hyprlock/src/renderer/mtx.hpp

#pragma once
#include <cstring>
#include <wayland-client.h>
#include "../helpers/Box.hpp"

enum wl_output_transform wlr_output_transform_invert(enum wl_output_transform tr) {
    // if ((tr & WL_OUTPUT_TRANSFORM_90) && !(tr & WL_OUTPUT_TRANSFORM_FLIPPED)) {
    //     tr ^= WL_OUTPUT_TRANSFORM_180;
    // }
    return tr;
}

void wlr_matrix_identity(float mat[9]) {
    const float identity[9] = {
        1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f,
    };
    memcpy(mat, identity, sizeof(identity));
}

void wlr_matrix_multiply(float mat[9], const float a[9], const float b[9]) {
    float product[9];

    product[0] = a[0] * b[0] + a[1] * b[3] + a[2] * b[6];
    product[1] = a[0] * b[1] + a[1] * b[4] + a[2] * b[7];
    product[2] = a[0] * b[2] + a[1] * b[5] + a[2] * b[8];

    product[3] = a[3] * b[0] + a[4] * b[3] + a[5] * b[6];
    product[4] = a[3] * b[1] + a[4] * b[4] + a[5] * b[7];
    product[5] = a[3] * b[2] + a[4] * b[5] + a[5] * b[8];

    product[6] = a[6] * b[0] + a[7] * b[3] + a[8] * b[6];
    product[7] = a[6] * b[1] + a[7] * b[4] + a[8] * b[7];
    product[8] = a[6] * b[2] + a[7] * b[5] + a[8] * b[8];

    memcpy(mat, product, sizeof(product));
}

void wlr_matrix_transpose(float mat[9], const float a[9]) {
    float transposition[9] = {
        a[0], a[3], a[6], a[1], a[4], a[7], a[2], a[5], a[8],
    };
    memcpy(mat, transposition, sizeof(transposition));
}

void wlr_matrix_translate(float mat[9], float x, float y) {
    float translate[9] = {
        1.0f, 0.0f, x, 0.0f, 1.0f, y, 0.0f, 0.0f, 1.0f,
    };
    wlr_matrix_multiply(mat, mat, translate);
}

void wlr_matrix_scale(float mat[9], float x, float y) {
    float scale[9] = {
        x, 0.0f, 0.0f, 0.0f, y, 0.0f, 0.0f, 0.0f, 1.0f,
    };
    wlr_matrix_multiply(mat, mat, scale);
}

void wlr_matrix_rotate(float mat[9], float rad) {
    float rotate[9] = {
        cos(rad), -sin(rad), 0.0f, sin(rad), cos(rad), 0.0f, 0.0f, 0.0f, 1.0f,
    };
    wlr_matrix_multiply(mat, mat, rotate);
}

const float transforms[][9] = {
    [WL_OUTPUT_TRANSFORM_NORMAL] =
        {
            1.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
        },
    [WL_OUTPUT_TRANSFORM_90] =
        {
            0.0f,
            1.0f,
            0.0f,
            -1.0f,
            0.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
        },
    [WL_OUTPUT_TRANSFORM_180] =
        {
            -1.0f,
            0.0f,
            0.0f,
            0.0f,
            -1.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
        },
    [WL_OUTPUT_TRANSFORM_270] =
        {
            0.0f,
            -1.0f,
            0.0f,
            1.0f,
            0.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
        },
    [WL_OUTPUT_TRANSFORM_FLIPPED] =
        {
            -1.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
        },
    [WL_OUTPUT_TRANSFORM_FLIPPED_90] =
        {
            0.0f,
            1.0f,
            0.0f,
            1.0f,
            0.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
        },
    [WL_OUTPUT_TRANSFORM_FLIPPED_180] =
        {
            1.0f,
            0.0f,
            0.0f,
            0.0f,
            -1.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
        },
    [WL_OUTPUT_TRANSFORM_FLIPPED_270] =
        {
            0.0f,
            -1.0f,
            0.0f,
            -1.0f,
            0.0f,
            0.0f,
            0.0f,
            0.0f,
            1.0f,
        },
};

void wlr_matrix_transform(float mat[9], enum wl_output_transform transform) {
    wlr_matrix_multiply(mat, mat, transforms[transform]);
}

void matrix_projection(float mat[9], int width, int height, enum wl_output_transform transform) {
    std::memset(mat, 0, sizeof(*mat) * 9);

    const float* t = transforms[transform];
    float        x = 2.0f / width;
    float        y = 2.0f / height;

    // Rotation + reflection
    mat[0] = x * t[0];
    mat[1] = x * t[1];
    mat[3] = y * -t[3];
    mat[4] = y * -t[4];

    // Translation
    mat[2] = -copysign(1.0f, mat[0] + mat[1]);
    mat[5] = -copysign(1.0f, mat[3] + mat[4]);

    // Identity
    mat[8] = 1.0f;
}

void wlr_matrix_project_box(float mat[9], const CBox* box, enum wl_output_transform transform, float rotation, const float projection[9]) {
    int x      = box->x;
    int y      = box->y;
    int width  = box->width;
    int height = box->height;

    wlr_matrix_identity(mat);
    wlr_matrix_translate(mat, x, y);

    if (rotation != 0) {
        wlr_matrix_translate(mat, width / 2, height / 2);
        wlr_matrix_rotate(mat, rotation);
        wlr_matrix_translate(mat, -width / 2, -height / 2);
    }

    wlr_matrix_scale(mat, width, height);

    if (transform != WL_OUTPUT_TRANSFORM_NORMAL) {
        wlr_matrix_translate(mat, 0.5, 0.5);
        wlr_matrix_transform(mat, transform);
        wlr_matrix_translate(mat, -0.5, -0.5);
    }

    wlr_matrix_multiply(mat, projection, mat);
}

void matrixProjection(float mat[9], int w, int h, wl_output_transform tr) {
    memset(mat, 0, sizeof(*mat) * 9);

    const float* t = transforms[tr];
    float        x = 2.0f / w;
    float        y = 2.0f / h;

    // Rotation + reflection
    mat[0] = x * t[0];
    mat[1] = x * t[1];
    mat[3] = y * t[3];
    mat[4] = y * t[4];

    // Translation
    mat[2] = -copysign(1.0f, mat[0] + mat[1]);
    mat[5] = -copysign(1.0f, mat[3] + mat[4]);

    // Identity
    mat[8] = 1.0f;
}