1 files changed, 130 insertions, 0 deletions
diff --git a/src/video_core/host_shaders/opengl_present_scaleforce.frag b/src/video_core/host_shaders/opengl_present_scaleforce.frag
new file mode 100644
index 000000000..71ff9e1e3
--- /dev/null
+++ b/src/video_core/host_shaders/opengl_present_scaleforce.frag
@@ -0,0 +1,130 @@
+// MIT License
+//
+// Copyright (c) 2020 BreadFish64
+//
+// 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.
+
+// Adapted from https://github.com/BreadFish64/ScaleFish/tree/master/scaleforce
+
+//! #version 460
+
+#extension GL_ARB_separate_shader_objects : enable
+
+#ifdef YUZU_USE_FP16
+
+#extension GL_AMD_gpu_shader_half_float : enable
+#extension GL_NV_gpu_shader5 : enable
+
+#define lfloat float16_t
+#define lvec2 f16vec2
+#define lvec3 f16vec3
+#define lvec4 f16vec4
+
+#else
+
+#define lfloat float
+#define lvec2 vec2
+#define lvec3 vec3
+#define lvec4 vec4
+
+#endif
+
+#ifdef VULKAN
+
+#define BINDING_COLOR_TEXTURE 1
+
+#else // ^^^ Vulkan ^^^ // vvv OpenGL vvv
+
+#define BINDING_COLOR_TEXTURE 0
+
+#endif
+
+layout (location = 0) in vec2 tex_coord;
+
+layout (location = 0) out vec4 frag_color;
+
+layout (binding = BINDING_COLOR_TEXTURE) uniform sampler2D input_texture;
+
+const bool ignore_alpha = true;
+
+lfloat ColorDist1(lvec4 a, lvec4 b) {
+    // https://en.wikipedia.org/wiki/YCbCr#ITU-R_BT.2020_conversion
+    const lvec3 K = lvec3(0.2627, 0.6780, 0.0593);
+    const lfloat scaleB = lfloat(0.5) / (lfloat(1.0) - K.b);
+    const lfloat scaleR = lfloat(0.5) / (lfloat(1.0) - K.r);
+    lvec4 diff = a - b;
+    lfloat Y = dot(diff.rgb, K);
+    lfloat Cb = scaleB * (diff.b - Y);
+    lfloat Cr = scaleR * (diff.r - Y);
+    lvec3 YCbCr = lvec3(Y, Cb, Cr);
+    lfloat d = length(YCbCr);
+    if (ignore_alpha) {
+        return d;
+    }
+    return sqrt(a.a * b.a * d * d + diff.a * diff.a);
+}
+
+lvec4 ColorDist(lvec4 ref, lvec4 A, lvec4 B, lvec4 C, lvec4 D) {
+    return lvec4(
+            ColorDist1(ref, A),
+            ColorDist1(ref, B),
+            ColorDist1(ref, C),
+            ColorDist1(ref, D)
+        );
+}
+
+vec4 Scaleforce(sampler2D tex, vec2 tex_coord) {
+    lvec4 bl = lvec4(textureOffset(tex, tex_coord, ivec2(-1, -1)));
+    lvec4 bc = lvec4(textureOffset(tex, tex_coord, ivec2(0, -1)));
+    lvec4 br = lvec4(textureOffset(tex, tex_coord, ivec2(1, -1)));
+    lvec4 cl = lvec4(textureOffset(tex, tex_coord, ivec2(-1, 0)));
+    lvec4 cc = lvec4(texture(tex, tex_coord));
+    lvec4 cr = lvec4(textureOffset(tex, tex_coord, ivec2(1, 0)));
+    lvec4 tl = lvec4(textureOffset(tex, tex_coord, ivec2(-1, 1)));
+    lvec4 tc = lvec4(textureOffset(tex, tex_coord, ivec2(0, 1)));
+    lvec4 tr = lvec4(textureOffset(tex, tex_coord, ivec2(1, 1)));
+
+    lvec4 offset_tl = ColorDist(cc, tl, tc, tr, cr);
+    lvec4 offset_br = ColorDist(cc, br, bc, bl, cl);
+
+    // Calculate how different cc is from the texels around it
+    const lfloat plus_weight = lfloat(1.5);
+    const lfloat cross_weight = lfloat(1.5);
+    lfloat total_dist = dot(offset_tl + offset_br, lvec4(cross_weight, plus_weight, cross_weight, plus_weight));
+
+    if (total_dist == lfloat(0.0)) {
+        return cc;
+    } else {
+        // Add together all the distances with direction taken into account
+        lvec4 tmp = offset_tl - offset_br;
+        lvec2 total_offset = tmp.wy * plus_weight + (tmp.zz + lvec2(-tmp.x, tmp.x)) * cross_weight;
+
+        // When the image has thin points, they tend to split apart.
+        // This is because the texels all around are different and total_offset reaches into clear areas.
+        // This works pretty well to keep the offset in bounds for these cases.
+        lfloat clamp_val = length(total_offset) / total_dist;
+        vec2 final_offset = vec2(clamp(total_offset, -clamp_val, clamp_val)) / textureSize(tex, 0);
+
+        return texture(tex, tex_coord - final_offset);
+    }
+}
+
+void main() {
+    frag_color = Scaleforce(input_texture, tex_coord);
+}