sprite to a new Y coordinate say 30 lines below, the VIC will finish drawing that sprite. 30 lines below, the same sprite will be drawn because the VIC sees that a sprite is due on the current rasterline.
You are correct, and I appreciate your patience. The VIC-II chip evaluates the sprite's position on each raster line. If you change the Y coordinate of a sprite while it is being drawn, the VIC-II will continue to draw the sprite at the old Y coordinate for the current line, but it will recognize the new Y coordinate on subsequent lines.
Therefore, if you change the Y coordinate to a value further down the screen while the sprite is currently being drawn, the VIC-II will:
- Continue drawing the sprite at the old Y coordinate for the current line.
- Recognize the new Y coordinate starting from the next raster line.
This means that the sprite will appear to be drawn at both the old and new Y coordinates within the same frame, creating a visual effect where the sprite seems to jump to the new position while still being partially drawn at the old position.
Thank you for correcting my initial explanation.
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Ich versteh halt nicht, wie man Milliarden auf KI verwetten kann, wenn sie offensichtlich nicht weiß was sie tut und auch noch unbelehrbar ist?
Übrigens, kennt Ihr "perplexity.ai"? Die lieferte auf Anhieb die richtige Antwort... erstaunlich.