adding basic tone mapping

res/shaders/FullscreenQuad.slang

@@ -0,0 +1,15 @@
+struct QuadOutput
+{
+	float2 uv : UV;
+	float4 position : SV_Position;
+}
+
+[shader("vertex")]
+QuadOutput quadMain(uint vertexIndex : SV_VertexID)
+{
+	QuadOutput result;
+	result.uv = float2((vertexIndex << 1) & 2, vertexIndex & 2);
+	result.position = float4(result.uv * 2.0f + -1.0f, 0.0f, 1.0f);
+	result.uv.y = 1 - result.uv.y;
+	return result;
+}