// ═══════════════════════════════════════════════════════════════
// ODIX Parade Match v1.0
// Per-channel lift/gain matching from RGB parade readings
//
// USAGE:
//   1. Open your reference shot. Read its parade:
//      note the shadow floor and highlight ceiling per channel.
//   2. Enter those values in SOURCE BLACK R/G/B and
//      SOURCE WHITE R/G/B.
//   3. Switch to your target shot (the one to match).
//      Enter its parade values in TARGET BLACK/WHITE.
//   4. The tool remaps each channel so the parade aligns.
//   5. Use Strength to blend back if needed.
//
//   TIP: For log footage, typical shadow values are 0.06–0.12
//   and highlight values are 0.85–1.0 depending on camera.
//   In scene-linear, shadows near 0.0, highlights near 1.0+.
//
// COLOR SPACE:
//   Scene-linear or log-encoded video.
//   Do NOT apply after output LUT.
//
// by Odbat Batsaikhan — odixbat.com — @odixbat
// ═══════════════════════════════════════════════════════════════

// ── Source parade readings (reference shot) ──
DEFINE_UI_PARAMS(p_SrcBlkR, Src Black R, DCTLUI_SLIDER_FLOAT, 0.0,  -0.2, 0.6, 0.001)
DEFINE_UI_PARAMS(p_SrcBlkG, Src Black G, DCTLUI_SLIDER_FLOAT, 0.0,  -0.2, 0.6, 0.001)
DEFINE_UI_PARAMS(p_SrcBlkB, Src Black B, DCTLUI_SLIDER_FLOAT, 0.0,  -0.2, 0.6, 0.001)
DEFINE_UI_PARAMS(p_SrcWhtR, Src White R, DCTLUI_SLIDER_FLOAT, 1.0,   0.3, 2.0, 0.001)
DEFINE_UI_PARAMS(p_SrcWhtG, Src White G, DCTLUI_SLIDER_FLOAT, 1.0,   0.3, 2.0, 0.001)
DEFINE_UI_PARAMS(p_SrcWhtB, Src White B, DCTLUI_SLIDER_FLOAT, 1.0,   0.3, 2.0, 0.001)

// ── Target parade values (shot you're matching) ──
DEFINE_UI_PARAMS(p_TgtBlkR, Tgt Black R, DCTLUI_SLIDER_FLOAT, 0.0,  -0.2, 0.6, 0.001)
DEFINE_UI_PARAMS(p_TgtBlkG, Tgt Black G, DCTLUI_SLIDER_FLOAT, 0.0,  -0.2, 0.6, 0.001)
DEFINE_UI_PARAMS(p_TgtBlkB, Tgt Black B, DCTLUI_SLIDER_FLOAT, 0.0,  -0.2, 0.6, 0.001)
DEFINE_UI_PARAMS(p_TgtWhtR, Tgt White R, DCTLUI_SLIDER_FLOAT, 1.0,   0.3, 2.0, 0.001)
DEFINE_UI_PARAMS(p_TgtWhtG, Tgt White G, DCTLUI_SLIDER_FLOAT, 1.0,   0.3, 2.0, 0.001)
DEFINE_UI_PARAMS(p_TgtWhtB, Tgt White B, DCTLUI_SLIDER_FLOAT, 1.0,   0.3, 2.0, 0.001)

// ── Global ──
DEFINE_UI_PARAMS(p_Strength,     Strength,          DCTLUI_SLIDER_FLOAT, 1.0, 0.0, 1.0, 0.01)
DEFINE_UI_PARAMS(p_MidCorrect,   Mid Correction,    DCTLUI_SLIDER_FLOAT, 1.0, 0.5, 2.0, 0.01)

__DEVICE__ float channelRemap(float v, float srcLo, float srcHi, float dstLo, float dstHi) {
    float range = srcHi - srcLo;
    if (_fabs(range) < 0.00001f) return dstLo;
    float t = (v - srcLo) / range;
    // Apply mild gamma (MidCorrect) to midtone mapping
    return dstLo + t * (dstHi - dstLo);
}

__DEVICE__ float3 transform(int p_Width, int p_Height, int p_X, int p_Y, float p_R, float p_G, float p_B) {
    float r_matched = channelRemap(p_R, p_SrcBlkR, p_SrcWhtR, p_TgtBlkR, p_TgtWhtR);
    float g_matched = channelRemap(p_G, p_SrcBlkG, p_SrcWhtG, p_TgtBlkG, p_TgtWhtG);
    float b_matched = channelRemap(p_B, p_SrcBlkB, p_SrcWhtB, p_TgtBlkB, p_TgtWhtB);

    // Mid correction — gamma-like adjustment on matched result
    float midPivot = (p_TgtBlkR + p_TgtWhtR) * 0.5f;
    if (p_MidCorrect != 1.0f) {
        float g_val = 1.0f / p_MidCorrect;
        r_matched = midPivot + _powf(_fmaxf((r_matched - midPivot) / (1.0f - midPivot + 0.001f), 0.0f), g_val) * (1.0f - midPivot);
        g_matched = midPivot + _powf(_fmaxf((g_matched - midPivot) / (1.0f - midPivot + 0.001f), 0.0f), g_val) * (1.0f - midPivot);
        b_matched = midPivot + _powf(_fmaxf((b_matched - midPivot) / (1.0f - midPivot + 0.001f), 0.0f), g_val) * (1.0f - midPivot);
    }

    float r = p_R + (r_matched - p_R) * p_Strength;
    float g = p_G + (g_matched - p_G) * p_Strength;
    float b = p_B + (b_matched - p_B) * p_Strength;

    return make_float3(r, g, b);
}