wave_scroll.c

The wavy background: scanline scroll offsets fed by HBlank DMA. Part of psynergy_effects.c, compiled only through it.

FunctionsCopy Anchor Link

DisplayScroll_ArmHBlankDmaCopy Anchor Link

void DisplayScroll_ArmHBlankDma(void)

Scheduler callback for the wavy background: restarts DMA 0 each frame to copy the current page's BG1 to BG3 scroll offsets into the scroll registers one scanline at a time. The first line is written directly; the DMA writes three words at each HBlank from then on.

Used by DisplayScroll_DisarmHBlankDma, DisplayScroll_InitializeHBlankDma, Ripple_Stop.

Line 11

DisplayScroll_BuildAndSwapHBlankPageCopy Anchor Link

void DisplayScroll_BuildAndSwapHBlankPage(void)

Scheduler callback for the wavy background: fills the hidden page with each scanline's BG3, BG2 and BG1 offsets, the scroll plus a sine wave for x and for y (an axis with no step stays flat), then shows that page.

Used by DisplayScroll_DisarmHBlankDma, DisplayScroll_InitializeHBlankDma, Ripple_Stop.

Line 44

DisplayScroll_DisarmHBlankDmaCopy Anchor Link

void DisplayScroll_DisarmHBlankDma(void)

Stops the wavy background: removes its two callbacks and stops DMA 0.

Used by Reveal_ShowSecrets.

Line 123