1 files changed, 101 insertions, 0 deletions
diff --git a/source/blender/draw/engines/eevee/shaders/effect_reflection_lib.glsl b/source/blender/draw/engines/eevee/shaders/effect_reflection_lib.glsl
new file mode 100644
index 00000000000..cc73bbbfe29
--- /dev/null
+++ b/source/blender/draw/engines/eevee/shaders/effect_reflection_lib.glsl
@@ -0,0 +1,101 @@
+
+#pragma BLENDER_REQUIRE(common_view_lib.glsl)
+
+/* Based on:
+ * "Stochastic Screen Space Reflections"
+ * by Tomasz Stachowiak.
+ * https://www.ea.com/frostbite/news/stochastic-screen-space-reflections
+ * and
+ * "Stochastic all the things: raytracing in hybrid real-time rendering"
+ * by Tomasz Stachowiak.
+ * https://media.contentapi.ea.com/content/dam/ea/seed/presentations/dd18-seed-raytracing-in-hybrid-real-time-rendering.pdf
+ */
+
+uniform ivec2 halfresOffset;
+
+struct HitData {
+  /** Hit direction scaled by intersection time. */
+  vec3 hit_dir;
+  /** Screen space [0..1] depth of the reflection hit position, or -1.0 for planar reflections. */
+  float hit_depth;
+  /** Inverse probability of ray spawning in this direction. */
+  float ray_pdf_inv;
+  /** True if ray has hit valid geometry. */
+  bool is_hit;
+  /** True if ray was generated from a planar reflection probe. */
+  bool is_planar;
+};
+
+void encode_hit_data(HitData data, vec3 hit_sP, vec3 vP, out vec4 hit_data, out float hit_depth)
+{
+  vec3 hit_vP = get_view_space_from_depth(hit_sP.xy, hit_sP.z);
+  hit_data.xyz = hit_vP - vP;
+  hit_depth = data.is_planar ? -1.0 : hit_sP.z;
+  /* Record 1.0 / pdf to reduce the computation in the resolve phase. */
+  /* Encode hit validity in sign. */
+  hit_data.w = data.ray_pdf_inv * ((data.is_hit) ? 1.0 : -1.0);
+}
+
+HitData decode_hit_data(vec4 hit_data, float hit_depth)
+{
+  HitData data;
+  data.hit_dir.xyz = hit_data.xyz;
+  data.hit_depth = hit_depth;
+  data.is_planar = (hit_depth == -1.0);
+  data.ray_pdf_inv = abs(hit_data.w);
+  data.is_hit = (hit_data.w > 0.0);
+  return data;
+}
+
+/* Blue noise categorised into 4 sets of samples.
+ * See "Stochastic all the things" presentation slide 32-37. */
+const int resolve_samples_count = 9;
+const vec2 resolve_sample_offsets[36] = vec2[36](
+    /* Set 1. */
+    /* First Ring (2x2). */
+    vec2(0, 0),
+    /* Second Ring (6x6). */
+    vec2(-1, 3),
+    vec2(1, 3),
+    vec2(-1, 1),
+    vec2(3, 1),
+    vec2(-2, 0),
+    vec2(3, 0),
+    vec2(2, -1),
+    vec2(1, -2),
+    /* Set 2. */
+    /* First Ring (2x2). */
+    vec2(1, 1),
+    /* Second Ring (6x6). */
+    vec2(-2, 3),
+    vec2(3, 3),
+    vec2(0, 2),
+    vec2(2, 2),
+    vec2(-2, -1),
+    vec2(1, -1),
+    vec2(0, -2),
+    vec2(3, -2),
+    /* Set 3. */
+    /* First Ring (2x2). */
+    vec2(0, 1),
+    /* Second Ring (6x6). */
+    vec2(0, 3),
+    vec2(3, 2),
+    vec2(-2, 1),
+    vec2(2, 1),
+    vec2(-1, 0),
+    vec2(-2, -2),
+    vec2(0, -1),
+    vec2(2, -2),
+    /* Set 4. */
+    /* First Ring (2x2). */
+    vec2(1, 0),
+    /* Second Ring (6x6). */
+    vec2(2, 3),
+    vec2(-2, 2),
+    vec2(-1, 2),
+    vec2(1, 2),
+    vec2(2, 0),
+    vec2(-1, -1),
+    vec2(3, -1),
+    vec2(-1, -2));
+\ No newline at end of file