Volumes: add render settings for volume datablock

* Space: volume density and step size in object or world space
* Step Size: override automatic step size
* Clipping: values below this are ignored for tighter volume bounds

The last two are Cycles only currently.

Ref T73201

1 files changed, 15 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/volume_render.cc b/source/blender/blenkernel/intern/volume_render.cc
index d8fbbce3bae..a4833f1ffa4 100644
--- a/source/blender/blenkernel/intern/volume_render.cc
+++ b/source/blender/blenkernel/intern/volume_render.cc
@@ -356,3 +356,18 @@ void BKE_volume_grid_wireframe(const Volume *volume,
   cb(cb_userdata, NULL, NULL, 0, 0);
 #endif
 }
+
+/* Render */
+
+float BKE_volume_density_scale(const Volume *volume, const float matrix[4][4])
+{
+  if (volume->render.space == VOLUME_SPACE_OBJECT) {
+    float unit[3] = {1.0f, 1.0f, 1.0f};
+    normalize_v3(unit);
+    mul_mat3_m4_v3(matrix, unit);
+    return 1.0f / len_v3(unit);
+  }
+  else {
+    return 1.0f;
+  }
+}