five_bit_hd_gamma_bitshift() [2/2]

void fl::five_bit_hd_gamma_bitshift	(	fl::span< const CRGB >	colors,
		CRGB	colors_scale,
		u8	global_brightness,
		fl::span< CRGBA5 >	out )

Definition at line 133 of file five_bit_hd_gamma.cpp.hpp.

                        {
 
    u16 n = static_cast<u16>(colors.size());
    if (out.size() < n) n = static_cast<u16>(out.size());
 
    // Brightness==0: zero everything and return immediately.
    if (global_brightness == 0) {
        for (u16 i = 0; i < n; ++i) {
            out[i].color = CRGB(0, 0, 0);
            out[i].brightness_5bit = 0;
        }
        return;
    }
 
    const aligned_ptr<const u16, 64> glut(GAMMA_2_8_LUT);
 
    // Precompute color-scale multipliers once (avoid per-pixel branches).
    const bool apply_r_scale = (colors_scale.r != 0xff);
    const bool apply_g_scale = (colors_scale.g != 0xff);
    const bool apply_b_scale = (colors_scale.b != 0xff);
    const u16 rscale_p1 = 1u + static_cast<u16>(colors_scale.r);
    const u16 gscale_p1 = 1u + static_cast<u16>(colors_scale.g);
    const u16 bscale_p1 = 1u + static_cast<u16>(colors_scale.b);
 
    // Precompute brightness multiplier once.
    const bool apply_brightness = (global_brightness != 0xff);
    const u16 bright_p1 = 1u + static_cast<u16>(global_brightness);
 
    for (u16 i = 0; i < n; ++i) {
        const CRGB &c = colors[i];
 
        u16 r16 = five_bit_impl::gamma_lut_read(glut, c.r);
        u16 g16 = five_bit_impl::gamma_lut_read(glut, c.g);
        u16 b16 = five_bit_impl::gamma_lut_read(glut, c.b);
 
        // Color-scale: branchless multiply, guarded by precomputed bools.
        if (apply_r_scale) r16 = five_bit_impl::scale16by8_nozero(r16, rscale_p1);
        if (apply_g_scale) g16 = five_bit_impl::scale16by8_nozero(g16, gscale_p1);
        if (apply_b_scale) b16 = five_bit_impl::scale16by8_nozero(b16, bscale_p1);
 
        five_bit_impl::five_bit_pixel(r16, g16, b16, global_brightness,
                                      bright_p1, apply_brightness,
                                      &out[i].color, &out[i].brightness_5bit);
    }
}

References GAMMA_2_8_LUT, and fl::span< T, Extent >::size().

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