Data: Include crt-royale

From https://github.com/akgunter/crt-royale-reshade

data/resources/shaders/reshade/Shaders/crt-royale/lib/downsampling-functions.fxh

@@ -0,0 +1,84 @@
+#ifndef _DOWNSAMPLING_FUNCTIONS_H
+#define _DOWNSAMPLING_FUNCTIONS_H
+
+/////////////////////////////////  MIT LICENSE  ////////////////////////////////
+
+//  Copyright (C) 2020 Alex Gunter <akg7634@gmail.com>
+//
+//  Permission is hereby granted, free of charge, to any person obtaining a copy
+//  of this software and associated documentation files (the "Software"), to
+//  deal in the Software without restriction, including without limitation the
+//  rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+//  sell copies of the Software, and to permit persons to whom the Software is
+//  furnished to do so, subject to the following conditions:
+//
+//  The above copyright notice and this permission notice shall be included in
+//  all copies or substantial portions of the Software.
+//
+//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+//  IN THE SOFTWARE.
+
+float3 opaque_linear_downsample(
+    const sampler2D tex,
+    const float2 texcoord,
+    const uint num_pairs,
+    const float2 delta_uv
+) {
+    const uint total_num_samples = num_pairs * 2 + 1;
+    const float2 coord_left = texcoord - delta_uv * num_pairs;
+
+    float3 acc = 0;
+    for(int i = 0; i < total_num_samples; i++) {
+        const float2 coord = coord_left + i * delta_uv;
+        acc += tex2D_nograd(tex, coord).rgb;
+    }
+    
+    return acc / total_num_samples;
+}
+
+
+float3 opaque_lanczos_downsample(
+    const sampler2D tex,
+    const float2 texcoord,
+    const uint num_pairs,
+    const float2 delta_uv,
+    const float num_sinc_lobes,
+    const float weight_at_center
+) {
+    const uint total_num_samples = num_pairs * 2 + 1;
+    const float2 coord_left = texcoord - delta_uv * num_pairs;
+    const float sinc_dx = num_sinc_lobes / num_pairs;  // 2 * num_sinc_lobes / (total_num_samples - 1)
+
+    float3 acc = 0;
+    float w_sum = 0;
+    for(int i = 0; i < total_num_samples; i++) {
+        const float2 coord = coord_left + i * delta_uv;
+        const float sinc_x = i * sinc_dx;
+
+        const float weight = (i != num_pairs) ?
+            num_sinc_lobes * sin(pi*sinc_x) * sin(pi*sinc_x/num_sinc_lobes) / (pi*pi * sinc_x*sinc_x) :
+            weight_at_center;
+
+        acc += weight * tex2D_nograd(tex, coord).rgb;
+        w_sum += weight;
+    }
+    
+    return acc / w_sum;
+}
+
+float3 opaque_lanczos_downsample(
+    const sampler2D tex,
+    const float2 texcoord,
+    const uint num_pairs,
+    const float2 delta_uv,
+    const float num_sinc_lobes
+) {
+    return opaque_lanczos_downsample(tex, texcoord, num_pairs, delta_uv, num_sinc_lobes, 1);
+}
+
+#endif  //  _DOWNSAMPLING_FUNCTIONS_H