Fix T98270: Cycles shows black with color values > 65K in GPU render

After recent changes to Nishita sky to clamp negative colors, the pixels ended
up a bit brighter which lead to them exceeding the half float max value. The
CUDA float to half function seems to need clamping.

1 files changed, 4 insertions, 4 deletions

diff --git a/intern/cycles/util/half.h b/intern/cycles/util/half.h
index 59ed652b346..434bc12d670 100644
--- a/intern/cycles/util/half.h
+++ b/intern/cycles/util/half.h
@@ -74,9 +74,9 @@ struct half4 {
 ccl_device_inline half float_to_half_image(float f)
 {
 #if defined(__KERNEL_METAL__)
-  return half(f);
+  return half(min(f, 65504.0f));
 #elif defined(__KERNEL_CUDA__) || defined(__KERNEL_HIP__)
-  return __float2half(f);
+  return __float2half(min(f, 65504.0f));
 #else
   const uint u = __float_as_uint(f);
   /* Sign bit, shifted to its position. */
@@ -137,9 +137,9 @@ ccl_device_inline float4 half4_to_float4_image(const half4 h)
 ccl_device_inline half float_to_half_display(const float f)
 {
 #if defined(__KERNEL_METAL__)
-  return half(f);
+  return half(min(f, 65504.0f));
 #elif defined(__KERNEL_CUDA__) || defined(__KERNEL_HIP__)
-  return __float2half(f);
+  return __float2half(min(f, 65504.0f));
 #else
   const int x = __float_as_int((f > 0.0f) ? ((f < 65504.0f) ? f : 65504.0f) : 0.0f);
   const int absolute = x & 0x7FFFFFFF;