Cycles: Implement texture coordinates for Point, Spot and Area Lamps

When using the Normal output of the Texture Coordinate node on Point and Spot lamps, the coordinates now depend on the rotation of the lamp.
On Area lamps, the Parametric output of the Geometry node now returns UV coordinates on the area lamp.

Credit for the Area lamp part goes to Stefan Werner (from D1995).

1 files changed, 17 insertions, 4 deletions

diff --git a/intern/cycles/kernel/kernel_light.h b/intern/cycles/kernel/kernel_light.h
index fffa9afb342..d4cc36d1495 100644
--- a/intern/cycles/kernel/kernel_light.h
+++ b/intern/cycles/kernel/kernel_light.h
@@ -297,7 +297,7 @@ ccl_device_inline float background_portal_pdf(KernelGlobals *kg,
 		float3 axisu = make_float3(data1.y, data1.z, data1.w);
 		float3 axisv = make_float3(data2.y, data2.z, data2.w);
 
-		if(!ray_quad_intersect(P, direction, 1e-4f, FLT_MAX, lightpos, axisu, axisv, dir, NULL, NULL))
+		if(!ray_quad_intersect(P, direction, 1e-4f, FLT_MAX, lightpos, axisu, axisv, dir, NULL, NULL, NULL, NULL))
 			continue;
 
 		portal_pdf += area_light_sample(P, &lightpos, axisu, axisv, 0.0f, 0.0f, false);
@@ -585,6 +585,10 @@ ccl_device_inline bool lamp_light_sample(KernelGlobals *kg,
 					return false;
 				}
 			}
+			float2 uv = map_to_sphere(ls->Ng);
+			ls->u = uv.x;
+			ls->v = uv.y;
+
 			ls->pdf *= lamp_light_pdf(kg, ls->Ng, -ls->D, ls->t);
 		}
 		else {
@@ -600,11 +604,16 @@ ccl_device_inline bool lamp_light_sample(KernelGlobals *kg,
 				return false;
 			}
 
+			float3 inplane = ls->P;
 			ls->pdf = area_light_sample(P, &ls->P,
 			                          axisu, axisv,
 			                          randu, randv,
 			                          true);
 
+			inplane = ls->P - inplane;
+			ls->u = dot(inplane, axisu) * (1.0f / dot(axisu, axisu)) + 0.5f;
+			ls->v = dot(inplane, axisv) * (1.0f / dot(axisv, axisv)) + 0.5f;
+
 			ls->Ng = D;
 			ls->D = normalize_len(ls->P - P, &ls->t);
 
@@ -706,6 +715,9 @@ ccl_device bool lamp_light_eval(KernelGlobals *kg, int lamp, float3 P, float3 D,
 			if(ls->eval_fac == 0.0f)
 				return false;
 		}
+		float2 uv = map_to_sphere(ls->Ng);
+		ls->u = uv.x;
+		ls->v = uv.y;
 
 		/* compute pdf */
 		if(ls->t != FLT_MAX)
@@ -730,8 +742,10 @@ ccl_device bool lamp_light_eval(KernelGlobals *kg, int lamp, float3 P, float3 D,
 
 		float3 light_P = make_float3(data0.y, data0.z, data0.w);
 
-		if(!ray_quad_intersect(P, D, 0.0f, t,
-		                       light_P, axisu, axisv, Ng, &ls->P, &ls->t))
+		if(!ray_quad_intersect(P, D, 0.0f, t, light_P,
+		                       axisu, axisv, Ng,
+		                       &ls->P, &ls->t,
+		                       &ls->u, &ls->v))
 		{
 			return false;
 		}
@@ -887,4 +901,3 @@ ccl_device int light_select_num_samples(KernelGlobals *kg, int index)
 }
 
 CCL_NAMESPACE_END
-