Simulation-space Particles | Handmade Hero Episode Guide

0:08Recap and set the stage for the day

1:22Blackboard: Particle Cache

6:07handmade_particles.h: Remove the notion of a particle system cache

7:37handmade_particles.cpp: Remove GetOrCreateParticleSystem(), TouchParticleSystem() and InitParticleSystem(), rename PlayAround() to UpdateAndRenderFire() and rework InitParticleCache()

11:49Run the game and see that this is all fine, although slower than it should be

13:52handmade_particles.cpp: Consider why UpdateAndRenderFire() is so slow

16:31handmade_particles.h: Introduce particle_4x, simplify particle_system and remove particle_v3, particle_v4 and the operator*()

17:55handmade_particles.cpp: Remove GetParticle() and make UpdateAndRenderFire() work on particle_4x

20:23handmade_particles.h: Introduce operator+=() for v3_4x

21:22Run the game and see that we are now running as fast as expected

22:43handmade_particles.h: Introduce operator*(), operator+() and operator+=() for v4_4x

24:48Run the game and see that we're still good

26:05Reflect on the importance of the profiler

28:49handmade_particles.cpp: Make UpdateAndRenderFire() take a dt and FrameDisplacementInit

31:03handmade_particles.h: Introduce ToV34x()

31:57handmade_particles.cpp: Enable UpdateAndRenderFire() to render particles through the standard path

44:04Run the game, note that we are theortically generating particles and investigate why we aren't seeing them

47:09handmade_world_mode.cpp: Prevent everything but the particles from being rendered, run the game and see them

47:42handmade_particles.cpp: Introduce SpawnFire()

49:54handmade_entity.cpp: Make entities call SpawnFire() when they land

50:43Run the game and see no spawning occurring

51:40handmade_world_mode.cpp: Reduce ScreenIndex to 1, run the game and see that the particle spawning is working just fine

52:15handmade_world_mode.cpp: Generate two horizontally aligned screens, run the game and see what happens to the particles upon leaving a room

55:15handmade_particles.cpp: Make UpdateAndRenderParticleSystems() take the FrameDisplacement

56:28handmade_world_mode.h: Add LastCameraP to the game_mode_world struct and make UpdateAndRenderWorld() compute that LastCameraP

58:06Run the game, see that the particles are not being displaced correctly and investigate why

1:01:51Blackboard: Calculating that displacement

1:02:33handmade_world_mode.cpp: Correctly compute the FrameToFrameCameraDeltaP and LastCameraOffset

1:04:34Run the game and see that our particles may now be correctly displaced

1:04:58handmade_particles.cpp: Tweak SpawnFire() to shorten the lifetime of the particles, run the game and check them out

1:06:37handmade_world_mode.cpp: Remove LastCameraOffset and displace the particles with the WorldTransform

1:09:51Run the game and admire the particles

1:10:33Q&A

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1:10:33Q&A

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1:10:33Q&A

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1:11:20mmozeiko gcc & clang don't have m128_f32 member for __m128. They need _mm_store_ps or something like ((float*)&A->P.x)[index] (or union with float array)

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1:11:20mmozeiko gcc & clang don't have m128_f32 member for __m128. They need _mm_store_ps or something like ((float*)&A->P.x)[index] (or union with float array)

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1:11:20mmozeiko gcc & clang don't have m128_f32 member for __m128. They need _mm_store_ps or something like ((float*)&A->P.x)[index] (or union with float array)

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1:12:05handmade_particles.cpp: Use the M macro for rendering the particles and introduce handmade_simd.h

1:16:04nxsy soysaucethekid was suggesting to slow down the time to make sure it is now right

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1:16:04nxsy soysaucethekid was suggesting to slow down the time to make sure it is now right

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1:16:04nxsy soysaucethekid was suggesting to slow down the time to make sure it is now right

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1:19:52thesizik Not too long ago, you changed world coordinates to be s32 instead of u32. I think they were unsigned originally so that overflow would work correctly to have the world wrap around

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1:19:52thesizik Not too long ago, you changed world coordinates to be s32 instead of u32. I think they were unsigned originally so that overflow would work correctly to have the world wrap around

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1:19:52thesizik Not too long ago, you changed world coordinates to be s32 instead of u32. I think they were unsigned originally so that overflow would work correctly to have the world wrap around

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1:20:27cyberpunkhobo Does the Z position of the particles not get affected by the perspective transform?

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1:20:27cyberpunkhobo Does the Z position of the particles not get affected by the perspective transform?

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1:20:27cyberpunkhobo Does the Z position of the particles not get affected by the perspective transform?

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1:22:58thesizik But when your position goes from INT_MIN to INT_MAX, won't it cause undefined behavior?

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1:22:58thesizik But when your position goes from INT_MIN to INT_MAX, won't it cause undefined behavior?

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1:22:58thesizik But when your position goes from INT_MIN to INT_MAX, won't it cause undefined behavior?

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1:23:49todo.txt: Update the TODO list

1:24:16thesizik Signed integer overflow?

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1:24:16thesizik Signed integer overflow?

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1:24:16thesizik Signed integer overflow?

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1:25:45Lament the absence of real 3D and close things down

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1:25:45Lament the absence of real 3D and close things down

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1:25:45Lament the absence of real 3D and close things down

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