Summerize Chapter 6: Textures

06-textures/README.md

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+# Chapter 6: Textures
+
+As I read this book, I summarize what I think is wrong. If you think my comments are wrong then please let me know. We can dicuss more and update your opinion.
+
+## sRGB color space
+
+* Actually we can't do math on non-linear space because `1 + 1 != 2` in non-linear space. Let's explain a reason in detail.
+
+![](./gamma-correction-gamma-curves.png)
+
+Data in the reality are in linear space and those are encoded non-linear space because the limitation of memory.
+It made sRGB color format that compromised between how cathode ray tube monitors worked and what colors the human eye sees.
+Let's think about that you are calculating `0.5 + 0.5` and the result must be `1.0`. However `0.5` is in non-linear space
+so it is `0.729` in linear space. So `0.5 + 0.5` in non-linear space equals to `0.729 + 0.729` so the result is `1.458` not `1.0`.
+Thus when you do the math, you must check values are in linear space.
+
+* If texture's format is sRGB then OpenGL, Vulkan and DirectX convert from non-linear space to linear space automatically
+when you fetch a texel with a sampler. However Metal don't do that. This book give a code how to convert from non-linear space to linear space.
+But the code is not compiled when you copy. Try this code `baseColor = pow(baseColor, 1.0 / 2.2);`. You can do the gamma correction by yourself.

06-textures/starter/Texture/Texture/Texturable.swift

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+//
+/**
+ * Copyright (c) 2019 Razeware LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * Notwithstanding the foregoing, you may not use, copy, modify, merge, publish,
+ * distribute, sublicense, create a derivative work, and/or sell copies of the
+ * Software in any work that is designed, intended, or marketed for pedagogical or
+ * instructional purposes related to programming, coding, application development,
+ * or information technology.  Permission for such use, copying, modification,
+ * merger, publication, distribution, sublicensing, creation of derivative works,
+ * or sale is expressly withheld.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+
+import Foundation

06-textures/starter/Texture/Texture/Textures.xcassets/Contents.json

@@ -0,0 +1,6 @@
+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

06-textures/starter/Texture/Texture/Textures.xcassets/barn.textureset/Contents.json

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+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  },
+  "properties" : {
+    "interpretation" : "data"
+  },
+  "textures" : [
+    {
+      "filename" : "Universal.mipmapset",
+      "idiom" : "universal",
+      "pixel-format" : "astc-8x8"
+    }
+  ]
+}

06-textures/starter/Texture/Texture/Textures.xcassets/barn.textureset/Universal.mipmapset/Contents.json

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+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  },
+  "levels" : [
+    {
+      "filename" : "lowpoly-barn-color.png",
+      "mipmap-level" : "base"
+    }
+  ]
+}

06-textures/starter/Texture/Texture/Textures.xcassets/grass.textureset/Contents.json

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+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  },
+  "properties" : {
+    "interpretation" : "data"
+  },
+  "textures" : [
+    {
+      "filename" : "Universal.mipmapset",
+      "idiom" : "universal",
+      "pixel-format" : "astc-8x8"
+    }
+  ]
+}

06-textures/starter/Texture/Texture/Textures.xcassets/grass.textureset/Universal.mipmapset/Contents.json

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+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  },
+  "levels" : [
+    {
+      "filename" : "barn-ground.png",
+      "mipmap-level" : "base"
+    }
+  ]
+}

README.md

@@ -17,6 +17,7 @@ You can also download the source code from [here](https://store.raywenderlich.co
  * [Chapter 3: The Rendering Pipeline](https://github.com/daemyung/MetalByTutorials/tree/main/03-rendering-pipeline)
  * [Chapter 4: Coordinate Spaces](https://github.com/daemyung/MetalByTutorials/tree/main/04-3d-transforms)
  * [Chapter 5: Lighting Fundamentals](https://github.com/daemyung/MetalByTutorials/tree/main/05-lighting-fundamentals)
+ * [Chapter 6: Textures](https://github.com/daemyung/MetalByTutorials/tree/main/06-textures)
 
 ## Copyright