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Feb 12th, 2016
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  1. #include <stdbool.h>
  2. #include <spu_intrinsics.h>
  3.  
  4. // shuffle helpers
  5. #define L0 0x00010203
  6. #define L1 0x04050607
  7. #define L2 0x08090a0b
  8. #define L3 0x0c0d0e0f
  9.  
  10. #define R0 0x10111213
  11. #define R1 0x14151617
  12. #define R2 0x18191a1b
  13. #define R3 0x1c1d1e1f
  14.  
  15. #define ZERO 0x80808080
  16.  
  17. #define SHUFFLE(l, r, x, y, z, w) si_shufb(l, r, ((qword)(vec_uint4){x, y, z, w}))
  18.  
  19. // splat helper
  20. #define SPLAT(v, idx) si_shufb(v, v, (qword)(vec_uint4)(L ## idx))
  21.  
  22. struct matrix_t
  23. {
  24. vec_float4 row0;
  25. vec_float4 row1;
  26. vec_float4 row2;
  27. vec_float4 row3;
  28. };
  29.  
  30. struct aabb_t
  31. {
  32. vec_float4 min;
  33. vec_float4 max;
  34. };
  35.  
  36. static inline void transform_points_4(qword* dest, qword x, qword y, qword z, const struct matrix_t* mat)
  37. {
  38. #define COMP(c) \
  39. qword res_ ## c = SPLAT((qword)mat->row3, c); \
  40. res_ ## c = si_fma(z, SPLAT((qword)mat->row2, c), res_ ## c); \
  41. res_ ## c = si_fma(y, SPLAT((qword)mat->row1, c), res_ ## c); \
  42. res_ ## c = si_fma(x, SPLAT((qword)mat->row0, c), res_ ## c); \
  43. dest[c] = res_ ## c;
  44.  
  45. COMP(0);
  46. COMP(1);
  47. COMP(2);
  48. COMP(3);
  49.  
  50. #undef COMP
  51. }
  52.  
  53. static inline void transform_matrix(struct matrix_t* dest, const struct matrix_t* lhs, const struct matrix_t* rhs)
  54. {
  55. #define COMP_0(c) \
  56. qword res_ ## c = si_fm((qword)lhs->row2, SPLAT((qword)rhs->row ## c, 2)); \
  57. res_ ## c = si_fma((qword)lhs->row1, SPLAT((qword)rhs->row ## c, 1), res_ ## c); \
  58. res_ ## c = si_fma((qword)lhs->row0, SPLAT((qword)rhs->row ## c, 0), res_ ## c); \
  59. dest->row ## c = (vec_float4)res_ ## c;
  60.  
  61. #define COMP_1(c) \
  62. qword res_ ## c = si_fma((qword)lhs->row2, SPLAT((qword)rhs->row ## c, 2), (qword)lhs->row3); \
  63. res_ ## c = si_fma((qword)lhs->row1, SPLAT((qword)rhs->row ## c, 1), res_ ## c); \
  64. res_ ## c = si_fma((qword)lhs->row0, SPLAT((qword)rhs->row ## c, 0), res_ ## c); \
  65. dest->row ## c = (vec_float4)res_ ## c;
  66.  
  67. COMP_0(0);
  68. COMP_0(1);
  69. COMP_0(2);
  70. COMP_1(3);
  71.  
  72. #undef COMP_0
  73. #undef COMP_1
  74. }
  75.  
  76. __attribute__((noinline)) unsigned int is_visible(const struct matrix_t* transform, const struct aabb_t* aabb, const struct matrix_t* frustum)
  77. {
  78. qword min = (qword)aabb->min;
  79. qword max = (qword)aabb->max;
  80.  
  81. // get aabb points (SoA)
  82. qword minmax_x = SHUFFLE(min, max, L0, R0, L0, R0); // x X x X
  83. qword minmax_y = SHUFFLE(min, max, L1, L1, R1, R1); // y y Y Y
  84. qword minmax_z_0 = SPLAT(min, 2); // z z z z
  85. qword minmax_z_1 = SPLAT(max, 2); // Z Z Z Z
  86.  
  87. // get clipping matrix
  88. struct matrix_t clip;
  89.  
  90. transform_matrix(&clip, frustum, transform);
  91.  
  92. // transform points to clip space
  93. qword points_cs_0[4];
  94. qword points_cs_1[4];
  95.  
  96. transform_points_4(points_cs_0, minmax_x, minmax_y, minmax_z_0, &clip);
  97. transform_points_4(points_cs_1, minmax_x, minmax_y, minmax_z_1, &clip);
  98.  
  99. // calculate -w
  100. qword points_cs_0_negw = si_xor(points_cs_0[3], (qword)(vec_uint4)(0x80000000));
  101. qword points_cs_1_negw = si_xor(points_cs_1[3], (qword)(vec_uint4)(0x80000000));
  102.  
  103. // for each plane...
  104. #define NOUT(a, b, c, d) si_orx(si_or(si_fcgt(a, b), si_fcgt(c, d)))
  105.  
  106. qword nout0 = NOUT(points_cs_0[0], points_cs_0_negw, points_cs_1[0], points_cs_1_negw);
  107. qword nout1 = NOUT(points_cs_0[3], points_cs_0[0], points_cs_1[3], points_cs_1[0]);
  108. qword nout2 = NOUT(points_cs_0[1], points_cs_0_negw, points_cs_1[1], points_cs_1_negw);
  109. qword nout3 = NOUT(points_cs_0[3], points_cs_0[1], points_cs_1[3], points_cs_1[1]);
  110. qword nout4 = NOUT(points_cs_0[2], (qword)(0), points_cs_1[2], (qword)(0));
  111. qword nout5 = NOUT(points_cs_0[3], points_cs_0[2], points_cs_1[3], points_cs_1[2]);
  112.  
  113. #undef NOUT
  114.  
  115. // merge "not outside" flags
  116. qword nout01 = si_and(nout0, nout1);
  117. qword nout012 = si_and(nout01, nout2);
  118.  
  119. qword nout34 = si_and(nout3, nout4);
  120. qword nout345 = si_and(nout34, nout5);
  121.  
  122. qword nout = si_and(nout012, nout345);
  123.  
  124. return si_to_uint(nout);
  125. }
  126.  
  127. // simple ortho frustum
  128. struct matrix_t frustum =
  129. {
  130. { 0.1f, 0, 0, 0 },
  131. { 0, 0.1f, 0, 0 },
  132. { 0, 0, 0.1f, 0 },
  133. { 0, 0, 0, 1 }
  134. };
  135.  
  136. // small box
  137. struct aabb_t aabb =
  138. {
  139. { -1, -2, -3 },
  140. { 1, 2, 3 }
  141. };
  142.  
  143. // and some weird matrix
  144. struct matrix_t transform =
  145. {
  146. { 0.123f, 0.456f, 0.789f },
  147. { 0.456f, 0.123f, 0.789f },
  148. { 0.789f, 0.123f, 0.456f },
  149. { 1.f, -1.f, 1.f }
  150. };
  151.  
  152. int main()
  153. {
  154. is_visible(&transform, &aabb, &frustum);
  155. si_stop(0);
  156. }
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