WEBVTT 1 00:00:00.080 --> 00:00:01.679 You know that feeling when you're playing a game and 2 00:00:01.720 --> 00:00:05.559 the graphics just pop, the way light catches the surface, 3 00:00:05.960 --> 00:00:10.359 or those subtle reflections, maybe even that really distinct stylized look, 4 00:00:10.439 --> 00:00:13.960 you know that makes a world feel real or sometimes 5 00:00:14.039 --> 00:00:17.120 magically hand drawn. Well, a lot of that visual match 6 00:00:17.160 --> 00:00:18.640 comes down to something called shads. 7 00:00:18.879 --> 00:00:21.399 Absolutely, they're kind of like the secret sauce. Whden't you say? 8 00:00:21.679 --> 00:00:24.640 They define how light interacts with everything you see exactly. 9 00:00:24.719 --> 00:00:27.679 It turns simple three D models into something visually rich. 10 00:00:27.800 --> 00:00:31.079 They're really the unsung heroes working away at the pixel level. 11 00:00:31.199 --> 00:00:33.240 It's where art definitely meets code. 12 00:00:33.399 --> 00:00:36.799 So today we're doing a deep dive into this fascinating 13 00:00:36.840 --> 00:00:40.320 world Unity Shads and Effects. Right, we're drawing from a 14 00:00:40.359 --> 00:00:43.799 really great resource, the Unity five point x Shaters and 15 00:00:43.799 --> 00:00:48.439 Effects Cookbook. Our mission is basically to unpack how developers 16 00:00:48.520 --> 00:00:52.240 use shader programming to really bring their Unity projects to life. 17 00:00:52.320 --> 00:00:54.759 Yeah, and give you a shortcut to understanding what's behind 18 00:00:54.880 --> 00:00:58.039 modern game visuals from you know, the basic building blocks 19 00:00:58.399 --> 00:01:01.359 right up to some really mind ending real time effects. 20 00:01:01.640 --> 00:01:05.640 And this cookbook the authors are top notch Alan Zuconi 21 00:01:05.680 --> 00:01:09.359 develops thirty under thirty developer behind zero Arbitalis and. 22 00:01:09.400 --> 00:01:12.840 Kenneth Lammers, He's got what over fifteen years in the industry, 23 00:01:13.040 --> 00:01:16.439 worked on huge titles like Call of Duty three, Alan Wake. 24 00:01:16.719 --> 00:01:19.680 So yeah, there definitely are expert guides for this for sure. 25 00:01:20.519 --> 00:01:23.280 So if you've ever wondered how games get those stunning visuals, 26 00:01:23.799 --> 00:01:26.799 how a simple cube can look like metal or wood, 27 00:01:26.920 --> 00:01:28.879 or how an explosion just looks. 28 00:01:28.719 --> 00:01:31.879 Right, then this deep dive is definitely for you. Get 29 00:01:31.920 --> 00:01:33.439 ready for some aha moments. 30 00:01:33.560 --> 00:01:35.799 Let's start right at the beginning. Then at its core, 31 00:01:35.920 --> 00:01:36.799 what is a shader? 32 00:01:37.280 --> 00:01:39.959 Okay? So think of it like a tiny program, a 33 00:01:40.000 --> 00:01:42.959 specialized program that runs on your graphics card, okay, and 34 00:01:43.040 --> 00:01:45.680 its job is to tell the graphics card how light 35 00:01:45.719 --> 00:01:48.840 should behave on a surface. Imagine you have a plane 36 00:01:48.879 --> 00:01:51.519 three D cube. Yep. The shader is what makes it 37 00:01:51.560 --> 00:01:54.840 look like shiny metal or rough wood or maybe even glass. 38 00:01:55.159 --> 00:01:57.879 It's not just slapping on a picture. It's simulating how 39 00:01:57.959 --> 00:01:59.840 light interacts with that material. 40 00:01:59.760 --> 00:02:02.400 A right, So it's about the light interaction, not just 41 00:02:02.439 --> 00:02:05.280 the color. Makes sense, it's the visual identity exactly. But 42 00:02:05.319 --> 00:02:08.039 how does this shader fit into, you know, the bigger 43 00:02:08.080 --> 00:02:12.199 picture in unity the rendering process? What's the chain of command. 44 00:02:12.199 --> 00:02:15.960 Good question. Let's break it down. So in Unity, everything 45 00:02:15.960 --> 00:02:17.800 you see is basically a game object. 46 00:02:17.719 --> 00:02:20.240 Right, characters, props everything. 47 00:02:20.280 --> 00:02:23.439 Yeah, And for a three D game object to show up, 48 00:02:23.719 --> 00:02:26.719 it usually needs a component called a mesh renderer. Think 49 00:02:26.719 --> 00:02:30.960 of the mesh render like the stage manager deciding how 50 00:02:31.000 --> 00:02:32.280 that three D model appears. 51 00:02:32.360 --> 00:02:35.240 Okay, like deciding its costume and lighting pretty much. 52 00:02:35.360 --> 00:02:37.919 Yeah, And that mesh render uses something called a material. 53 00:02:38.000 --> 00:02:40.560 The material is like the specific recipe is its silk 54 00:02:40.840 --> 00:02:43.479 is a burlap? Got it? And that material contains the shader. 55 00:02:43.800 --> 00:02:46.560 The shader is the actual set of instructions defining how 56 00:02:46.680 --> 00:02:49.360 light bounces off that silk or burlap. So the chain 57 00:02:49.439 --> 00:02:52.319 is game object, mish renderer, material. 58 00:02:51.960 --> 00:02:55.520 Shader, clear object renderer, material shader. And speaking of Unity, 59 00:02:55.639 --> 00:02:58.039 Unity five brought a big change rate hebr oh. 60 00:02:57.960 --> 00:03:01.599 Huge physically based rendering PBR that became the new standard. 61 00:03:01.800 --> 00:03:04.599 What was so revolutionary about it? More realistic graphics? 62 00:03:04.879 --> 00:03:07.120 Well, yes, but it was more than that. The real 63 00:03:07.159 --> 00:03:12.120 insight was that PBR provided a consistent, physically plausible way 64 00:03:12.240 --> 00:03:16.719 to describe materials. Consistent how meaning artists could define a material, 65 00:03:16.800 --> 00:03:19.960 say brushed aluminum, and it would look correct under almost 66 00:03:20.000 --> 00:03:24.400 any lighting condition morning sun, dim, indoor lights, whatever. No 67 00:03:24.560 --> 00:03:26.520 more endless tweaking for every scene. 68 00:03:26.719 --> 00:03:30.680 Ah okay, so it behaves predictably based on physics Exactly. 69 00:03:30.680 --> 00:03:33.280 It was a massive step up from the older diffuse 70 00:03:33.319 --> 00:03:36.400 and specular models in Unity four, which often needed a 71 00:03:36.400 --> 00:03:37.560 lot more manual fiddling. 72 00:03:37.680 --> 00:03:40.080 That sounds like a life saver for artists, and I 73 00:03:40.120 --> 00:03:42.280 hear properties make it even easier for them. 74 00:03:42.319 --> 00:03:45.000 What are those properties? Are Billiant. They're basically controls that 75 00:03:45.039 --> 00:03:48.159 show up in the Unity Editor in the Materials Inspector tab. 76 00:03:48.120 --> 00:03:49.520 Like sliders and color pickers. 77 00:03:49.599 --> 00:03:52.759 Precisely, a shaded programmer writes a line of code like 78 00:03:52.879 --> 00:03:55.120 color main, color color and boom, the artist get a 79 00:03:55.159 --> 00:03:59.199 color swatch in the editor. Or roughness roughness range zero 80 00:03:59.240 --> 00:04:02.560 one zero point gives them a slider, so the artists. 81 00:04:02.240 --> 00:04:05.080 Can tweet the look, change the color, adjust roughness without 82 00:04:05.120 --> 00:04:06.439 needing to code exactly. 83 00:04:06.520 --> 00:04:09.360 That's the whole point. It separates the technical shader logic 84 00:04:09.400 --> 00:04:10.599 from the artistic tweaking. 85 00:04:10.680 --> 00:04:13.840 And crucially, where are the values for those properties stored 86 00:04:14.319 --> 00:04:14.960 in the shader? 87 00:04:15.240 --> 00:04:18.160 No, that's the key distinction. The properties are defined in 88 00:04:18.199 --> 00:04:22.040 the shader, but there's specific values the chosen color the 89 00:04:22.079 --> 00:04:24.560 slider setting are stored in the material. 90 00:04:24.800 --> 00:04:28.240 Ah, so you can have one shader like metal, but 91 00:04:28.519 --> 00:04:32.399 multiple materials using it, shiny steel, rusty iron, each with 92 00:04:32.439 --> 00:04:33.680 different property values. 93 00:04:33.720 --> 00:04:36.120 You got it. Change a property on the shiny steel 94 00:04:36.160 --> 00:04:40.839 material and all objects using that material update instantly. Super flexible. 95 00:04:41.000 --> 00:04:43.920 Okay, Now, for anyone brave enough to write their own shaders, 96 00:04:44.000 --> 00:04:48.000 debugging sounds like fun. That magenta color, ah, the dreaded magenta. 97 00:04:48.199 --> 00:04:50.680 Yeah, unlike C sharp scripts that just stop your game 98 00:04:50.879 --> 00:04:56.279 shader errors, don't halt anything. Instead, your object turns bright unshaded. 99 00:04:55.839 --> 00:04:57.920 Magenta, a very clear error message. 100 00:04:57.959 --> 00:05:01.600 It certainly gets your attention. Commonness, the steaks are you know, typos, 101 00:05:01.680 --> 00:05:05.639 missing semicolms forgetting a bracket or having a property defined 102 00:05:05.639 --> 00:05:07.439 but not actually using it in the shader code. It 103 00:05:07.480 --> 00:05:08.120 needs that link. 104 00:05:08.360 --> 00:05:11.160 Good to know. Also heard something about floats in CIG 105 00:05:11.360 --> 00:05:12.439 being slightly different. 106 00:05:12.680 --> 00:05:16.120 Yeah, minor thing, but it catches people. In CIG the 107 00:05:16.199 --> 00:05:19.240 shader language you just write one point zero, one point 108 00:05:19.240 --> 00:05:22.040 oh f like you often do in Sea Shark, small detail, 109 00:05:22.120 --> 00:05:23.879 big magenta headache if you forget. 110 00:05:24.079 --> 00:05:26.959 Okay, so we've got the basics. Shaders tell light what 111 00:05:27.079 --> 00:05:30.600 to do. Artists use materials and properties to tweak them. 112 00:05:30.879 --> 00:05:34.519 But how do we get specific looks making something actually 113 00:05:34.560 --> 00:05:36.079 look like wood or stone? 114 00:05:36.160 --> 00:05:39.279 Right? That takes us into surface shaders, textures and lighting models. 115 00:05:39.600 --> 00:05:41.519 This is where the real visual magic. 116 00:05:41.240 --> 00:05:44.199 Happens surface shaders. What's the core idea there? 117 00:05:44.439 --> 00:05:47.680 A surface shad basically has two main parts. First, there's 118 00:05:47.680 --> 00:05:50.680 a surface function. In this function, you tell unity about 119 00:05:50.720 --> 00:05:54.079 the physical properties of your surface, like it's base color, albedo, 120 00:05:54.439 --> 00:05:59.279 how smooth or rough it is, smoothness if it's metallic, metallic, maybe, 121 00:05:59.279 --> 00:06:00.000 how transparent? 122 00:06:00.079 --> 00:06:03.199 And alpha okay, describing the material itself exactly. 123 00:06:03.279 --> 00:06:05.639 Then all that information gets past to a lighting model. 124 00:06:06.000 --> 00:06:08.680 The lighting model takes those surface properties and information about 125 00:06:08.680 --> 00:06:11.519 the lights in your scene and calculates the final color 126 00:06:11.560 --> 00:06:12.360 for each pixel. 127 00:06:12.600 --> 00:06:15.639 So it combines the what it is with how it's 128 00:06:15.680 --> 00:06:16.639 lit precisely. 129 00:06:16.720 --> 00:06:19.759 And there are different structs or data packages for these properties, 130 00:06:19.800 --> 00:06:23.439 like Surf's output standard for PBR. They hold things like albedo, 131 00:06:23.560 --> 00:06:27.680 normal emission, metallic, smoothness, alpha, got it, and. 132 00:06:27.680 --> 00:06:30.720 I understand c The shader language is pretty smart about 133 00:06:30.759 --> 00:06:32.600 handling data pact rays. 134 00:06:32.839 --> 00:06:35.240 Yeah, CG is really efficient. It uses things like float 135 00:06:35.240 --> 00:06:37.800 three or float four. These packed rays. Think a float 136 00:06:37.839 --> 00:06:42.240 three holding xyz for position or RGB for color. A 137 00:06:42.319 --> 00:06:45.000 float four adds W or alpha. 138 00:06:44.800 --> 00:06:47.120 So it groups related numbers together, right, and. 139 00:06:47.000 --> 00:06:48.920 This lets you do cool stuff called swizzling. Like if 140 00:06:48.920 --> 00:06:50.720 you have a color and a float four called color, 141 00:06:50.959 --> 00:06:53.199 you can grab just the RGB parts really easily by 142 00:06:53.199 --> 00:06:56.360 writing color dot RGB, or even rearrange them like color 143 00:06:56.360 --> 00:06:59.680 dot bgr meat, trek, or even smearing. Assigning a single 144 00:06:59.720 --> 00:07:02.360 value you like point five to a float three will 145 00:07:02.360 --> 00:07:05.720 set all three components xyz two point five. It's all 146 00:07:05.759 --> 00:07:09.399 about doing math on multiple values at once, which gpuser. 147 00:07:08.920 --> 00:07:10.839 Great app Okay, back to textures. How do you get 148 00:07:10.839 --> 00:07:14.079 a flat image, say bricks, onto a three D wall. 149 00:07:14.160 --> 00:07:17.120 That's texture mapping. It relies on something called UV data 150 00:07:17.160 --> 00:07:18.959 stored in the three D model itself. 151 00:07:19.360 --> 00:07:21.360 UV data like coordinates. 152 00:07:21.399 --> 00:07:24.879 Exactly each vertex corner point of your three D model 153 00:07:24.959 --> 00:07:28.079 has two coordinates U and V, usually ranging from zero 154 00:07:28.120 --> 00:07:30.759 to one. Think of it like flattening a three D 155 00:07:30.839 --> 00:07:34.120 model onto a two D plane. These uvs tell the 156 00:07:34.120 --> 00:07:36.720 shader exactly which part of the two D texture image 157 00:07:36.879 --> 00:07:39.480 corresponds to which part of the three D model's. 158 00:07:39.120 --> 00:07:41.800 Surface, and the GPU figures out the bits in between 159 00:07:41.839 --> 00:07:42.399 the vertices. 160 00:07:42.480 --> 00:07:45.279 Yep, it interpolates the uvs across the surface. Then the 161 00:07:45.319 --> 00:07:49.040 shader uses a function usually text two D, to look 162 00:07:49.120 --> 00:07:51.439 up or sample the color from the texture at that 163 00:07:51.519 --> 00:07:53.519 specific UV coordinate for each pixel. 164 00:07:53.759 --> 00:07:57.040 Clever? Can you animate textures this way like flowing water? 165 00:07:57.240 --> 00:08:00.480 Absolutely? You can modify the UV coordinates over time. Just 166 00:08:00.519 --> 00:08:03.279 add unities built in time variable or some fraction of 167 00:08:03.319 --> 00:08:07.319 it to the U or V coordinate before sampling the texture. Presto. 168 00:08:07.480 --> 00:08:10.240 Scrolling texture a classic way to fake movement. 169 00:08:10.519 --> 00:08:12.959 Nice, But what about adding really fine detail, like the 170 00:08:13.000 --> 00:08:15.879 tiny bumps on that brick wall where scratches on metal. 171 00:08:16.120 --> 00:08:19.000 Adding tons of polygons would kill performance, right. 172 00:08:18.920 --> 00:08:21.120 You definitely don'tant a model every single bump. That's where 173 00:08:21.160 --> 00:08:23.480 normal mapping comes in. It's a fantastic technique. 174 00:08:23.480 --> 00:08:25.399 How does that work? Is it another texture? 175 00:08:25.600 --> 00:08:28.959 It is. It's a special texture, often purplish, called a 176 00:08:28.959 --> 00:08:31.920 normal map or sometimes a bump map. But instead of 177 00:08:31.920 --> 00:08:36.159 storing color, the RGB values in this texture actually represent 178 00:08:36.360 --> 00:08:39.679 directions direction. Yeah, they represent the direction that the surface 179 00:08:39.759 --> 00:08:42.799 normal is pointing at that specific pixel. The normal is 180 00:08:42.840 --> 00:08:45.480 like an imaginary line pointing straight out from the surface. 181 00:08:46.039 --> 00:08:48.759 By slightly changing the direction of this normal according to 182 00:08:48.799 --> 00:08:51.559 the map, you trick the lighting calculation aw. 183 00:08:51.440 --> 00:08:53.200 So the light bounces off as if there was a 184 00:08:53.240 --> 00:08:55.960 bump there, even though the geometry is flat exactly. 185 00:08:56.080 --> 00:08:59.240 It gives this incredible illusion of surface detail bumps, grooves, 186 00:08:59.320 --> 00:09:03.000 rivet scratches without adding any extra polygons. It's super efficient. 187 00:09:03.559 --> 00:09:07.480 Unity even provides a function unpacked normal to easily decode 188 00:09:07.480 --> 00:09:09.279 the information from the normal map texture. 189 00:09:09.559 --> 00:09:13.559 That's seriously cool. Okay, so normal maps fake detail on 190 00:09:13.639 --> 00:09:16.879 solid surfaces. What about things that aren't solid, like glass 191 00:09:17.080 --> 00:09:21.200 or ghosts or fire. Transparency sounds difficult. 192 00:09:21.440 --> 00:09:25.159 It is surprisingly more complex than you might think. See 193 00:09:25.240 --> 00:09:28.799 for solid objects, the graphics card does clever stuff like 194 00:09:28.919 --> 00:09:32.120 z ordering, figuring out what's in front and only drawing that, 195 00:09:32.279 --> 00:09:35.080 and culling like not drawing the back faces of objects 196 00:09:35.080 --> 00:09:35.639 you can't see. 197 00:09:35.879 --> 00:09:37.039 Makes sense, saves work. 198 00:09:37.559 --> 00:09:40.879 But transparent objects mess that up. You need to see 199 00:09:40.879 --> 00:09:44.480 what's behind them, so they need special handling. You use 200 00:09:44.519 --> 00:09:46.799 shader tags to tell Unity how to handle them, like 201 00:09:46.879 --> 00:09:50.039 setting que transparent tells Unity to draw them after all. 202 00:09:49.919 --> 00:09:53.519 The solid stuff, so order matters a lot critically, and. 203 00:09:53.399 --> 00:09:57.120 You need specific shader directives like hashtag, pregma, surface dot 204 00:09:57.159 --> 00:10:00.399 alpha dot fade to enable blending so the it's parent 205 00:10:00.440 --> 00:10:02.600 object mixes correctly with the background pixels. 206 00:10:02.679 --> 00:10:05.200 Can you do stylized transparency too? I think the book 207 00:10:05.240 --> 00:10:06.639 mentioned a hologram shader. 208 00:10:06.759 --> 00:10:08.639 Oh yeah, that's a neat one. You can use a 209 00:10:08.639 --> 00:10:11.960 mathematical operation called the dot product. You calculate the dot 210 00:10:11.960 --> 00:10:14.200 product between the surface normal and the view direction. 211 00:10:14.440 --> 00:10:15.600 Okay, what does that tell you? 212 00:10:15.840 --> 00:10:18.399 It tells you how much a surface is facing towards 213 00:10:18.480 --> 00:10:21.799 or away from the camera. Surfaces facing you get one value, 214 00:10:21.840 --> 00:10:24.639 Surfaces facing away get another. You can then use this 215 00:10:24.720 --> 00:10:26.759 to make only the edges or the parts facing you 216 00:10:26.799 --> 00:10:30.279 slightly visible, creating that classic sci fi hologram rim. 217 00:10:30.120 --> 00:10:32.840 Effect, just showing the outlines kind of yeah. 218 00:10:32.759 --> 00:10:36.840 Or a faint semi transparent look. It's computationally cheap and 219 00:10:37.039 --> 00:10:40.720 great for ghosts, force fields, selected object outlines, that kind 220 00:10:40.759 --> 00:10:41.000 of thing. 221 00:10:41.759 --> 00:10:44.360 All right, we're using all these textures, color normal maps, 222 00:10:44.399 --> 00:10:47.840 maybe others. Textures take up memory, right, especially on mobile, 223 00:10:48.200 --> 00:10:49.600 any tricks for optimizing that. 224 00:10:49.799 --> 00:10:53.240 Big time textures are often a major memory hog. A 225 00:10:53.320 --> 00:10:56.679 really common technique is texture packing, sometimes called channel. 226 00:10:56.399 --> 00:10:59.240 Packing, packing like zipping files sort of. 227 00:10:59.399 --> 00:11:02.960 But for data, many maps you need might only be grayscale, 228 00:11:03.039 --> 00:11:05.200 like a roughness map or a metallic map, or an 229 00:11:05.240 --> 00:11:08.039 ambient inclusion map. They only need one channel of. 230 00:11:08.080 --> 00:11:11.080 Data instead of the usual three for RGB color exactly. 231 00:11:11.320 --> 00:11:13.759 So you can take say your roughness map and put 232 00:11:13.759 --> 00:11:15.960 it into the red channel of a texture. Take your 233 00:11:16.000 --> 00:11:18.600 metallic map, put it in the green channel, maybe an 234 00:11:18.639 --> 00:11:21.120 ambient inclusion map in the blue channel, and something else 235 00:11:21.120 --> 00:11:21.960 in the alpha channel. 236 00:11:22.039 --> 00:11:25.960 Ah. So one our GBA texture holds four different gray 237 00:11:26.000 --> 00:11:26.840 scale maps. 238 00:11:26.919 --> 00:11:29.080 You got it. It saves a ton of memory and 239 00:11:29.200 --> 00:11:32.039 reduces the number of texture samples the shader needs to do. 240 00:11:32.600 --> 00:11:36.720 Super common for character models and especially terrain. For terrain, 241 00:11:37.080 --> 00:11:41.279 you might have one packed texture controlling how grass, dirt, rock, 242 00:11:41.480 --> 00:11:45.080 and snow blend together using a function called LURP. 243 00:11:44.879 --> 00:11:46.440 LURP linear interpolation. 244 00:11:46.639 --> 00:11:49.720 Yeah, it smoothly blends between two values based on a 245 00:11:49.720 --> 00:11:51.960 third value. So you could use the red channel of 246 00:11:51.960 --> 00:11:54.559 your blend map to control the blend between dirt and grass, 247 00:11:54.759 --> 00:11:56.679 the green channel for grass and rock, and so on. 248 00:11:57.200 --> 00:11:57.879 Very efficient. 249 00:11:57.960 --> 00:12:00.879 Okay, that makes sense. We mentioned lighting models earlier as 250 00:12:00.960 --> 00:12:04.200 part of surface shaders. Why would a developer bother making 251 00:12:04.200 --> 00:12:06.840 a custom lighting model. If Unity has good built in 252 00:12:06.879 --> 00:12:09.320 ones like PBR, well, PBR. 253 00:12:08.960 --> 00:12:13.039 Is fantastic for realism. But sometimes you don't want realism. 254 00:12:13.279 --> 00:12:15.840 You want a specific artistic style. Maybe you want your 255 00:12:15.879 --> 00:12:17.559 game to look like a comic book or an old 256 00:12:17.639 --> 00:12:21.080 cartoon or something completely unique. Custom lighting models give you 257 00:12:21.120 --> 00:12:24.919 that precise control over how light and shadow behave, letting 258 00:12:24.960 --> 00:12:26.759 you define your own visual language. 259 00:12:26.799 --> 00:12:30.399 So for non photorealistic rendering NPR. 260 00:12:30.399 --> 00:12:33.360 Exactly, or even just for optimizing for very low end 261 00:12:33.360 --> 00:12:36.720 platforms where PBR might be too expensive. Understanding the classic 262 00:12:36.720 --> 00:12:37.399 models helps too. 263 00:12:37.519 --> 00:12:40.080 Let's talk about those classics. What's Lambertune reflectants. 264 00:12:40.320 --> 00:12:45.000 Lambertine was basically the default diffuse lighting model in Unity four. 265 00:12:45.279 --> 00:12:49.399 It's super simple, very fast. It calculates brightness based only 266 00:12:49.399 --> 00:12:52.159 on the angle between the light hitting the surface and 267 00:12:52.200 --> 00:12:53.840 the surface normal itself. 268 00:12:53.480 --> 00:12:55.960 So how directly the light hits it right, uses a. 269 00:12:55.879 --> 00:12:58.240 Dot product for that. It results in a very matt 270 00:12:58.440 --> 00:13:02.240 non shiny look. Thinks bull flat shading great for stylized 271 00:13:02.240 --> 00:13:04.000 low poly games, very efficient. 272 00:13:03.799 --> 00:13:06.840 And then the opposite end stylistically is maybe tune shading 273 00:13:06.960 --> 00:13:09.360 or cell shading. That comic book look. 274 00:13:09.360 --> 00:13:13.519 Yeah, totally different. Goal tune shading aims for that flat, 275 00:13:13.840 --> 00:13:17.559 hand drawn cartoon style. The trick here is usually a 276 00:13:17.600 --> 00:13:20.679 custom Whiting model that takes the smooth gradient of light 277 00:13:20.720 --> 00:13:21.759 intensity you'd get from. 278 00:13:21.679 --> 00:13:24.120 Lambursha makes it chunky exactly. 279 00:13:24.240 --> 00:13:26.840 It uses something called a ramp map. It's usually a 280 00:13:26.879 --> 00:13:29.919 small one D texture, like a thin strip with distinct 281 00:13:29.919 --> 00:13:33.720 bands of color or brightness. The shader calculates the normal 282 00:13:33.799 --> 00:13:37.879 light intensity often called n Dattel, the dot product of 283 00:13:37.919 --> 00:13:41.000 normal and light direction. Uses that value to look up 284 00:13:41.000 --> 00:13:43.519 a color on the ramp map, and poof, Instead of 285 00:13:43.519 --> 00:13:46.320 a smooth gradient, you get sharp defined bands of color. 286 00:13:46.600 --> 00:13:47.879 That's the cell shaded look. 287 00:13:48.080 --> 00:13:51.919 Clever use of a texture to change the lighting result. Okay, 288 00:13:51.960 --> 00:13:56.519 what about shininess speculat highlights, We've got pong blind fall right. 289 00:13:56.399 --> 00:13:58.519 These are about adding those bright spots you see on 290 00:13:58.559 --> 00:14:02.679 shiny objects. Is sort of a classic foundational model. It 291 00:14:02.720 --> 00:14:05.600 calculates the reflection based on the angle between the direction 292 00:14:05.679 --> 00:14:07.919 the camera is viewing from and the direction the light 293 00:14:07.919 --> 00:14:09.759 would perfectly reflect off the surface, So. 294 00:14:09.759 --> 00:14:11.519 It depends on where you're looking from very. 295 00:14:11.519 --> 00:14:14.279 Much, so it's view dependent. It gives a decent shiny. 296 00:14:13.960 --> 00:14:16.559 Look and Blindphong is it just better. 297 00:14:17.159 --> 00:14:19.799 It's often preferred. Yeah, it's generally faster to calculate, and 298 00:14:20.120 --> 00:14:22.399 in many cases looks a bit more realistic or at 299 00:14:22.440 --> 00:14:25.480 least softer than basic fong. Instead of calculating the full 300 00:14:25.519 --> 00:14:29.039 reflection vector, it uses a clever shortcut involving a half vector, 301 00:14:29.320 --> 00:14:31.399 which is the vector halfway between the light direction and 302 00:14:31.440 --> 00:14:34.120 the view direction. It was the default specular model and 303 00:14:34.240 --> 00:14:36.200 unity for still very useful. 304 00:14:36.279 --> 00:14:40.159 Okay, simple shininess covered. But then there's anisotropic speculator that 305 00:14:40.279 --> 00:14:43.960 sounds complex. Brushed metal hair? How does that work? 306 00:14:44.159 --> 00:14:48.200 Anisotropic is really cool. It simulates materials where the shininess 307 00:14:48.279 --> 00:14:52.240 isn't uniform because the surface has tiny parallel grooves or 308 00:14:52.279 --> 00:14:55.120 fibers I think brushed aluminum. The back of a CD 309 00:14:55.799 --> 00:14:58.120 vinyl records even strands of hair. 310 00:14:58.000 --> 00:15:00.600 So the highlight isn't just a round dot exactly. 311 00:15:00.799 --> 00:15:03.679 Instead of a circular highlight, it stretches the specular highlight 312 00:15:03.720 --> 00:15:06.759 perpendicularly to the direction of those tiny grooves or strands. 313 00:15:07.240 --> 00:15:11.120 It requires extra information, usually from another texture or model data, 314 00:15:11.480 --> 00:15:13.840 telling the shadeer which way the grain or fibers run 315 00:15:13.879 --> 00:15:16.480 on the surface. It has a massive amount of realism 316 00:15:16.519 --> 00:15:17.720 for those kinds of materials. 317 00:15:17.960 --> 00:15:22.240 Wow, Okay, that's pretty specific control. Let's circle back to 318 00:15:22.279 --> 00:15:25.000 PBR and unity five. You said it was a revolution. 319 00:15:25.679 --> 00:15:26.919 What are the main workflows? 320 00:15:27.120 --> 00:15:30.799 The two main ones are standard and standard a specular setup. 321 00:15:30.960 --> 00:15:33.879 The most common one is the standard workflow, which uses 322 00:15:33.919 --> 00:15:34.799 a metallic map. 323 00:15:35.159 --> 00:15:38.679 Metallic workflow. How does that enforce realism? 324 00:15:39.000 --> 00:15:41.919 It works based on a key physical principle. Things are 325 00:15:41.960 --> 00:15:45.840 generally either metallic or non metallic dielectric. Pure metals get 326 00:15:45.879 --> 00:15:48.360 almost all their color from reflected light. They have very 327 00:15:48.440 --> 00:15:52.360 dark or black diffuse color. Their albedo map basically defines 328 00:15:52.399 --> 00:15:53.399 the color of the reflection. 329 00:15:53.960 --> 00:15:56.759 Okay, and non metals like plastic or wood. 330 00:15:57.200 --> 00:16:00.600 Non metals have a colored diffuse component that's their albedo 331 00:16:00.679 --> 00:16:04.159 map color, and their specular reflections are generally noncolored, reflecting 332 00:16:04.200 --> 00:16:06.519 the color of the light source itself. The metallic map, 333 00:16:06.600 --> 00:16:09.639 usually a grayscale texture packed new channel tells the shade 334 00:16:09.679 --> 00:16:12.279 or how metallic. Each part of the surface is. Black 335 00:16:12.320 --> 00:16:15.360 means non metal, white means pure metal, gray is somewhere 336 00:16:15.399 --> 00:16:17.279 in between like dusty or corroded metal. 337 00:16:17.399 --> 00:16:19.039 And smoothness is that packed in there too? 338 00:16:19.320 --> 00:16:24.120 Often? Yes, the smoothness value controlling how sharp or blurry 339 00:16:24.120 --> 00:16:27.000 reflections are is frequently packed into the alpha channel of 340 00:16:27.039 --> 00:16:30.919 the metallic map texture. So one map controls both metalness 341 00:16:30.960 --> 00:16:31.799 and smoothness. 342 00:16:32.159 --> 00:16:35.039 It's efficient PBR in transparency. How does that work? Does 343 00:16:35.080 --> 00:16:37.919 it handle glass and ghosts differently? 344 00:16:38.080 --> 00:16:41.559 It does. PBR offers specific modes. Transparent mode is for 345 00:16:41.639 --> 00:16:45.480 things like proper glass or clear plastics. Crucially, it keeps 346 00:16:45.480 --> 00:16:49.759 all the PBR goodness speculat highlights, reflections, Fresnel effect where 347 00:16:49.919 --> 00:16:53.240 reflectivity changes with the young angle. It looks physically correct. 348 00:16:53.519 --> 00:16:54.919 Okay, what about ghosts? 349 00:16:55.240 --> 00:16:57.639 For that, you'd probably use fade mode. In fade mode, 350 00:16:57.799 --> 00:17:00.559 as the object becomes more transparent, everything fades out, including 351 00:17:00.600 --> 00:17:03.879 the specular highlights and reflections. Perfect for effects where things 352 00:17:03.919 --> 00:17:05.279 need to dissolve completely. 353 00:17:05.359 --> 00:17:06.480 And the third one cut out. 354 00:17:06.640 --> 00:17:09.079 Cutout mode is for things that are geometrically solid but 355 00:17:09.240 --> 00:17:11.880 need to look like they have holes, like chain link fences, 356 00:17:12.000 --> 00:17:15.079 leaves on a tree, or detailed grates. It uses the 357 00:17:15.079 --> 00:17:18.480 alpha channel of the texture, but it's not blended transparency. 358 00:17:18.759 --> 00:17:21.640 It's either fully opaque or fully invisible based on an 359 00:17:21.640 --> 00:17:25.160 alpha cutoff slider, sharp edges, no semi transparency. 360 00:17:25.400 --> 00:17:30.480 Got it makes sense for foliage. Now realistic reflections like 361 00:17:30.680 --> 00:17:34.400 mirrors or shiny floors. You mentioned reflection probes right. 362 00:17:34.519 --> 00:17:37.960 Real time reflections are super expensive, So reflection probes are 363 00:17:37.960 --> 00:17:40.400 a way to capture the environment around a certain point. 364 00:17:40.799 --> 00:17:42.640 Think of it like taking a three hundred and sixty 365 00:17:42.640 --> 00:17:45.200 degree photo from that spot and storing it as a 366 00:17:45.200 --> 00:17:47.319 special texture called a cube map. 367 00:17:47.240 --> 00:17:49.359 Six images, one for each direction. 368 00:17:49.279 --> 00:17:53.839 Exactly up, down, left, right, front, back. Then shiny objects 369 00:17:53.880 --> 00:17:56.359 near that probe can sample this cube map to show 370 00:17:56.359 --> 00:17:58.279 reflections of the surrounding static scenery. 371 00:17:58.319 --> 00:17:59.200 Are they expensive? 372 00:17:59.599 --> 00:18:01.799 They can be, especially if they need to update in 373 00:18:01.880 --> 00:18:04.559 real time, like if dynamic objects need to be reflected. 374 00:18:05.000 --> 00:18:08.359 Often they're baked, meaning they capture the static environment once 375 00:18:08.400 --> 00:18:10.599 in the editor, which is much cheaper at run time. 376 00:18:10.960 --> 00:18:14.200 They're crucial for making metallic PBR materials look believable. 377 00:18:14.400 --> 00:18:18.240 Speaking of baking, light baking, that sounds like pre calculating lighting. 378 00:18:18.559 --> 00:18:21.759 That's exactly what it is. Calculating how light bounces around 379 00:18:21.759 --> 00:18:26.519 realistically in real time. Global illumination or GI is incredibly demanding, 380 00:18:27.240 --> 00:18:31.000 So light baking lets unity pre calculate all that complex 381 00:18:31.119 --> 00:18:35.279 light bouncing for objects that don't move. Your buildings terrain static. 382 00:18:34.839 --> 00:18:36.720 Props and saves that lighting information. 383 00:18:36.839 --> 00:18:40.200 Yeah, saves it into special textures called light maps. At runtime, 384 00:18:40.319 --> 00:18:43.039 these static objects just look up their pre calculated lighting 385 00:18:43.079 --> 00:18:45.640 from the light map. It looks great and is super 386 00:18:45.680 --> 00:18:48.359 fast compared to calculating GI every frame. 387 00:18:48.960 --> 00:18:52.599 But what about things that do move your player character NPCs, 388 00:18:52.720 --> 00:18:56.319 moving objects, They can't use static lightmaps. 389 00:18:55.920 --> 00:18:59.200 Correct for them. We use light probes. You scatter these 390 00:18:59.240 --> 00:19:02.920 probes around your scene, especially where lighting conditions change. Like 391 00:19:03.000 --> 00:19:06.240 light maps, they get baked. They sample the complex bounced 392 00:19:06.319 --> 00:19:08.599 lighting at the specific locations during the bake. 393 00:19:08.519 --> 00:19:11.160 Process, so they store the lighting info at points in 394 00:19:11.200 --> 00:19:12.279 space exactly. 395 00:19:12.960 --> 00:19:15.880 Then, as your character or a dynamic object moves through 396 00:19:15.920 --> 00:19:19.440 the scene, it looks at the nearest light probes, blends 397 00:19:19.480 --> 00:19:22.599 the lighting information sampled by them, and uses that to 398 00:19:22.680 --> 00:19:26.920 light itself. This allows moving objects to feel realistically integrated 399 00:19:26.960 --> 00:19:30.440 into the baked static environment. It's a clever way to 400 00:19:30.480 --> 00:19:33.640 get the best of both worlds, detailed lighting on static 401 00:19:33.680 --> 00:19:35.799