[client] egl: implement C wrappers for FidelityFX constant computation

client/renderers/EGL/ffx.h

@@ -0,0 +1,28 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2021 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#pragma once
+#include <stdint.h>
+
+void ffxCasConst(uint32_t consts[8], float sharpness, float inputX, float inputY,
+    float outputX, float outputY);
+void ffxFsrEasuConst(uint32_t consts[16], float viewportX, float viewportY,
+    float inputX, float inputY, float outputX, float outputY);
+void ffxFsrRcasConst(uint32_t consts[4], float sharpness);