PD-LogC-Exposure.dctl

// Copyright 2022-present Contributors to the photographic-dctl project.
// SPDX-License-Identifier: BSD-3-Clause
// https://github.com/mikaelsundell/photographic-dctls

// clang-format off
DEFINE_UI_PARAMS(logc, LogC, DCTLUI_COMBO_BOX, 0, {LOGC3, LOGC4}, {LogC3, LogC4})
DEFINE_UI_PARAMS(ei, LogC3 EI, DCTLUI_COMBO_BOX, 7, {EI160, EI200, EI250, EI320, EI400, EI500, EI640, EI800, EI1000, EI1280, EI1600}, {EI 160, EI 200, EI 250, EI 320, EI 400, EI 500, EI 640, EI 800, EI 1000, EI 1280, EI 1600})
DEFINE_UI_PARAMS(exposure, Exposure, DCTLUI_SLIDER_FLOAT, 0.0, -8.0, 8.0, 0.1)
DEFINE_UI_PARAMS(ev, Exposure EV, DCTLUI_COMBO_BOX, 3, {EV_3, EV_2, EV_1, EV0, EV1, EV2, EV3}, {EV -3, EV -2, EV -1, EV 0, EV 1, EV 2, EV 3})
DEFINE_UI_PARAMS(adjustdisplay, Adjust for display, DCTLUI_CHECK_BOX, 0)
DEFINE_UI_PARAMS(showcolors, Show colors, DCTLUI_CHECK_BOX, 0)
DEFINE_UI_PARAMS(showlegend, Show legend, DCTLUI_CHECK_BOX, 0)

// headers
#include "PD-Common.h"
#include "PD-LogC.h"

// ev stops
__DEVICE__ float evstops(int ev) {
    if (ev == EV_3) {
        return -3.0f;
    } else if (ev == EV_2) {
        return -2.0f;
    } else if (ev == EV_1) {
        return -1.0f;
    } else if (ev == EV0) {
        return 0.0f;
    } else if (ev == EV1) {
        return 1.0f;
    } else if (ev == EV2) {
        return 2.0f;
    } else if (ev == EV3) {
        return 3.0f;
    }
    return 0.0;
}

// logc3 color
__DEVICE__ float3 logC_ev_color(float3 input_rgb, int ei, int ev, int logc) {
    struct LogCColor colors[logC_stops];
    if (logc == LOGC3) {
        struct LogC3Curve cv = logC3_curve(ei);
        float evs = evstops(ev);
        for (unsigned long i = 0; i < logC_stops; i++) {
            colors[i] = logC_colors[i];
            float lin = pow_f(2.0f, colors[i].stop + evs + 0.5f) * 0.18f;
            float log = min_f(LogC3Curve_lin_logC3(cv, lin), 1.0f);
            colors[i].stop = log;
        }
    }
    else {
        struct LogC4Curve cv = logC4_curve();
        float evs = evstops(ev);
        for (unsigned long i = 0; i < logC_stops; i++) {
            colors[i] = logC_colors[i];
            float lin = pow_f(2.0f, colors[i].stop + evs + 0.5f) * 0.18f;
            float log = min_f(LogC4Curve_lin_logC4(cv, lin), 1.0f);
            colors[i].stop = log;
        }
    }
    float3 result = make_float3(0.0f, 0.0f, 0.0f);
    float lum = luma_rec709(input_rgb);
    for (unsigned long i = 0; i < logC_stops; i++) {
        if (lum <= colors[i].stop || i == (sizeof(logC_colors) / sizeof(struct LogCColor)) - 1) {
            result = make_float3(colors[i].r, colors[i].g, colors[i].b);
            break;
        }
    }
    return result; 
}

// transform
__DEVICE__ float3 transform(int p_Width, int p_Height, int p_X, int p_Y, float p_R, float p_G, float p_B)
{
    float3 rgb = make_float3(p_R, p_G, p_B);
    if (logc == LOGC3) {
        rgb = lin_logC3(logC3_lin(rgb, ei) * pow_f(2.0, exposure), ei);
    }
    else {
        rgb = lin_logC4(logC4_lin(rgb) * pow_f(2.0, exposure));
    }
    if (showcolors > 0) {
        rgb = logC_ev_color(rgb, ei, ev, logc);
    }
    if (showlegend > 0) {
        int legendwidth = p_Width * 0.8;
        int offset = p_Height * 0.02;
        int barheight = p_Height * 0.05;
        int startY = p_Height - barheight - offset;
        int startX = p_Width * 0.1;
        int endX = startX + legendwidth;
        if (p_Y >= startY && p_Y < startY + barheight && p_X >= startX && p_X < endX) {
            int width = legendwidth / logC_stops;
            int index = (p_X - startX) / width;
            if (index >= 0 && index < logC_stops) {
                return make_float3(logC_colors[index].r, logC_colors[index].g, logC_colors[index].b);
            }
        }
    }
    if (adjustdisplay) {
        rgb = adjust_display(rgb);
    }
    return rgb;
}