Fix atan2 argument order for HLSL (#1712)

doug-walker · web-flow · commit 8a93946cb32a · 2022-10-27T20:33:58.000-04:00
Signed-off-by: Doug Walker &lt;doug.walker@autodesk.com&gt;

Signed-off-by: Doug Walker &lt;doug.walker@autodesk.com&gt;
diff --git a/src/OpenColorIO/GpuShaderUtils.cpp b/src/OpenColorIO/GpuShaderUtils.cpp
@@ -1087,8 +1087,10 @@ std::string GpuShaderText::atan2(const std::string & y,
         }
         case GPU_LANGUAGE_HLSL_DX11:
         {
-            // note: operand order is swapped in HLSL
-            kw << "atan2(" << x << ", " << y << ")";
+            // note: Various internet sources claim that the x & y arguments need to be
+            // swapped for HLSL (relative to GLSL).  However, recent testing on Windows
+            // has revealed that the argument order needs to be the same as GLSL.
+            kw << "atan2(" << y << ", " << x << ")";
             break;
         }
         case LANGUAGE_OSL_1:

Original file line number	Diff line number	Diff line change
`@@ -1087,8 +1087,10 @@ std::string GpuShaderText::atan2(const std::string & y,`
`1087`	`1087`	`}`
`1088`	`1088`	`case GPU_LANGUAGE_HLSL_DX11:`
`1089`	`1089`	`{`
`1090`		`- // note: operand order is swapped in HLSL`
`1091`		`- kw << "atan2(" << x << ", " << y << ")";`
	`1090`	`+ // note: Various internet sources claim that the x & y arguments need to be`
	`1091`	`+ // swapped for HLSL (relative to GLSL). However, recent testing on Windows`
	`1092`	`+ // has revealed that the argument order needs to be the same as GLSL.`
	`1093`	`+ kw << "atan2(" << y << ", " << x << ")";`
`1092`	`1094`	`break;`
`1093`	`1095`	`}`
`1094`	`1096`	`case LANGUAGE_OSL_1:`