/* Copyright  (C) 2010-2017 The RetroArch team
 *
 * ---------------------------------------------------------------------------------------
 * The following license statement only applies to this file (matrix_4x4.h).
 * ---------------------------------------------------------------------------------------
 *
 * 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.
 */

#ifndef __LIBRETRO_SDK_GFX_MATH_MATRIX_4X4_H__
#define __LIBRETRO_SDK_GFX_MATH_MATRIX_4X4_H__

#include <retro_common_api.h>

#include <math.h>
#include <gfx/math/vector_3.h>

/* Column-major matrix (OpenGL-style).
 * Reimplements functionality from FF OpenGL pipeline to be able 
 * to work on GLES 2.0 and modern GL variants.
 */

#define MAT_ELEM_4X4(mat, row, column) ((mat).data[4 * (column) + (row)])

RETRO_BEGIN_DECLS

typedef struct math_matrix_4x4
{
   float data[16];
} math_matrix_4x4;

#define matrix_4x4_copy(dst, src) \
   MAT_ELEM_4X4(dst, 0, 0) = MAT_ELEM_4X4(src, 0, 0); \
   MAT_ELEM_4X4(dst, 0, 1) = MAT_ELEM_4X4(src, 0, 1); \
   MAT_ELEM_4X4(dst, 0, 2) = MAT_ELEM_4X4(src, 0, 2); \
   MAT_ELEM_4X4(dst, 0, 3) = MAT_ELEM_4X4(src, 0, 3); \
   MAT_ELEM_4X4(dst, 1, 0) = MAT_ELEM_4X4(src, 1, 0); \
   MAT_ELEM_4X4(dst, 1, 1) = MAT_ELEM_4X4(src, 1, 1); \
   MAT_ELEM_4X4(dst, 1, 2) = MAT_ELEM_4X4(src, 1, 2); \
   MAT_ELEM_4X4(dst, 1, 3) = MAT_ELEM_4X4(src, 1, 3); \
   MAT_ELEM_4X4(dst, 2, 0) = MAT_ELEM_4X4(src, 2, 0); \
   MAT_ELEM_4X4(dst, 2, 1) = MAT_ELEM_4X4(src, 2, 1); \
   MAT_ELEM_4X4(dst, 2, 2) = MAT_ELEM_4X4(src, 2, 2); \
   MAT_ELEM_4X4(dst, 2, 3) = MAT_ELEM_4X4(src, 2, 3); \
   MAT_ELEM_4X4(dst, 3, 0) = MAT_ELEM_4X4(src, 3, 0); \
   MAT_ELEM_4X4(dst, 3, 1) = MAT_ELEM_4X4(src, 3, 1); \
   MAT_ELEM_4X4(dst, 3, 2) = MAT_ELEM_4X4(src, 3, 2); \
   MAT_ELEM_4X4(dst, 3, 3) = MAT_ELEM_4X4(src, 3, 3)

/*
 * Sets mat to an identity matrix
 */
#define matrix_4x4_identity(mat) \
   MAT_ELEM_4X4(mat, 0, 0)    = 1.0f; \
   MAT_ELEM_4X4(mat, 0, 1)    = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 2)    = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 3)    = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 0)    = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 1)    = 1.0f; \
   MAT_ELEM_4X4(mat, 1, 2)    = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 3)    = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 0)    = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 1)    = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 2)    = 1.0f; \
   MAT_ELEM_4X4(mat, 2, 3)    = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 0)    = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 1)    = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 2)    = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 3)    = 1.0f

/*
 * Sets out to the transposed matrix of in
 */

#define matrix_4x4_transpose(out, in) \
   MAT_ELEM_4X4(out, 0, 0) = MAT_ELEM_4X4(in, 0, 0); \
   MAT_ELEM_4X4(out, 1, 0) = MAT_ELEM_4X4(in, 0, 1); \
   MAT_ELEM_4X4(out, 2, 0) = MAT_ELEM_4X4(in, 0, 2); \
   MAT_ELEM_4X4(out, 3, 0) = MAT_ELEM_4X4(in, 0, 3); \
   MAT_ELEM_4X4(out, 0, 1) = MAT_ELEM_4X4(in, 1, 0); \
   MAT_ELEM_4X4(out, 1, 1) = MAT_ELEM_4X4(in, 1, 1); \
   MAT_ELEM_4X4(out, 2, 1) = MAT_ELEM_4X4(in, 1, 2); \
   MAT_ELEM_4X4(out, 3, 1) = MAT_ELEM_4X4(in, 1, 3); \
   MAT_ELEM_4X4(out, 0, 2) = MAT_ELEM_4X4(in, 2, 0); \
   MAT_ELEM_4X4(out, 1, 2) = MAT_ELEM_4X4(in, 2, 1); \
   MAT_ELEM_4X4(out, 2, 2) = MAT_ELEM_4X4(in, 2, 2); \
   MAT_ELEM_4X4(out, 3, 2) = MAT_ELEM_4X4(in, 2, 3); \
   MAT_ELEM_4X4(out, 0, 3) = MAT_ELEM_4X4(in, 3, 0); \
   MAT_ELEM_4X4(out, 1, 3) = MAT_ELEM_4X4(in, 3, 1); \
   MAT_ELEM_4X4(out, 2, 3) = MAT_ELEM_4X4(in, 3, 2); \
   MAT_ELEM_4X4(out, 3, 3) = MAT_ELEM_4X4(in, 3, 3)

/*
 * Builds an X-axis rotation matrix
 */
#define matrix_4x4_rotate_x(mat, radians) \
{ \
   float cosine            = cosf(radians); \
   float sine              = sinf(radians); \
   MAT_ELEM_4X4(mat, 0, 0) = 1.0f; \
   MAT_ELEM_4X4(mat, 0, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 1) = cosine; \
   MAT_ELEM_4X4(mat, 1, 2) = -sine; \
   MAT_ELEM_4X4(mat, 1, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 1) = sine; \
   MAT_ELEM_4X4(mat, 2, 2) = cosine; \
   MAT_ELEM_4X4(mat, 2, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 3) = 1.0f; \
}

/*
 * Builds a rotation matrix using the 
 * rotation around the Y-axis.
 */

#define matrix_4x4_rotate_y(mat, radians) \
{ \
   float cosine            = cosf(radians); \
   float sine              = sinf(radians); \
   MAT_ELEM_4X4(mat, 0, 0) = cosine; \
   MAT_ELEM_4X4(mat, 0, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 2) = -sine; \
   MAT_ELEM_4X4(mat, 0, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 1) = 1.0f; \
   MAT_ELEM_4X4(mat, 1, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 0) = sine; \
   MAT_ELEM_4X4(mat, 2, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 2) = cosine; \
   MAT_ELEM_4X4(mat, 2, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 3) = 1.0f; \
}

/*
 * Builds a rotation matrix using the 
 * rotation around the Z-axis.
 */
#define matrix_4x4_rotate_z(mat, radians) \
{ \
   float cosine            = cosf(radians); \
   float sine              = sinf(radians); \
   MAT_ELEM_4X4(mat, 0, 0) = cosine; \
   MAT_ELEM_4X4(mat, 0, 1) = -sine; \
   MAT_ELEM_4X4(mat, 0, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 0) = sine; \
   MAT_ELEM_4X4(mat, 1, 1) = cosine; \
   MAT_ELEM_4X4(mat, 1, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 2) = 1.0f; \
   MAT_ELEM_4X4(mat, 2, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 3) = 1.0f; \
}

/*
 * Creates an orthographic projection matrix.
 */
#define matrix_4x4_ortho(mat, left, right, bottom, top, znear, zfar) \
{ \
   float rl                = (right) - (left); \
   float tb                = (top)   - (bottom); \
   float fn                = (zfar)  - (znear); \
   MAT_ELEM_4X4(mat, 0, 0) =  2.0f / rl; \
   MAT_ELEM_4X4(mat, 0, 1) =  0.0f; \
   MAT_ELEM_4X4(mat, 0, 2) =  0.0f; \
   MAT_ELEM_4X4(mat, 0, 3) = -((left) + (right))  / rl; \
   MAT_ELEM_4X4(mat, 1, 0) =  0.0f; \
   MAT_ELEM_4X4(mat, 1, 1) =  2.0f / tb; \
   MAT_ELEM_4X4(mat, 1, 2) =  0.0f; \
   MAT_ELEM_4X4(mat, 1, 3) = -((top)  + (bottom)) / tb; \
   MAT_ELEM_4X4(mat, 2, 0) =  0.0f; \
   MAT_ELEM_4X4(mat, 2, 1) =  0.0f; \
   MAT_ELEM_4X4(mat, 2, 2) = -2.0f / fn; \
   MAT_ELEM_4X4(mat, 2, 3) = -((zfar) + (znear))  / fn; \
   MAT_ELEM_4X4(mat, 3, 0) =  0.0f; \
   MAT_ELEM_4X4(mat, 3, 1) =  0.0f; \
   MAT_ELEM_4X4(mat, 3, 2) =  0.0f; \
   MAT_ELEM_4X4(mat, 3, 3) =  1.0f; \
}

#define matrix_4x4_lookat(out, eye, center, up) \
{ \
   vec3_t zaxis;   /* the "forward" vector */ \
   vec3_t xaxis;   /* the "right"   vector */ \
   vec3_t yaxis;   /* the "up"      vector */ \
   vec3_copy(zaxis, center); \
   vec3_subtract(zaxis, eye); \
   vec3_normalize(zaxis); \
   vec3_cross(xaxis, zaxis, up); \
   vec3_normalize(xaxis); \
   vec3_cross(yaxis, xaxis, zaxis); \
   MAT_ELEM_4X4(out, 0, 0) = xaxis[0]; \
   MAT_ELEM_4X4(out, 0, 1) = yaxis[0]; \
   MAT_ELEM_4X4(out, 0, 2) = -zaxis[0]; \
   MAT_ELEM_4X4(out, 0, 3) = 0.0; \
   MAT_ELEM_4X4(out, 1, 0) = xaxis[1]; \
   MAT_ELEM_4X4(out, 1, 1) = yaxis[1]; \
   MAT_ELEM_4X4(out, 1, 2) = -zaxis[1]; \
   MAT_ELEM_4X4(out, 1, 3) = 0.0f; \
   MAT_ELEM_4X4(out, 2, 0) = xaxis[2]; \
   MAT_ELEM_4X4(out, 2, 1) = yaxis[2]; \
   MAT_ELEM_4X4(out, 2, 2) = -zaxis[2]; \
   MAT_ELEM_4X4(out, 2, 3) = 0.0f; \
   MAT_ELEM_4X4(out, 3, 0) = -(xaxis[0] * eye[0] + xaxis[1] * eye[1] + xaxis[2] * eye[2]); \
   MAT_ELEM_4X4(out, 3, 1) = -(yaxis[0] * eye[0] + yaxis[1] * eye[1] + yaxis[2] * eye[2]); \
   MAT_ELEM_4X4(out, 3, 2) = (zaxis[0] * eye[0] + zaxis[1] * eye[1] + zaxis[2] * eye[2]); \
   MAT_ELEM_4X4(out, 3, 3) = 1.f; \
}

/*
 * Multiplies a with b, stores the result in out
 */

#define matrix_4x4_multiply(out, a, b) \
   MAT_ELEM_4X4(out, 0, 0) =  \
      MAT_ELEM_4X4(a, 0, 0) * MAT_ELEM_4X4(b, 0, 0) + \
      MAT_ELEM_4X4(a, 0, 1) * MAT_ELEM_4X4(b, 1, 0) + \
      MAT_ELEM_4X4(a, 0, 2) * MAT_ELEM_4X4(b, 2, 0) + \
      MAT_ELEM_4X4(a, 0, 3) * MAT_ELEM_4X4(b, 3, 0); \
   MAT_ELEM_4X4(out, 0, 1) =  \
      MAT_ELEM_4X4(a, 0, 0) * MAT_ELEM_4X4(b, 0, 1) + \
      MAT_ELEM_4X4(a, 0, 1) * MAT_ELEM_4X4(b, 1, 1) + \
      MAT_ELEM_4X4(a, 0, 2) * MAT_ELEM_4X4(b, 2, 1) + \
      MAT_ELEM_4X4(a, 0, 3) * MAT_ELEM_4X4(b, 3, 1); \
   MAT_ELEM_4X4(out, 0, 2) =  \
      MAT_ELEM_4X4(a, 0, 0) * MAT_ELEM_4X4(b, 0, 2) + \
      MAT_ELEM_4X4(a, 0, 1) * MAT_ELEM_4X4(b, 1, 2) + \
      MAT_ELEM_4X4(a, 0, 2) * MAT_ELEM_4X4(b, 2, 2) + \
      MAT_ELEM_4X4(a, 0, 3) * MAT_ELEM_4X4(b, 3, 2); \
   MAT_ELEM_4X4(out, 0, 3) =  \
      MAT_ELEM_4X4(a, 0, 0) * MAT_ELEM_4X4(b, 0, 3) + \
      MAT_ELEM_4X4(a, 0, 1) * MAT_ELEM_4X4(b, 1, 3) + \
      MAT_ELEM_4X4(a, 0, 2) * MAT_ELEM_4X4(b, 2, 3) + \
      MAT_ELEM_4X4(a, 0, 3) * MAT_ELEM_4X4(b, 3, 3); \
   MAT_ELEM_4X4(out, 1, 0) =  \
      MAT_ELEM_4X4(a, 1, 0) * MAT_ELEM_4X4(b, 0, 0) + \
      MAT_ELEM_4X4(a, 1, 1) * MAT_ELEM_4X4(b, 1, 0) + \
      MAT_ELEM_4X4(a, 1, 2) * MAT_ELEM_4X4(b, 2, 0) + \
      MAT_ELEM_4X4(a, 1, 3) * MAT_ELEM_4X4(b, 3, 0); \
   MAT_ELEM_4X4(out, 1, 1) =  \
      MAT_ELEM_4X4(a, 1, 0) * MAT_ELEM_4X4(b, 0, 1) + \
      MAT_ELEM_4X4(a, 1, 1) * MAT_ELEM_4X4(b, 1, 1) + \
      MAT_ELEM_4X4(a, 1, 2) * MAT_ELEM_4X4(b, 2, 1) + \
      MAT_ELEM_4X4(a, 1, 3) * MAT_ELEM_4X4(b, 3, 1); \
   MAT_ELEM_4X4(out, 1, 2) =  \
      MAT_ELEM_4X4(a, 1, 0) * MAT_ELEM_4X4(b, 0, 2) + \
      MAT_ELEM_4X4(a, 1, 1) * MAT_ELEM_4X4(b, 1, 2) + \
      MAT_ELEM_4X4(a, 1, 2) * MAT_ELEM_4X4(b, 2, 2) + \
      MAT_ELEM_4X4(a, 1, 3) * MAT_ELEM_4X4(b, 3, 2); \
   MAT_ELEM_4X4(out, 1, 3) =  \
      MAT_ELEM_4X4(a, 1, 0) * MAT_ELEM_4X4(b, 0, 3) + \
      MAT_ELEM_4X4(a, 1, 1) * MAT_ELEM_4X4(b, 1, 3) + \
      MAT_ELEM_4X4(a, 1, 2) * MAT_ELEM_4X4(b, 2, 3) + \
      MAT_ELEM_4X4(a, 1, 3) * MAT_ELEM_4X4(b, 3, 3); \
   MAT_ELEM_4X4(out, 2, 0) =  \
      MAT_ELEM_4X4(a, 2, 0) * MAT_ELEM_4X4(b, 0, 0) + \
      MAT_ELEM_4X4(a, 2, 1) * MAT_ELEM_4X4(b, 1, 0) + \
      MAT_ELEM_4X4(a, 2, 2) * MAT_ELEM_4X4(b, 2, 0) + \
      MAT_ELEM_4X4(a, 2, 3) * MAT_ELEM_4X4(b, 3, 0); \
   MAT_ELEM_4X4(out, 2, 1) =  \
      MAT_ELEM_4X4(a, 2, 0) * MAT_ELEM_4X4(b, 0, 1) + \
      MAT_ELEM_4X4(a, 2, 1) * MAT_ELEM_4X4(b, 1, 1) + \
      MAT_ELEM_4X4(a, 2, 2) * MAT_ELEM_4X4(b, 2, 1) + \
      MAT_ELEM_4X4(a, 2, 3) * MAT_ELEM_4X4(b, 3, 1); \
   MAT_ELEM_4X4(out, 2, 2) =  \
      MAT_ELEM_4X4(a, 2, 0) * MAT_ELEM_4X4(b, 0, 2) + \
      MAT_ELEM_4X4(a, 2, 1) * MAT_ELEM_4X4(b, 1, 2) + \
      MAT_ELEM_4X4(a, 2, 2) * MAT_ELEM_4X4(b, 2, 2) + \
      MAT_ELEM_4X4(a, 2, 3) * MAT_ELEM_4X4(b, 3, 2); \
   MAT_ELEM_4X4(out, 2, 3) =  \
      MAT_ELEM_4X4(a, 2, 0) * MAT_ELEM_4X4(b, 0, 3) + \
      MAT_ELEM_4X4(a, 2, 1) * MAT_ELEM_4X4(b, 1, 3) + \
      MAT_ELEM_4X4(a, 2, 2) * MAT_ELEM_4X4(b, 2, 3) + \
      MAT_ELEM_4X4(a, 2, 3) * MAT_ELEM_4X4(b, 3, 3); \
   MAT_ELEM_4X4(out, 3, 0) =  \
      MAT_ELEM_4X4(a, 3, 0) * MAT_ELEM_4X4(b, 0, 0) + \
      MAT_ELEM_4X4(a, 3, 1) * MAT_ELEM_4X4(b, 1, 0) + \
      MAT_ELEM_4X4(a, 3, 2) * MAT_ELEM_4X4(b, 2, 0) + \
      MAT_ELEM_4X4(a, 3, 3) * MAT_ELEM_4X4(b, 3, 0); \
   MAT_ELEM_4X4(out, 3, 1) =  \
      MAT_ELEM_4X4(a, 3, 0) * MAT_ELEM_4X4(b, 0, 1) + \
      MAT_ELEM_4X4(a, 3, 1) * MAT_ELEM_4X4(b, 1, 1) + \
      MAT_ELEM_4X4(a, 3, 2) * MAT_ELEM_4X4(b, 2, 1) + \
      MAT_ELEM_4X4(a, 3, 3) * MAT_ELEM_4X4(b, 3, 1); \
   MAT_ELEM_4X4(out, 3, 2) = \
      MAT_ELEM_4X4(a, 3, 0) * MAT_ELEM_4X4(b, 0, 2) + \
      MAT_ELEM_4X4(a, 3, 1) * MAT_ELEM_4X4(b, 1, 2) + \
      MAT_ELEM_4X4(a, 3, 2) * MAT_ELEM_4X4(b, 2, 2) + \
      MAT_ELEM_4X4(a, 3, 3) * MAT_ELEM_4X4(b, 3, 2); \
   MAT_ELEM_4X4(out, 3, 3) =  \
      MAT_ELEM_4X4(a, 3, 0) * MAT_ELEM_4X4(b, 0, 3) + \
      MAT_ELEM_4X4(a, 3, 1) * MAT_ELEM_4X4(b, 1, 3) + \
      MAT_ELEM_4X4(a, 3, 2) * MAT_ELEM_4X4(b, 2, 3) + \
      MAT_ELEM_4X4(a, 3, 3) * MAT_ELEM_4X4(b, 3, 3)

#define matrix_4x4_scale(mat, x, y, z) \
   MAT_ELEM_4X4(mat, 0, 0) = x; \
   MAT_ELEM_4X4(mat, 0, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 1) = y; \
   MAT_ELEM_4X4(mat, 1, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 2) = z; \
   MAT_ELEM_4X4(mat, 2, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 3) = 1.0f

/*
 * Builds a translation matrix. All other elements in 
 * the matrix will be set to zero except for the
 * diagonal which is set to 1.0
 */

#define matrix_4x4_translate(mat, x, y, z) \
   MAT_ELEM_4X4(mat, 0, 0) = 1.0f; \
   MAT_ELEM_4X4(mat, 0, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 3) = x; \
   MAT_ELEM_4X4(mat, 1, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 1) = 1.0f; \
   MAT_ELEM_4X4(mat, 1, 2) = 1.0f; \
   MAT_ELEM_4X4(mat, 1, 3) = y; \
   MAT_ELEM_4X4(mat, 2, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 2) = 1.0f; \
   MAT_ELEM_4X4(mat, 2, 3) = z; \
   MAT_ELEM_4X4(mat, 3, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 3) = 1.0f

/*
 * Creates a perspective projection matrix.
 */

#define  matrix_4x4_projection(mat, y_fov, aspect, znear, zfar) \
{ \
   float const a           = 1.f / tan((y_fov) / 2.f); \
   float delta_z           = (zfar) - (znear); \
   MAT_ELEM_4X4(mat, 0, 0) = a / (aspect); \
   MAT_ELEM_4X4(mat, 0, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 0, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 1) = a; \
   MAT_ELEM_4X4(mat, 1, 2) = 0.0f; \
   MAT_ELEM_4X4(mat, 1, 3) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 2, 2) = -(((zfar) + (znear)) / delta_z); \
   MAT_ELEM_4X4(mat, 2, 3) = -1.f; \
   MAT_ELEM_4X4(mat, 3, 0) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 1) = 0.0f; \
   MAT_ELEM_4X4(mat, 3, 2) = -((2.f * (zfar) * (znear)) / delta_z); \
   MAT_ELEM_4X4(mat, 3, 3) = 0.0f; \
}

RETRO_END_DECLS

#endif