Merge pull request #23743 from BastiaanOlij/csg_mikkt_tangent

Adding mikkt tangent support to CSG objects

3 files changed, 145 insertions, 3 deletions

diff --git a/modules/csg/csg_shape.cpp b/modules/csg/csg_shape.cpp
index 4eb798de11..23d879e1cd 100644
--- a/modules/csg/csg_shape.cpp
+++ b/modules/csg/csg_shape.cpp
@@ -159,6 +159,74 @@ CSGBrush *CSGShape::_get_brush() {
 	return brush;
 }
 
+int CSGShape::mikktGetNumFaces(const SMikkTSpaceContext *pContext) {
+	ShapeUpdateSurface &surface = *((ShapeUpdateSurface *)pContext->m_pUserData);
+
+	return surface.vertices.size() / 3;
+}
+
+int CSGShape::mikktGetNumVerticesOfFace(const SMikkTSpaceContext *pContext, const int iFace) {
+	// always 3
+	return 3;
+}
+
+void CSGShape::mikktGetPosition(const SMikkTSpaceContext *pContext, float fvPosOut[], const int iFace, const int iVert) {
+	ShapeUpdateSurface &surface = *((ShapeUpdateSurface *)pContext->m_pUserData);
+
+	Vector3 v = surface.verticesw[iFace * 3 + iVert];
+	fvPosOut[0] = v.x;
+	fvPosOut[1] = v.y;
+	fvPosOut[2] = v.z;
+}
+
+void CSGShape::mikktGetNormal(const SMikkTSpaceContext *pContext, float fvNormOut[], const int iFace, const int iVert) {
+	ShapeUpdateSurface &surface = *((ShapeUpdateSurface *)pContext->m_pUserData);
+
+	Vector3 n = surface.normalsw[iFace * 3 + iVert];
+	fvNormOut[0] = n.x;
+	fvNormOut[1] = n.y;
+	fvNormOut[2] = n.z;
+}
+
+void CSGShape::mikktGetTexCoord(const SMikkTSpaceContext *pContext, float fvTexcOut[], const int iFace, const int iVert) {
+	ShapeUpdateSurface &surface = *((ShapeUpdateSurface *)pContext->m_pUserData);
+
+	Vector2 t = surface.uvsw[iFace * 3 + iVert];
+	fvTexcOut[0] = t.x;
+	fvTexcOut[1] = t.y;
+}
+
+void CSGShape::mikktSetTSpaceBasic(const SMikkTSpaceContext *pContext, const float fvTangent[], const float fSign, const int iFace, const int iVert) {
+	ShapeUpdateSurface &surface = *((ShapeUpdateSurface *)pContext->m_pUserData);
+
+	int i = (iFace * 3 + iVert) * 4;
+
+	// Godot seems to want the tangent flipped because our handedness is reversed..
+	surface.tansw[i++] = -fvTangent[0];
+	surface.tansw[i++] = -fvTangent[1];
+	surface.tansw[i++] = -fvTangent[2];
+	surface.tansw[i++] = fSign;
+}
+
+void CSGShape::mikktSetTSpaceDefault(const SMikkTSpaceContext *pContext, const float fvTangent[], const float fvBiTangent[], const float fMagS, const float fMagT,
+		const tbool bIsOrientationPreserving, const int iFace, const int iVert) {
+
+	ShapeUpdateSurface &surface = *((ShapeUpdateSurface *)pContext->m_pUserData);
+
+	int i = iFace * 3 + iVert;
+	Vector3 normal = surface.normalsw[i];
+	Vector3 tangent = Vector3(fvTangent[0], fvTangent[1], fvTangent[2]);
+	Vector3 bitangent = Vector3(fvBiTangent[0], fvBiTangent[1], fvBiTangent[2]);
+	float d = bitangent.dot(normal.cross(tangent));
+
+	// Godot seems to want the tangent flipped because our handedness is reversed..
+	i *= 4;
+	surface.tansw[i++] = -tangent.x;
+	surface.tansw[i++] = -tangent.y;
+	surface.tansw[i++] = -tangent.z;
+	surface.tansw[i++] = d < 0 ? -1 : 1;
+}
+
 void CSGShape::_update_shape() {
 
 	if (parent)
@@ -211,6 +279,9 @@ void CSGShape::_update_shape() {
 		surfaces.write[i].vertices.resize(face_count[i] * 3);
 		surfaces.write[i].normals.resize(face_count[i] * 3);
 		surfaces.write[i].uvs.resize(face_count[i] * 3);
+		if (calculate_tangents) {
+			surfaces.write[i].tans.resize(face_count[i] * 3 * 4);
+		}
 		surfaces.write[i].last_added = 0;
 
 		if (i != surfaces.size() - 1) {
@@ -220,6 +291,9 @@ void CSGShape::_update_shape() {
 		surfaces.write[i].verticesw = surfaces.write[i].vertices.write();
 		surfaces.write[i].normalsw = surfaces.write[i].normals.write();
 		surfaces.write[i].uvsw = surfaces.write[i].uvs.write();
+		if (calculate_tangents) {
+			surfaces.write[i].tansw = surfaces.write[i].tans.write();
+		}
 	}
 
 	//fill arrays
@@ -274,9 +348,19 @@ void CSGShape::_update_shape() {
 					normal = -normal;
 				}
 
-				surfaces[idx].verticesw[last + order[j]] = v;
-				surfaces[idx].uvsw[last + order[j]] = n->faces[i].uvs[j];
-				surfaces[idx].normalsw[last + order[j]] = normal;
+				int k = last + order[j];
+				surfaces[idx].verticesw[k] = v;
+				surfaces[idx].uvsw[k] = n->faces[i].uvs[j];
+				surfaces[idx].normalsw[k] = normal;
+
+				if (calculate_tangents) {
+					// zero out our tangents for now
+					k *= 4;
+					surfaces[idx].tansw[k++] = 0.0;
+					surfaces[idx].tansw[k++] = 0.0;
+					surfaces[idx].tansw[k++] = 0.0;
+					surfaces[idx].tansw[k++] = 0.0;
+				}
 			}
 
 			surfaces.write[idx].last_added += 3;
@@ -287,20 +371,43 @@ void CSGShape::_update_shape() {
 	//create surfaces
 
 	for (int i = 0; i < surfaces.size(); i++) {
+		// calculate tangents for this surface
+		bool have_tangents = calculate_tangents;
+		if (have_tangents) {
+			SMikkTSpaceInterface mkif;
+			mkif.m_getNormal = mikktGetNormal;
+			mkif.m_getNumFaces = mikktGetNumFaces;
+			mkif.m_getNumVerticesOfFace = mikktGetNumVerticesOfFace;
+			mkif.m_getPosition = mikktGetPosition;
+			mkif.m_getTexCoord = mikktGetTexCoord;
+			mkif.m_setTSpace = mikktSetTSpaceDefault;
+			mkif.m_setTSpaceBasic = NULL;
+
+			SMikkTSpaceContext msc;
+			msc.m_pInterface = &mkif;
+			msc.m_pUserData = &surfaces.write[i];
+			have_tangents = genTangSpaceDefault(&msc);
+		}
 
+		// unset write access
 		surfaces.write[i].verticesw = PoolVector<Vector3>::Write();
 		surfaces.write[i].normalsw = PoolVector<Vector3>::Write();
 		surfaces.write[i].uvsw = PoolVector<Vector2>::Write();
+		surfaces.write[i].tansw = PoolVector<float>::Write();
 
 		if (surfaces[i].last_added == 0)
 			continue;
 
+		// and convert to surface array
 		Array array;
 		array.resize(Mesh::ARRAY_MAX);
 
 		array[Mesh::ARRAY_VERTEX] = surfaces[i].vertices;
 		array[Mesh::ARRAY_NORMAL] = surfaces[i].normals;
 		array[Mesh::ARRAY_TEX_UV] = surfaces[i].uvs;
+		if (have_tangents) {
+			array[Mesh::ARRAY_TANGENT] = surfaces[i].tans;
+		}
 
 		int idx = root_mesh->get_surface_count();
 		root_mesh->add_surface_from_arrays(Mesh::PRIMITIVE_TRIANGLES, array);
@@ -400,6 +507,15 @@ CSGShape::Operation CSGShape::get_operation() const {
 	return operation;
 }
 
+void CSGShape::set_calculate_tangents(bool p_calculate_tangents) {
+	calculate_tangents = p_calculate_tangents;
+	_make_dirty();
+}
+
+bool CSGShape::is_calculating_tangents() const {
+	return calculate_tangents;
+}
+
 void CSGShape::_validate_property(PropertyInfo &property) const {
 	if (is_inside_tree() && property.name.begins_with("use_collision") && !is_root_shape()) {
 		//hide collision if not root
@@ -421,9 +537,13 @@ void CSGShape::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_snap", "snap"), &CSGShape::set_snap);
 	ClassDB::bind_method(D_METHOD("get_snap"), &CSGShape::get_snap);
 
+	ClassDB::bind_method(D_METHOD("set_calculate_tangents", "enabled"), &CSGShape::set_calculate_tangents);
+	ClassDB::bind_method(D_METHOD("is_calculating_tangents"), &CSGShape::is_calculating_tangents);
+
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "operation", PROPERTY_HINT_ENUM, "Union,Intersection,Subtraction"), "set_operation", "get_operation");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_collision"), "set_use_collision", "is_using_collision");
 	ADD_PROPERTY(PropertyInfo(Variant::REAL, "snap", PROPERTY_HINT_RANGE, "0.0001,1,0.001"), "set_snap", "get_snap");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "calculate_tangents"), "set_calculate_tangents", "is_calculating_tangents");
 
 	BIND_ENUM_CONSTANT(OPERATION_UNION);
 	BIND_ENUM_CONSTANT(OPERATION_INTERSECTION);
@@ -438,6 +558,7 @@ CSGShape::CSGShape() {
 	use_collision = false;
 	operation = OPERATION_UNION;
 	snap = 0.001;
+	calculate_tangents = true;
 }
 
 CSGShape::~CSGShape() {
diff --git a/modules/csg/csg_shape.h b/modules/csg/csg_shape.h
index 6898cdaf64..0a4bb5f665 100644
--- a/modules/csg/csg_shape.h
+++ b/modules/csg/csg_shape.h
@@ -36,6 +36,7 @@
 #include "csg.h"
 #include "scene/3d/visual_instance.h"
 #include "scene/resources/concave_polygon_shape.h"
+#include "thirdparty/misc/mikktspace.h"
 
 class CSGShape : public VisualInstance {
 	GDCLASS(CSGShape, VisualInstance);
@@ -63,6 +64,8 @@ private:
 	Ref<ConcavePolygonShape> root_collision_shape;
 	RID root_collision_instance;
 
+	bool calculate_tangents;
+
 	Ref<ArrayMesh> root_mesh;
 
 	struct Vector3Hasher {
@@ -78,14 +81,26 @@ private:
 		PoolVector<Vector3> vertices;
 		PoolVector<Vector3> normals;
 		PoolVector<Vector2> uvs;
+		PoolVector<float> tans;
 		Ref<Material> material;
 		int last_added;
 
 		PoolVector<Vector3>::Write verticesw;
 		PoolVector<Vector3>::Write normalsw;
 		PoolVector<Vector2>::Write uvsw;
+		PoolVector<float>::Write tansw;
 	};
 
+	//mikktspace callbacks
+	static int mikktGetNumFaces(const SMikkTSpaceContext *pContext);
+	static int mikktGetNumVerticesOfFace(const SMikkTSpaceContext *pContext, const int iFace);
+	static void mikktGetPosition(const SMikkTSpaceContext *pContext, float fvPosOut[], const int iFace, const int iVert);
+	static void mikktGetNormal(const SMikkTSpaceContext *pContext, float fvNormOut[], const int iFace, const int iVert);
+	static void mikktGetTexCoord(const SMikkTSpaceContext *pContext, float fvTexcOut[], const int iFace, const int iVert);
+	static void mikktSetTSpaceBasic(const SMikkTSpaceContext *pContext, const float fvTangent[], const float fSign, const int iFace, const int iVert);
+	static void mikktSetTSpaceDefault(const SMikkTSpaceContext *pContext, const float fvTangent[], const float fvBiTangent[], const float fMagS, const float fMagT,
+			const tbool bIsOrientationPreserving, const int iFace, const int iVert);
+
 	void _update_shape();
 
 protected:
@@ -115,6 +130,9 @@ public:
 	void set_snap(float p_snap);
 	float get_snap() const;
 
+	void set_calculate_tangents(bool p_calculate_tangents);
+	bool is_calculating_tangents() const;
+
 	bool is_root_shape() const;
 	CSGShape();
 	~CSGShape();
diff --git a/modules/csg/doc_classes/CSGShape.xml b/modules/csg/doc_classes/CSGShape.xml
index 90621b94f4..ac3c2342fc 100644
--- a/modules/csg/doc_classes/CSGShape.xml
+++ b/modules/csg/doc_classes/CSGShape.xml
@@ -20,6 +20,9 @@
 		</method>
 	</methods>
 	<members>
+		<member name="calculate_tangents" type="bool" setter="set_calculate_tangents" getter="is_calculating_tangents">
+			Calculate tangents for the CSG shape which allows the use of normal maps. This is only applied on the root shape, this setting is ignored on any child.
+		</member>
 		<member name="operation" type="int" setter="set_operation" getter="get_operation" enum="CSGShape.Operation">
 			The operation that is performed on this shape. This is ignored for the first CSG child node as the operation is between this node and the previous child of this nodes parent.
 		</member>