From 9d7cee23343593145e88e9c59ece189bca0b6120 Mon Sep 17 00:00:00 2001
From: Dennis Postma <dennis@directonline.io>
Date: Tue, 28 Jan 2025 15:34:21 +0100
Subject: [PATCH] Combining sprites to generate a spritesheet works again.

---
 .../gameMaster/assetManager/sprite/update.ts  | 120 +++++++++++++++---
 1 file changed, 100 insertions(+), 20 deletions(-)

diff --git a/src/events/gameMaster/assetManager/sprite/update.ts b/src/events/gameMaster/assetManager/sprite/update.ts
index bdd036e..09f00e9 100644
--- a/src/events/gameMaster/assetManager/sprite/update.ts
+++ b/src/events/gameMaster/assetManager/sprite/update.ts
@@ -3,6 +3,7 @@ import { UUID } from '#application/types'
 import SpriteRepository from '#repositories/spriteRepository'
 import { SpriteAction } from '#entities/spriteAction'
 import sharp from 'sharp'
+import fs from 'fs'
 
 type Payload = {
   id: UUID
@@ -52,11 +53,14 @@ export default class SpriteUpdateEvent extends BaseEvent {
           .setSprites(actionData.sprites)
           .setOriginX(actionData.originX)
           .setOriginY(actionData.originY)
-          .setFrameWidth(await this.calculateWidth(actionData.sprites[0]))
-          .setFrameHeight(await this.calculateHeight(actionData.sprites[0]))
+          .setFrameWidth(await this.calculateMaxWidth(actionData.sprites))
+          .setFrameHeight(await this.calculateMaxHeight(actionData.sprites))
           .setFrameRate(actionData.frameRate)
 
         await spriteRepository.getEntityManager().persistAndFlush(spriteAction)
+        
+        // Generate sprite sheet for this action
+        await this.generateSpriteSheet(actionData.sprites, sprite.getId(), actionData.action)
       }
 
       return callback(true)
@@ -66,27 +70,103 @@ export default class SpriteUpdateEvent extends BaseEvent {
     }
   }
 
-  private async calculateWidth(base64: string): Promise<number> {
-    const uri = base64.split(';base64,').pop()
-    if (!uri) return 0
-
-    const imgBuffer = Buffer.from(uri, 'base64')
-    const image = await sharp(imgBuffer).metadata()
-    return image.width ?? 0
+  private async calculateMaxWidth(sprites: string[]): Promise<number> {
+    if (!sprites.length) return 0
+    
+    const widths = await Promise.all(sprites.map(async (base64) => {
+      const uri = base64.split(';base64,').pop()
+      if (!uri) return 0
+      
+      const imgBuffer = Buffer.from(uri, 'base64')
+      const image = await sharp(imgBuffer).metadata()
+      return image.width ?? 0
+    }))
+    
+    return Math.max(...widths)
   }
 
-  private async calculateHeight(base64: string): Promise<number> {
-    const uri = base64.split(';base64,').pop()
-    if (!uri) return 0
-
-    const imgBuffer = Buffer.from(uri, 'base64')
-    const image = await sharp(imgBuffer).metadata()
-    return image.height ?? 0
+  private async calculateMaxHeight(sprites: string[]): Promise<number> {
+    if (!sprites.length) return 0
+    
+    const heights = await Promise.all(sprites.map(async (base64) => {
+      const uri = base64.split(';base64,').pop()
+      if (!uri) return 0
+      
+      const imgBuffer = Buffer.from(uri, 'base64')
+      const image = await sharp(imgBuffer).metadata()
+      return image.height ?? 0
+    }))
+    
+    return Math.max(...heights)
   }
 
-  private generateSpriteSheet(sprites: string[]) {
-    // In here comes a function that generates a sprite sheet from the given sprites using Sharp.
-    // This function takes an array of base64 encoded sprites and generates a single png sprite sheet.
-    // Then proceeds to save ths sprite sheet to the public/sprites/{spriteId}/ directory. The file name is {action}.png.
+  private async generateSpriteSheet(sprites: string[], spriteId: string, action: string): Promise<void> {
+    try {
+      // Skip if no sprites
+      if (!sprites.length) return
+
+      // Process all base64 images to buffers and get their dimensions
+      const imageData = await Promise.all(
+        sprites.map(async (base64) => {
+          const uri = base64.split(';base64,').pop()
+          if (!uri) throw new Error('Invalid base64 image')
+          const buffer = Buffer.from(uri, 'base64')
+          const metadata = await sharp(buffer).metadata()
+          return { buffer, width: metadata.width ?? 0, height: metadata.height ?? 0 }
+        })
+      )
+
+      // Find the largest dimensions
+      const maxWidth = Math.max(...imageData.map(data => data.width))
+      const maxHeight = Math.max(...imageData.map(data => data.height))
+
+      // Extend all images to match the largest dimensions without resizing
+      const resizedBuffers = await Promise.all(
+        imageData.map(async ({ buffer, width, height }) => {
+          // Calculate padding to center the sprite
+          const leftPadding = Math.floor((maxWidth - width) / 2)
+          const topPadding = Math.floor((maxHeight - height) / 2)
+
+          return await sharp(buffer)
+            .extend({
+              top: topPadding,
+              bottom: Math.ceil((maxHeight - height) / 2),
+              left: leftPadding,
+              right: Math.ceil((maxWidth - width) / 2),
+              background: { r: 0, g: 0, b: 0, alpha: 0 }
+            })
+            .toBuffer()
+        })
+      )
+
+      // Create sprite sheet by combining images horizontally
+      const spriteSheet = await sharp({
+        create: {
+          width: maxWidth * sprites.length,
+          height: maxHeight,
+          channels: 4,
+          background: { r: 0, g: 0, b: 0, alpha: 0 }
+        }
+      })
+        .composite(
+          resizedBuffers.map((buffer, index) => ({
+            input: buffer,
+            left: index * maxWidth,
+            top: 0
+          }))
+        )
+        .png()
+        .toBuffer()
+
+      // Ensure directory exists
+      const dir = `public/sprites/${spriteId}`
+      await fs.promises.mkdir(dir, { recursive: true })
+
+      // Save the sprite sheet
+      await fs.promises.writeFile(`${dir}/${action}.png`, spriteSheet)
+    } catch (error) {
+      console.error('Error generating sprite sheet:', error)
+      throw error
+    }
   }
 }