pi5-pio-protomatter/include/piomatter/render.h

#pragma once

#include <span>
#include <vector>
#include <cassert>
#include "matrixmap.h"

namespace piomatter {


constexpr unsigned DATA_OVERHEAD = 3;
constexpr unsigned CLOCKS_PER_DATA = 2;
constexpr unsigned DELAY_OVERHEAD = 5;
constexpr unsigned CLOCKS_PER_DELAY = 1;

constexpr uint32_t command_data = 1u <<31;
constexpr uint32_t command_delay = 0;

struct gamma_lut {
    gamma_lut(double exponent=2.2) {
        for(int i=0; i<256; i++) {
            auto v = std::max(i, int(round(1023 * pow(i / 255, exponent))));
            lut[i] = v;
        }
    }

    unsigned convert(unsigned v) {
        if(v >= std::size(lut)) return 1023;
        return lut[v];
    }

    void convert_rgb888_packed_to_rgb10(std::vector<uint32_t> &result, std::span<const uint8_t> source) {
        result.resize(source.size() / 3);
        for(size_t i=0; i<source.size(); i+=3) {
            uint32_t r = source[i+0] & 0xff;
            uint32_t g = source[i+1] & 0xff;
            uint32_t b = source[i+2] & 0xff;
            result[i] = (convert(r) << 20) | (convert(g) << 10) | convert(b);
        }
    }


    void convert_rgb888_to_rgb10(std::vector<uint32_t> &result, std::span<const uint32_t> source) {
        result.resize(source.size());
        for(size_t i=0; i<source.size(); i++) {
            uint32_t data = source[i];
            uint32_t r = (data >> 16) & 0xff;
            uint32_t g = (data >> 8) & 0xff;
            uint32_t b = data & 0xff;
            result[i] = (convert(r) << 20) | (convert(g) << 10) | convert(b);
        }
    }


    void convert_rgb565_to_rgb10(std::vector<uint32_t> &result, std::span<const uint16_t> source) {
        result.resize(source.size());
        for(size_t i=0; i<source.size(); i++) {
            uint32_t data = source[i];
            unsigned r5 = (data >> 11) & 0x1f;
            unsigned r = (r5 << 3) | (r5 >> 2);
            unsigned g6 = (data >> 5) & 0x3f;
            unsigned g = (g6 << 2) | (g6 >> 4);
            unsigned b5 = (data) & 0x1f;
            unsigned b = (b5 << 3) | (b5 >> 2);

            result[i] = (convert(r) << 20) | (convert(g) << 10) | convert(b);
        }
    }

    uint16_t lut[256];
};

struct colorspace_rgb565 {
    using data_type = uint16_t;

    colorspace_rgb565(float gamma=2.2) : lut{gamma} {}
    gamma_lut lut;
    const std::span<const uint32_t> convert(std::span<const data_type> data_in) {
        lut.convert_rgb565_to_rgb10(rgb10, data_in);
        return rgb10;
    }
    std::vector<uint32_t> rgb10;
};

struct colorspace_rgb888 {
    using data_type = uint32_t;

    colorspace_rgb888(float gamma=2.2) : lut{gamma} {}
    gamma_lut lut;
    const std::span<const uint32_t> convert(std::span<const data_type> data_in) {
        lut.convert_rgb888_to_rgb10(rgb10, data_in);
        return rgb10;
    }
    std::vector<uint32_t> rgb10;
};

struct colorspace_rgb888_packed {
    using data_type = uint8_t;

    colorspace_rgb888_packed(float gamma=2.2) : lut{gamma} {}
    gamma_lut lut;
    const std::span<const uint32_t> convert(std::span<const data_type> data_in) {
        lut.convert_rgb888_packed_to_rgb10(rgb10, data_in);
        return rgb10;
    }
    std::vector<uint32_t> rgb10;
};

struct colorspace_rgb10 {
    using data_type = uint32_t;

    const std::span<const uint32_t> convert(std::span<const data_type> data_in) {
        return data_in;
    }
};


// Render a buffer in linear RGB10 format into a piomatter stream
template<typename pinout>
void protomatter_render_rgb10(std::vector<uint32_t> &result, const matrix_geometry &matrixmap, const uint32_t *pixels) {
    result.clear();

    int data_count = 0;

    auto do_delay = [&](uint32_t delay) {
        if (delay == 0) return;
        assert(delay < 1000000);
        assert(!data_count);
        result.push_back(command_delay | (delay ? delay - 1 : 0));
    };

    auto prep_data = [&data_count, &result](uint32_t n) {
        assert(!data_count);
        assert(n);
        assert(n < 60000);
        result.push_back(command_data | (n - 1));
        data_count = n;
    };

    auto do_data = [&](uint32_t d) {
        assert(data_count);
        data_count --;
        result.push_back(d);
    };

    auto do_data_delay = [&](uint32_t d, uint32_t delay) {
        prep_data(1);
        do_data(d);
        do_delay(delay);
    };

    auto calc_addr_bits = [](int addr) {
        uint32_t data = 0;
        if(addr & 1) data |= (1 << pinout::PIN_ADDR[0]);
        if(addr & 2) data |= (1 << pinout::PIN_ADDR[1]);
        if(addr & 4) data |= (1 << pinout::PIN_ADDR[2]);
        if constexpr(std::size(pinout::PIN_ADDR) >= 4) {
            if(addr & 8) data |= (1 << pinout::PIN_ADDR[3]);
        }
        if constexpr(std::size(pinout::PIN_ADDR) >= 5) {
            if(addr & 16) data |= (1 << pinout::PIN_ADDR[4]);
        }
        return data;
    };

    auto add_pixels = [&do_data, &result](uint32_t addr_bits, bool r0, bool g0, bool b0, bool r1, bool g1, bool b1, bool active) {
        uint32_t data = (active ? pinout::oe_active : pinout::oe_inactive) | addr_bits;
        if(r0) data |= (1 << pinout::PIN_RGB[0]);
        if(g0) data |= (1 << pinout::PIN_RGB[1]);
        if(b0) data |= (1 << pinout::PIN_RGB[2]);
        if(r1) data |= (1 << pinout::PIN_RGB[3]);
        if(g1) data |= (1 << pinout::PIN_RGB[4]);
        if(b1) data |= (1 << pinout::PIN_RGB[5]);

        do_data(data);
        do_data(data | pinout::clk_bit);
    };


    int last_bit = 0;
    int prev_addr = 7;
    // illuminate the right row for data in the shift register (the previous address)
    uint32_t addr_bits = calc_addr_bits(prev_addr);

    const auto n_addr = 1u << matrixmap.n_addr_lines;
    const auto n_planes = matrixmap.n_planes;
    constexpr auto n_bits = 10u;
    unsigned offset = n_bits - n_planes;
    const auto pixels_across = matrixmap.pixels_across;

    for(int addr = 0; addr < n_addr; addr++) {
        for(int bit = n_planes - 1; bit >= 0; bit--) {
            uint32_t r = 1 << (20 + offset + bit);
            uint32_t g = 1 << (10 + offset + bit);
            uint32_t b = 1 << (0 + offset + bit);

            // the shortest /OE we can do is one DATA_OVERHEAD...
            // TODO: should make sure desired duration of MSB is at least `pixels_across`
            uint32_t desired_duration = 1 << last_bit;
            last_bit = bit;


            prep_data(2 * pixels_across);
            auto mapiter = matrixmap.map.begin() + 2 * addr * pixels_across;
            for(int x = 0; x < pixels_across; x++) {
                assert(mapiter != matrixmap.map.end());
                auto pixel0 = pixels[*mapiter++];
                auto r0 = pixel0 & r;
                auto g0 = pixel0 & g;
                auto b0 = pixel0 & b;
                assert(mapiter != matrixmap.map.end());
                auto pixel1 = pixels[*mapiter++];
                auto r1 = pixel1 & r;
                auto g1 = pixel1 & g;
                auto b1 = pixel1 & b;

                add_pixels(addr_bits, r0, g0, b0, r1, g1, b1, x < desired_duration);
            }

            // hold /OE low until desired time has elapsed to illuminate the LAST line
            int remain = desired_duration - pixels_across;
            if (remain > 0) {
                do_data_delay(addr_bits | pinout::oe_active, remain * CLOCKS_PER_DATA - DELAY_OVERHEAD);
            }

            do_data_delay(addr_bits | pinout::oe_inactive, pinout::post_oe_delay);
            do_data_delay(addr_bits | pinout::oe_inactive | pinout::lat_bit, pinout::post_latch_delay);

            // with oe inactive, set address bits to illuminate THIS line
            if (addr != prev_addr) {
                addr_bits = calc_addr_bits(addr);
                do_data_delay(addr_bits | pinout::oe_inactive, pinout::post_addr_delay);
                prev_addr = addr;
            }
        }
    }
}

}