Fix T48732: New GGX breaks OpenCL kernel

Make sure we don't perform any implicit address space conversion.

A bit annoying, but less intrusive approaches (like using temp private
variable in .cl kernel) do not work correct here.

Using generic address space will help from code side here, but will
be somewhat slower due to extra things happening as far as i know.

1 files changed, 18 insertions, 2 deletions

diff --git a/intern/cycles/kernel/kernel_random.h b/intern/cycles/kernel/kernel_random.h
index bf3c25d2cb2..94598e2565e 100644
--- a/intern/cycles/kernel/kernel_random.h
+++ b/intern/cycles/kernel/kernel_random.h
@@ -232,14 +232,14 @@ ccl_device void path_rng_end(KernelGlobals *kg, ccl_global uint *rng_state, RNG
 
 /* Linear Congruential Generator */
 
-ccl_device uint lcg_step_uint(ccl_addr_space uint *rng)
+ccl_device uint lcg_step_uint(uint *rng)
 {
 	/* implicit mod 2^32 */
 	*rng = (1103515245*(*rng) + 12345);
 	return *rng;
 }
 
-ccl_device float lcg_step_float(ccl_addr_space uint *rng)
+ccl_device float lcg_step_float(uint *rng)
 {
 	/* implicit mod 2^32 */
 	*rng = (1103515245*(*rng) + 12345);
@@ -314,5 +314,21 @@ ccl_device_inline uint lcg_state_init(RNG *rng, const ccl_addr_space PathState *
 	return lcg_init(*rng + state->rng_offset + state->sample*scramble);
 }
 
+/* TODO(sergey): For until we can use generic address space from OpenCL 2.0. */
+
+ccl_device_inline uint lcg_state_init_addrspace(ccl_addr_space RNG *rng,
+                                                const ccl_addr_space PathState *state,
+                                                uint scramble)
+{
+	return lcg_init(*rng + state->rng_offset + state->sample*scramble);
+}
+
+ccl_device float lcg_step_float_addrspace(ccl_addr_space uint *rng)
+{
+	/* implicit mod 2^32 */
+	*rng = (1103515245*(*rng) + 12345);
+	return (float)*rng * (1.0f/(float)0xFFFFFFFF);
+}
+
 CCL_NAMESPACE_END