Halo: Highlight selected face

This is a slightly modified and cleaned up version of #3774 by RealBadAngel.
By sofar: Remove color change (just make it lighter) and some minor cleanups.

src/game.cpp

@@ -362,6 +362,7 @@ PointedThing getPointedThing(Client *client, Hud *hud, const v3f &player_positio
 
 			min_distance = (selected_object->getPosition() - camera_position).getLength();
 
+			hud->setSelectedFaceNormal(v3f(0.0, 0.0, 0.0));
 			result.type = POINTEDTHING_OBJECT;
 			result.object_id = selected_object->getId();
 		}
@@ -473,6 +474,7 @@ PointedThing getPointedThing(Client *client, Hud *hud, const v3f &player_positio
 				if (!facebox.intersectsWithLine(shootline))
 					continue;
 				result.node_abovesurface = pointed_pos + facedir;
+				hud->setSelectedFaceNormal(v3f(facedir.X, facedir.Y, facedir.Z));
 				face_min_distance = distance;
 			}
 		}

src/hud.cpp

@@ -544,6 +544,12 @@ void Hud::drawSelectionMesh()
 		video::SMaterial oldmaterial = driver->getMaterial2D();
 		driver->setMaterial(m_selection_material);
 		setMeshColor(m_selection_mesh, m_selection_mesh_color);
+		video::SColor face_color(0,
+			MYMIN(255, m_selection_mesh_color.getRed() * 1.5),
+			MYMIN(255, m_selection_mesh_color.getGreen() * 1.5),
+			MYMIN(255, m_selection_mesh_color.getBlue() * 1.5));
+		setMeshColorByNormal(m_selection_mesh, m_selected_face_normal,
+			face_color);
 		scene::IMesh* mesh = cloneMesh(m_selection_mesh);
 		translateMesh(mesh, m_selection_pos_with_offset);
 		u32 mc = m_selection_mesh->getMeshBufferCount();

src/hud.h

@@ -139,8 +139,11 @@ class Hud {
 	v3f getSelectionPos() const
 	{ return m_selection_pos; }
 
-	void setSelectionMeshColor(const video::SColor &c)
-	{ m_selection_mesh_color = c; }
+	void setSelectionMeshColor(const video::SColor &color)
+	{ m_selection_mesh_color = color; }
+
+	void setSelectedFaceNormal(const v3f &face_normal)
+	{ m_selected_face_normal = face_normal; }
 
 	void drawLuaElements(const v3s16 &camera_offset);
 
@@ -169,6 +172,8 @@ class Hud {
 
 	scene::IMesh* m_selection_mesh;
 	video::SColor m_selection_mesh_color;
+	v3f m_selected_face_normal;
+
 	video::SMaterial m_selection_material;
 	bool m_use_selection_mesh;
 };

src/mesh.cpp

@@ -226,7 +226,27 @@ void setMeshColorByNormalXYZ(scene::IMesh *mesh,
 				vertex->Color = colorY;
 			else
 				vertex->Color = colorZ;
+		}
+	}
+}
+
+void setMeshColorByNormal(scene::IMesh *mesh, const v3f &normal,
+		const video::SColor &color)
+{
+	if (!mesh)
+		return;
 
+	u16 mc = mesh->getMeshBufferCount();
+	for (u16 j = 0; j < mc; j++) {
+		scene::IMeshBuffer *buf = mesh->getMeshBuffer(j);
+		const u32 stride = getVertexPitchFromType(buf->getVertexType());
+		u32 vertex_count = buf->getVertexCount();
+		u8 *vertices = (u8 *)buf->getVertices();
+		for (u32 i = 0; i < vertex_count; i++) {
+			video::S3DVertex *vertex = (video::S3DVertex *)(vertices + i * stride);
+			if (normal == vertex->Normal) {
+				vertex->Color = color;
+			}
 		}
 	}
 }

src/mesh.h

@@ -64,6 +64,10 @@ void setMeshColorByNormalXYZ(scene::IMesh *mesh,
 		const video::SColor &colorX,
 		const video::SColor &colorY,
 		const video::SColor &colorZ);
+
+void setMeshColorByNormal(scene::IMesh *mesh, const v3f &normal,
+		const video::SColor &color);
+
 /*
 	Rotate the mesh by 6d facedir value.
 	Method only for meshnodes, not suitable for entities.