src/glsl/builtins/glsl/inverse.glsl

   1 /* Copyright (c) 2005 - 2012 G-Truc Creation (www.g-truc.net)
   2  * Copyright © 2012 Intel Corporation
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  22
  23 #version 120
  24 mat2 inverse(mat2 m)
  25 {
  26    mat2 adj;
  27    adj[0][0] = m[1][1];
  28    adj[0][1] = -m[0][1];
  29    adj[1][0] = -m[1][0];
  30    adj[1][1] = m[0][0];
  31    float det = m[0][0] * m[1][1] - m[1][0] * m[0][1];
  32    return adj / det;
  33 }
  34
  35 mat3 inverse(mat3 m)
  36 {
  37    mat3 adj;
  38    adj[0][0] = + (m[1][1] * m[2][2] - m[2][1] * m[1][2]);
  39    adj[1][0] = - (m[1][0] * m[2][2] - m[2][0] * m[1][2]);
  40    adj[2][0] = + (m[1][0] * m[2][1] - m[2][0] * m[1][1]);
  41    adj[0][1] = - (m[0][1] * m[2][2] - m[2][1] * m[0][2]);
  42    adj[1][1] = + (m[0][0] * m[2][2] - m[2][0] * m[0][2]);
  43    adj[2][1] = - (m[0][0] * m[2][1] - m[2][0] * m[0][1]);
  44    adj[0][2] = + (m[0][1] * m[1][2] - m[1][1] * m[0][2]);
  45    adj[1][2] = - (m[0][0] * m[1][2] - m[1][0] * m[0][2]);
  46    adj[2][2] = + (m[0][0] * m[1][1] - m[1][0] * m[0][1]);
  47
  48    float det = (+ m[0][0] * (m[1][1] * m[2][2] - m[1][2] * m[2][1])
  49                 - m[0][1] * (m[1][0] * m[2][2] - m[1][2] * m[2][0])
  50                 + m[0][2] * (m[1][0] * m[2][1] - m[1][1] * m[2][0]));
  51
  52    return adj / det;
  53 }
  54
  55 mat4 inverse(mat4 m)
  56 {
  57    float SubFactor00 = m[2][2] * m[3][3] - m[3][2] * m[2][3];
  58    float SubFactor01 = m[2][1] * m[3][3] - m[3][1] * m[2][3];
  59    float SubFactor02 = m[2][1] * m[3][2] - m[3][1] * m[2][2];
  60    float SubFactor03 = m[2][0] * m[3][3] - m[3][0] * m[2][3];
  61    float SubFactor04 = m[2][0] * m[3][2] - m[3][0] * m[2][2];
  62    float SubFactor05 = m[2][0] * m[3][1] - m[3][0] * m[2][1];
  63    float SubFactor06 = m[1][2] * m[3][3] - m[3][2] * m[1][3];
  64    float SubFactor07 = m[1][1] * m[3][3] - m[3][1] * m[1][3];
  65    float SubFactor08 = m[1][1] * m[3][2] - m[3][1] * m[1][2];
  66    float SubFactor09 = m[1][0] * m[3][3] - m[3][0] * m[1][3];
  67    float SubFactor10 = m[1][0] * m[3][2] - m[3][0] * m[1][2];
  68    float SubFactor11 = m[1][1] * m[3][3] - m[3][1] * m[1][3];
  69    float SubFactor12 = m[1][0] * m[3][1] - m[3][0] * m[1][1];
  70    float SubFactor13 = m[1][2] * m[2][3] - m[2][2] * m[1][3];
  71    float SubFactor14 = m[1][1] * m[2][3] - m[2][1] * m[1][3];
  72    float SubFactor15 = m[1][1] * m[2][2] - m[2][1] * m[1][2];
  73    float SubFactor16 = m[1][0] * m[2][3] - m[2][0] * m[1][3];
  74    float SubFactor17 = m[1][0] * m[2][2] - m[2][0] * m[1][2];
  75    float SubFactor18 = m[1][0] * m[2][1] - m[2][0] * m[1][1];
  76
  77    mat4 adj;
  78
  79    adj[0][0] = + (m[1][1] * SubFactor00 - m[1][2] * SubFactor01 + m[1][3] * SubFactor02);
  80    adj[1][0] = - (m[1][0] * SubFactor00 - m[1][2] * SubFactor03 + m[1][3] * SubFactor04);
  81    adj[2][0] = + (m[1][0] * SubFactor01 - m[1][1] * SubFactor03 + m[1][3] * SubFactor05);
  82    adj[3][0] = - (m[1][0] * SubFactor02 - m[1][1] * SubFactor04 + m[1][2] * SubFactor05);
  83
  84    adj[0][1] = - (m[0][1] * SubFactor00 - m[0][2] * SubFactor01 + m[0][3] * SubFactor02);
  85    adj[1][1] = + (m[0][0] * SubFactor00 - m[0][2] * SubFactor03 + m[0][3] * SubFactor04);
  86    adj[2][1] = - (m[0][0] * SubFactor01 - m[0][1] * SubFactor03 + m[0][3] * SubFactor05);
  87    adj[3][1] = + (m[0][0] * SubFactor02 - m[0][1] * SubFactor04 + m[0][2] * SubFactor05);
  88
  89    adj[0][2] = + (m[0][1] * SubFactor06 - m[0][2] * SubFactor07 + m[0][3] * SubFactor08);
  90    adj[1][2] = - (m[0][0] * SubFactor06 - m[0][2] * SubFactor09 + m[0][3] * SubFactor10);
  91    adj[2][2] = + (m[0][0] * SubFactor11 - m[0][1] * SubFactor09 + m[0][3] * SubFactor12);
  92    adj[3][2] = - (m[0][0] * SubFactor08 - m[0][1] * SubFactor10 + m[0][2] * SubFactor12);
  93
  94    adj[0][3] = - (m[0][1] * SubFactor13 - m[0][2] * SubFactor14 + m[0][3] * SubFactor15);
  95    adj[1][3] = + (m[0][0] * SubFactor13 - m[0][2] * SubFactor16 + m[0][3] * SubFactor17);
  96    adj[2][3] = - (m[0][0] * SubFactor14 - m[0][1] * SubFactor16 + m[0][3] * SubFactor18);
  97    adj[3][3] = + (m[0][0] * SubFactor15 - m[0][1] * SubFactor17 + m[0][2] * SubFactor18);
  98
  99    float det = (+ m[0][0] * adj[0][0]
 100                 + m[0][1] * adj[1][0]
 101                 + m[0][2] * adj[2][0]
 102                 + m[0][3] * adj[3][0]);
 103
 104    return adj / det;
 105 }
 106