Fix accuracy loss when generating mipmap (#7)

CHANGELOG.md

@@ -1,4 +1,6 @@
 ## [Unreleased]
+### Fixed
+- Fix accuracy loss when generating mipmap (#7)
 
 ## [0.1.2] - 2022-02-17
 ### Fixed

Runtime/ImageImporter.cs

@@ -294,15 +294,15 @@ static void FilterMipmapRGB24(ref FilterMipmapJob job, int outputIndex) {
             var inputX = min(mad(2, outputX, offsetX), job.inputDimensions.x - 1);
             var inputY = min(mad(2, outputY, offsetY), job.inputDimensions.y - 1);
             var inputIndex = mad(job.inputDimensions.x, inputY, inputX);
-            outputColor.x += (uint)job.inputMipmap[mad(3, inputIndex, 0)] >> 2;
-            outputColor.y += (uint)job.inputMipmap[mad(3, inputIndex, 1)] >> 2;
-            outputColor.z += (uint)job.inputMipmap[mad(3, inputIndex, 2)] >> 2;
+            outputColor.x += (uint)job.inputMipmap[mad(3, inputIndex, 0)];
+            outputColor.y += (uint)job.inputMipmap[mad(3, inputIndex, 1)];
+            outputColor.z += (uint)job.inputMipmap[mad(3, inputIndex, 2)];
           }
         }
 
-        job.outputMipmap[mad(3, outputIndex, 0)] = (byte)outputColor.x;
-        job.outputMipmap[mad(3, outputIndex, 1)] = (byte)outputColor.y;
-        job.outputMipmap[mad(3, outputIndex, 2)] = (byte)outputColor.z;
+        job.outputMipmap[mad(3, outputIndex, 0)] = (byte)(outputColor.x >> 2);
+        job.outputMipmap[mad(3, outputIndex, 1)] = (byte)(outputColor.y >> 2);
+        job.outputMipmap[mad(3, outputIndex, 2)] = (byte)(outputColor.z >> 2);
       }
 
       [BurstCompile(CompileSynchronously = true)]
@@ -316,17 +316,17 @@ static void FilterMipmapRGBA32(ref FilterMipmapJob job, int outputIndex) {
             var inputX = min(mad(2, outputX, offsetX), job.inputDimensions.x - 1);
             var inputY = min(mad(2, outputY, offsetY), job.inputDimensions.y - 1);
             var inputIndex = mad(job.inputDimensions.x, inputY, inputX);
-            outputColor.x += (uint)job.inputMipmap[mad(4, inputIndex, 0)] >> 2;
-            outputColor.y += (uint)job.inputMipmap[mad(4, inputIndex, 1)] >> 2;
-            outputColor.z += (uint)job.inputMipmap[mad(4, inputIndex, 2)] >> 2;
-            outputColor.w += (uint)job.inputMipmap[mad(4, inputIndex, 3)] >> 2;
+            outputColor.x += (uint)job.inputMipmap[mad(4, inputIndex, 0)];
+            outputColor.y += (uint)job.inputMipmap[mad(4, inputIndex, 1)];
+            outputColor.z += (uint)job.inputMipmap[mad(4, inputIndex, 2)];
+            outputColor.w += (uint)job.inputMipmap[mad(4, inputIndex, 3)];
           }
         }
 
-        job.outputMipmap[mad(4, outputIndex, 0)] = (byte)outputColor.x;
-        job.outputMipmap[mad(4, outputIndex, 1)] = (byte)outputColor.y;
-        job.outputMipmap[mad(4, outputIndex, 2)] = (byte)outputColor.z;
-        job.outputMipmap[mad(4, outputIndex, 3)] = (byte)outputColor.w;
+        job.outputMipmap[mad(4, outputIndex, 0)] = (byte)(outputColor.x >> 2);
+        job.outputMipmap[mad(4, outputIndex, 1)] = (byte)(outputColor.y >> 2);
+        job.outputMipmap[mad(4, outputIndex, 2)] = (byte)(outputColor.z >> 2);
+        job.outputMipmap[mad(4, outputIndex, 3)] = (byte)(outputColor.w >> 2);
       }
 
       [ReadOnly]

Tests/AsyncImageLoader.Tests.asmdef

@@ -0,0 +1,11 @@
+{
+    "name": "AsyncImageLoader.Tests",
+    "references": [
+        "AsyncImageLoader.Runtime"
+    ],
+    "optionalUnityReferences": [
+        "TestAssemblies"
+    ],
+    "includePlatforms": [],
+    "excludePlatforms": []
+}

Tests/TestMipmap.cs

@@ -0,0 +1,97 @@
+using NUnit.Framework;
+using UnityEngine;
+using UnityEngine.TestTools;
+
+public class TestMipmap {
+  [Test]
+  public void TestPNGImage() {
+    var data = new byte[] {
+      0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, 0x00, 0x00, 0x00, 0x0D, 0x49, 0x48, 0x44, 0x52,
+      0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x02, 0x08, 0x06, 0x00, 0x00, 0x00, 0x72, 0xB6, 0x0D,
+      0x24, 0x00, 0x00, 0x00, 0x1B, 0x49, 0x44, 0x41, 0x54, 0x08, 0xD7, 0x63, 0x60, 0xF8, 0xCF, 0xD0,
+      0xC0, 0xC0, 0xF0, 0xDF, 0x81, 0xE1, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x33, 0x30, 0xEC, 0x07, 0x00,
+      0x43, 0x18, 0x08, 0x79, 0xEB, 0xE3, 0x55, 0xB4, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4E, 0x44,
+      0xAE, 0x42, 0x60, 0x82
+    };
+
+    var texture = AsyncImageLoader.CreateFromImage(data);
+    var mipmapLevel0 = texture.GetPixelData<int>(0);
+    var mipmapLevel1 = texture.GetPixelData<int>(1);
+
+    Assert.That(texture.format, Is.EqualTo(TextureFormat.RGBA32));
+    Assert.That(texture.width, Is.EqualTo(2));
+    Assert.That(texture.height, Is.EqualTo(2));
+    Assert.That(texture.mipmapCount, Is.EqualTo(2));
+
+    Assert.That(mipmapLevel0.Length, Is.EqualTo(4));
+    Assert.That(mipmapLevel0[0], Is.EqualTo(unchecked((int)0xFF_FF_FF_FF)));
+    Assert.That(mipmapLevel0[1], Is.EqualTo(unchecked((int)0xBF_00_00_FF)));
+    Assert.That(mipmapLevel0[2], Is.EqualTo(unchecked((int)0x80_00_FF_00)));
+    Assert.That(mipmapLevel0[3], Is.EqualTo(unchecked((int)0x40_FF_00_00)));
+
+    Assert.That(mipmapLevel1.Length, Is.EqualTo(1));
+    Assert.That(mipmapLevel1[0], Is.EqualTo(unchecked((int)0x9F_7F_7F_7F)));
+  }
+
+  [Test]
+  public void TestJPEGImage() {
+    var data = new byte[] {
+      0xFF, 0xD8, 0xFF, 0xE0, 0x00, 0x10, 0x4A, 0x46, 0x49, 0x46, 0x00, 0x01, 0x01, 0x01, 0x01, 0x2C,
+      0x01, 0x2C, 0x00, 0x00, 0xFF, 0xDB, 0x00, 0x43, 0x00, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+      0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+      0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+      0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+      0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0xFF, 0xDB, 0x00, 0x43, 0x01, 0x01, 0x01,
+      0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+      0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+      0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+      0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0xFF, 0xC9,
+      0x00, 0x11, 0x08, 0x00, 0x02, 0x00, 0x02, 0x03, 0x01, 0x11, 0x00, 0x02, 0x11, 0x01, 0x03, 0x11,
+      0x01, 0xFF, 0xCC, 0x00, 0x0A, 0x00, 0x10, 0x10, 0x05, 0x01, 0x10, 0x11, 0x05, 0xFF, 0xDA, 0x00,
+      0x0C, 0x03, 0x01, 0x00, 0x02, 0x11, 0x03, 0x11, 0x00, 0x3F, 0x00, 0xFF, 0x00, 0xED, 0x83, 0x1F,
+      0x33, 0xBE, 0xF8, 0x94, 0x15, 0x70, 0xB2, 0xBB, 0x79, 0x32, 0xF4, 0x33, 0x76, 0x95, 0xE5, 0x72,
+      0x12, 0x80, 0xC7, 0xBB, 0xD4, 0xFB, 0xA3, 0x62, 0x4D, 0xF7, 0x60, 0x15, 0xAF, 0x52, 0x24, 0xCD,
+      0xD2, 0xBF, 0xC1, 0x1C, 0xF3, 0x9A, 0x08, 0x87, 0xEE, 0x86, 0xB1, 0xD7, 0xE2, 0xC8, 0x9D, 0x24,
+      0x55, 0xC1, 0x6D, 0xFF, 0x00, 0x4F, 0x49, 0x19, 0x7B, 0x42, 0xB3, 0x28, 0xB9, 0xB6, 0x05, 0x0E,
+      0x5F, 0xCF, 0x84, 0x92, 0x6C, 0xB5, 0x54, 0x89, 0xBF, 0xFE, 0xE0, 0x0F, 0x33, 0x5E, 0x63, 0xB3,
+      0x89, 0xEB, 0x11, 0x5A, 0x95, 0xD5, 0x09, 0x39, 0x2C, 0xB6, 0x04, 0x72, 0x3D, 0xF4, 0x9B, 0xB4,
+      0x58, 0x49, 0x64, 0x46, 0x1D, 0x65, 0x60, 0x14, 0xBD, 0x04, 0x5C, 0xA4, 0xF0, 0x82, 0xAF, 0x10,
+      0xC8, 0xFD, 0x60, 0x8E, 0x9C, 0x55, 0x8C, 0xA4, 0xFF, 0x00, 0x3C, 0xAE, 0x16, 0xBB, 0x53, 0xC2,
+      0x59, 0x82, 0xDD, 0xAD, 0x3F, 0x7D, 0x68, 0x04, 0x6D, 0x7E, 0xD3, 0x6B, 0xA9, 0xA2, 0x01, 0x7F,
+      0x6E, 0xA9, 0xBE, 0xE9, 0x3E, 0xB6, 0x24, 0x9E, 0xAB, 0xAD, 0xD8, 0xE7, 0x60, 0x64, 0x73, 0xC3,
+      0x8F, 0xDC, 0xDC, 0xC2, 0x2F, 0x35, 0xF1, 0xEB, 0x2F, 0xA2, 0x75, 0x61, 0x01, 0xDF, 0x11, 0xF4,
+      0xD0, 0xC1, 0x62, 0x5A, 0x28, 0x22, 0xEC, 0x05, 0x2A, 0x41, 0x14, 0xC2, 0xA0, 0x4D, 0xB7, 0x9F,
+      0x3C, 0xF5, 0xD8, 0x90, 0xF1, 0x6F, 0x87, 0x09, 0xBE, 0xA9, 0xFD, 0x44, 0xBD, 0x59, 0x0C, 0x8B,
+      0x03, 0xF8, 0xB1, 0x0E, 0x07, 0x73, 0x3C, 0x82, 0xDA, 0x09, 0x83, 0x35, 0x03, 0x90, 0x3E, 0xBC,
+      0x65, 0x4B, 0x44, 0xAF, 0x2C, 0x80, 0xFF, 0xD9
+    };
+
+    var texture = AsyncImageLoader.CreateFromImage(data);
+    var mipmapLevel0 = texture.GetPixelData<byte>(0);
+    var mipmapLevel1 = texture.GetPixelData<byte>(1);
+
+    Assert.That(texture.format, Is.EqualTo(TextureFormat.RGB24));
+    Assert.That(texture.width, Is.EqualTo(2));
+    Assert.That(texture.height, Is.EqualTo(2));
+    Assert.That(texture.mipmapCount, Is.EqualTo(2));
+
+    Assert.That(mipmapLevel0.Length, Is.EqualTo(3 * 4));
+    Assert.That(mipmapLevel0[0], Is.EqualTo(0XF7));
+    Assert.That(mipmapLevel0[1], Is.EqualTo(0XFF));
+    Assert.That(mipmapLevel0[2], Is.EqualTo(0XFF));
+    Assert.That(mipmapLevel0[3], Is.EqualTo(0XF7));
+    Assert.That(mipmapLevel0[4], Is.EqualTo(0X07));
+    Assert.That(mipmapLevel0[5], Is.EqualTo(0X08));
+    Assert.That(mipmapLevel0[6], Is.EqualTo(0X00));
+    Assert.That(mipmapLevel0[7], Is.EqualTo(0XFF));
+    Assert.That(mipmapLevel0[8], Is.EqualTo(0X00));
+    Assert.That(mipmapLevel0[9], Is.EqualTo(0X00));
+    Assert.That(mipmapLevel0[10], Is.EqualTo(0X08));
+    Assert.That(mipmapLevel0[11], Is.EqualTo(0XFF));
+
+    Assert.That(mipmapLevel1.Length, Is.EqualTo(3));
+    Assert.That(mipmapLevel1[0], Is.EqualTo(0x7B));
+    Assert.That(mipmapLevel1[1], Is.EqualTo(0x83));
+    Assert.That(mipmapLevel1[2], Is.EqualTo(0x81));
+  }
+}