Culling the Battlefield: Data Oriented Design in Practice

1. Culling the Battlefield Daniel Collin (DICE)Monday, March 7, 2011

2. OverviewMonday, March 7, 2011

3. Overview ›BackgroundMonday, March 7, 2011

4. Overview ›Background ›Why rewrite it?Monday, March 7, 2011

5. Overview ›Background ›Why rewrite it? ›RequirementsMonday, March 7, 2011

6. Overview ›Background ›Why rewrite it? ›Requirements ›Target hardwareMonday, March 7, 2011

7. Overview ›Background ›Why rewrite it? ›Requirements ›Target hardware ›DetailsMonday, March 7, 2011

8. Overview ›Background ›Why rewrite it? ›Requirements ›Target hardware ›Details ›Software OcclusionMonday, March 7, 2011

9. Overview ›Background ›Why rewrite it? ›Requirements ›Target hardware ›Details ›Software Occlusion ›ConclusionMonday, March 7, 2011

10. Background of the old cullingMonday, March 7, 2011

11. Background of the old culling ›Hierarchical Sphere TreesMonday, March 7, 2011

12. Background of the old culling ›Hierarchical Sphere Trees ›StaticCullTreeMonday, March 7, 2011

13. Background of the old culling ›Hierarchical Sphere Trees ›StaticCullTree ›DynamicCullTreeMonday, March 7, 2011

14. Background of the old cullingMonday, March 7, 2011

15. Why rewrite it?Monday, March 7, 2011

16. Why rewrite it? ›DynamicCullTree scalingMonday, March 7, 2011

17. Why rewrite it? ›DynamicCullTree scaling ›Sub-levelsMonday, March 7, 2011

18. Why rewrite it? ›DynamicCullTree scaling ›Sub-levels ›Pipeline dependenciesMonday, March 7, 2011

19. Why rewrite it? ›DynamicCullTree scaling ›Sub-levels ›Pipeline dependencies ›Hard to scaleMonday, March 7, 2011

20. Why rewrite it? ›DynamicCullTree scaling ›Sub-levels ›Pipeline dependencies ›Hard to scale ›One job per frustumMonday, March 7, 2011

21. Job graph (Old Culling) Job 0 Job 1 Job 2 Job 3BitmasksMonday, March 7, 2011

22. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Job 1 Job 2 Job 3BitmasksMonday, March 7, 2011

23. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Shadow 1 Job 1 frustum Job 2 Job 3BitmasksMonday, March 7, 2011

24. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Shadow 1 Job 1 frustum Job 2 Job 3BitmasksMonday, March 7, 2011

25. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Shadow 1 Job 1 frustum Shadow 2 Job 2 frustum Job 3BitmasksMonday, March 7, 2011

26. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Shadow 1 Job 1 frustum Shadow 2 Job 2 frustum Job 3BitmasksMonday, March 7, 2011

27. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Shadow 1 Job 1 frustum Shadow 2 Job 2 frustum Job 3 View frustumBitmasksMonday, March 7, 2011

28. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Shadow 1 Job 1 frustum Shadow 2 Job 2 frustum Job 3 View frustumBitmasksMonday, March 7, 2011

29. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Shadow 1 Job 1 frustum Merge Job Shadow 2 Job 2 frustum Merge Job Job 3 View frustum Merge JobBitmasksMonday, March 7, 2011

30. Job graph (Old Culling) Job 0 DynamicCullJob (Shadow 1, 2, View frustum) Shadow 1 Job 1 frustum Merge Job Shadow 2 Job 2 frustum Merge Job Job 3 View frustum Merge JobBitmasksMonday, March 7, 2011

31. Requirements for new systemMonday, March 7, 2011

32. Requirements for new system›Better scalingMonday, March 7, 2011

33. Requirements for new system›Better scaling›DestructionMonday, March 7, 2011

34. Requirements for new system›Better scaling›Destruction›Real-time editingMonday, March 7, 2011

35. Requirements for new system›Better scaling›Destruction›Real-time editing›Simpler codeMonday, March 7, 2011

36. Requirements for new system›Better scaling›Destruction›Real-time editing›Simpler code›Uniﬁcation of sub-systemsMonday, March 7, 2011

37. Target hardwareMonday, March 7, 2011

38. What doesn’t work well on these systems?Monday, March 7, 2011

39. What doesn’t work well on these systems?›Non-local dataMonday, March 7, 2011

40. What doesn’t work well on these systems?›Non-local data›BranchesMonday, March 7, 2011

41. What doesn’t work well on these systems?›Non-local data›Branches›Switching between register types (LHS)Monday, March 7, 2011

42. What doesn’t work well on these systems?›Non-local data›Branches›Switching between register types (LHS)›Tree based structures are usually branch heavyMonday, March 7, 2011

43. What doesn’t work well on these systems?›Non-local data›Branches›Switching between register types (LHS)›Tree based structures are usually branch heavy›Data is the most important thing to addressMonday, March 7, 2011

44. What does work well on these systems?Monday, March 7, 2011

45. What does work well on these systems?›Local dataMonday, March 7, 2011

46. What does work well on these systems?›Local data›(SIMD) Computing powerMonday, March 7, 2011

47. What does work well on these systems?›Local data›(SIMD) Computing power›ParallelismMonday, March 7, 2011

48. The new cullingMonday, March 7, 2011

49. The new culling›Our worlds usually has max ~15000 objectsMonday, March 7, 2011

50. The new culling›Our worlds usually has max ~15000 objects›First try was to just use parallel brute forceMonday, March 7, 2011

51. The new culling›Our worlds usually has max ~15000 objects›First try was to just use parallel brute force›3x times faster than the old cullingMonday, March 7, 2011

52. The new culling›Our worlds usually has max ~15000 objects›First try was to just use parallel brute force›3x times faster than the old culling›1/5 code sizeMonday, March 7, 2011

53. The new culling›Our worlds usually has max ~15000 objects›First try was to just use parallel brute force›3x times faster than the old culling›1/5 code size›Easier to optimize even furtherMonday, March 7, 2011

55. The new culling›Linear arrays scale greatMonday, March 7, 2011

56. The new culling›Linear arrays scale great›Predictable dataMonday, March 7, 2011

57. The new culling›Linear arrays scale great›Predictable data›Few branchesMonday, March 7, 2011

58. The new culling›Linear arrays scale great›Predictable data›Few branches›Uses the computing powerMonday, March 7, 2011

62. Performance numbers (no occlusion) 15000 SpheresMonday, March 7, 2011

63. Performance numbers (no occlusion) 15000 Spheres Platform 1 Job 4 Jobs Xbox 360 1.55 ms (2.10 ms / 4) = 0.52 x86 (Core i7, 2.66 GHz) 1.0 ms (1.30 ms / 4) = 0.32 Playstation 3 0.85 ms ((0.95 ms / 4) = 0.23 Playstation 3 (SPA) 0.63 ms (0.75 ms / 4) = 0.18Monday, March 7, 2011

68. Details of the new cullingMonday, March 7, 2011

69. Details of the new culling›Improve performance with a simple gridMonday, March 7, 2011

70. Details of the new culling›Improve performance with a simple grid›Really an AABB assigned to a “cell” with spheresMonday, March 7, 2011

71. Details of the new culling›Improve performance with a simple grid›Really an AABB assigned to a “cell” with spheres›Separate grids forMonday, March 7, 2011

72. Details of the new culling›Improve performance with a simple grid›Really an AABB assigned to a “cell” with spheres›Separate grids for›Monday, March 7, 2011

73. Details of the new culling›Improve performance with a simple grid›Really an AABB assigned to a “cell” with spheres›Separate grids for›› Rendering: StaticMonday, March 7, 2011

74. Details of the new culling›Improve performance with a simple grid›Really an AABB assigned to a “cell” with spheres›Separate grids for›› Rendering: Static› Rendering: DynamicMonday, March 7, 2011

75. Details of the new culling›Improve performance with a simple grid›Really an AABB assigned to a “cell” with spheres›Separate grids for›› Rendering: Static› Rendering: Dynamic› Physics: StaticMonday, March 7, 2011

76. Details of the new culling›Improve performance with a simple grid›Really an AABB assigned to a “cell” with spheres›Separate grids for›› Rendering: Static› Rendering: Dynamic› Physics: Static› Physics: DynamicMonday, March 7, 2011

77. Data layout EntityGridCell BlockBlock* Pointer Pointer Pointer positions x, y, z, r x, y, z, r … u8 Count Count Count entityInfo handle, Handle, … u32 Total Count transformData … … … struct TransformData { half rotation[4]; half minAabb[3]; half pad[1]; half maxAabb[3]; half scale[3]; };Monday, March 7, 2011

78. Adding objects • Pre-allocated array that we can grab data from AtomicAdd(…) to “alloc” new block 4k 4k … EntityGridCell Block* Pointer Pointer Pointer u8 Count Count Count u32 Total CountMonday, March 7, 2011

79. Adding objects Cell 0 Cell 1 Cell 2 Cell 3Monday, March 7, 2011

80. Adding objects Cell 0 Cell 1 Cell 4 Cell 2 Cell 3Monday, March 7, 2011

81. Adding objects Cell 0 Cell 1 Cell 4 Cell 2 Cell 3Monday, March 7, 2011

82. Removing objectsMonday, March 7, 2011

83. Removing objects›Use the “swap trick”Monday, March 7, 2011

84. Removing objects›Use the “swap trick”›Data doesn’t need to be sortedMonday, March 7, 2011

85. Removing objects›Use the “swap trick”›Data doesn’t need to be sorted›Just swap with the last entry and decrease the countMonday, March 7, 2011

86. Rendering culling • Let’s look at what the rendering expects struct EntityRenderCullInfo { Handle entity; // handle to the entity u16 visibleViews; // bits of which frustums that was visible u16 classId; // type of mesh float screenArea; // at which screen area entity should be culled };Monday, March 7, 2011

87. Culling code while (1) { uint blockIter = interlockedIncrement(currentBlockIndex) - 1; if (blockIter >= blockCount) break; u32 masks[EntityGridCell::Block::MaxCount] = {}, frustumMask = 1; block = gridCell->blocks[blockIter]; foreach (frustum in frustums, frustumMask <<= 1) { for (i = 0; i < gridCell->blockCounts[blockIter]; ++i) { u32 inside = intersect(frustum, block->postition[i]); masks[i] |= frustumMask & inside; } } for (i = 0; i < gridCell->blockCounts[blockIter]; ++i) { // ﬁlter list here (if masks[i] is zero it should be skipped) // ... } }Monday, March 7, 2011

92. Intersection Code bool intersect(const Plane* frustumPlanes, Vec4 pos) { ﬂoat radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Right], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; return true; }Monday, March 7, 2011

93. Monday, March 7, 2011

94. See “Typical C++ Bullshit” by @mike_actonMonday, March 7, 2011

95. Intersection Code bool intersect(const Plane* frustumPlanes, Vec4 pos) { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Right], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; return true; }Monday, March 7, 2011

96. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Right], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; return true; }Monday, March 7, 2011

97. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Right], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; return true; }Monday, March 7, 2011

98. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Right], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; return true; }Monday, March 7, 2011

99. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) Float branch! { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Right], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; return true; }Monday, March 7, 2011

100. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) Float branch! { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Right], pos) >Float branch! radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; return true; }Monday, March 7, 2011

101. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) Float branch! { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Right], pos) >Float branch! radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; Float branch! return true; }Monday, March 7, 2011

102. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) Float branch! { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Right], pos) >Float branch! radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; Float branch! return true; } LHS!Monday, March 7, 2011

103. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) Float branch! { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Right], pos) >Float branch! radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; Float branch! return true; } LHS! Float branch!Monday, March 7, 2011

104. Intersection Code LHS! bool intersect(const Plane* frustumPlanes, Vec4 pos) Float branch! { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return So what do the consoles false; think? if (distance(frustumPlanes[Frustum::Near], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Right], pos) >Float branch! :( radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) LHS! return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; Float branch! return true; } LHS! Float branch!Monday, March 7, 2011

105. Intersection Code bool intersect(const Plane* frustumPlanes, Vec4 pos) { float radius = pos.w; if (distance(frustumPlanes[Frustum::Far], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Near], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Right], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Left], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Upper], pos) > radius) return false; if (distance(frustumPlanes[Frustum::Lower], pos) > radius) return false; return true; }Monday, March 7, 2011

106. Intersection CodeMonday, March 7, 2011

107. Intersection Code›How can we improve this?Monday, March 7, 2011

108. Intersection Code›How can we improve this?›Dot products are not very SIMD friendlyMonday, March 7, 2011

109. Intersection Code›How can we improve this?›Dot products are not very SIMD friendly›Usually need to shuffle data around to get resultMonday, March 7, 2011

110. Intersection Code›How can we improve this?›Dot products are not very SIMD friendly›Usually need to shuffle data around to get result›(x0 * x1 + y0 * y1 + z0 * z1 + w0 * w1)Monday, March 7, 2011

111. Intersection Code›How can we improve this?›Dot products are not very SIMD friendly›Usually need to shuffle data around to get result›(x0 * x1 + y0 * y1 + z0 * z1 + w0 * w1)Monday, March 7, 2011

112. Intersection CodeMonday, March 7, 2011

113. Intersection Code›Rearrange the data from AoS to SoAMonday, March 7, 2011

114. Intersection Code›Rearrange the data from AoS to SoA Vec 0 X0 Y0 Z0 W0 Vec 1 X1 Y1 Z1 W1 Vec 2 X2 Y2 Z2 W2 Vec 3 X3 Y3 Z3 W3Monday, March 7, 2011

115. Intersection Code›Rearrange the data from AoS to SoA Vec 0 X0 Y0 Z0 W0 Vec 1 X1 Y1 Z1 W1 Vec 2 X2 Y2 Z2 W2 Vec 3 X3 Y3 Z3 W3Monday, March 7, 2011

116. Intersection Code›Rearrange the data from AoS to SoA Vec 0 X0 Y0 Z0 W0 VecX X0 X1 X2 X3 Vec 1 X1 Y1 Z1 W1 VecY Y0 Y1 Y2 Y3 Vec 2 X2 Y2 Z2 W2 VecZ Z0 Z1 Z2 Z3 Vec 3 X3 Y3 Z3 W3 VecW W0 W1 W2 W3Monday, March 7, 2011

117. Intersection Code›Rearrange the data from AoS to SoA Vec 0 X0 Y0 Z0 W0 VecX X0 X1 X2 X3 Vec 1 X1 Y1 Z1 W1 VecY Y0 Y1 Y2 Y3 Vec 2 X2 Y2 Z2 W2 VecZ Z0 Z1 Z2 Z3 Vec 3 X3 Y3 Z3 W3 VecW W0 W1 W2 W3›Now we only need 3 instructions for 4 dots!Monday, March 7, 2011

118. Rearrange the frustum planesMonday, March 7, 2011

119. Rearrange the frustum planes Plane 0 X0 Y0 Z0 W0 Plane 1 X1 Y1 Z1 W1 Plane 2 X2 Y2 Z2 W2 Plane 3 X3 Y3 Z3 W3 Plane 4 X4 Y4 Z4 W4 Plane 5 X5 Y5 Z5 W5Monday, March 7, 2011

120. Rearrange the frustum planes Plane 0 X0 Y0 Z0 W0 Plane 1 X1 Y1 Z1 W1 Plane 2 X2 Y2 Z2 W2 Plane 3 X3 Y3 Z3 W3 Plane 4 X4 Y4 Z4 W4 Plane 5 X5 Y5 Z5 W5Monday, March 7, 2011

121. Rearrange the frustum planes X0 X1 X2 X3 Plane 0 X0 Y0 Z0 W0 Y0 Y1 Y2 Y3 Plane 1 X1 Y1 Z1 W1 Z0 Z1 Z2 Z3 Plane 2 X2 Y2 Z2 W2 W0 W1 W2 W3 Plane 3 X3 Y3 Z3 W3 Plane 4 X4 Y4 Z4 W4 X4 X5 X4 X5 Plane 5 X5 Y5 Z5 W5 Y4 Y5 Y4 Y5 Z4 Z5 Z4 Z5 W4 W5 W4 W5Monday, March 7, 2011

122. New intersection codeMonday, March 7, 2011

123. New intersection code›Two frustum vs Sphere intersections per loopMonday, March 7, 2011

124. New intersection code›Two frustum vs Sphere intersections per loop›4 * 3 dot products with 9 instructionsMonday, March 7, 2011

125. New intersection code›Two frustum vs Sphere intersections per loop›4 * 3 dot products with 9 instructions›Loop over all frustums and merge the resultMonday, March 7, 2011

126. New intersection code›Two frustum vs Sphere intersections per loop›4 * 3 dot products with 9 instructions›Loop over all frustums and merge the resultMonday, March 7, 2011

127. New intersection code (1/4) Vec posA_xxxx = vecShuffle<VecMask::_xxxx>(posA); Vec posA_yyyy = vecShuffle<VecMask::_yyyy>(posA); Vec posA_zzzz = vecShuffle<VecMask::_zzzz>(posA); Vec posA_rrrr = vecShuffle<VecMask::_wwww>(posA); // 4 dot products dotA_0123 = vecMulAdd(posA_zzzz, pl_z0z1z2z3, pl_w0w1w2w3); dotA_0123 = vecMulAdd(posA_yyyy, pl_y0y1y2y3, dotA_0123); dotA_0123 = vecMulAdd(posA_xxxx, pl_x0x1x2x3, dotA_0123);Monday, March 7, 2011

130. New intersection code (2/4) Vec posB_xxxx = vecShuffle<VecMask::_xxxx>(posB); Vec posB_yyyy = vecShuffle<VecMask::_yyyy>(posB); Vec posB_zzzz = vecShuffle<VecMask::_zzzz>(posB); Vec posB_rrrr = vecShuffle<VecMask::_wwww>(posB); // 4 dot products dotB_0123 = vecMulAdd(posB_zzzz, pl_z0z1z2z3, pl_w0w1w2w3); dotB_0123 = vecMulAdd(posB_yyyy, pl_y0y1y2y3, dotB_0123); dotB_0123 = vecMulAdd(posB_xxxx, pl_x0x1x2x3, dotB_0123Monday, March 7, 2011

133. New intersection code (3/4) Vec posAB_xxxx = vecInsert<VecMask::_0011>(posA_xxxx, posB_xxxx); Vec posAB_yyyy = vecInsert<VecMask::_0011>(posA_yyyy, posB_yyyy); Vec posAB_zzzz = vecInsert<VecMask::_0011>(posA_zzzz, posB_zzzz); Vec posAB_rrrr = vecInsert<VecMask::_0011>(posA_rrrr, posB_rrrr); // 4 dot products dotA45B45 = vecMulAdd(posAB_zzzz, pl_z4z5z4z5, pl_w4w5w4w5); dotA45B45 = vecMulAdd(posAB_yyyy, pl_y4y5y4y5, dotA45B45); dotA45B45 = vecMulAdd(posAB_xxxx, pl_x4x5x4x5, dotA45B45);Monday, March 7, 2011

136. New intersection code (4/4) // Compare against radius dotA_0123 = vecCmpGTMask(dotA_0123, posA_rrrr); dotB_0123 = vecCmpGTMask(dotB_0123, posB_rrrr); dotA45B45 = vecCmpGTMask(dotA45B45, posAB_rrrr); Vec dotA45 = vecInsert<VecMask::_0011>(dotA45B45, zero); Vec dotB45 = vecInsert<VecMask::_0011>(zero, dotA45B45); // collect the results Vec resA = vecOrx(dotA_0123); Vec resB = vecOrx(dotB_0123); resA = vecOr(resA, vecOrx(dotA45)); resB = vecOr(resB, vecOrx(dotB45)); // resA = inside or outside of frustum for point A, resB for point B Vec rA = vecNotMask(resA); Vec rB = vecNotMask(resB); masksCurrent[0] |= frustumMask & rA; masksCurrent[1] |= frustumMask & rB;Monday, March 7, 2011

140. SPU Pipelining Assembler (SPA)Monday, March 7, 2011

141. SPU Pipelining Assembler (SPA)›Like VCL (for PS2) but for PS3 SPUMonday, March 7, 2011

142. SPU Pipelining Assembler (SPA)›Like VCL (for PS2) but for PS3 SPU›Can give you that extra boost if neededMonday, March 7, 2011

143. SPU Pipelining Assembler (SPA)›Like VCL (for PS2) but for PS3 SPU›Can give you that extra boost if needed›Does software pipelining for youMonday, March 7, 2011

144. SPU Pipelining Assembler (SPA)›Like VCL (for PS2) but for PS3 SPU›Can give you that extra boost if needed›Does software pipelining for you›Gives about 35% speed boost in the cullingMonday, March 7, 2011

145. SPU Pipelining Assembler (SPA)›Like VCL (for PS2) but for PS3 SPU›Can give you that extra boost if needed›Does software pipelining for you›Gives about 35% speed boost in the culling›Not really that different from using intrinsicsMonday, March 7, 2011

146. SPU Pipelining Assembler (SPA)›Like VCL (for PS2) but for PS3 SPU›Can give you that extra boost if needed›Does software pipelining for you›Gives about 35% speed boost in the culling›Not really that different from using intrinsics›And coding assembler is fun :)Monday, March 7, 2011

147. SPU Pipelining Assembler (SPA)›Like VCL (for PS2) but for PS3 SPU›Can give you that extra boost if needed›Does software pipelining for you›Gives about 35% speed boost in the culling›Not really that different from using intrinsics›And coding assembler is fun :)Monday, March 7, 2011

148. SPA Inner loop (partly) lqd posA, -0x20(currentPos) lqd posB, -0x10(currentPos) shufb posA_xxxx, posA, posA, Mask_xxxx shufb posA_yyyy, posA, posA, Mask_yyyy shufb posA_zzzz, posA, posA, Mask_zzzz shufb posA_rrrr, posA, posA, Mask_wwww // 4 dot products fma dotA_0123, posA_zzzz, pl_z0z1z2z3, pl_w0w1w2w3 fma dotA_0123, posA_yyyy, pl_y0y1y2y3, dotA_0123 fma dotA_0123, posA_xxxx, pl_x0x1x2x3, dotA_0123 shufb posB_xxxx, posB, posB, Mask_xxxx shufb posB_yyyy, posB, posB, Mask_yyyy shufb posB_zzzz, posB, posB, Mask_zzzz shufb posB_rrrr, posB, posB, Mask_wwww // 4 dot products fma dotB_0123, posB_zzzz, pl_z0z1z2z3, pl_w0w1w2w3 fma dotB_0123, posB_yyyy, pl_y0y1y2y3, dotB_0123 fma dotB_0123, posB_xxxx, pl_x0x1x2x3, dotB_0123Monday, March 7, 2011

149. SPA Inner loop # Loop stats - frustumCull::loop # (ims enabled, sms disabled, optimisation level 2) # resmii : 24 (*) (resource constrained) # recmii : 2 (recurrence constrained) # resource usage: # even pipe : 24 inst. (100% use) (*) # FX[15] SP[9] # odd pipe : 24 inst. (100% use) (*) # SH[17] LS[6] BR[1] # misc: # linear schedule = 57 cycles (for information only) # software pipelining: # best pipelined schedule = 24 cycles (pipelined, 3 iterations in parallel) # software pipelining adjustments: # not generating non-pipelined loop since trip count >=3 (3) # estimated loop performance: # =24*n+59 cyclesMonday, March 7, 2011

150. _local_c0de000000000002: SPA Inner loop fma $46,$42,$30,$29; /* +1 */ shufb $47,$44,$37,$33 /* +2 */ fcgt $57,$20,$24; /* +2 */ orx $48,$15 /* +2 */ selb $55,$37,$44,$33; /* +2 */ shufb $56,$21,$16,$33 /* +1 */ fma $52,$16,$28,$41; /* +1 */ orx $49,$57 /* +2 */ ai $4,$4,32; orx $54,$47 /* +2 */ fma $51,$19,$26,$45; /* +1 */ orx $53,$55 /* +2 */ fma $50,$56,$27,$46; /* +1 */ shufb $24,$23,$23,$34 /* +1 */ ai $2,$2,32; /* +2 */ lqd $13,-32($4) or $69,$48,$54; /* +2 */ lqd $23,-16($4) fma $20,$18,$26,$52; /* +1 */ lqd $12,-32($2) /* +2 */ nor $60,$69,$69; /* +2 */ lqd $43,-16($2) /* +2 */ or $62,$49,$53; /* +2 */ shufb $59,$22,$17,$33 /* +1 */ and $39,$60,$35; /* +2 */ shufb $11,$14,$24,$33 /* +1 */ nor $61,$62,$60; /* +2 */ shufb $22,$13,$13,$36 fcgt $15,$51,$14; /* +1 */ shufb $17,$23,$23,$36 and $58,$61,$35; /* +2 */ shufb $19,$13,$13,$3 fma $10,$59,$25,$50; /* +1 */ shufb $18,$23,$23,$3 fma $9,$22,$32,$31; shufb $16,$23,$23,$38 or $8,$58,$43; /* +2 */ shufb $21,$13,$13,$38 or $40,$39,$12; /* +2 */ shufb $14,$13,$13,$34 ai $7,$7,-1; /* +2 */ shufb $42,$19,$18,$33 fma $41,$17,$32,$31; stqd $8,-16($2) /* +2 */ fcgt $44,$10,$11; /* +1 */ stqd $40,-32($2) /* +2 */ fma $45,$21,$28,$9; brnz $7,_local_c0de000000000002 /* +2 */ nop ; hbrrMonday, March 7, 2011

151. Additional cullingMonday, March 7, 2011

152. Additional culling›Frustum vs AABBMonday, March 7, 2011

153. Additional culling›Frustum vs AABB›Project AABB to screen spaceMonday, March 7, 2011

154. Additional culling›Frustum vs AABB›Project AABB to screen space›Software OcclusionMonday, March 7, 2011

155. Additional culling›Frustum vs AABB›Project AABB to screen space›Software OcclusionMonday, March 7, 2011

156. Project AABB to screen spaceMonday, March 7, 2011

157. Project AABB to screen space›Calculate the area of the AABB in screen spaceMonday, March 7, 2011

158. Project AABB to screen space›Calculate the area of the AABB in screen space›If area is smaller than setting just skip itMonday, March 7, 2011

159. Project AABB to screen space›Calculate the area of the AABB in screen space›If area is smaller than setting just skip it›Due to FOV taking distance doesn’t workMonday, March 7, 2011

160. Project AABB to screen space›Calculate the area of the AABB in screen space›If area is smaller than setting just skip it›Due to FOV taking distance doesn’t workMonday, March 7, 2011

161. Software OcclusionMonday, March 7, 2011

162. Software Occlusion›Used in Frostbite for 3 yearsMonday, March 7, 2011

163. Software Occlusion›Used in Frostbite for 3 years›Cross platformMonday, March 7, 2011

164. Software Occlusion›Used in Frostbite for 3 years›Cross platform›Artist made occludersMonday, March 7, 2011

165. Software Occlusion›Used in Frostbite for 3 years›Cross platform›Artist made occluders›TerrainMonday, March 7, 2011

166. Software Occlusion›Used in Frostbite for 3 years›Cross platform›Artist made occluders›TerrainMonday, March 7, 2011

167. Why Software Occlusion?Monday, March 7, 2011

168. Why Software Occlusion?›Want to remove CPU time not just GPUMonday, March 7, 2011

169. Why Software Occlusion?›Want to remove CPU time not just GPU›Cull as early as possibleMonday, March 7, 2011

170. Why Software Occlusion?›Want to remove CPU time not just GPU›Cull as early as possible›GPU queries troublesome as lagging behind CPUMonday, March 7, 2011

171. Why Software Occlusion?›Want to remove CPU time not just GPU›Cull as early as possible›GPU queries troublesome as lagging behind CPU›Must support destructionMonday, March 7, 2011

172. Why Software Occlusion?›Want to remove CPU time not just GPU›Cull as early as possible›GPU queries troublesome as lagging behind CPU›Must support destruction›Easy for artists to controlMonday, March 7, 2011

173. Why Software Occlusion?›Want to remove CPU time not just GPU›Cull as early as possible›GPU queries troublesome as lagging behind CPU›Must support destruction›Easy for artists to controlMonday, March 7, 2011

175. Software Occlusion›So how does it work?Monday, March 7, 2011

176. Software Occlusion›So how does it work?›Render PS1 style geometry to a zbuffer using software renderingMonday, March 7, 2011

177. Software Occlusion›So how does it work?›Render PS1 style geometry to a zbuffer using software rendering›The zbuffer is 256 x 114 ﬂoatMonday, March 7, 2011

178. Software Occlusion›So how does it work?›Render PS1 style geometry to a zbuffer using software rendering›The zbuffer is 256 x 114 ﬂoatMonday, March 7, 2011

180. Software Occlusion›Occluder triangle setupMonday, March 7, 2011

181. Software Occlusion›Occluder triangle setup›Terrain triangle setupMonday, March 7, 2011

182. Software Occlusion›Occluder triangle setup›Terrain triangle setup›Rasterize trianglesMonday, March 7, 2011

183. Software Occlusion›Occluder triangle setup›Terrain triangle setup›Rasterize triangles›CullingMonday, March 7, 2011

184. Software Occlusion›Occluder triangle setup›Terrain triangle setup›Rasterize triangles›CullingMonday, March 7, 2011

185. Software Occlusion (Occluders)Monday, March 7, 2011

186. Software Occlusion (In-game)Monday, March 7, 2011

189. Culling jobs Culling Jobs Job 0 Job 1 Job 2 Job 3 Job 4Monday, March 7, 2011

190. Culling jobs Culling Jobs Job 0 Occluder Triangles Job 1 Occluder Triangles Job 2 Occluder Triangles Job 3 Occluder Triangles Job 4 Terrain TrianglesMonday, March 7, 2011

191. Culling jobs Culling Jobs Job 0 Occluder Triangles Rasterize Triangles Job 1 Occluder Triangles Rasterize Triangles Job 2 Occluder Triangles Rasterize Triangles Job 3 Occluder Triangles Rasterize Triangles Job 4 Terrain Triangles Rasterize TrianglesMonday, March 7, 2011

192. Culling jobs Culling Jobs Job 0 Occluder Triangles Rasterize Triangles Culling Z-buffer Test Job 1 Occluder Triangles Rasterize Triangles Culling Z-buffer Test Job 2 Occluder Triangles Rasterize Triangles Culling Z-buffer Test Job 3 Occluder Triangles Rasterize Triangles Culling Z-buffer Test Job 4 Terrain Triangles Rasterize Triangles Culling Z-buffer TestMonday, March 7, 2011

193. Occluder triangles Job 0 Job 1 Job 2 Job 3 OutputMonday, March 7, 2011

194. Occluder triangles Job 0 Job 1 Job 2 Job 3 OutputMonday, March 7, 2011

195. Occluder triangles Job 0 Inside, Project triangles Job 1 Job 2 Job 3 OutputMonday, March 7, 2011

196. Occluder triangles Job 0 Inside, Project triangles Job 1 Job 2 Job 3 OutputMonday, March 7, 2011

197. Occluder triangles Job 0 Inside, Project triangles Job 1 Inside, Project triangles Job 2 Job 3 OutputMonday, March 7, 2011

198. Occluder triangles Job 0 Inside, Project triangles Job 1 Inside, Project triangles Job 2 Job 3 OutputMonday, March 7, 2011

199. Occluder triangles Job 0 Inside, Project triangles Job 1 Inside, Project triangles Job 2 Intersecting, Clip, Project Job 3 OutputMonday, March 7, 2011

200. Occluder triangles Job 0 Inside, Project triangles Job 1 Inside, Project triangles Job 2 Intersecting, Clip, Project Job 3 OutputMonday, March 7, 2011

201. Occluder triangles Job 0 Inside, Project triangles Job 1 Inside, Project triangles Job 2 Intersecting, Clip, Project Job 3 Outside, Skip OutputMonday, March 7, 2011

202. Occluder triangles Rasterize Triangles Input 16 Triangles 16 Triangles 16 Triangles 16 Triangles 256 x 114 zbuffer 256 x 114 zbuffer 256 x 114 zbuffer Job 0 Job 1 Merge step <Todo: Fix Colors>Monday, March 7, 2011

213. z-buffer testingMonday, March 7, 2011

214. z-buffer testing›Calculate screen space AABB for objectMonday, March 7, 2011

215. z-buffer testing›Calculate screen space AABB for object›Get single distance valueMonday, March 7, 2011

216. z-buffer testing›Calculate screen space AABB for object›Get single distance value›Test the square against the z-bufferMonday, March 7, 2011

223. ConclusionMonday, March 7, 2011

224. Conclusion›Accurate and high performance culling is essentialMonday, March 7, 2011

225. Conclusion›Accurate and high performance culling is essential›Reduces pressure on low-level systems/renderingMonday, March 7, 2011

226. Conclusion›Accurate and high performance culling is essential›Reduces pressure on low-level systems/rendering›It’s all about dataMonday, March 7, 2011

227. Conclusion›Accurate and high performance culling is essential›Reduces pressure on low-level systems/rendering›It’s all about data›Simple data often means simple codeMonday, March 7, 2011

228. Conclusion›Accurate and high performance culling is essential›Reduces pressure on low-level systems/rendering›It’s all about data›Simple data often means simple code›Understanding your target hardwareMonday, March 7, 2011

229. Conclusion›Accurate and high performance culling is essential›Reduces pressure on low-level systems/rendering›It’s all about data›Simple data often means simple code›Understanding your target hardwareMonday, March 7, 2011

230. Thanks to›Andreas Fredriksson (@deplinenoise)›Christina Coffin (@christinacoffin)›Johan Andersson (@repi)›Stephen Hill (@self_shadow)›Steven Tovey (@nonchaotic)›Halldor Fannar›Evelyn DonisMonday, March 7, 2011

231. Questions? Email: daniel@collin.com Blog: zenic.org Twitter: @daniel_collinBattlefield 3 & Frostbite 2 talks at GDC’11:Mon 1:45 DX11 Rendering in Battlefield 3 Johan AnderssonWed 10:30 SPU-based Deferred Shading in Battlefield 3 Christina Coffin for PlayStation 3Wed 3:00 Culling the Battlefield: Data Oriented Design Daniel Collin in PracticeThu 1:30 Lighting You Up in Battlefield 3 Kenny MagnussonFri 4:05 Approximating Translucency for a Fast, Colin Barré-Brisebois Cheap & Convincing Subsurface Scattering Look For more DICE talks: http://publications.dice.seMonday, March 7, 2011

Culling the Battlefield: Data Oriented Design in Practice

Electronic Arts / DICE

Culling the Battlefield: Data Oriented Design in Practice