Debugging Lighting Transfer — Handmade Hero — Episode Guide

0:07Recap and set the stage for the day

1:14Run the game to see how the lighting is looking at the moment

7:39Note some oddities in the lighting solution

10:14handmade_render_group.cpp: Prevent the ambient occlusion code from running and run the game to still see the bright flashes

11:50handmade_config.h: Only do one pass of the lighting solution, and run the game to see that this is relatively stable

13:14handmade_config.h: Add Global_Renderer_Occlusion_IterationCount for LightingTest() to use

13:43Run the game doing two ambient occlusion passes

14:44handmade_config.h: Switch to the game view, with two ambient occlusion passes, and run the game to see how that looks

18:01handmade_config.h: Increase the number of lighting iteration passes and run the game with the determination to investigate the flashes

20:35Launch Milton and try out the tablet tracking

22:58Blackboard: Light Conservation

28:45Blackboard: Converging on a good lighting solution

30:00handmade_render_group.cpp: Consider making emission a first-pass-only process

32:40Blackboard: Occluded Reflectors, and Total Emittance

37:37The difficulty of parallelised summation

39:48Blackboard: Radiosity, and stabilising the contribution of light by multiple proximate reflectors, with a recommendation to read literature on the problem

43:37Blackboard: Considering how to handle over-contribution of light distribution

48:04handmade_render_group.cpp: Organise lighting_element to aid our conceptualisation of the light conservation problem

53:18Hit an error in OpenGLDebugCallback()

54:30Blackboard: All light must go somewhere

55:33handmade_render_group.cpp: Enable LightingTest() to make RefC converge towards 0, and track the transference and accumulation of light

1:03:25handmade_render_group.cpp: Enable LightingTest() to correct for the wrongness of the transfer

1:11:10Step through LightingTest()

1:13:10Consider how to handle emission

1:13:46handmade_render_group.cpp: Prevent LightingTest() from performing the correction and just letting the light bounce ad infinitum

1:14:27Run the game to see the flickery results

1:14:56handmade_render_group.cpp: Let LightingTest() perform the correction again, and run the game to see the flickering still

1:15:36Consider how to handle the total light transfer

1:17:35handmade_render_group.cpp: Add PhotonsToSend and PhotosReceived to lighting_element, for LightingTest() to use

1:22:14handmade_render_group.cpp: Enable LightingTest() to draw the photons

1:23:31Run the game to see the photons transference

1:24:08handmade_render_group.cpp: Assert in LightingTest() that PhotonsToSend <= TotalPhotonCount, run the game, hit that assertion and investigate why

1:26:43handmade_render_group.cpp: Make LightingTest() actually multiply in the correction

1:27:14Run the game in release, and see that it is more correct but that the flickering is still there

1:30:36Run the game on a loop and change the lighting iteration count to see how that affects it

1:32:40handmade_world_mode.cpp: Prevent AddPlayer() from adding any body parts and hit points

1:34:06Run the game and move just the light, to determine that the hero himself was causing the flickering problem

1:36:39handmade_render_group.cpp: Make LightingTest() strictly sum the FrontEmitC, and run the game without flickering, noting that the occluders are spaced far apart

1:39:31Determine to fix the distance falloff for close objects

1:40:11handmade_render_group.cpp: Let LightingTest() temper the FrontEmitC by the number of lighting iterations

1:41:42handmade_render_group.cpp: Remove PhotonsToSend and PhotonsReceived from lighting_element

1:42:34Run the game to see the stable light

1:42:44handmade_world_mode.cpp: Let AddPlayer() add body parts, and run the game noting that these body parts are very bright

1:44:28handmade_render_group.cpp: Fix the DistanceFalloff computation in LightingTest()

1:44:44Blackboard: Distance Falloff

1:48:25Run the game to see that the flickering has gone

1:49:27handmade_world_mode.cpp: Make AddStandardRoom() draw the walls in red

1:51:18Run the game to see if we get red light bleeding from the walls

1:51:53handmade_config.h: Perform two ambient occlusion passes and run the game

1:54:34Q&A

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1:54:34Q&A

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1:54:34Q&A

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1:54:47macielda Is it supposed to be Square(...) and not SquareRoot(...)?

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1:54:47macielda Is it supposed to be Square(...) and not SquareRoot(...)?

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1:54:47macielda Is it supposed to be Square(...) and not SquareRoot(...)?

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1:56:15handmade_render_group.cpp: Make LightingTest() prevent the DistanceFalloff from getting below 1

1:56:44Run the game to see how that looks

1:57:58the_8th_mage Now we don't need to do a global pass to normalize light?

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1:57:58the_8th_mage Now we don't need to do a global pass to normalize light?

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1:57:58the_8th_mage Now we don't need to do a global pass to normalize light?

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1:59:07macielda Is it useful to convert the surface color from RGB to YUV in these equations, as in using Y to modulate light contribution somehow?

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1:59:07macielda Is it useful to convert the surface color from RGB to YUV in these equations, as in using Y to modulate light contribution somehow?

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1:59:07macielda Is it useful to convert the surface color from RGB to YUV in these equations, as in using Y to modulate light contribution somehow?

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2:00:55the_8th_mage Do you know how much does a GPU gather cost compared to a load from a linear memory read?

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2:00:55the_8th_mage Do you know how much does a GPU gather cost compared to a load from a linear memory read?

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2:00:55the_8th_mage Do you know how much does a GPU gather cost compared to a load from a linear memory read?

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2:02:01the_8th_mage I wrote GPU, not CPU

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2:02:01the_8th_mage I wrote GPU, not CPU

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2:02:01the_8th_mage I wrote GPU, not CPU

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2:02:37handmade_config.h: Play with the lighting IterationCount and run

2:03:17cubercaleb Spectral lighting is something I never heard of before. Can you point out some good resources on the topic?¹

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2:03:17cubercaleb Spectral lighting is something I never heard of before. Can you point out some good resources on the topic?¹

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2:03:17cubercaleb Spectral lighting is something I never heard of before. Can you point out some good resources on the topic?¹

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2:05:44the_8th_mage In CPU it's much more efficient to read a cache line using _mm_load and not use the gather commands. Is the same true of the GPU?

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2:05:44the_8th_mage In CPU it's much more efficient to read a cache line using _mm_load and not use the gather commands. Is the same true of the GPU?

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2:05:44the_8th_mage In CPU it's much more efficient to read a cache line using _mm_load and not use the gather commands. Is the same true of the GPU?

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2:12:25the_8th_mage Thanks, so you usually don't want to swizzle it yourself?

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2:12:25the_8th_mage Thanks, so you usually don't want to swizzle it yourself?

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2:12:25the_8th_mage Thanks, so you usually don't want to swizzle it yourself?

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2:15:59the_8th_mage Is HMCon 3 still at the start of 2018?

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2:15:59the_8th_mage Is HMCon 3 still at the start of 2018?

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2:15:59the_8th_mage Is HMCon 3 still at the start of 2018?

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2:16:32Brian ctray improvement: Would you be so kind as to give a suggestion of how you tackle saving the day? Do you prefer temp files (i.e. in %AppData%)? Just keep it simple like how you read settings.ctray. Should I look at how you save state like in ctime? I can try to tackle an alternative this week for I do need to become more confident in reading / writing to files

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2:16:32Brian ctray improvement: Would you be so kind as to give a suggestion of how you tackle saving the day? Do you prefer temp files (i.e. in %AppData%)? Just keep it simple like how you read settings.ctray. Should I look at how you save state like in ctime? I can try to tackle an alternative this week for I do need to become more confident in reading / writing to files

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2:16:32Brian ctray improvement: Would you be so kind as to give a suggestion of how you tackle saving the day? Do you prefer temp files (i.e. in %AppData%)? Just keep it simple like how you read settings.ctray. Should I look at how you save state like in ctime? I can try to tackle an alternative this week for I do need to become more confident in reading / writing to files

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2:18:04Brian But that's what I did! I made it an ini file and rewrote that

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2:18:04Brian But that's what I did! I made it an ini file and rewrote that

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2:18:04Brian But that's what I did! I made it an ini file and rewrote that

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2:19:15macielda Is it possible to mode-change monitor frequency nowadays (say from 75Hz to 60Hz) so I always try to get my game loop to run at 60Hz?

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2:19:15macielda Is it possible to mode-change monitor frequency nowadays (say from 75Hz to 60Hz) so I always try to get my game loop to run at 60Hz?

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2:19:15macielda Is it possible to mode-change monitor frequency nowadays (say from 75Hz to 60Hz) so I always try to get my game loop to run at 60Hz?

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2:22:07Brian ctray question: As an exercise, I would like to investigate the cost of just bringing the overlays to the top and checking first if the overlays need to be brought forward. What should I look for? Should I profile the calls? Should I run it continuously to see if I get an error case? I realize this may not be the best thing to use as an example, but it was something I struggled with

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2:22:07Brian ctray question: As an exercise, I would like to investigate the cost of just bringing the overlays to the top and checking first if the overlays need to be brought forward. What should I look for? Should I profile the calls? Should I run it continuously to see if I get an error case? I realize this may not be the best thing to use as an example, but it was something I struggled with

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2:22:07Brian ctray question: As an exercise, I would like to investigate the cost of just bringing the overlays to the top and checking first if the overlays need to be brought forward. What should I look for? Should I profile the calls? Should I run it continuously to see if I get an error case? I realize this may not be the best thing to use as an example, but it was something I struggled with

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2:24:35Close that

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2:24:35Close that

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2:24:35Close that

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