From ad192fe7068081ed88f8616581bf450d601e99b1 Mon Sep 17 00:00:00 2001
From: James Barnett <noreply@jamesbarnett.xyz>
Date: Tue, 29 Dec 2020 20:13:01 +0000
Subject: Add textures

---
 src/main/kotlin/TextureManager.kt | 49 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 src/main/kotlin/TextureManager.kt

(limited to 'src/main/kotlin/TextureManager.kt')

diff --git a/src/main/kotlin/TextureManager.kt b/src/main/kotlin/TextureManager.kt
new file mode 100644
index 0000000..58005e9
--- /dev/null
+++ b/src/main/kotlin/TextureManager.kt
@@ -0,0 +1,49 @@
+import kotlinx.browser.document
+import org.khronos.webgl.get
+import org.w3c.dom.CanvasRenderingContext2D
+import org.w3c.dom.HTMLCanvasElement
+import org.w3c.dom.HTMLImageElement
+import org.w3c.dom.asList
+
+class TextureManager {
+
+  private lateinit var textures: List<Texture>
+
+  fun getTexture(id: Int): Texture {
+    return textures.first { it.id == id }
+  }
+
+  fun loadTextures() {
+    textures = document.getElementsByClassName("texture-definition").asList()
+      .map { it as HTMLImageElement }
+      .map {
+        val id = it.id.toInt()
+        val width = it.getAttribute("data-width")?.toInt() ?: 64
+        val height = it.getAttribute("data-height")?.toInt() ?: 64
+        Texture(id, width, height, parseImage(it, width, height))
+      }
+
+    console.log("Loaded ${textures.size} texture(s)")
+  }
+
+  private fun parseImage(image: HTMLImageElement, imageWidth: Int, imageHeight: Int): List<String> {
+    val canvas = (document.createElement("canvas") as HTMLCanvasElement)
+      .apply {
+        width = imageWidth
+        height = imageHeight
+      }
+
+    // Draw image to canvas and read back out to get RGBA data
+    val imageData = with(canvas.getContext("2d") as CanvasRenderingContext2D) {
+      drawImage(image, 0.0, 0.0, imageWidth.toDouble(), imageHeight.toDouble())
+      getImageData(0.0, 0.0, imageWidth.toDouble(), imageHeight.toDouble()).data
+    }
+
+    val cssColourPixelList = mutableListOf<String>()
+    for (i in 0 until imageData.length step 4) {
+      cssColourPixelList.add("rgb(${imageData[i]},${imageData[i+1]},${imageData[i+2]}")
+    }
+
+    return cssColourPixelList
+  }
+}
\ No newline at end of file
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