Fix Vulkan validation errors on default depth textures

The validation layers were complaining that we use DEFAULT_RD_TEXTURE_WHITE (which is RGBA8) in places where it's sampled as a depth texture. This commit adds the new default texture DEFAULT_RD_TEXTURE_DEPTH and uses it where needed.

servers/rendering/renderer_rd/forward_clustered/render_forward_clustered.cpp

@@ -2273,7 +2273,7 @@ RID RenderForwardClustered::_setup_render_pass_uniform_set(RenderListType p_rend
 			texture = shadow_atlas_get_texture(p_render_data->shadow_atlas);
 		}
 		if (!texture.is_valid()) {
-			texture = texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_WHITE);
+			texture = texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_DEPTH);
 		}
 		u.append_id(texture);
 		uniforms.push_back(u);
@@ -2285,7 +2285,7 @@ RID RenderForwardClustered::_setup_render_pass_uniform_set(RenderListType p_rend
 		if (p_use_directional_shadow_atlas && directional_shadow_get_texture().is_valid()) {
 			u.append_id(directional_shadow_get_texture());
 		} else {
-			u.append_id(texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_WHITE));
+			u.append_id(texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_DEPTH));
 		}
 		uniforms.push_back(u);
 	}
@@ -2342,7 +2342,7 @@ RID RenderForwardClustered::_setup_render_pass_uniform_set(RenderListType p_rend
 		u.binding = 9;
 		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
 		RID dbt = rb ? render_buffers_get_back_depth_texture(p_render_data->render_buffers) : RID();
-		RID texture = (dbt.is_valid()) ? dbt : texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_WHITE);
+		RID texture = (dbt.is_valid()) ? dbt : texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_DEPTH);
 		u.append_id(texture);
 		uniforms.push_back(u);
 	}
@@ -2499,7 +2499,7 @@ RID RenderForwardClustered::_setup_sdfgi_render_pass_uniform_set(RID p_albedo_te
 		RD::Uniform u;
 		u.binding = 4;
 		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
-		RID texture = texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_WHITE);
+		RID texture = texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_DEPTH);
 		u.append_id(texture);
 		uniforms.push_back(u);
 	}
@@ -2509,7 +2509,7 @@ RID RenderForwardClustered::_setup_sdfgi_render_pass_uniform_set(RID p_albedo_te
 		RD::Uniform u;
 		u.binding = 5;
 		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
-		RID texture = texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_WHITE);
+		RID texture = texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_DEPTH);
 		u.append_id(texture);
 		uniforms.push_back(u);
 	}

servers/rendering/renderer_rd/forward_mobile/render_forward_mobile.cpp

@@ -350,7 +350,7 @@ RID RenderForwardMobile::_setup_render_pass_uniform_set(RenderListType p_render_
 			texture = shadow_atlas_get_texture(p_render_data->shadow_atlas);
 		}
 		if (!texture.is_valid()) {
-			texture = texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_WHITE);
+			texture = texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_DEPTH);
 		}
 		u.append_id(texture);
 		uniforms.push_back(u);
@@ -362,7 +362,7 @@ RID RenderForwardMobile::_setup_render_pass_uniform_set(RenderListType p_render_
 		if (p_use_directional_shadow_atlas && directional_shadow_get_texture().is_valid()) {
 			u.append_id(directional_shadow_get_texture());
 		} else {
-			u.append_id(texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_WHITE));
+			u.append_id(texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_DEPTH));
 		}
 		uniforms.push_back(u);
 	}
@@ -425,7 +425,7 @@ RID RenderForwardMobile::_setup_render_pass_uniform_set(RenderListType p_render_
 		u.binding = 9;
 		u.uniform_type = RD::UNIFORM_TYPE_TEXTURE;
 		RID dbt = rb ? render_buffers_get_back_depth_texture(p_render_data->render_buffers) : RID();
-		RID texture = (dbt.is_valid()) ? dbt : texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_WHITE);
+		RID texture = (dbt.is_valid()) ? dbt : texture_storage->texture_rd_get_default(RendererRD::DEFAULT_RD_TEXTURE_DEPTH);
 		u.append_id(texture);
 		uniforms.push_back(u);
 	}

servers/rendering/renderer_rd/storage_rd/texture_storage.cpp

@@ -124,6 +124,26 @@ TextureStorage::TextureStorage() {
 			default_rd_textures[DEFAULT_RD_TEXTURE_ANISO] = RD::get_singleton()->texture_create(tformat, RD::TextureView(), vpv);
 		}
 
+		{
+			RD::TextureFormat tf;
+			tf.format = RD::DATA_FORMAT_D16_UNORM;
+			tf.width = 4;
+			tf.height = 4;
+			tf.usage_bits = RD::TEXTURE_USAGE_SAMPLING_BIT | RD::TEXTURE_USAGE_CAN_UPDATE_BIT | RD::TEXTURE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT;
+			tf.texture_type = RD::TEXTURE_TYPE_2D;
+
+			Vector<uint8_t> sv;
+			sv.resize(16 * 2);
+			uint16_t *ptr = (uint16_t *)sv.ptrw();
+			for (int i = 0; i < 16; i++) {
+				ptr[i] = Math::make_half_float(1.0f);
+			}
+
+			Vector<Vector<uint8_t>> vpv;
+			vpv.push_back(sv);
+			default_rd_textures[DEFAULT_RD_TEXTURE_DEPTH] = RD::get_singleton()->texture_create(tf, RD::TextureView(), vpv);
+		}
+
 		for (int i = 0; i < 16; i++) {
 			pv.set(i * 4 + 0, 0);
 			pv.set(i * 4 + 1, 0);

servers/rendering/renderer_rd/storage_rd/texture_storage.h

@@ -42,6 +42,7 @@ enum DefaultRDTexture {
 	DEFAULT_RD_TEXTURE_BLACK,
 	DEFAULT_RD_TEXTURE_NORMAL,
 	DEFAULT_RD_TEXTURE_ANISO,
+	DEFAULT_RD_TEXTURE_DEPTH,
 	DEFAULT_RD_TEXTURE_MULTIMESH_BUFFER,
 	DEFAULT_RD_TEXTURE_CUBEMAP_BLACK,
 	DEFAULT_RD_TEXTURE_CUBEMAP_ARRAY_BLACK,