6 files changed, 60 insertions, 18 deletions
diff --git a/ui/builders/join.cpp b/ui/builders/join.cpp
index cc2ca2d..caa635f 100644
--- a/ui/builders/join.cpp
+++ b/ui/builders/join.cpp
@@ -1,11 +1,6 @@
 #include "join.h"
 #include <game/geoData.h>
 
-void
-BuilderJoin::render(const Shader &) const
-{
-}
-
 std::string
 BuilderJoin::hint() const
 {
@@ -16,6 +11,19 @@ BuilderJoin::hint() const
 }
 
 void
+BuilderJoin::move(Network * network, const GeoData *, const SDL_MouseMotionEvent &, const Ray & ray)
+{
+	if (p1) {
+		if (const auto p = network->intersectRayNodes(ray)) {
+			candidateLinks.objects = network->candidateJoins(p1->pos, p->pos);
+		}
+		else {
+			candidateLinks.removeAll();
+		}
+	}
+}
+
+void
 BuilderJoin::click(Network * network, const GeoData *, const SDL_MouseButtonEvent & e, const Ray & ray)
 {
 	switch (e.button) {
@@ -24,6 +32,7 @@ BuilderJoin::click(Network * network, const GeoData *, const SDL_MouseButtonEven
 				if (p1) {
 					create(network, p1, p);
 					p1.reset();
+					candidateLinks.removeAll();
 				}
 				else {
 					p1 = p;
diff --git a/ui/builders/join.h b/ui/builders/join.h
index 30d39cd..bb0bd4c 100644
--- a/ui/builders/join.h
+++ b/ui/builders/join.h
@@ -5,9 +5,9 @@ class Network;
 class GeoData;
 
 class BuilderJoin : public EditNetwork::Builder {
-	void render(const Shader &) const override;
 	std::string hint() const override;
 	void click(Network * network, const GeoData * geoData, const SDL_MouseButtonEvent & e, const Ray & ray) override;
+	void move(Network * network, const GeoData * geoData, const SDL_MouseMotionEvent & e, const Ray & ray) override;
 
 	void create(Network * network, const Node::Ptr & p1, const Node::Ptr & p2) const;
 
diff --git a/ui/builders/straight.cpp b/ui/builders/straight.cpp
index 7024746..477b40d 100644
--- a/ui/builders/straight.cpp
+++ b/ui/builders/straight.cpp
@@ -1,11 +1,6 @@
 #include "straight.h"
 #include <game/geoData.h>
 
-void
-BuilderStraight::render(const Shader &) const
-{
-}
-
 std::string
 BuilderStraight::hint() const
 {
@@ -16,6 +11,19 @@ BuilderStraight::hint() const
 }
 
 void
+BuilderStraight::move(Network * network, const GeoData * geoData, const SDL_MouseMotionEvent &, const Ray & ray)
+{
+	if (p1) {
+		if (const auto p = geoData->intersectRay(ray)) {
+			candidateLinks.objects = network->candidateStraight(*p1, *p);
+		}
+		else {
+			candidateLinks.removeAll();
+		}
+	}
+}
+
+void
 BuilderStraight::click(Network * network, const GeoData * geoData, const SDL_MouseButtonEvent & e, const Ray & ray)
 {
 	switch (e.button) {
@@ -23,12 +31,14 @@ BuilderStraight::click(Network * network, const GeoData * geoData, const SDL_Mou
 			if (const auto p = geoData->intersectRay(ray)) {
 				if (p1) {
 					create(network, *p1, *p);
+					candidateLinks.removeAll();
 				}
 				p1 = *p;
 			}
 			return;
 		case SDL_BUTTON_MIDDLE:
 			p1.reset();
+			candidateLinks.removeAll();
 			return;
 	}
 }
diff --git a/ui/builders/straight.h b/ui/builders/straight.h
index 77847dd..1cde2b0 100644
--- a/ui/builders/straight.h
+++ b/ui/builders/straight.h
@@ -5,9 +5,9 @@ class Network;
 class GeoData;
 
 class BuilderStraight : public EditNetwork::Builder {
-	void render(const Shader &) const override;
 	std::string hint() const override;
 	void click(Network * network, const GeoData * geoData, const SDL_MouseButtonEvent & e, const Ray & ray) override;
+	void move(Network * network, const GeoData * geoData, const SDL_MouseMotionEvent & e, const Ray & ray) override;
 
 	void create(Network * network, glm::vec3 p1, glm::vec3 p2) const;
 
diff --git a/ui/editNetwork.cpp b/ui/editNetwork.cpp
index 3ab7059..9f4a186 100644
--- a/ui/editNetwork.cpp
+++ b/ui/editNetwork.cpp
@@ -4,12 +4,18 @@
 #include "text.h"
 #include <game/gamestate.h>
 #include <game/geoData.h>
+#include <gfx/gl/shader.h>
+#include <gfx/models/texture.h>
+
+constexpr const glm::u8vec4 TRANSPARENT_BLUE {30, 50, 255, 200};
 
 EditNetwork::EditNetwork(Network * n) :
-	network {n}, builderToolbar {
-						 {"ui/icon/network.png", mode.toggle<BuilderStraight>()},
-						 {"ui/icon/network.png", mode.toggle<BuilderJoin>()},
-				 }
+	network {n},
+	builderToolbar {
+			{"ui/icon/network.png", mode.toggle<BuilderStraight>()},
+			{"ui/icon/network.png", mode.toggle<BuilderJoin>()},
+	},
+	blue {1, 1, &TRANSPARENT_BLUE}
 {
 }
 
@@ -26,8 +32,11 @@ EditNetwork::click(const SDL_MouseButtonEvent & e, const Ray & ray)
 }
 
 bool
-EditNetwork::move(const SDL_MouseMotionEvent &, const Ray &)
+EditNetwork::move(const SDL_MouseMotionEvent & e, const Ray & ray)
 {
+	if (builder) {
+		builder->move(network, gameState->geoData.get(), e, ray);
+	}
 	return false;
 }
 
@@ -41,11 +50,19 @@ void
 EditNetwork::render(const Shader & shader) const
 {
 	if (builder) {
+		blue.Bind();
+		shader.setModel(Location {}, Shader::Program::StaticPos);
 		builder->render(shader);
 	}
 }
 
 void
+EditNetwork::Builder::render(const Shader & shader) const
+{
+	candidateLinks.apply<const Renderable>(&Renderable::render, shader);
+}
+
+void
 EditNetwork::render(const UIShader & shader, const UIComponent::Position & parentPos) const
 {
 	if (builder) {
diff --git a/ui/editNetwork.h b/ui/editNetwork.h
index bd01eb8..df89cdc 100644
--- a/ui/editNetwork.h
+++ b/ui/editNetwork.h
@@ -6,6 +6,7 @@
 #include "worldOverlay.h"
 #include <game/gamestate.h>
 #include <game/network/network.h>
+#include <gfx/models/texture.h>
 #include <optional>
 
 class Ray;
@@ -26,11 +27,15 @@ public:
 	class Builder {
 	public:
 		virtual ~Builder() = default;
-		virtual void render(const Shader & shader) const = 0;
+		virtual void render(const Shader & shader) const;
 		virtual std::string hint() const = 0;
 		virtual void click(Network *, const GeoData *, const SDL_MouseButtonEvent &, const Ray &) = 0;
+		virtual void move(Network *, const GeoData *, const SDL_MouseMotionEvent &, const Ray &) = 0;
 
 		using Ptr = std::unique_ptr<Builder>;
+
+	protected:
+		Collection<const Link> candidateLinks;
 	};
 
 private:
@@ -38,6 +43,7 @@ private:
 	Builder::Ptr builder;
 	Mode<Builder::Ptr, ModeSecondClick::NoAction> mode {builder};
 	Toolbar builderToolbar;
+	Texture blue;
 };
 
 template<typename T> class EditNetworkOf : public EditNetwork {