Fix T102853: radius of spot and point lamps shares same value with area lamp size

If we change the radius of a point or spot lamp, we also change the area lamp size.

As shown in T102853, this is bad for animating the lamp type.

The solution is to make the property point to another member of the DNA
struct `Light`.

Differential Revision: https://developer.blender.org/D16669

source/blender/blenkernel/BKE_blender_version.h

@@ -25,7 +25,7 @@ extern "C" {
 
 /* Blender file format version. */
 #define BLENDER_FILE_VERSION BLENDER_VERSION
-#define BLENDER_FILE_SUBVERSION 6
+#define BLENDER_FILE_SUBVERSION 7
 
 /* Minimum Blender version that supports reading file written with the current
  * version. Older Blender versions will test this and show a warning if the file

source/blender/blenkernel/intern/object.cc

@@ -2891,6 +2891,7 @@ void BKE_object_obdata_size_init(struct Object *ob, const float size)
     case OB_LAMP: {
       Light *lamp = (Light *)ob->data;
       lamp->dist *= size;
+      lamp->radius *= size;
       lamp->area_size *= size;
       lamp->area_sizey *= size;
       lamp->area_sizez *= size;

source/blender/blenloader/intern/versioning_300.cc

@@ -28,6 +28,7 @@
 #include "DNA_curves_types.h"
 #include "DNA_genfile.h"
 #include "DNA_gpencil_modifier_types.h"
+#include "DNA_light_types.h"
 #include "DNA_lineart_types.h"
 #include "DNA_listBase.h"
 #include "DNA_mask_types.h"
@@ -3836,6 +3837,13 @@ void blo_do_versions_300(FileData *fd, Library * /*lib*/, Main *bmain)
       }
     }
   }
+
+  if (!MAIN_VERSION_ATLEAST(bmain, 305, 7)) {
+    LISTBASE_FOREACH (Light *, light, &bmain->lights) {
+      light->radius = light->area_size;
+    }
+  }
+
   /**
    * Versioning code until next subversion bump goes here.
    *

source/blender/draw/engines/eevee/eevee_lights.c

@@ -45,7 +45,7 @@ static void light_shape_parameters_set(EEVEE_Light *evli, const Light *la, const
     evli->sizey = scale[1] / scale[2];
     evli->spotsize = cosf(la->spotsize * 0.5f);
     evli->spotblend = (1.0f - evli->spotsize) * la->spotblend;
-    evli->radius = max_ff(0.001f, la->area_size);
+    evli->radius = max_ff(0.001f, la->radius);
   }
   else if (la->type == LA_AREA) {
     evli->sizex = max_ff(0.003f, la->area_size * scale[0] * 0.5f);
@@ -62,7 +62,7 @@ static void light_shape_parameters_set(EEVEE_Light *evli, const Light *la, const
     evli->radius = max_ff(0.001f, tanf(min_ff(la->sun_angle, DEG2RADF(179.9f)) / 2.0f));
   }
   else {
-    evli->radius = max_ff(0.001f, la->area_size);
+    evli->radius = max_ff(0.001f, la->radius);
   }
 }
 

source/blender/draw/engines/eevee_next/eevee_light.cc

@@ -178,7 +178,7 @@ void Light::shape_parameters_set(const ::Light *la, const float scale[3])
       _area_size_x = tanf(min_ff(la->sun_angle, DEG2RADF(179.9f)) / 2.0f);
     }
     else {
-      _area_size_x = la->area_size;
+      _area_size_x = la->radius;
     }
     _area_size_y = _area_size_x = max_ff(0.001f, _area_size_x);
     radius_squared = square_f(_area_size_x);

source/blender/draw/engines/overlay/overlay_extra.cc

@@ -637,7 +637,7 @@ void OVERLAY_light_cache_populate(OVERLAY_Data *vedata, Object *ob)
   DRW_buffer_add_entry(cb->groundline, instdata.pos);
 
   if (la->type == LA_LOCAL) {
-    instdata.area_size_x = instdata.area_size_y = la->area_size;
+    instdata.area_size_x = instdata.area_size_y = la->radius;
     DRW_buffer_add_entry(cb->light_point, color, &instdata);
   }
   else if (la->type == LA_SUN) {
@@ -661,7 +661,7 @@ void OVERLAY_light_cache_populate(OVERLAY_Data *vedata, Object *ob)
     instdata.spot_blend = sqrtf((-a - c * a) / (c - c * a));
     instdata.spot_cosine = a;
     /* HACK: We pack the area size in alpha color. This is decoded by the shader. */
-    color[3] = -max_ff(la->area_size, FLT_MIN);
+    color[3] = -max_ff(la->radius, FLT_MIN);
     DRW_buffer_add_entry(cb->light_spot, color, &instdata);
 
     if ((la->mode & LA_SHOW_CONE) && !DRW_state_is_select()) {

source/blender/io/collada/DocumentImporter.cpp

@@ -1019,6 +1019,7 @@ bool DocumentImporter::writeLight(const COLLADAFW::Light *light)
     et->setData("bias", &(lamp->bias));
     et->setData("bufsize", &(lamp->bufsize));
     et->setData("buffers", &(lamp->buffers));
+    et->setData("radius", &(lamp->radius));
     et->setData("area_shape", &(lamp->area_shape));
     et->setData("area_size", &(lamp->area_size));
     et->setData("area_sizey", &(lamp->area_sizey));

source/blender/io/collada/LightExporter.cpp

@@ -132,6 +132,7 @@ bool LightsExporter::exportBlenderProfile(COLLADASW::Light &cla, Light *la)
   cla.addExtraTechniqueParameter("blender", "bufsize", la->bufsize);
   cla.addExtraTechniqueParameter("blender", "samp", la->samp);
   cla.addExtraTechniqueParameter("blender", "buffers", la->buffers);
+  cla.addExtraTechniqueParameter("blender", "radius", la->radius);
   cla.addExtraTechniqueParameter("blender", "area_shape", la->area_shape);
   cla.addExtraTechniqueParameter("blender", "area_size", la->area_size);
   cla.addExtraTechniqueParameter("blender", "area_sizey", la->area_sizey);

source/blender/io/usd/intern/usd_reader_light.cc

@@ -175,7 +175,7 @@ void USDLightReader::read_object_data(Main *bmain, const double motionSampleTime
         if (pxr::UsdAttribute radius_attr = sphere_light.GetRadiusAttr()) {
           float radius = 0.0f;
           if (radius_attr.Get(&radius, motionSampleTime)) {
-            blight->area_size = radius;
+            blight->radius = radius;
           }
         }
       }
@@ -192,7 +192,7 @@ void USDLightReader::read_object_data(Main *bmain, const double motionSampleTime
         if (pxr::UsdAttribute radius_attr = sphere_light.GetRadiusAttr()) {
           float radius = 0.0f;
           if (radius_attr.Get(&radius, motionSampleTime)) {
-            blight->area_size = radius;
+            blight->radius = radius;
           }
         }
 

source/blender/io/usd/intern/usd_writer_light.cc

@@ -80,7 +80,7 @@ void USDLightWriter::do_write(HierarchyContext &context)
       break;
     case LA_LOCAL: {
       pxr::UsdLuxSphereLight sphere_light = pxr::UsdLuxSphereLight::Define(stage, usd_path);
-      sphere_light.CreateRadiusAttr().Set(light->area_size, timecode);
+      sphere_light.CreateRadiusAttr().Set(light->radius, timecode);
 #if PXR_VERSION >= 2111
       usd_light_api = sphere_light.LightAPI();
 #else

source/blender/makesdna/DNA_light_types.h

@@ -48,7 +48,7 @@ typedef struct Light {
 
   float clipsta, clipend;
   float bias;
-  char _pad1[4];
+  float radius;
   short bufsize, samp, buffers, filtertype;
   char bufflag, buftype;
 

source/blender/makesrna/intern/rna_light.c

@@ -336,7 +336,7 @@ static void rna_def_light_shadow(StructRNA *srna, bool sun)
   RNA_def_property_update(prop, 0, "rna_Light_update");
 
   prop = RNA_def_property(srna, "shadow_soft_size", PROP_FLOAT, PROP_DISTANCE);
-  RNA_def_property_float_sdna(prop, NULL, "area_size");
+  RNA_def_property_float_sdna(prop, NULL, "radius");
   RNA_def_property_range(prop, 0.0f, FLT_MAX);
   RNA_def_property_ui_range(prop, 0, 100, 0.1, 3);
   RNA_def_property_ui_text(