Function DoPaletteAnimations

src/palette.cpp:245–353

#define EXTR2(p, q) (((uint16_t)(~palette_animation_counter * (p)) * (q)) >> 16)

void DoPaletteAnimations()
{
	std::lock_guard<std::recursive_mutex> lock(_palette_mutex);

	/* Animation counter for the palette animation. */
	static int palette_animation_counter = 0;
	palette_animation_counter += 8;

	Blitter *blitter = BlitterFactory::GetCurrentBlitter();
	const Colour *s;
	const ExtraPaletteValues *ev = &_extra_palette_values;
	const uint old_tc = palette_animation_counter;
	uint j;

	if (blitter != nullptr && blitter->UsePaletteAnimation() == Blitter::PaletteAnimation::None) {
		palette_animation_counter = 0;
	}

	std::span<Colour> current_palette{&_cur_palette.palette[PALETTE_ANIM_START], PALETTE_ANIM_SIZE};
	/* Makes a copy of the current animation palette in old_val,
	 * so the work on the current palette could be compared, see if there has been any changes */
	std::array<Colour, PALETTE_ANIM_SIZE> original_palette;
	std::ranges::copy(current_palette, original_palette.begin());
	auto palette_pos = current_palette.begin(); // Points to where animations are taking place on the palette

	/* Fizzy Drink bubbles animation */
	s = ev->fizzy_drink;
	j = EXTR2(512, EPV_CYCLES_FIZZY_DRINK);
	for (uint i = 0; i != EPV_CYCLES_FIZZY_DRINK; i++) {
		*palette_pos++ = s[j];
		j++;
		if (j == EPV_CYCLES_FIZZY_DRINK) j = 0;
	}

	/* Oil refinery fire animation */
	s = ev->oil_refinery;
	j = EXTR2(512, EPV_CYCLES_OIL_REFINERY);
	for (uint i = 0; i != EPV_CYCLES_OIL_REFINERY; i++) {
		*palette_pos++ = s[j];
		j++;
		if (j == EPV_CYCLES_OIL_REFINERY) j = 0;
	}

	/* Radio tower blinking */
	{
		uint8_t i = (palette_animation_counter >> 1) & 0x7F;
		uint8_t v;

		if (i < 0x3f) {
			v = 255;
		} else if (i < 0x4A || i >= 0x75) {
			v = 128;
		} else {
			v = 20;
		}
		palette_pos->r = v;
		palette_pos->g = 0;
		palette_pos->b = 0;