Drawing a Circle on a 286 — Handmade Chat — Episode Guide

2:11Upgrade remedybg to 0.2.4.2

🗹

2:11Upgrade remedybg to 0.2.4.2

🗹

2:11Upgrade remedybg to 0.2.4.2

🗹

3:12egnadh Q: I remember you were asked what's the best way to draw a circle at a Microsoft job interview. What's the answer?

🗪

3:12egnadh Q: I remember you were asked what's the best way to draw a circle at a Microsoft job interview. What's the answer?

🗪

3:12egnadh Q: I remember you were asked what's the best way to draw a circle at a Microsoft job interview. What's the answer?

🗪

5:40The "free" aspects of drawing a circle on a 286: the centre and cardinal radius points

🖌

5:40The "free" aspects of drawing a circle on a 286: the centre and cardinal radius points

🖌

5:40The "free" aspects of drawing a circle on a 286: the centre and cardinal radius points

🖌

8:10Our target requirements: no floating point, wide instructions or threading; but branching is fine

🖌

8:10Our target requirements: no floating point, wide instructions or threading; but branching is fine

🖌

8:10Our target requirements: no floating point, wide instructions or threading; but branching is fine

🖌

11:10Efficiently computing the circle's arc

🖌

11:10Efficiently computing the circle's arc

🖌

11:10Efficiently computing the circle's arc

🖌

26:13Storing the error value, x and y

🖌

26:13Storing the error value, x and y

🖌

26:13Storing the error value, x and y

🖌

31:55Plotting a mere eighth of the circle

🖌

31:55Plotting a mere eighth of the circle

🖌

31:55Plotting a mere eighth of the circle

🖌

37:11Create bcircle.cpp (from "Bresenham Circle") and create a pixel grid to contain our circle

🖌

🖮

37:11Create bcircle.cpp (from "Bresenham Circle") and create a pixel grid to contain our circle

🖌

🖮

37:11Create bcircle.cpp (from "Bresenham Circle") and create a pixel grid to contain our circle

🖌

🖮

40:10Build and run bcircle to see our pixel grid

🏃

🖮

40:10Build and run bcircle to see our pixel grid

🏃

🖮

40:10Build and run bcircle to see our pixel grid

🏃

🖮

40:49Reduce the size of our pixel grid to 32×32 characters

🖮

40:49Reduce the size of our pixel grid to 32×32 characters

🖮

40:49Reduce the size of our pixel grid to 32×32 characters

🖮

41:04Check out our smaller pixel grid

🏃

41:04Check out our smaller pixel grid

🏃

41:04Check out our smaller pixel grid

🏃

41:19Implement our error-based circle drawing routine

🖮

41:19Implement our error-based circle drawing routine

🖮

41:19Implement our error-based circle drawing routine

🖮

48:44Check out our circle, to find that it is positioned incorrectly

🏃

48:44Check out our circle, to find that it is positioned incorrectly

🏃

48:44Check out our circle, to find that it is positioned incorrectly

🏃

48:51Fix our routine to plot the circle around its centre

🖮

48:51Fix our routine to plot the circle around its centre

🖮

48:51Fix our routine to plot the circle around its centre

🖮

48:57Check out our circle, one eighth of it

🏃

48:57Check out our circle, one eighth of it

🏃

48:57Check out our circle, one eighth of it

🏃

49:32Make our routine plot our eighth of the circle around the entire circumference

🖮

49:32Make our routine plot our eighth of the circle around the entire circumference

🖮

49:32Make our routine plot our eighth of the circle around the entire circumference

🖮

50:05Check out our fuller circle

🏃

50:05Check out our fuller circle

🏃

50:05Check out our fuller circle

🏃

50:11Prevent our routine from plotting the pixel grid's centre point

🖮

50:11Prevent our routine from plotting the pixel grid's centre point

🖮

50:11Prevent our routine from plotting the pixel grid's centre point

🖮

50:16Check out our fuller circle

🏃

50:16Check out our fuller circle

🏃

50:16Check out our fuller circle

🏃

50:24Plot the initial pixel

🖮

50:24Plot the initial pixel

🖮

50:24Plot the initial pixel

🖮

50:32Check out our perfect circle

🏃

50:32Check out our perfect circle

🏃

50:32Check out our perfect circle

🏃

50:39Optimise our routine, using one pointer initialised at the circle's centre in lieu of two stored Cx and Cy values

🖮

50:39Optimise our routine, using one pointer initialised at the circle's centre in lieu of two stored Cx and Cy values

🖮

50:39Optimise our routine, using one pointer initialised at the circle's centre in lieu of two stored Cx and Cy values

🖮

54:31Check out our same circle

🏃

54:31Check out our same circle

🏃

54:31Check out our same circle

🏃

54:41Consider how to remove the eight integer multiplies by the WIDTH

58:25Temporarily make our routine test abs(E0) < abs(E1)

🖮

58:25Temporarily make our routine test abs(E0) < abs(E1)

🖮

58:25Temporarily make our routine test abs(E0) < abs(E1)

🖮

58:46Check out our identical circle

🏃

58:46Check out our identical circle

🏃

58:46Check out our identical circle

🏃

58:55Revert that -E0 < E1 test

🖮

58:55Revert that -E0 < E1 test

🖮

58:55Revert that -E0 < E1 test

🖮

59:07See that all remains identical

🏃

59:07See that all remains identical

🏃

59:07See that all remains identical

🏃

59:10Continue to consider how to remove the eight integer multiplies by the WIDTH

1:00:15Rounin cmuratori: X<<5?

🗪

1:00:15Rounin cmuratori: X<<5?

🗪

1:00:15Rounin cmuratori: X<<5?

🗪

1:00:20Sully the WIDTH and HEIGHT so that they are not a power of two

🖮

1:00:20Sully the WIDTH and HEIGHT so that they are not a power of two

🖮

1:00:20Sully the WIDTH and HEIGHT so that they are not a power of two

🖮

1:00:51ggn2 handmade_hero Calculate the initial X/Y into a pointer and increment that?

🗪

1:00:51ggn2 handmade_hero Calculate the initial X/Y into a pointer and increment that?

🗪

1:00:51ggn2 handmade_hero Calculate the initial X/Y into a pointer and increment that?

🗪

1:01:26said6289 handmade_hero Store XWidth and YWidth pointers that you increment accordingly every run

🗪

1:01:26said6289 handmade_hero Store XWidth and YWidth pointers that you increment accordingly every run

🗪

1:01:26said6289 handmade_hero Store XWidth and YWidth pointers that you increment accordingly every run

🗪

1:02:12Ruminate on our circle drawing routine

1:02:50ggn2 handmade_hero Well, I'm thinking on 68000 terms where there were a bit more registers than x86

🗪

1:02:50ggn2 handmade_hero Well, I'm thinking on 68000 terms where there were a bit more registers than x86

🗪

1:02:50ggn2 handmade_hero Well, I'm thinking on 68000 terms where there were a bit more registers than x86

🗪

1:03:22Consider the WIDTH multiply to have potential for improvement

1:04:00Try to remove the Ep += 1 from the equation

🖮

1:04:00Try to remove the Ep += 1 from the equation

🖮

1:04:00Try to remove the Ep += 1 from the equation

🖮

1:04:43Check out our (different) circle

🏃

1:04:43Check out our (different) circle

🏃

1:04:43Check out our (different) circle

🏃

1:04:50Reinstate the Ep += 1

🖮

1:04:50Reinstate the Ep += 1

🖮

1:04:50Reinstate the Ep += 1

🖮

1:06:29x13pixels Q: Can you get rid of the "Ep += 1" line?

🗪

1:06:29x13pixels Q: Can you get rid of the "Ep += 1" line?

🗪

1:06:29x13pixels Q: Can you get rid of the "Ep += 1" line?

🗪

1:07:09Try to negate X the whole way through

🖮

1:07:09Try to negate X the whole way through

🖮

1:07:09Try to negate X the whole way through

🖮

1:08:17Check out our same circle

🏃

1:08:17Check out our same circle

🏃

1:08:17Check out our same circle

🏃

1:08:37Assess our options, with X negated, and try plotting X and Y pixels from different eights of the circle

🖮

1:08:37Assess our options, with X negated, and try plotting X and Y pixels from different eights of the circle

🖮

1:08:37Assess our options, with X negated, and try plotting X and Y pixels from different eights of the circle

🖮

1:13:31Check out our barely-plotted circle

🏃

1:13:31Check out our barely-plotted circle

🏃

1:13:31Check out our barely-plotted circle

🏃

1:13:35Try looping while X <= (R / 2)

🖮

1:13:35Try looping while X <= (R / 2)

🖮

1:13:35Try looping while X <= (R / 2)

🖮

1:14:02Check out our big X

🏃

1:14:02Check out our big X

🏃

1:14:02Check out our big X

🏃

1:14:06Continue to try plotting X and Y pixels from different eights of the circle

🖮

1:14:06Continue to try plotting X and Y pixels from different eights of the circle

🖮

1:14:06Continue to try plotting X and Y pixels from different eights of the circle

🖮

1:17:16Plotting X and Y pixels from different eights of the circle

🖌

1:17:16Plotting X and Y pixels from different eights of the circle

🖌

1:17:16Plotting X and Y pixels from different eights of the circle

🖌

1:18:41Understanding why our X / Y plotting on different eighths doesn't work

1:20:55filiadelski Q: I'm sorry we decided to go with another candidate because he went to Harvard

🗪

1:20:55filiadelski Q: I'm sorry we decided to go with another candidate because he went to Harvard

🗪

1:20:55filiadelski Q: I'm sorry we decided to go with another candidate because he went to Harvard

🗪

1:21:20Midpoint¹ and Bresenham's circle drawing algorithm²

📖

1:21:20Midpoint¹ and Bresenham's circle drawing algorithm²

📖

1:21:20Midpoint¹ and Bresenham's circle drawing algorithm²

📖

1:23:22Temporarily make our routine always increment the Y

🖮

1:23:22Temporarily make our routine always increment the Y

🖮

1:23:22Temporarily make our routine always increment the Y

🖮

1:23:48Check out our circle with the Y always incrementing

🏃

1:23:48Check out our circle with the Y always incrementing

🏃

1:23:48Check out our circle with the Y always incrementing

🏃

1:24:36Revert our routine to not always increment the Y

🖮

1:24:36Revert our routine to not always increment the Y

🖮

1:24:36Revert our routine to not always increment the Y

🖮

1:24:39Compare our circle

🏃

1:24:39Compare our circle

🏃

1:24:39Compare our circle

🏃

1:24:41Increase the radius of our circle

🖮

1:24:41Increase the radius of our circle

🖮

1:24:41Increase the radius of our circle

🖮

1:24:50Check out our larger circle

🏃

1:24:50Check out our larger circle

🏃

1:24:50Check out our larger circle

🏃

1:25:17Leave further optimisation as an exercise for the reader

1:26:40Check out the register count of the Intel 386³ and 286⁴^,5^,6 and suggest writing this routine in x86 assembly targeted at DOSBox's emulation of a 286⁷

📖

1:26:40Check out the register count of the Intel 386³ and 286⁴^,5^,6 and suggest writing this routine in x86 assembly targeted at DOSBox's emulation of a 286⁷

📖

1:26:40Check out the register count of the Intel 386³ and 286⁴^,5^,6 and suggest writing this routine in x86 assembly targeted at DOSBox's emulation of a 286⁷

📖

1:31:41alex_deak Q: Hi Casey! (Sorry, it's pretty long, and has nothing to do with circles) I'm a mathematician, trying to be a graphics / engine programmer. I made some pet projects using OpenGL and Vulkan, in which I was able to make the things I wanted, but since my lack of enough experience, I had a hard time figuring out what "professional programming" is. I started watching Handmade Hero in December from day 1, and I almost caught up (currently I'm at day 520). Thanks for this amazing series, it has been inc… [sic]

🗪

1:31:41alex_deak Q: Hi Casey! (Sorry, it's pretty long, and has nothing to do with circles) I'm a mathematician, trying to be a graphics / engine programmer. I made some pet projects using OpenGL and Vulkan, in which I was able to make the things I wanted, but since my lack of enough experience, I had a hard time figuring out what "professional programming" is. I started watching Handmade Hero in December from day 1, and I almost caught up (currently I'm at day 520). Thanks for this amazing series, it has been inc… [sic]

🗪

1:31:41alex_deak Q: Hi Casey! (Sorry, it's pretty long, and has nothing to do with circles) I'm a mathematician, trying to be a graphics / engine programmer. I made some pet projects using OpenGL and Vulkan, in which I was able to make the things I wanted, but since my lack of enough experience, I had a hard time figuring out what "professional programming" is. I started watching Handmade Hero in December from day 1, and I almost caught up (currently I'm at day 520). Thanks for this amazing series, it has been inc… [sic]

🗪

1:32:29Wonder who is responsible for the message truncation

1:33:43alex_deak Q: Do you have any advice about starting a career in graphics / engine programming for someone, who has a very strong background in mathematics, physics, can do research, perhaps can come up with creative ideas, wants to learn ab… [sic]⁸^,9

🗪

1:33:43alex_deak Q: Do you have any advice about starting a career in graphics / engine programming for someone, who has a very strong background in mathematics, physics, can do research, perhaps can come up with creative ideas, wants to learn ab… [sic]⁸^,9

🗪

1:33:43alex_deak Q: Do you have any advice about starting a career in graphics / engine programming for someone, who has a very strong background in mathematics, physics, can do research, perhaps can come up with creative ideas, wants to learn ab… [sic]⁸^,9

🗪

1:43:01ggn2 handmade_hero For what it's worth, PCem¹⁰ has cycle exact CPU cores if you want to be more accurate

🗪

1:43:01ggn2 handmade_hero For what it's worth, PCem¹⁰ has cycle exact CPU cores if you want to be more accurate

🗪

1:43:01ggn2 handmade_hero For what it's worth, PCem¹⁰ has cycle exact CPU cores if you want to be more accurate

🗪

1:43:46tshugako Q: On one of the first Handmade Hero streams you said that it was faster to work (bitwise operations) on a uint32 than a uint8. Why?

🗪

1:43:46tshugako Q: On one of the first Handmade Hero streams you said that it was faster to work (bitwise operations) on a uint32 than a uint8. Why?

🗪

1:43:46tshugako Q: On one of the first Handmade Hero streams you said that it was faster to work (bitwise operations) on a uint32 than a uint8. Why?

🗪

1:50:08toideng Q: Any opinion of Linux's way to define integer types with one letter (like u8, i16, i64)?

🗪

1:50:08toideng Q: Any opinion of Linux's way to define integer types with one letter (like u8, i16, i64)?

🗪

1:50:08toideng Q: Any opinion of Linux's way to define integer types with one letter (like u8, i16, i64)?

🗪

1:51:21flightlesshippo Q: Pug with a gun needs to be an enemy in the game

🗪

1:51:21flightlesshippo Q: Pug with a gun needs to be an enemy in the game

🗪

1:51:21flightlesshippo Q: Pug with a gun needs to be an enemy in the game

🗪

1:51:32printf_armin Q: For a program for Windows only is DX the better or OpenGL?

🗪

1:51:32printf_armin Q: For a program for Windows only is DX the better or OpenGL?

🗪

1:51:32printf_armin Q: For a program for Windows only is DX the better or OpenGL?

🗪

1:51:55saidwho12 handmade_hero What do you think of getting a college degree in information technology? Should you instead be working on hobby projects? My dad has been wanting me to get into a post-secondary school for a long time

🗪

1:51:55saidwho12 handmade_hero What do you think of getting a college degree in information technology? Should you instead be working on hobby projects? My dad has been wanting me to get into a post-secondary school for a long time

🗪

1:51:55saidwho12 handmade_hero What do you think of getting a college degree in information technology? Should you instead be working on hobby projects? My dad has been wanting me to get into a post-secondary school for a long time

🗪

1:55:37centhusiast Q: I have done lots of tools in C like a string utility, JSON parser, data visualization on Linux using X11, vector library and some other tools. Do you think these can be valuable for the CV?

🗪

1:55:37centhusiast Q: I have done lots of tools in C like a string utility, JSON parser, data visualization on Linux using X11, vector library and some other tools. Do you think these can be valuable for the CV?

🗪

1:55:37centhusiast Q: I have done lots of tools in C like a string utility, JSON parser, data visualization on Linux using X11, vector library and some other tools. Do you think these can be valuable for the CV?

🗪

1:59:32alex_deak Q: Great, thank you! Do you think it's maybe enough to have a YouTube channel, instead of a webpage? Since I have no idea how to do a webpage... Or is it very basic knowledge that I should know?

🗪

1:59:32alex_deak Q: Great, thank you! Do you think it's maybe enough to have a YouTube channel, instead of a webpage? Since I have no idea how to do a webpage... Or is it very basic knowledge that I should know?

🗪

1:59:32alex_deak Q: Great, thank you! Do you think it's maybe enough to have a YouTube channel, instead of a webpage? Since I have no idea how to do a webpage... Or is it very basic knowledge that I should know?

🗪

2:00:31Recommend The ryg blog¹¹

📖

2:00:31Recommend The ryg blog¹¹

📖

2:00:31Recommend The ryg blog¹¹

📖

2:01:55joeyiswatching Q: Why were you suggesting to look at how to do it under 286? I just joined as you were talking about that

🗪

2:01:55joeyiswatching Q: Why were you suggesting to look at how to do it under 286? I just joined as you were talking about that

🗪

2:01:55joeyiswatching Q: Why were you suggesting to look at how to do it under 286? I just joined as you were talking about that

🗪

2:02:56boonetbe Q: I've been using a language with function polymorphism similar, I think, to what Jon is doing in JAI, i.e. "multiple dispatch" / dispatch on input types. I recently tried out some different languages and found this is not at all very common. How come not more languages have this? Is it hard to implement, other issues?

🗪

2:02:56boonetbe Q: I've been using a language with function polymorphism similar, I think, to what Jon is doing in JAI, i.e. "multiple dispatch" / dispatch on input types. I recently tried out some different languages and found this is not at all very common. How come not more languages have this? Is it hard to implement, other issues?

🗪

2:02:56boonetbe Q: I've been using a language with function polymorphism similar, I think, to what Jon is doing in JAI, i.e. "multiple dispatch" / dispatch on input types. I recently tried out some different languages and found this is not at all very common. How come not more languages have this? Is it hard to implement, other issues?

🗪

2:04:40flightlesshippo Q: I heard JAI is close to beta release? Will you be playing about with that or leaving it until it's matured more?

🗪

2:04:40flightlesshippo Q: I heard JAI is close to beta release? Will you be playing about with that or leaving it until it's matured more?

🗪

2:04:40flightlesshippo Q: I heard JAI is close to beta release? Will you be playing about with that or leaving it until it's matured more?

🗪

2:05:10centhusiast Q: Have you met the Amiga programmer like Bruce Dawson? It seems like they were the great programmers

🗪

2:05:10centhusiast Q: Have you met the Amiga programmer like Bruce Dawson? It seems like they were the great programmers

🗪

2:05:10centhusiast Q: Have you met the Amiga programmer like Bruce Dawson? It seems like they were the great programmers

🗪

2:06:33toideng Q: Would you use sine / cosine now?

🗪

2:06:33toideng Q: Would you use sine / cosine now?

🗪

2:06:33toideng Q: Would you use sine / cosine now?

🗪

2:07:18victorn Q: Are you going to push the circle solution to GitHub?

🗪

2:07:18victorn Q: Are you going to push the circle solution to GitHub?

🗪

2:07:18victorn Q: Are you going to push the circle solution to GitHub?

🗪

2:07:28unxx Q: Do you ever use any scripting language?

🗪

2:07:28unxx Q: Do you ever use any scripting language?

🗪

2:07:28unxx Q: Do you ever use any scripting language?

🗪

2:07:37toideng Q: Is there any computer world outside US?

🗪

2:07:37toideng Q: Is there any computer world outside US?

🗪

2:07:37toideng Q: Is there any computer world outside US?

🗪

2:19:59centhusiast Q: I saw some codes that use the array of function pointers and enums to avoid branching. enums like action type move_right, move_left and then function pointers associated with them. Do you think it is a good idea to do that?

🗪

2:19:59centhusiast Q: I saw some codes that use the array of function pointers and enums to avoid branching. enums like action type move_right, move_left and then function pointers associated with them. Do you think it is a good idea to do that?

🗪

2:19:59centhusiast Q: I saw some codes that use the array of function pointers and enums to avoid branching. enums like action type move_right, move_left and then function pointers associated with them. Do you think it is a good idea to do that?

🗪

2:22:52Understanding a Skylake core¹²

📖

2:22:52Understanding a Skylake core¹²

📖

2:22:52Understanding a Skylake core¹²

📖

2:33:51Branch-prediction in the context of a Skylake core¹³

📖

2:33:51Branch-prediction in the context of a Skylake core¹³

📖

2:33:51Branch-prediction in the context of a Skylake core¹³

📖

2:38:48Understanding the Skylake CALL instruction¹⁴

📖

2:38:48Understanding the Skylake CALL instruction¹⁴

📖

2:38:48Understanding the Skylake CALL instruction¹⁴

📖

2:45:23boonetbe Q: I saw Jon implement a compare and swap intrinsic recently for lock-free multithreading. Except for incrementing counters and stuff, what is it useful for? Do I understand it correctly that it's only useful when the thread-unsafe code / task is small?¹⁵

🗪

2:45:23boonetbe Q: I saw Jon implement a compare and swap intrinsic recently for lock-free multithreading. Except for incrementing counters and stuff, what is it useful for? Do I understand it correctly that it's only useful when the thread-unsafe code / task is small?¹⁵

🗪

2:45:23boonetbe Q: I saw Jon implement a compare and swap intrinsic recently for lock-free multithreading. Except for incrementing counters and stuff, what is it useful for? Do I understand it correctly that it's only useful when the thread-unsafe code / task is small?¹⁵

🗪

2:48:16boonetbe Q: Why aren't we using analog computing, i.e. instead of bits use frequencies. Noise?

🗪

2:48:16boonetbe Q: Why aren't we using analog computing, i.e. instead of bits use frequencies. Noise?

🗪

2:48:16boonetbe Q: Why aren't we using analog computing, i.e. instead of bits use frequencies. Noise?

🗪

2:49:17florian3321 Q: I am 50k lines into a C++ Android engine development (tried to stay away from inheritance and stuff. Note that I am still learning). Should I rewrite it the "C" way? How can I change my thinking? You at some point said that one should come to the point where OOP fails and then use non-OOP, but I think I am not really there yet. Hope this is not a dumb question

🗪

2:49:17florian3321 Q: I am 50k lines into a C++ Android engine development (tried to stay away from inheritance and stuff. Note that I am still learning). Should I rewrite it the "C" way? How can I change my thinking? You at some point said that one should come to the point where OOP fails and then use non-OOP, but I think I am not really there yet. Hope this is not a dumb question

🗪

2:49:17florian3321 Q: I am 50k lines into a C++ Android engine development (tried to stay away from inheritance and stuff. Note that I am still learning). Should I rewrite it the "C" way? How can I change my thinking? You at some point said that one should come to the point where OOP fails and then use non-OOP, but I think I am not really there yet. Hope this is not a dumb question

🗪

2:50:24garryjohanson Q: He did do a video on branch predictions, though I don't know if it's germane to what we're talking about¹⁶

🗪

2:50:24garryjohanson Q: He did do a video on branch predictions, though I don't know if it's germane to what we're talking about¹⁶

🗪

2:50:24garryjohanson Q: He did do a video on branch predictions, though I don't know if it's germane to what we're talking about¹⁶

🗪

2:52:22Recommend Fabian's entire YouTube channel¹⁷

📖

2:52:22Recommend Fabian's entire YouTube channel¹⁷

📖

2:52:22Recommend Fabian's entire YouTube channel¹⁷

📖

2:53:01Wind down

Keyboard Navigation

Global Keys

Menu toggling

In-Menu and Index Controls

Quotes and References Menus and Index

Quotes, References and Credits Menus

Filter Menu

Filter and Link Menus

Credits Menu