Fix Eevee blackbody wrong with non-default scene linear color space

* Port over new code tables from Cycles
* Convert Rec.709 to scene linear for lookup table.
* Move code for wavelength and blackbody to IMB so they can access the
  required transforms, which are not in blenlib.
* Remove clamping from blackbody shader to bypass the texture read.
  Since it's variable now easiest to just always read from the texture
  than pass additional parameters.
* Fold XYZ to RGB conversion into the wavelength table.

Ref T68926

1 files changed, 12 insertions, 0 deletions

diff --git a/source/blender/imbuf/IMB_colormanagement.h b/source/blender/imbuf/IMB_colormanagement.h
index 50af946cd95..512dc674fc7 100644
--- a/source/blender/imbuf/IMB_colormanagement.h
+++ b/source/blender/imbuf/IMB_colormanagement.h
@@ -514,6 +514,18 @@ enum {
 
 /** \} */
 
+/* -------------------------------------------------------------------- */
+/** \name Rendering Tables
+ * \{ */
+
+void IMB_colormanagement_blackbody_temperature_to_rgb_table(float *r_table,
+                                                            const int width,
+                                                            const float min,
+                                                            const float max);
+void IMB_colormanagement_wavelength_to_rgb_table(float *r_table, const int width);
+
+/** \} */
+
 #ifdef __cplusplus
 }
 #endif