src/glsl/builtins/glsl/determinant.glsl

   1 /*
   2  * Copyright © 2012 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  21  * DEALINGS IN THE SOFTWARE.
  22  */
  23
  24 #version 120
  25
  26 // Forward declaration because builtins don't know about other builtins.
  27 float dot(vec4, vec4);
  28
  29 float determinant(mat2 m)
  30 {
  31    return m[0][0] * m[1][1] - m[1][0] * m[0][1];
  32 }
  33
  34 float determinant(mat3 m)
  35 {
  36    return (+ m[0][0] * (m[1][1] * m[2][2] - m[1][2] * m[2][1])
  37            - m[0][1] * (m[1][0] * m[2][2] - m[1][2] * m[2][0])
  38            + m[0][2] * (m[1][0] * m[2][1] - m[1][1] * m[2][0]));
  39 }
  40
  41 float determinant(mat4 m)
  42 {
  43    float SubFactor00 = m[2][2] * m[3][3] - m[3][2] * m[2][3];
  44    float SubFactor01 = m[2][1] * m[3][3] - m[3][1] * m[2][3];
  45    float SubFactor02 = m[2][1] * m[3][2] - m[3][1] * m[2][2];
  46    float SubFactor03 = m[2][0] * m[3][3] - m[3][0] * m[2][3];
  47    float SubFactor04 = m[2][0] * m[3][2] - m[3][0] * m[2][2];
  48    float SubFactor05 = m[2][0] * m[3][1] - m[3][0] * m[2][1];
  49    float SubFactor06 = m[1][2] * m[3][3] - m[3][2] * m[1][3];
  50    float SubFactor07 = m[1][1] * m[3][3] - m[3][1] * m[1][3];
  51    float SubFactor08 = m[1][1] * m[3][2] - m[3][1] * m[1][2];
  52    float SubFactor09 = m[1][0] * m[3][3] - m[3][0] * m[1][3];
  53    float SubFactor10 = m[1][0] * m[3][2] - m[3][0] * m[1][2];
  54    float SubFactor11 = m[1][1] * m[3][3] - m[3][1] * m[1][3];
  55    float SubFactor12 = m[1][0] * m[3][1] - m[3][0] * m[1][1];
  56    float SubFactor13 = m[1][2] * m[2][3] - m[2][2] * m[1][3];
  57    float SubFactor14 = m[1][1] * m[2][3] - m[2][1] * m[1][3];
  58    float SubFactor15 = m[1][1] * m[2][2] - m[2][1] * m[1][2];
  59    float SubFactor16 = m[1][0] * m[2][3] - m[2][0] * m[1][3];
  60    float SubFactor17 = m[1][0] * m[2][2] - m[2][0] * m[1][2];
  61    float SubFactor18 = m[1][0] * m[2][1] - m[2][0] * m[1][1];
  62
  63    vec4 adj_0;
  64
  65    adj_0[0] = + (m[1][1] * SubFactor00 - m[1][2] * SubFactor01 + m[1][3] * SubFactor02);
  66    adj_0[1] = - (m[1][0] * SubFactor00 - m[1][2] * SubFactor03 + m[1][3] * SubFactor04);
  67    adj_0[2] = + (m[1][0] * SubFactor01 - m[1][1] * SubFactor03 + m[1][3] * SubFactor05);
  68    adj_0[3] = - (m[1][0] * SubFactor02 - m[1][1] * SubFactor04 + m[1][2] * SubFactor05);
  69
  70    return dot(m[0], adj_0);
  71 }