Cycles: remove prefix from source code file names

Remove prefix of filenames that is the same as the folder name. This used
to help when #includes were using individual files, but now they are always
relative to the cycles root directory and so the prefixes are redundant.

For patches and branches, git merge and rebase should be able to detect the
renames and move over code to the right file.

1 files changed, 227 insertions, 0 deletions

diff --git a/intern/cycles/kernel/light/common.h b/intern/cycles/kernel/light/common.h
new file mode 100644
index 00000000000..75331d32d44
--- /dev/null
+++ b/intern/cycles/kernel/light/common.h
@@ -0,0 +1,227 @@
+/*
+ * Copyright 2011-2020 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include "kernel/sample/mapping.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* Area light sampling */
+
+/* Uses the following paper:
+ *
+ * Carlos Urena et al.
+ * An Area-Preserving Parametrization for Spherical Rectangles.
+ *
+ * https://www.solidangle.com/research/egsr2013_spherical_rectangle.pdf
+ *
+ * Note: light_p is modified when sample_coord is true.
+ */
+ccl_device_inline float rect_light_sample(float3 P,
+                                          ccl_private float3 *light_p,
+                                          float3 axisu,
+                                          float3 axisv,
+                                          float randu,
+                                          float randv,
+                                          bool sample_coord)
+{
+  /* In our name system we're using P for the center,
+   * which is o in the paper.
+   */
+
+  float3 corner = *light_p - axisu * 0.5f - axisv * 0.5f;
+  float axisu_len, axisv_len;
+  /* Compute local reference system R. */
+  float3 x = normalize_len(axisu, &axisu_len);
+  float3 y = normalize_len(axisv, &axisv_len);
+  float3 z = cross(x, y);
+  /* Compute rectangle coords in local reference system. */
+  float3 dir = corner - P;
+  float z0 = dot(dir, z);
+  /* Flip 'z' to make it point against Q. */
+  if (z0 > 0.0f) {
+    z *= -1.0f;
+    z0 *= -1.0f;
+  }
+  float x0 = dot(dir, x);
+  float y0 = dot(dir, y);
+  float x1 = x0 + axisu_len;
+  float y1 = y0 + axisv_len;
+  /* Compute internal angles (gamma_i). */
+  float4 diff = make_float4(x0, y1, x1, y0) - make_float4(x1, y0, x0, y1);
+  float4 nz = make_float4(y0, x1, y1, x0) * diff;
+  nz = nz / sqrt(z0 * z0 * diff * diff + nz * nz);
+  float g0 = safe_acosf(-nz.x * nz.y);
+  float g1 = safe_acosf(-nz.y * nz.z);
+  float g2 = safe_acosf(-nz.z * nz.w);
+  float g3 = safe_acosf(-nz.w * nz.x);
+  /* Compute predefined constants. */
+  float b0 = nz.x;
+  float b1 = nz.z;
+  float b0sq = b0 * b0;
+  float k = M_2PI_F - g2 - g3;
+  /* Compute solid angle from internal angles. */
+  float S = g0 + g1 - k;
+
+  if (sample_coord) {
+    /* Compute cu. */
+    float au = randu * S + k;
+    float fu = (cosf(au) * b0 - b1) / sinf(au);
+    float cu = 1.0f / sqrtf(fu * fu + b0sq) * (fu > 0.0f ? 1.0f : -1.0f);
+    cu = clamp(cu, -1.0f, 1.0f);
+    /* Compute xu. */
+    float xu = -(cu * z0) / max(sqrtf(1.0f - cu * cu), 1e-7f);
+    xu = clamp(xu, x0, x1);
+    /* Compute yv. */
+    float z0sq = z0 * z0;
+    float y0sq = y0 * y0;
+    float y1sq = y1 * y1;
+    float d = sqrtf(xu * xu + z0sq);
+    float h0 = y0 / sqrtf(d * d + y0sq);
+    float h1 = y1 / sqrtf(d * d + y1sq);
+    float hv = h0 + randv * (h1 - h0), hv2 = hv * hv;
+    float yv = (hv2 < 1.0f - 1e-6f) ? (hv * d) / sqrtf(1.0f - hv2) : y1;
+
+    /* Transform (xu, yv, z0) to world coords. */
+    *light_p = P + xu * x + yv * y + z0 * z;
+  }
+
+  /* return pdf */
+  if (S != 0.0f)
+    return 1.0f / S;
+  else
+    return 0.0f;
+}
+
+ccl_device_inline float3 ellipse_sample(float3 ru, float3 rv, float randu, float randv)
+{
+  to_unit_disk(&randu, &randv);
+  return ru * randu + rv * randv;
+}
+
+ccl_device float3 disk_light_sample(float3 v, float randu, float randv)
+{
+  float3 ru, rv;
+
+  make_orthonormals(v, &ru, &rv);
+
+  return ellipse_sample(ru, rv, randu, randv);
+}
+
+ccl_device float3 distant_light_sample(float3 D, float radius, float randu, float randv)
+{
+  return normalize(D + disk_light_sample(D, randu, randv) * radius);
+}
+
+ccl_device float3
+sphere_light_sample(float3 P, float3 center, float radius, float randu, float randv)
+{
+  return disk_light_sample(normalize(P - center), randu, randv) * radius;
+}
+
+ccl_device float spot_light_attenuation(float3 dir, float spot_angle, float spot_smooth, float3 N)
+{
+  float attenuation = dot(dir, N);
+
+  if (attenuation <= spot_angle) {
+    attenuation = 0.0f;
+  }
+  else {
+    float t = attenuation - spot_angle;
+
+    if (t < spot_smooth && spot_smooth != 0.0f)
+      attenuation *= smoothstepf(t / spot_smooth);
+  }
+
+  return attenuation;
+}
+
+ccl_device float light_spread_attenuation(const float3 D,
+                                          const float3 lightNg,
+                                          const float tan_spread,
+                                          const float normalize_spread)
+{
+  /* Model a soft-box grid, computing the ratio of light not hidden by the
+   * slats of the grid at a given angle. (see D10594). */
+  const float cos_a = -dot(D, lightNg);
+  const float sin_a = safe_sqrtf(1.0f - sqr(cos_a));
+  const float tan_a = sin_a / cos_a;
+  return max((1.0f - (tan_spread * tan_a)) * normalize_spread, 0.0f);
+}
+
+/* Compute subset of area light that actually has an influence on the shading point, to
+ * reduce noise with low spread. */
+ccl_device bool light_spread_clamp_area_light(const float3 P,
+                                              const float3 lightNg,
+                                              ccl_private float3 *lightP,
+                                              ccl_private float3 *axisu,
+                                              ccl_private float3 *axisv,
+                                              const float tan_spread)
+{
+  /* Closest point in area light plane and distance to that plane. */
+  const float3 closest_P = P - dot(lightNg, P - *lightP) * lightNg;
+  const float t = len(closest_P - P);
+
+  /* Radius of circle on area light that actually affects the shading point. */
+  const float radius = t / tan_spread;
+
+  /* TODO: would be faster to store as normalized vector + length, also in rect_light_sample. */
+  float len_u, len_v;
+  const float3 u = normalize_len(*axisu, &len_u);
+  const float3 v = normalize_len(*axisv, &len_v);
+
+  /* Local uv coordinates of closest point. */
+  const float closest_u = dot(u, closest_P - *lightP);
+  const float closest_v = dot(v, closest_P - *lightP);
+
+  /* Compute rectangle encompassing the circle that affects the shading point,
+   * clamped to the bounds of the area light. */
+  const float min_u = max(closest_u - radius, -len_u * 0.5f);
+  const float max_u = min(closest_u + radius, len_u * 0.5f);
+  const float min_v = max(closest_v - radius, -len_v * 0.5f);
+  const float max_v = min(closest_v + radius, len_v * 0.5f);
+
+  /* Skip if rectangle is empty. */
+  if (min_u >= max_u || min_v >= max_v) {
+    return false;
+  }
+
+  /* Compute new area light center position and axes from rectangle in local
+   * uv coordinates. */
+  const float new_center_u = 0.5f * (min_u + max_u);
+  const float new_center_v = 0.5f * (min_v + max_v);
+  const float new_len_u = max_u - min_u;
+  const float new_len_v = max_v - min_v;
+
+  *lightP = *lightP + new_center_u * u + new_center_v * v;
+  *axisu = u * new_len_u;
+  *axisv = v * new_len_v;
+
+  return true;
+}
+
+ccl_device float lamp_light_pdf(KernelGlobals kg, const float3 Ng, const float3 I, float t)
+{
+  float cos_pi = dot(Ng, I);
+
+  if (cos_pi <= 0.0f)
+    return 0.0f;
+
+  return t * t / cos_pi;
+}
+
+CCL_NAMESPACE_END