/* Freetype GL - A C OpenGL Freetype engine
 *
 * Distributed under the OSI-approved BSD 2-Clause License.  See accompanying
 * file `LICENSE` for more details.
 */
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "mat4.h"

mat4 *mat4_new(void)
{
    mat4 *self = (mat4 *) malloc(sizeof(mat4));
    return self;
}

void mat4_set_zero(mat4 *self)
{
    if (!self)
        return;

    memset(self, 0, sizeof(mat4));
}

void mat4_set_identity(mat4 *self)
{
    if (!self)
        return;

    memset(self, 0, sizeof(mat4));
    self->m00 = 1.0;
    self->m11 = 1.0;
    self->m22 = 1.0;
    self->m33 = 1.0;
}

void mat4_multiply(mat4 *self, mat4 *other)
{
    mat4 m;
    size_t i;

    if (!self || !other)
        return;

    for (i = 0; i < 4; ++i)
    {
        m.data[i * 4 + 0] = (self->data[i * 4 + 0] * other->data[0 * 4 + 0]) +
                            (self->data[i * 4 + 1] * other->data[1 * 4 + 0]) +
                            (self->data[i * 4 + 2] * other->data[2 * 4 + 0]) +
                            (self->data[i * 4 + 3] * other->data[3 * 4 + 0]);

        m.data[i * 4 + 1] = (self->data[i * 4 + 0] * other->data[0 * 4 + 1]) +
                            (self->data[i * 4 + 1] * other->data[1 * 4 + 1]) +
                            (self->data[i * 4 + 2] * other->data[2 * 4 + 1]) +
                            (self->data[i * 4 + 3] * other->data[3 * 4 + 1]);

        m.data[i * 4 + 2] = (self->data[i * 4 + 0] * other->data[0 * 4 + 2]) +
                            (self->data[i * 4 + 1] * other->data[1 * 4 + 2]) +
                            (self->data[i * 4 + 2] * other->data[2 * 4 + 2]) +
                            (self->data[i * 4 + 3] * other->data[3 * 4 + 2]);

        m.data[i * 4 + 3] = (self->data[i * 4 + 0] * other->data[0 * 4 + 3]) +
                            (self->data[i * 4 + 1] * other->data[1 * 4 + 3]) +
                            (self->data[i * 4 + 2] * other->data[2 * 4 + 3]) +
                            (self->data[i * 4 + 3] * other->data[3 * 4 + 3]);
    }
    memcpy(self, &m, sizeof(mat4));
}

void mat4_set_orthographic(mat4 *self, float left, float right, float bottom,
                           float top, float znear, float zfar)
{
    if (!self)
        return;

    if (left == right || bottom == top || znear == zfar)
        return;

    mat4_set_zero(self);

    self->m00 = +2.0f / (right - left);
    self->m30 = -(right + left) / (right - left);
    self->m11 = +2.0f / (top - bottom);
    self->m31 = -(top + bottom) / (top - bottom);
    self->m22 = -2.0f / (zfar - znear);
    self->m32 = -(zfar + znear) / (zfar - znear);
    self->m33 = 1.0f;
}

void mat4_set_perspective(mat4 *self, float fovy, float aspect, float znear,
                          float zfar)
{
    float h, w;

    if (!self)
        return;

    if (znear == zfar)
        return;

    h = (float) tan(fovy / 360.0 * M_PI) * znear;
    w = h * aspect;

    mat4_set_frustum(self, -w, w, -h, h, znear, zfar);
}

void mat4_set_frustum(mat4 *self, float left, float right, float bottom,
                      float top, float znear, float zfar)
{

    if (!self)
        return;

    if (left == right || bottom == top || znear == zfar)
        return;

    mat4_set_zero(self);

    self->m00 = (2.0f * znear) / (right - left);
    self->m20 = (right + left) / (right - left);

    self->m11 = (2.0f * znear) / (top - bottom);
    self->m21 = (top + bottom) / (top - bottom);

    self->m22 = -(zfar + znear) / (zfar - znear);
    self->m32 = -(2.0f * zfar * znear) / (zfar - znear);

    self->m23 = -1.0f;
}

void mat4_set_rotation(mat4 *self, float angle, float x, float y, float z)
{
    float c, s, norm;

    if (!self)
        return;

    c    = (float) cos(M_PI * angle / 180.0);
    s    = (float) sin(M_PI * angle / 180.0);
    norm = (float) sqrt(x * x + y * y + z * z);

    x /= norm;
    y /= norm;
    z /= norm;

    mat4_set_identity(self);

    self->m00 = x * x * (1 - c) + c;
    self->m10 = y * x * (1 - c) - z * s;
    self->m20 = z * x * (1 - c) + y * s;

    self->m01 = x * y * (1 - c) + z * s;
    self->m11 = y * y * (1 - c) + c;
    self->m21 = z * y * (1 - c) - x * s;

    self->m02 = x * z * (1 - c) - y * s;
    self->m12 = y * z * (1 - c) + x * s;
    self->m22 = z * z * (1 - c) + c;
}

void mat4_set_translation(mat4 *self, float x, float y, float z)
{
    if (!self)
        return;

    mat4_set_identity(self);
    self->m30 = x;
    self->m31 = y;
    self->m32 = z;
}

void mat4_set_scaling(mat4 *self, float x, float y, float z)
{
    if (!self)
        return;

    mat4_set_identity(self);
    self->m00 = x;
    self->m11 = y;
    self->m22 = z;
}

void mat4_rotate(mat4 *self, float angle, float x, float y, float z)
{
    mat4 m;

    if (!self)
        return;

    mat4_set_rotation(&m, angle, x, y, z);
    mat4_multiply(self, &m);
}

void mat4_translate(mat4 *self, float x, float y, float z)
{
    mat4 m;

    if (!self)
        return;

    mat4_set_translation(&m, x, y, z);
    mat4_multiply(self, &m);
}

void mat4_scale(mat4 *self, float x, float y, float z)
{
    mat4 m;

    if (!self)
        return;

    mat4_set_scaling(&m, x, y, z);
    mat4_multiply(self, &m);
}