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, 4 insertions, 13 deletions

diff --git a/source/blender/nodes/shader/nodes/node_shader_wavelength.cc b/source/blender/nodes/shader/nodes/node_shader_wavelength.cc
index 522928a30fa..34fa639dd07 100644
--- a/source/blender/nodes/shader/nodes/node_shader_wavelength.cc
+++ b/source/blender/nodes/shader/nodes/node_shader_wavelength.cc
@@ -3,6 +3,8 @@
 
 #include "node_shader_util.hh"
 
+#include "IMB_colormanagement.h"
+
 namespace blender::nodes::node_shader_wavelength_cc {
 
 static void node_declare(NodeDeclarationBuilder &b)
@@ -20,22 +22,11 @@ static int node_shader_gpu_wavelength(GPUMaterial *mat,
   const int size = CM_TABLE + 1;
   float *data = static_cast<float *>(MEM_mallocN(sizeof(float) * size * 4, "cie_xyz texture"));
 
-  wavelength_to_xyz_table(data, size);
+  IMB_colormanagement_wavelength_to_rgb_table(data, size);
 
   float layer;
   GPUNodeLink *ramp_texture = GPU_color_band(mat, size, data, &layer);
-  XYZ_to_RGB xyz_to_rgb;
-  get_XYZ_to_RGB_for_gpu(&xyz_to_rgb);
-  return GPU_stack_link(mat,
-                        node,
-                        "node_wavelength",
-                        in,
-                        out,
-                        ramp_texture,
-                        GPU_constant(&layer),
-                        GPU_uniform(xyz_to_rgb.r),
-                        GPU_uniform(xyz_to_rgb.g),
-                        GPU_uniform(xyz_to_rgb.b));
+  return GPU_stack_link(mat, node, "node_wavelength", in, out, ramp_texture, GPU_constant(&layer));
 }
 
 }  // namespace blender::nodes::node_shader_wavelength_cc