Cycles: Move intersection math to own header file

There are following benefits:

- Modifying intersection algorithm will not cause so much re-compilation.
- It works around header dependency hell and allows us to use vectorization
  types much easier in there.

3 files changed, 159 insertions, 135 deletions

diff --git a/intern/cycles/util/CMakeLists.txt b/intern/cycles/util/CMakeLists.txt
index d8abf671bd6..6bd47120482 100644
--- a/intern/cycles/util/CMakeLists.txt
+++ b/intern/cycles/util/CMakeLists.txt
@@ -52,6 +52,7 @@ set(SRC_HEADERS
 	util_math.h
 	util_math_cdf.h
 	util_math_fast.h
+	util_math_intersect.h
 	util_md5.h
 	util_opengl.h
 	util_optimization.h
diff --git a/intern/cycles/util/util_math.h b/intern/cycles/util/util_math.h
index da18ae907a0..329b7f645c5 100644
--- a/intern/cycles/util/util_math.h
+++ b/intern/cycles/util/util_math.h
@@ -1451,140 +1451,6 @@ ccl_device_inline float beta(float x, float y)
 #endif
 }
 
-/* Ray Intersection */
-
-ccl_device bool ray_sphere_intersect(
-	float3 ray_P, float3 ray_D, float ray_t,
-	float3 sphere_P, float sphere_radius,
-	float3 *isect_P, float *isect_t)
-{
-	float3 d = sphere_P - ray_P;
-	float radiussq = sphere_radius*sphere_radius;
-	float tsq = dot(d, d);
-
-	if(tsq > radiussq) { /* ray origin outside sphere */
-		float tp = dot(d, ray_D);
-
-		if(tp < 0.0f) /* dir points away from sphere */
-			return false;
-
-		float dsq = tsq - tp*tp; /* pythagoras */
-
-		if(dsq > radiussq) /* closest point on ray outside sphere */
-			return false;
-
-		float t = tp - sqrtf(radiussq - dsq); /* pythagoras */
-
-		if(t < ray_t) {
-			*isect_t = t;
-			*isect_P = ray_P + ray_D*t;
-			return true;
-		}
-	}
-
-	return false;
-}
-
-ccl_device bool ray_aligned_disk_intersect(
-	float3 ray_P, float3 ray_D, float ray_t,
-	float3 disk_P, float disk_radius,
-	float3 *isect_P, float *isect_t)
-{
-	/* aligned disk normal */
-	float disk_t;
-	float3 disk_N = normalize_len(ray_P - disk_P, &disk_t);
-	float div = dot(ray_D, disk_N);
-
-	if(UNLIKELY(div == 0.0f))
-		return false;
-
-	/* compute t to intersection point */
-	float t = -disk_t/div;
-	if(t < 0.0f || t > ray_t)
-		return false;
-	
-	/* test if within radius */
-	float3 P = ray_P + ray_D*t;
-	if(len_squared(P - disk_P) > disk_radius*disk_radius)
-		return false;
-
-	*isect_P = P;
-	*isect_t = t;
-
-	return true;
-}
-
-ccl_device_inline bool ray_triangle_intersect_uv(
-        float3 ray_P, float3 ray_D, float ray_t,
-        float3 v0, float3 v1, float3 v2,
-        float *isect_u, float *isect_v, float *isect_t)
-{
-	/* Calculate intersection */
-	float3 e1 = v1 - v0;
-	float3 e2 = v2 - v0;
-	float3 s1 = cross(ray_D, e2);
-
-	const float divisor = dot(s1, e1);
-	if(UNLIKELY(divisor == 0.0f))
-		return false;
-
-	const float invdivisor = 1.0f/divisor;
-
-	/* compute first barycentric coordinate */
-	const float3 d = ray_P - v0;
-	const float u = dot(d, s1)*invdivisor;
-	if(u < 0.0f)
-		return false;
-
-	/* Compute second barycentric coordinate */
-	const float3 s2 = cross(d, e1);
-	const float v = dot(ray_D, s2)*invdivisor;
-	if(v < 0.0f)
-		return false;
-
-	const float b0 = 1.0f - u - v;
-	if(b0 < 0.0f)
-		return false;
-
-	/* compute t to intersection point */
-	const float t = dot(e2, s2)*invdivisor;
-	if(t < 0.0f || t > ray_t)
-		return false;
-
-	*isect_u = u;
-	*isect_v = v;
-	*isect_t = t;
-
-	return true;
-}
-
-ccl_device bool ray_quad_intersect(float3 ray_P, float3 ray_D, float ray_mint, float ray_maxt,
-                                   float3 quad_P, float3 quad_u, float3 quad_v, float3 quad_n,
-                                   float3 *isect_P, float *isect_t, float *isect_u, float *isect_v)
-{
-	float t = -(dot(ray_P, quad_n) - dot(quad_P, quad_n)) / dot(ray_D, quad_n);
-	if(t < ray_mint || t > ray_maxt)
-		return false;
-
-	float3 hit = ray_P + t*ray_D;
-	float3 inplane = hit - quad_P;
-
-	float u = dot(inplane, quad_u) / dot(quad_u, quad_u) + 0.5f;
-	if(u < 0.0f || u > 1.0f)
-		return false;
-
-	float v = dot(inplane, quad_v) / dot(quad_v, quad_v) + 0.5f;
-	if(v < 0.0f || v > 1.0f)
-		return false;
-
-	if(isect_P) *isect_P = hit;
-	if(isect_t) *isect_t = t;
-	if(isect_u) *isect_u = u;
-	if(isect_v) *isect_v = v;
-
-	return true;
-}
-
 /* projections */
 ccl_device_inline float2 map_to_tube(const float3 co)
 {
@@ -1647,4 +1513,3 @@ ccl_device_inline int util_max_axis(float3 vec)
 CCL_NAMESPACE_END
 
 #endif /* __UTIL_MATH_H__ */
-
diff --git a/intern/cycles/util/util_math_intersect.h b/intern/cycles/util/util_math_intersect.h
new file mode 100644
index 00000000000..0cf3cbcff97
--- /dev/null
+++ b/intern/cycles/util/util_math_intersect.h
@@ -0,0 +1,158 @@
+/*
+ * Copyright 2011-2017 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.
+ */
+
+#ifndef __UTIL_MATH_INTERSECT_H__
+#define __UTIL_MATH_INTERSECT_H__
+
+CCL_NAMESPACE_BEGIN
+
+/* Ray Intersection */
+
+ccl_device bool ray_sphere_intersect(
+	float3 ray_P, float3 ray_D, float ray_t,
+	float3 sphere_P, float sphere_radius,
+	float3 *isect_P, float *isect_t)
+{
+	float3 d = sphere_P - ray_P;
+	float radiussq = sphere_radius*sphere_radius;
+	float tsq = dot(d, d);
+
+	if(tsq > radiussq) { /* ray origin outside sphere */
+		float tp = dot(d, ray_D);
+
+		if(tp < 0.0f) /* dir points away from sphere */
+			return false;
+
+		float dsq = tsq - tp*tp; /* pythagoras */
+
+		if(dsq > radiussq) /* closest point on ray outside sphere */
+			return false;
+
+		float t = tp - sqrtf(radiussq - dsq); /* pythagoras */
+
+		if(t < ray_t) {
+			*isect_t = t;
+			*isect_P = ray_P + ray_D*t;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+ccl_device bool ray_aligned_disk_intersect(
+	float3 ray_P, float3 ray_D, float ray_t,
+	float3 disk_P, float disk_radius,
+	float3 *isect_P, float *isect_t)
+{
+	/* aligned disk normal */
+	float disk_t;
+	float3 disk_N = normalize_len(ray_P - disk_P, &disk_t);
+	float div = dot(ray_D, disk_N);
+
+	if(UNLIKELY(div == 0.0f))
+		return false;
+
+	/* compute t to intersection point */
+	float t = -disk_t/div;
+	if(t < 0.0f || t > ray_t)
+		return false;
+	
+	/* test if within radius */
+	float3 P = ray_P + ray_D*t;
+	if(len_squared(P - disk_P) > disk_radius*disk_radius)
+		return false;
+
+	*isect_P = P;
+	*isect_t = t;
+
+	return true;
+}
+
+ccl_device_inline bool ray_triangle_intersect_uv(
+        float3 ray_P, float3 ray_D, float ray_t,
+        float3 v0, float3 v1, float3 v2,
+        float *isect_u, float *isect_v, float *isect_t)
+{
+	/* Calculate intersection */
+	float3 e1 = v1 - v0;
+	float3 e2 = v2 - v0;
+	float3 s1 = cross(ray_D, e2);
+
+	const float divisor = dot(s1, e1);
+	if(UNLIKELY(divisor == 0.0f))
+		return false;
+
+	const float invdivisor = 1.0f/divisor;
+
+	/* compute first barycentric coordinate */
+	const float3 d = ray_P - v0;
+	const float u = dot(d, s1)*invdivisor;
+	if(u < 0.0f)
+		return false;
+
+	/* Compute second barycentric coordinate */
+	const float3 s2 = cross(d, e1);
+	const float v = dot(ray_D, s2)*invdivisor;
+	if(v < 0.0f)
+		return false;
+
+	const float b0 = 1.0f - u - v;
+	if(b0 < 0.0f)
+		return false;
+
+	/* compute t to intersection point */
+	const float t = dot(e2, s2)*invdivisor;
+	if(t < 0.0f || t > ray_t)
+		return false;
+
+	*isect_u = u;
+	*isect_v = v;
+	*isect_t = t;
+
+	return true;
+}
+
+ccl_device bool ray_quad_intersect(float3 ray_P, float3 ray_D, float ray_mint, float ray_maxt,
+                                   float3 quad_P, float3 quad_u, float3 quad_v, float3 quad_n,
+                                   float3 *isect_P, float *isect_t, float *isect_u, float *isect_v)
+{
+	float t = -(dot(ray_P, quad_n) - dot(quad_P, quad_n)) / dot(ray_D, quad_n);
+	if(t < ray_mint || t > ray_maxt)
+		return false;
+
+	float3 hit = ray_P + t*ray_D;
+	float3 inplane = hit - quad_P;
+
+	float u = dot(inplane, quad_u) / dot(quad_u, quad_u) + 0.5f;
+	if(u < 0.0f || u > 1.0f)
+		return false;
+
+	float v = dot(inplane, quad_v) / dot(quad_v, quad_v) + 0.5f;
+	if(v < 0.0f || v > 1.0f)
+		return false;
+
+	if(isect_P) *isect_P = hit;
+	if(isect_t) *isect_t = t;
+	if(isect_u) *isect_u = u;
+	if(isect_v) *isect_v = v;
+
+	return true;
+}
+
+CCL_NAMESPACE_END
+
+#endif /* __UTIL_MATH_INTERSECT_H__ */