Sun angle to angular diameter
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Authored by Tim Stullich (tstullich) on May 7 2019, 4:27 PM.

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Reviewers

Brecht Van Lommel (brecht)

Group Reviewers

Cycles

Maniphest Tasks

T37953: Separate sun lamp size as angular diameter

Commits

rC3a0602c8e219: Lights: change sun light size to be specified as angle
rBS5ba1a6bee042: Lights: change sun light size to be specified as angle
rB5ba1a6bee042: Lights: change sun light size to be specified as angle

Summary

This patch introduces the ability to set the size of the Sun light property through the use of the angular diameter as viewed from Earth.
There are two unanswered questions regarding this change:

The default value of 0.526 radians is not properly set in the EEVEE UI and is instead set to 0
How the new 'sun_angle' property is meant to be used within the renderer is still unclear. To me it looks like that value can be set through the UI but internal rendering code does not actually use this property in any meaningful way.

Once these two issues are addressed these changes should be able to be shipped.

Diff Detail

Event Timeline

Tim Stullich (tstullich) created this revision.May 7 2019, 4:27 PM

Tim Stullich (tstullich) added a task: T37953: Separate sun lamp size as angular diameter.

Duarte Farrajota Ramos (duarteframos) added a subscriber: Duarte Farrajota Ramos (duarteframos).May 7 2019, 4:32 PM

Jason Clarke (jtheninja) added a subscriber: Jason Clarke (jtheninja).May 8 2019, 7:59 PM

Tim Stullich (tstullich) added a reviewer: Cycles.May 9 2019, 2:39 PM

The default value of 0.526 radians is not properly set in the EEVEE UI and is instead set to 0

This should be initialized in two places. One is in BKE_light_init for new lights.

The other is in versioning code, which you already have in version_update.py but it's only applying to files saved in 2.79. It's easier to remove that and do it in C. The following code can be added at the end of versioning_280.c (I didn't test it):

if (!DNA_struct_elem_find(fd->filesdna, "Light", "float", "sun_angle")) {
  LISTBASE_FOREACH (Light *, light, &bmain->lights) {
    light->sun_angle = 2.0f * atanf(light_size / 2.0f);
  }
}

intern/cycles/blender/addon/properties.py
940–947	This can be removed entirely, Cycles and Eevee can share the same property. It should just read `light.sun_angle` always instead of using the Cycles property.
source/blender/draw/engines/eevee/shaders/lights_lib.glsl
281–290	Easiest is no to change any GLSL code, but rather update the code that passes the parameters to it. That's in `light_shape_parameters_set`.