Fixed flipy issue

CHANGES.md

@@ -1,5 +1,11 @@
 # Change Log
 
+### 1.71.0 - 2020-07-01
+
+##### Fixes :wrench:
+
+- Fixed a bug with handling of PixelFormat's flipY. [#8893](https://github.com/CesiumGS/cesium/pull/8893)
+
 ### 1.70.0 - 2020-06-01
 
 ##### Major Announcements :loudspeaker:

CONTRIBUTORS.md

@@ -143,6 +143,7 @@ See [CONTRIBUTING.md](CONTRIBUTING.md) for details on how to contribute to Cesiu
   - [Samuel Vargas](https://github.com/Samulus)
   - [Sam Suhag](https://github.com/sanjeetsuhag)
   - [Youssef Victor](https://github.com/YoussefV)
+  - [Eli Bogomolny](https://github.com/ebogo1)
 - [Northrop Grumman](http://www.northropgrumman.com)
   - [Joseph Stein](https://github.com/nahgrin)
 - [EOX IT Services GmbH](https://eox.at)

Source/Core/PixelFormat.js

@@ -360,8 +360,8 @@ PixelFormat.flipY = function (
   var numberOfComponents = PixelFormat.componentsLength(pixelFormat);
   var textureWidth = width * numberOfComponents;
   for (var i = 0; i < height; ++i) {
-    var row = i * height * numberOfComponents;
-    var flippedRow = (height - i - 1) * height * numberOfComponents;
+    var row = i * width * numberOfComponents;
+    var flippedRow = (height - i - 1) * width * numberOfComponents;
     for (var j = 0; j < textureWidth; ++j) {
       flipped[flippedRow + j] = bufferView[row + j];
     }

Specs/Core/PixelFormatSpec.js

@@ -0,0 +1,38 @@
+import { PixelDatatype } from "../../Source/Cesium.js";
+import { PixelFormat } from "../../Source/Cesium.js";
+
+describe("Core/PixelFormat", function () {
+  it("flipY works", function () {
+    var width = 1;
+    var height = 2;
+    var values = [255, 0, 0, 0, 255, 0];
+    var expectedValues = [0, 255, 0, 255, 0, 0];
+    var dataBuffer = new Uint8Array(values);
+    var expectedDataBuffer = new Uint8Array(expectedValues);
+
+    var flipped = PixelFormat.flipY(
+      dataBuffer,
+      PixelFormat.RGB,
+      PixelDatatype.UNSIGNED_BYTE,
+      width,
+      height
+    );
+    expect(flipped).toEqual(expectedDataBuffer);
+  });
+
+  it("flipY returns early if height is 1", function () {
+    var width = 1;
+    var height = 1;
+    var values = [255, 255, 255];
+    var dataBuffer = new Uint8Array(values);
+
+    var flipped = PixelFormat.flipY(
+      dataBuffer,
+      PixelFormat.RGB,
+      PixelDatatype.UNSIGNED_BYTE,
+      width,
+      height
+    );
+    expect(flipped).toBe(dataBuffer);
+  });
+});