Alistair_Findlay commented

I am experiencing a similar issue. the buildings will become fully dark at far zoom levels and at certain angles. I can provide video and/or logs if wanted.

AMDGPU ARCH

Forgon commented

Replying to Warzone2100/old-trac-import#4375 (comment:1):

I am experiencing a similar issue. the buildings will become fully dark at far zoom levels and at certain angles. I can provide video and/or logs if wanted.

AMDGPU ARCH
Berg has already made a video (you can watch it here).

Forgon changed blocking which not transferred by tractive

Forgon changed blockedby which not transferred by tractive

Alistair_Findlay commented

Ah yes, that seems like the same bug.

Forgon changed type from bug to patch (an actual patch, not a request for one)

Forgon commented

The problem exists since at least version 3.1.0.
Its cause is diffuse lighting, which simulates light direction:
The larger the angle at which light hits the surface of an object, the darker
it will appear.

The light source in our game is called the sun.
Its position is initialized in src/display3d.cpp:

bool init3DView()
{
	/* Arbitrary choice - from direct read! */
	const Vector3f theSun(225.0f, -600.0f, 450.0f);

Lighting is calculated based on a simple model, which combines ambient lighting
(a background light), diffuse lighting (light reflection based on surface angle)
and specular lighting (which depends on the shininess of objects).
A practical introduction to the topic can be found
here.

When diffuse lighting is disabled, the map zoom distance does not influence the
brightness of objects.
To compensate for its absence, ambient lighting should be as bright as possible.
As a result, the terrain will appears brighter overall.

The sun's lighting intensities are initialized in lib/ivis_opengl/piedraw.cpp:

void pie_InitLighting()
{
	// set scene color, ambient, diffuse and specular light intensities of sun
	// diffuse lighting is turned off because players dislike it
	const gfx_api::gfxFloat defaultLight[LIGHT_MAX][4] = [0.0f, 0.0f, 0.0f, 1.0f},  {1.0f, 1.0f, 1.0f, 1.0f},  {0.0f, 0.0f, 0.0f, 1.0f},  {1.0f, 1.0f, 1.0f, 1.0f];
	memcpy(lighting0, defaultLight, sizeof(lighting0));
}

Two script functions allow changing the sun's position and lighting intensities:

## setSunPosition(x, y, z)

Move the position of the Sun, which in turn moves where shadows are cast. (3.2+ only)

## setSunIntensity(ambient r, g, b, diffuse r, g, b, specular r, g, b)

Set the ambient, diffuse and specular colour intensities of the Sun lighting source. (3.2+ only)

Forgon uploaded file diffuse_lighting.patch (1.3 KiB)

patch file based on revision 400191c9c47a4e39aeb12240283f355a57e30290

Forgon uploaded file diffuse_lighting_distance_2500_old.png (543.0 KiB)

screenshot of Sk-Rush at distance 2500 before applying the patch

Forgon uploaded file diffuse_lighting_distance_5000_old.png (460.1 KiB)

screenshot of Sk-Rush at distance 5000 before applying the patch

Forgon uploaded file diffuse_lighting_old.mkv (3062.5 KiB)

video of lighting with increasing map zoom distances before applying this patch

Forgon uploaded file diffuse_lighting_distance_2500_new.png (548.8 KiB)

screenshot of Sk-Rush at distance 2500 after applying the patch

Forgon uploaded file diffuse_lighting_distance_5000_new.png (470.8 KiB)

screenshot of Sk-Rush at distance 5000 after applying the patch

Forgon uploaded file diffuse_lighting_new.mkv (3122.6 KiB)

video of lighting with increasing map zoom distances after applying this patch

Forgon uploaded file diffuse_lighting_recording (1.8 KiB)

shell script to record video and take screenshots for documentation of this bug

Forgon uploaded file diffuse_lighting_savegame.wz (66.0 KiB)

savegame with damaged buildings for shell script diffuse_lighting_recording

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Forgon2100 <forgon2100@...> committed [456]

In Warzone2100/warzone2100@456a74e:

#CommitTicketReference repository="" revision="456a74edb1fa76e66bf8e0e2c888b54c0b5c6299"
Change lighting of sun to avoid objects darkening

* turn off diffuse lighting because players dislike objects darkening
  when zooming out, making them look as though they were damaged
* increase ambient lighting to compensate for resulting darkness
* overall increase in brightness of terrain

Fixes #4375