Support skybox textures with alpha channel

doc/lua_api.md

@@ -8790,8 +8790,8 @@ child will follow movement and rotation of that bone.
             Some top and bottom textures expect to be aligned with the north face and will need to be rotated
             by -90 and 90 degrees, respectively, to fit the eastward orientation.
         * `clouds`: Boolean for whether clouds appear. (default: `true`)
-        * `sky_color`: A table used in `"regular"` type only, containing the
-          following values (alpha is ignored):
+        * `sky_color`: A table used in `"regular"` and `"skybox"` types only. If used with the later,
+            the `textures` should have an alpha channel. Contains the following values (alpha is ignored):
             * `day_sky`: ColorSpec, for the top half of the sky during the day.
               (default: `#61b5f5`)
             * `day_horizon`: ColorSpec, for the bottom half of the sky during the day.

src/client/game.cpp

@@ -2866,11 +2866,10 @@ void Game::handleClientEvent_SetSky(ClientEvent *event, CameraOrientation *cam)
 		);
 	} else if (event->set_sky->type == "skybox" &&
 			event->set_sky->textures.size() == 6) {
-		// Disable the dyanmic mesh skybox:
-		sky->setVisible(false);
-		// Set fog colors:
-		sky->setFallbackBgColor(event->set_sky->bgcolor);
-		// Set sunrise and sunset fog tinting:
+		// Shows the mesh skybox
+		sky->setVisible(true);
+		// Update mesh based skybox colours if applicable.
+		sky->setSkyColors(event->set_sky->sky_color);
 		sky->setHorizonTint(
 			event->set_sky->fog_sun_tint,
 			event->set_sky->fog_moon_tint,

src/client/sky.cpp

@@ -158,6 +158,7 @@ void Sky::render()
 
 		const f32 t = 1.0f;
 		const f32 o = 0.0f;
+		const bool has_tex = m_sky_params.textures.size() == 6;
 		static const u16 indices[6] = {0, 1, 2, 0, 2, 3};
 		video::S3DVertex vertices[4];
 
@@ -171,7 +172,7 @@ void Sky::render()
 			return;
 
 		// Draw the six sided skybox,
-		if (m_sky_params.textures.size() == 6) {
+		if (has_tex) {
 			for (u32 j = 5; j < 11; j++) {
 				video::SColor c(255, 255, 255, 255);
 				driver->setMaterial(m_materials[j]);
@@ -205,7 +206,8 @@ void Sky::render()
 		}
 
 		// Draw far cloudy fog thing blended with skycolor
-		if (m_visible) {
+		// Disabled when using a textured skybox to prevent clipping
+		if (m_visible && !has_tex) {
 			driver->setMaterial(m_materials[1]);
 			for (u32 j = 0; j < 4; j++) {
 				vertices[0] = video::S3DVertex(-1, -0.02, -1, 0, 0, 1, m_bgcolor, t, t);
@@ -268,9 +270,9 @@ void Sky::render()
 		if (m_moon_params.visible)
 			draw_moon(driver, mooncolor, mooncolor2, wicked_time_of_day);
 
-		// Draw far cloudy fog thing below all horizons in front of sun, moon
-		// and stars.
-		if (m_visible) {
+		// Draw far cloudy fog thing below all horizons in front of sun, moon and stars.
+		// Disabled when using a textured skybox to prevent clipping
+		if (m_visible && !has_tex) {
 			driver->setMaterial(m_materials[1]);
 
 			for (u32 j = 0; j < 4; j++) {
@@ -881,7 +883,7 @@ void Sky::addTextureToSkybox(const std::string &texture, int material_id,
 	video::ITexture *result = tsrc->getTextureForMesh(texture);
 	m_materials[material_id+5] = baseMaterial();
 	m_materials[material_id+5].setTexture(0, result);
-	m_materials[material_id+5].MaterialType = video::EMT_SOLID;
+	m_materials[material_id+5].MaterialType = video::EMT_TRANSPARENT_ALPHA_CHANNEL;
 }
 
 float getWickedTimeOfDay(float time_of_day)

src/network/clientpackethandler.cpp

@@ -1302,8 +1302,8 @@ void Client::handleCommand_HudSetSky(NetworkPacket* pkt)
 		MoonParams moon = SkyboxDefaults::getMoonDefaults();
 		StarParams stars = SkyboxDefaults::getStarDefaults();
 
-		// Fix for "regular" skies, as color isn't kept:
-		if (skybox.type == "regular") {
+		// Fix for "regular" and "skybox" skies, as color isn't kept:
+		if (skybox.type == "regular" || skybox.type == "skybox") {
 			skybox.sky_color = SkyboxDefaults::getSkyColorDefaults();
 			skybox.fog_tint_type = "default";
 			skybox.fog_moon_tint = video::SColor(255, 255, 255, 255);
@@ -1351,7 +1351,8 @@ void Client::handleCommand_HudSetSky(NetworkPacket* pkt)
 			*pkt >> texture;
 			skybox.textures.emplace_back(texture);
 		}
-	} else if (skybox.type == "regular") {
+	}
+	if (skybox.type == "regular" || skybox.type == "skybox") {
 		auto &c = skybox.sky_color;
 		*pkt >> c.day_sky >> c.day_horizon >> c.dawn_sky >> c.dawn_horizon
 			>> c.night_sky >> c.night_horizon >> c.indoors;

src/script/lua_api/l_object.cpp

@@ -2140,7 +2140,7 @@ int ObjectRef::l_set_sky(lua_State *L)
 
 		// Preserve old behavior of the sun, moon and stars
 		// when using the old set_sky call.
-		if (sky_params.type == "regular") {
+		if (sky_params.type == "regular" || sky_params.type == "skybox") {
 			sun_params.visible = true;
 			sun_params.sunrise_visible = true;
 			moon_params.visible = true;
@@ -2181,7 +2181,7 @@ int ObjectRef::l_set_sky(lua_State *L)
 static void push_sky_color(lua_State *L, const SkyboxParams &params)
 {
 	lua_newtable(L);
-	if (params.type == "regular") {
+	if (params.type == "regular" || params.type == "skybox") {
 		push_ARGB8(L, params.sky_color.day_sky);
 		lua_setfield(L, -2, "day_sky");
 		push_ARGB8(L, params.sky_color.day_horizon);

src/server.cpp

@@ -1867,7 +1867,8 @@ void Server::SendSetSky(session_t peer_id, const SkyboxParams &params)
 			pkt << (u16) params.textures.size();
 			for (const std::string &texture : params.textures)
 				pkt << texture;
-		} else if (params.type == "regular") {
+		}
+		if (params.type == "regular" || params.type == "skybox") {
 			auto &c = params.sky_color;
 			pkt << c.day_sky << c.day_horizon << c.dawn_sky << c.dawn_horizon
 				<< c.night_sky << c.night_horizon << c.indoors;