Cycles: Fix T49901: OpenCL build error after recent light texture coordinate commit

Basically, the problem here was that the transform that's used to bring texture coordinates
to world space is either fetched while setting up the shader (with Object Motion is enabled) or
fetched when needed (otherwise). That helps to save ShaderData memory on OpenCL when Object Motion isn't needed.

Now, if OM is enabled, the Lamp transform can just be stored inside the ShaderData as well. The original commit just assumed it is.
However, when it's not (on OpenCL by default, for example), there is no easy way to fetch it when needed, since the ShaderData doesn't
store the Lamp index.

So, for now the lamps just don't support local texture coordinates anymore when Object Motion is disabled.
To fix and support this properly, one of the following could be done:
- Just always pre-fetch the transform. Downside: Memory Usage increases when not using OM on OpenCL
- Add a variable to ShaderData that stores the Lamp ID to allow fetching it when needed
- Store the Lamp ID inside prim or object. Problem: Cycles currently checks these for whether an object was hit - these checks would need to be changed.
- Enable OM whenever a Texture Coordinate's Normal output is used. Downside: Might not actually be needed.

1 files changed, 2 insertions, 5 deletions

diff --git a/intern/cycles/kernel/kernel_shader.h b/intern/cycles/kernel/kernel_shader.h
index b4b980c4e90..c1b3153d8fe 100644
--- a/intern/cycles/kernel/kernel_shader.h
+++ b/intern/cycles/kernel/kernel_shader.h
@@ -276,16 +276,13 @@ ccl_device_inline void shader_setup_from_sample(KernelGlobals *kg,
 
 #ifdef __OBJECT_MOTION__
 		shader_setup_object_transforms(kg, sd, time);
-#endif
+		ccl_fetch(sd, time) = time;
 	}
 	else if(lamp != LAMP_NONE) {
 		ccl_fetch(sd, ob_tfm)  = lamp_fetch_transform(kg, lamp, false);
 		ccl_fetch(sd, ob_itfm) = lamp_fetch_transform(kg, lamp, true);
-	}
-
-#ifdef __OBJECT_MOTION__
-	ccl_fetch(sd, time) = time;
 #endif
+	}
 
 	/* transform into world space */
 	if(object_space) {