Added some basic geometry functionality (only tangent generation for now).

2023-12-07 17:16:08 +01:00
parent b89f19ed98
commit 1d8ef0bac8
3 changed files with 242 additions and 0 deletions
--- a/source/mijin/geo/tangent_generation.hpp
+++ b/source/mijin/geo/tangent_generation.hpp
@@ -0,0 +1,102 @@
+
+
+#pragma once
+
+#if !defined(MIJIN_GEO_TANGENT_GENERATION_HPP_INCLUDED)
+#define MIJIN_GEO_TANGENT_GENERATION_HPP_INCLUDED 1
+
+#include <mikktspace.h>
+#include "./geometry_traits.hpp"
+
+namespace mijin
+{
+namespace impl
+{
+template<FullMesh3D TMesh>
+struct MikktData
+{
+    Mesh3DTraits<TMesh> traits;
+    Vector2Traits<typename TMesh::vector2_t> vec2Traits;
+    Vector3Traits<typename TMesh::vector3_t> vec3Traits;
+    TMesh* mesh;
+};
+
+template<FullMesh3D TMesh>
+int mikktGetNumFaces(const SMikkTSpaceContext* context)
+{
+    const MikktData<TMesh>& data = *static_cast<MikktData<TMesh>*>(context->m_pUserData);
+    return static_cast<int>(data.traits.getNumFaces(*data.mesh));
+}
+
+template<FullMesh3D TMesh>
+int mikktGetNumVerticesOfFace(const SMikkTSpaceContext* context, const int face)
+{
+    const MikktData<TMesh>& data = *static_cast<MikktData<TMesh>*>(context->m_pUserData);
+    return static_cast<int>(data.traits.getFaceNumVertices(*data.mesh, face));
+}
+
+template<FullMesh3D TMesh>
+void mikktGetPosition(const SMikkTSpaceContext* context, float posOut[], const int face, const int vert) // NOLINT
+{
+    const MikktData<TMesh>& data = *static_cast<MikktData<TMesh>*>(context->m_pUserData);
+    const auto position = data.traits.getPosition(*data.mesh, face, vert);
+    posOut[0] = data.vec3Traits.getX(position);
+    posOut[1] = data.vec3Traits.getY(position);
+    posOut[2] = data.vec3Traits.getZ(position);
+}
+
+template<FullMesh3D TMesh>
+void mikktGetNormal(const SMikkTSpaceContext* context, float normOut[], const int face, const int vert) // NOLINT
+{
+    const MikktData<TMesh>& data = *static_cast<MikktData<TMesh>*>(context->m_pUserData);
+    const auto normal = data.traits.getNormal(*data.mesh, face, vert);
+    normOut[0] = data.vec3Traits.getX(normal);
+    normOut[1] = data.vec3Traits.getY(normal);
+    normOut[2] = data.vec3Traits.getZ(normal);
+}
+
+template<FullMesh3D TMesh>
+void mikktGetTexCoord(const SMikkTSpaceContext* context, float texcOut[], const int face, const int vert) // NOLINT
+{
+    const MikktData<TMesh>& data = *static_cast<MikktData<TMesh>*>(context->m_pUserData);
+    const auto texCoord = data.traits.getTexCoord(*data.mesh, face, vert);
+    texcOut[0] = data.vec2Traits.getX(texCoord);
+    texcOut[1] = data.vec2Traits.getY(texCoord);
+}
+
+template<FullMesh3D TMesh>
+void mikktSetTSpaceBasic(const SMikkTSpaceContext* context, const float resultTangent[], const float sign, const int face, const int vert) // NOLINT
+{
+    // TODO: what do we do with sign? (it should be used for the direction of the bitangent)
+    (void) sign;
+    const MikktData<TMesh>& data = *static_cast<MikktData<TMesh>*>(context->m_pUserData);
+    typename Mesh3DTraits<TMesh>::vector3_t tangent;
+    data.vec3Traits.setX(tangent, resultTangent[0]);
+    data.vec3Traits.setY(tangent, resultTangent[1]);
+    data.vec3Traits.setZ(tangent, resultTangent[2]);
+    data.traits.setTangent(*data.mesh, face, vert, tangent);
+}
+}
+template<FullMesh3D TMesh>
+bool generateTangentsMikkt(TMesh& mesh)
+{
+    SMikkTSpaceInterface mikktInterface = {
+        .m_getNumFaces = &impl::mikktGetNumFaces<TMesh>,
+        .m_getNumVerticesOfFace = &impl::mikktGetNumVerticesOfFace<TMesh>,
+        .m_getPosition = &impl::mikktGetPosition<TMesh>,
+        .m_getNormal = &impl::mikktGetNormal<TMesh>,
+        .m_getTexCoord = &impl::mikktGetTexCoord<TMesh>,
+        .m_setTSpaceBasic = &impl::mikktSetTSpaceBasic<TMesh>
+    };
+    impl::MikktData<TMesh> data = {
+        .mesh = &mesh
+    };
+    const SMikkTSpaceContext context = {
+        .m_pInterface = &mikktInterface,
+        .m_pUserData = &data
+    };
+    return genTangSpaceDefault(&context);
+}
+}
+
+#endif // MIJIN_GEO_TANGENT_GENERATION_HPP_INCLUDED