From a0ab216617b16d87ed363a590979b4cdc8879012 Mon Sep 17 00:00:00 2001
From: FabsTheFabs <flamingkitty24@gmail.com>
Date: Thu, 18 Jul 2024 06:04:19 +0100
Subject: [PATCH] merged rain shader stuff from 'feature/week2-erect-bg-rain'

---
 .../shaders/RuntimePostEffectShader.hx        | 31 +++++++++++++++++++
 .../graphics/shaders/RuntimeRainShader.hx     |  8 +++++
 2 files changed, 39 insertions(+)

diff --git a/source/funkin/graphics/shaders/RuntimePostEffectShader.hx b/source/funkin/graphics/shaders/RuntimePostEffectShader.hx
index 9f49da075..d39f57efe 100644
--- a/source/funkin/graphics/shaders/RuntimePostEffectShader.hx
+++ b/source/funkin/graphics/shaders/RuntimePostEffectShader.hx
@@ -2,6 +2,7 @@ package funkin.graphics.shaders;
 
 import flixel.FlxCamera;
 import flixel.FlxG;
+import flixel.graphics.frames.FlxFrame;
 import flixel.addons.display.FlxRuntimeShader;
 import lime.graphics.opengl.GLProgram;
 import lime.utils.Log;
@@ -32,6 +33,9 @@ class RuntimePostEffectShader extends FlxRuntimeShader
 		// equals (camera.viewLeft, camera.viewTop, camera.viewRight, camera.viewBottom)
 		uniform vec4 uCameraBounds;
 
+		// equals (frame.left, frame.top, frame.right, frame.bottom)
+		uniform vec4 uFrameBounds;
+
 		// screen coord -> world coord conversion
 		// returns world coord in px
 		vec2 screenToWorld(vec2 screenCoord) {
@@ -56,6 +60,25 @@ class RuntimePostEffectShader extends FlxRuntimeShader
 			return (worldCoord - offset) / scale;
 		}
 
+		// screen coord -> frame coord conversion
+		// returns normalized frame coord
+		vec2 screenToFrame(vec2 screenCoord) {
+			float left = uFrameBounds.x;
+			float top = uFrameBounds.y;
+			float right = uFrameBounds.z;
+			float bottom = uFrameBounds.w;
+			float width = right - left;
+			float height = bottom - top;
+
+			float clampedX = clamp(screenCoord.x, left, right);
+			float clampedY = clamp(screenCoord.y, top, bottom);
+
+			return vec2(
+				(clampedX - left) / (width),
+				(clampedY - top) / (height)
+			);
+		}
+
 		// internally used to get the maximum `openfl_TextureCoordv`
 		vec2 bitmapCoordScale() {
 			return openfl_TextureCoordv / screenCoord;
@@ -80,6 +103,8 @@ class RuntimePostEffectShader extends FlxRuntimeShader
   {
     super(fragmentSource, null, glVersion);
     uScreenResolution.value = [FlxG.width, FlxG.height];
+    uCameraBounds.value = [0, 0, FlxG.width, FlxG.height];
+    uFrameBounds.value = [0, 0, FlxG.width, FlxG.height];
   }
 
   // basically `updateViewInfo(FlxG.width, FlxG.height, FlxG.camera)` is good
@@ -89,6 +114,12 @@ class RuntimePostEffectShader extends FlxRuntimeShader
     uCameraBounds.value = [camera.viewLeft, camera.viewTop, camera.viewRight, camera.viewBottom];
   }
 
+  public function updateFrameInfo(frame:FlxFrame)
+  {
+    // NOTE: uv.width is actually the right pos and uv.height is the bottom pos
+    uFrameBounds.value = [frame.uv.x, frame.uv.y, frame.uv.width, frame.uv.height];
+  }
+
   override function __createGLProgram(vertexSource:String, fragmentSource:String):GLProgram
   {
     try
diff --git a/source/funkin/graphics/shaders/RuntimeRainShader.hx b/source/funkin/graphics/shaders/RuntimeRainShader.hx
index 239276bbe..68a203179 100644
--- a/source/funkin/graphics/shaders/RuntimeRainShader.hx
+++ b/source/funkin/graphics/shaders/RuntimeRainShader.hx
@@ -32,6 +32,14 @@ class RuntimeRainShader extends RuntimePostEffectShader
     return time = value;
   }
 
+  public var spriteMode(default, set):Bool = false;
+
+  function set_spriteMode(value:Bool):Bool
+  {
+    this.setBool('uSpriteMode', value);
+    return spriteMode = value;
+  }
+
   // The scale of the rain depends on the world coordinate system, so higher resolution makes
   // the raindrops smaller. This parameter can be used to adjust the total scale of the scene.
   // The size of the raindrops is proportional to the value of this parameter.