some 08 highlights

Author: cdhanna

articles/tutorials/advanced/2d_shaders/08_light_effect/index.md

@@ -70,7 +70,7 @@ The second stage references a new term, called the _Normal_ Map. We will come ba
 
    Right before the `SpriteBatch.Begin()` class, invoke the `StartColorPhase()` method. Here is the `Draw()` method with most of the code left out, but it demonstrates where the `StartColorPhase()` and `Finish()` methods belong:
 
-[!code-csharp[](./snippets/snippet-8-06.cs)]
+[!code-csharp[](./snippets/snippet-8-06.cs?highlight=6,17)]
 
 7. If you run the game now, the game will appear blank except for the UI. That is because the game is rendering to an off-screen texture, but nothing is rendering the off-screen texture _back_ to the screen. For now, we will add some diagnostic visualization of the off-screen texture. Add the following function to the `DeferredRenderer` class. 
 
@@ -106,11 +106,11 @@ The next step is to create some lights and render them to a second off-screen te
 
 4. Then, we need to call the new method in the `GameScene`'s `Draw()` method between the current `SpriteBatch.End()` call and the `deferredRenderer.Finish()` call:
 
-[!code-csharp[](./snippets/snippet-8-12.cs)]
+[!code-csharp[](./snippets/snippet-8-12.cs?highlight=9)]
 
 5. To finish off with the `DeferredRenderer` changes for now, add the `LightBuffer` to the `DebugDraw()` view as well:
 
-[!code-csharp[](./snippets/snippet-8-13.cs)]
+[!code-csharp[](./snippets/snippet-8-13.cs?highlight=41)]
 
 Now when you run the game, you'll see a blank texture in the top-right. It is blank because there are no lights yet.
 
@@ -134,11 +134,11 @@ Each light will be drawn using a shader so that the fall-off and intensity can b
 
 3. And then load the `Material` in the `LoadContent()` method:
 
-[!code-csharp[](./snippets/snippet-8-15.cs)]
+[!code-csharp[](./snippets/snippet-8-15.cs?highlight=7)]
 
 4. And do not forget to enable the hot-reload by adding the `Update()` line in the `Update()` method:
 
-[!code-csharp[](./snippets/snippet-8-16.cs)]
+[!code-csharp[](./snippets/snippet-8-16.cs?highlight=5)]
 
 5. In order to handle multiple lights, it will be helpful to have a class to represent each light. Create a new file in the _MonoGameLibrary_'s graphics folder called `PointLight.cs`:
 
@@ -158,7 +158,7 @@ Each light will be drawn using a shader so that the fall-off and intensity can b
 
 9. And call it from the `GameScene`'s `Draw()` method after the `StartLightPhase()` invocation:
 
-[!code-csharp[](./snippets/snippet-8-21.cs)]
+[!code-csharp[](./snippets/snippet-8-21.cs?highlight=7)]
 
 Now when you run the game, you will see a blank white square where the point light is located (at 300,300). 
 
@@ -180,41 +180,41 @@ The next task is to write the `pointLightEffect.fx` shader file so that the whit
 | :----------------------------------------------------------------------------------------------------------------: |
 |                **Figure 8-6: Showing the distance from the center of the light in the red channel**                |
 
-2. That starts to look like a light, but in reverse. Create a new variable, `falloff` which inverts the distance. The `saturate` function is shorthand for clamping the value between `0` and `1`:
+2. That starts to look like a light, but in reverse. Create a new variable, `falloff` which inverts the distance. The [`saturate`](https://learn.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-saturate) function is shorthand for clamping the value between `0` and `1`:
 
-[!code-hlsl[](./snippets/snippet-8-23.hlsl)]
+[!code-hlsl[](./snippets/snippet-8-23.hlsl?highlight=5)]
 
 | ![Figure 8-7: Invert the distance](./images/point-light-falloff-1.png) |
 | :--------------------------------------------------------------------: |
 |                  **Figure 8-7: Invert the distance**                   |
 
 3. That looks more light-like. Now it is time to add some artistic control parameters to the shader. First, it would be good to be able to increase the brightness of the light. Multiplying the `falloff` by some number larger than 1 would increase the brightness, but leave the unlit sections completely unlit:
 
-[!code-hlsl[](./snippets/snippet-8-24.hlsl)]
+[!code-hlsl[](./snippets/snippet-8-24.hlsl?highlight=1,7)]
 
 | ![Figure 8-8: A LightBrightness parameter](./gifs/point-light-brightness.gif) |
 | :---------------------------------------------------------------------------: |
 |                  **Figure 8-8: A LightBrightness parameter**                  |
 
 4. It would also be good to control the sharpness of the fall off. The `pow()` function raises the `falloff` to some exponent value:
 
-[!code-hlsl[](./snippets/snippet-8-25.hlsl)]
+[!code-hlsl[](./snippets/snippet-8-25.hlsl?highlight=2,9)]
 
 | ![Figure 8-9: A LightSharpness parameter](./gifs/point-light-sharpness.gif) |
 | :-------------------------------------------------------------------------: |
 |                 **Figure 8-9: A LightSharpness parameter**                  |
 
 5. Finally, the shader parameters from `0` to `1`, but it would be nice to push the brightness and sharpness beyond `1`. Add a `range` multiplier in the shader code:
 
-[!code-hlsl[](./snippets/snippet-8-26.hlsl)]
+[!code-hlsl[](./snippets/snippet-8-26.hlsl?highlight=8)]
 
 | ![Figure 8-10: Increase the range of the artistic parameters](./gifs/point-light-range.gif) |
 | :----------------------------------------------------------------------------------------: |
 |               **Figure 8-10: Increase the range of the artistic parameters**                |
 
 6. The final touch is to return the `Color` of the light, instead of the red debug value. The `input.Color` carries the `Color` passed through the `SpriteBatch`, so we can use that. Multiply the alpha channel of the color by the `falloff` to _fade_ the light out without changing the light color itself:
 
-[!code-hlsl[](./snippets/snippet-8-27.hlsl)]
+[!code-hlsl[](./snippets/snippet-8-27.hlsl?highlight=14)]
 
 7. Change the light color in C# to `CornflowerBlue`:
 
@@ -349,7 +349,7 @@ Now that we have the art assets, it is time to work the normal maps into the cod
 
 5. And do not forget to update the `technique` to reference the new `MainPS` function:
 
-[!code-hlsl[](./snippets/snippet-8-45.hlsl)]
+[!code-hlsl[](./snippets/snippet-8-45.hlsl?highlight=6)]
 
 6. In C#, when the `GraphcisDevice.SetRenderTarget()` function is called, it sets the texture that the `COLOR0` semantic will be sent to. However, there is an overload called `SetRenderTargets()` that accepts _multiple_ `RenderTarget2D`s, and each additional texture will be assigned to the next `COLOR` semantic. 
 
@@ -386,7 +386,7 @@ To start rendering the normal values themselves, we need to load the normal text
 
 3. And finally, pass it to the `_gameEffect` material as a parameter:
 
-[!code-csharp[](./snippets/snippet-8-50.cs)]
+[!code-csharp[](./snippets/snippet-8-50.cs?highlight=10)]
 
 4. The shader itself needs to expose a `Texture2D` and `Sampler` state for the new normal texture:
 

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-08.cs

@@ -1,2 +1,7 @@
-// Render the debug view for the game  
-_deferredRenderer.DebugDraw();
+public override void Draw(GameTime gameTime)
+{
+    // ...
+    
+    // Render the debug view for the game  
+    _deferredRenderer.DebugDraw();
+}

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-10.cs

@@ -1,7 +1,12 @@
-LightBuffer = new RenderTarget2D(
-	graphicsDevice: Core.GraphicsDevice, 
-	width: viewport.Width,
-	height: viewport.Height,
-	mipMap: false,
-	preferredFormat: SurfaceFormat.Color, 
-	preferredDepthFormat: DepthFormat.None);
+public DeferredRenderer()
+{
+	// ...
+
+	LightBuffer = new RenderTarget2D(
+		graphicsDevice: Core.GraphicsDevice,
+		width: viewport.Width,
+		height: viewport.Height,
+		mipMap: false,
+		preferredFormat: SurfaceFormat.Color,
+		preferredDepthFormat: DepthFormat.None);
+}

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-12.cs

@@ -1,10 +1,17 @@
-// Always end the sprite batch when finished.  
-Core.SpriteBatch.End();  
-  
-// start rendering the lights  
-_deferredRenderer.StartLightPhase();  
-  
-// TODO: draw lights  
-  
-// finish the deferred rendering  
-_deferredRenderer.Finish();
+public override void Draw(GameTime gameTime)
+{
+    // ...
+
+    // Always end the sprite batch when finished.  
+    Core.SpriteBatch.End();
+
+    // start rendering the lights  
+    _deferredRenderer.StartLightPhase();
+
+    // TODO: draw lights  
+
+    // finish the deferred rendering  
+    _deferredRenderer.Finish();
+
+    // ...
+}

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-15.cs

@@ -1 +1,10 @@
-PointLightMaterial = SharedContent.WatchMaterial("effects/pointLightEffect");
+protected override void LoadContent()
+{
+    base.LoadContent();
+
+    // ...
+
+    PointLightMaterial = SharedContent.WatchMaterial("effects/pointLightEffect");
+
+    // ...
+}

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-16.cs

@@ -1 +1,8 @@
-PointLightMaterial.Update();
+protected override void Update(GameTime gameTime)
+{
+    // ...
+
+    PointLightMaterial.Update();
+
+    // ...
+}

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-19.cs

@@ -1,4 +1,9 @@
-_lights.Add(new PointLight  
-{  
-    Position = new Vector2(300,300)  
-});
+public override void Initialize()
+{
+    // ...
+    
+    _lights.Add(new PointLight
+    {
+        Position = new Vector2(300, 300)
+    });
+}

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-21.cs

@@ -1 +1,10 @@
-PointLight.Draw(Core.SpriteBatch, _lights);
+public override void Draw(GameTime gameTime)
+{
+    // ...
+
+    // start rendering the lights
+    _deferredRenderer.StartLightPhase();
+    PointLight.Draw(Core.SpriteBatch, _lights);
+
+    // ...
+}

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-23.hlsl

@@ -5,5 +5,4 @@ float4 MainPS(VertexShaderOutput input) : COLOR
     float falloff = saturate(.5 - dist);  
 
     return float4(falloff, 0, 0, 1);  
-      
-}
+}

articles/tutorials/advanced/2d_shaders/08_light_effect/snippets/snippet-8-24.hlsl

@@ -7,5 +7,4 @@ float4 MainPS(VertexShaderOutput input) : COLOR
     float falloff = saturate(.5 - dist) * (LightBrightness + 1);  
 
     return float4(falloff, 0, 0, 1);  
-      
 }