/*
 * Cogl
 *
 * A Low Level GPU Graphics and Utilities API
 *
 * Copyright (C) 2010 Intel Corporation.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Authors:
 *   Robert Bragg <robert@linux.intel.com>
 */

#include "cogl-config.h"

#include <cogl-util.h>
#include <cogl-vector.h>

#include <glib.h>
#include <math.h>
#include <string.h>

#define X 0
#define Y 1
#define Z 2
#define W 3

void
cogl_vector3_init (float *vector, float x, float y, float z)
{
  vector[X] = x;
  vector[Y] = y;
  vector[Z] = z;
}

void
cogl_vector3_init_zero (float *vector)
{
  memset (vector, 0, sizeof (float) * 3);
}

gboolean
cogl_vector3_equal (const void *v1, const void *v2)
{
  float *vector0 = (float *)v1;
  float *vector1 = (float *)v2;

  g_return_val_if_fail (v1 != NULL, FALSE);
  g_return_val_if_fail (v2 != NULL, FALSE);

  /* There's no point picking an arbitrary epsilon that's appropriate
   * for comparing the components so we just use == that will at least
   * consider -0 and 0 to be equal. */
  return
    vector0[X] == vector1[X] &&
    vector0[Y] == vector1[Y] &&
    vector0[Z] == vector1[Z];
}

gboolean
cogl_vector3_equal_with_epsilon (const float *vector0,
                                 const float *vector1,
                                 float epsilon)
{
  g_return_val_if_fail (vector0 != NULL, FALSE);
  g_return_val_if_fail (vector1 != NULL, FALSE);

  if (fabsf (vector0[X] - vector1[X]) < epsilon &&
      fabsf (vector0[Y] - vector1[Y]) < epsilon &&
      fabsf (vector0[Z] - vector1[Z]) < epsilon)
    return TRUE;
  else
    return FALSE;
}

float *
cogl_vector3_copy (const float *vector)
{
  if (vector)
    return g_slice_copy (sizeof (float) * 3, vector);
  return NULL;
}

void
cogl_vector3_free (float *vector)
{
  g_slice_free1 (sizeof (float) * 3, vector);
}

void
cogl_vector3_invert (float *vector)
{
  vector[X] = -vector[X];
  vector[Y] = -vector[Y];
  vector[Z] = -vector[Z];
}

void
cogl_vector3_add (float *result,
                  const float *a,
                  const float *b)
{
  result[X] = a[X] + b[X];
  result[Y] = a[Y] + b[Y];
  result[Z] = a[Z] + b[Z];
}

void
cogl_vector3_subtract (float *result,
                       const float *a,
                       const float *b)
{
  result[X] = a[X] - b[X];
  result[Y] = a[Y] - b[Y];
  result[Z] = a[Z] - b[Z];
}

void
cogl_vector3_multiply_scalar (float *vector,
                              float scalar)
{
  vector[X] *= scalar;
  vector[Y] *= scalar;
  vector[Z] *= scalar;
}

void
cogl_vector3_divide_scalar (float *vector,
                            float scalar)
{
  float one_over_scalar = 1.0f / scalar;
  vector[X] *= one_over_scalar;
  vector[Y] *= one_over_scalar;
  vector[Z] *= one_over_scalar;
}

void
cogl_vector3_normalize (float *vector)
{
  float mag_squared =
    vector[X] * vector[X] +
    vector[Y] * vector[Y] +
    vector[Z] * vector[Z];

  if (mag_squared > 0.0f)
    {
      float one_over_mag = 1.0f / sqrtf (mag_squared);
      vector[X] *= one_over_mag;
      vector[Y] *= one_over_mag;
      vector[Z] *= one_over_mag;
    }
}

float
cogl_vector3_magnitude (const float *vector)
{
  return sqrtf (vector[X] * vector[X] +
                vector[Y] * vector[Y] +
                vector[Z] * vector[Z]);
}

void
cogl_vector3_cross_product (float *result,
                            const float *a,
                            const float *b)
{
  float tmp[3];

  tmp[X] = a[Y] * b[Z] - a[Z] * b[Y];
  tmp[Y] = a[Z] * b[X] - a[X] * b[Z];
  tmp[Z] = a[X] * b[Y] - a[Y] * b[X];
  result[X] = tmp[X];
  result[Y] = tmp[Y];
  result[Z] = tmp[Z];
}

float
cogl_vector3_dot_product (const float *a, const float *b)
{
  return a[X] * b[X] + a[Y] * b[Y] + a[Z] * b[Z];
}

float
cogl_vector3_distance (const float *a, const float *b)
{
  float dx = b[X] - a[X];
  float dy = b[Y] - a[Y];
  float dz = b[Z] - a[Z];

  return sqrtf (dx * dx + dy * dy + dz * dz);
}

#if 0
void
cogl_vector4_init (float *vector, float x, float y, float z)
{
  vector[X] = x;
  vector[Y] = y;
  vector[Z] = z;
  vector[W] = w;
}

void
cogl_vector4_init_zero (float *vector)
{
  memset (vector, 0, sizeof (CoglVector4));
}

void
cogl_vector4_init_from_vector4 (float *vector, float *src)
{
  *vector4 = *src;
}

gboolean
cogl_vector4_equal (const void *v0, const void *v1)
{
  g_return_val_if_fail (v1 != NULL, FALSE);
  g_return_val_if_fail (v2 != NULL, FALSE);

  return memcmp (v1, v2, sizeof (float) * 4) == 0 ? TRUE : FALSE;
}

float *
cogl_vector4_copy (float *vector)
{
  if (vector)
    return g_slice_dup (CoglVector4, vector);
  return NULL;
}

void
cogl_vector4_free (float *vector)
{
  g_slice_free (CoglVector4, vector);
}

void
cogl_vector4_invert (float *vector)
{
  vector.x = -vector.x;
  vector.y = -vector.y;
  vector.z = -vector.z;
  vector.w = -vector.w;
}

void
cogl_vector4_add (float *result,
                  float *a,
                  float *b)
{
  result.x = a.x + b.x;
  result.y = a.y + b.y;
  result.z = a.z + b.z;
  result.w = a.w + b.w;
}

void
cogl_vector4_subtract (float *result,
                       float *a,
                       float *b)
{
  result.x = a.x - b.x;
  result.y = a.y - b.y;
  result.z = a.z - b.z;
  result.w = a.w - b.w;
}

void
cogl_vector4_divide (float *vector,
                     float scalar)
{
  float one_over_scalar = 1.0f / scalar;
  result.x *= one_over_scalar;
  result.y *= one_over_scalar;
  result.z *= one_over_scalar;
  result.w *= one_over_scalar;
}

#endif
