Support capturing rotated displays on Windows (#1602)

src_assets/windows/assets/shaders/directx/CursorVS.hlsl

@@ -0,0 +1,37 @@
+struct PS_INPUT
+{
+    float4 pos : SV_POSITION;
+    float2 tex : TEXCOORD;
+};
+
+cbuffer rotation_info : register(b2) {
+    int rotation;
+};
+
+PS_INPUT main_vs(uint vI : SV_VERTEXID)
+{
+    PS_INPUT output;
+
+    if (vI == 0) {
+        output.pos = float4(-1, -1, 0, 1);
+        output.tex = float2(0, 1);
+    }
+    else if (vI == 1) {
+        output.pos = float4(-1, 3, 0, 1);
+        output.tex = float2(0, -1);
+    }
+    else if (vI == 2) {
+        output.pos = float4(3, -1, 0, 1);
+        output.tex = float2(2, 1);
+    }
+
+    if (rotation != 0) {
+        float rotation_radians = radians(90 * rotation);
+        float2x2 rotation_matrix = { cos(rotation_radians), -sin(rotation_radians),
+                                     sin(rotation_radians), cos(rotation_radians) };
+        float2 rotation_center = { 0.5, 0.5 };
+        output.tex = round(rotation_center + mul(rotation_matrix, output.tex - rotation_center));
+    }
+
+    return output;
+}