feat: new vertex impl

engine/include/engine/3d/vertex.hpp

@@ -0,0 +1,63 @@
+#pragma once
+
+#include <cstring>
+#include <glm/glm.hpp>
+
+#define VERTICES_INITIAL_CAPACITY 256
+#define INDICES_INITIAL_CAPACITY 512
+
+namespace Core {
+
+struct Vertex {
+public:
+    Vertex(glm::vec3 position, glm::vec3 normal, glm::vec2 uv)
+        : position(position), normal(normal), uv(uv) {}
+    Vertex()
+        : position(glm::vec3()), normal(glm::vec3()), uv(glm::vec2()) {}
+
+    Vertex(const Vertex&) noexcept = default;
+    Vertex(Vertex&&) noexcept = default;
+
+    bool operator ==(Vertex const& o) const noexcept {
+        return o.position == position
+            && o.normal == normal
+            && o.uv == uv;
+    }
+public:
+    glm::vec3 position;
+    glm::vec3 normal;
+    glm::vec2 uv;
+    
+    friend class VertexHash;
+};
+
+struct VertexHash {
+    size_t operator()(Vertex const& v) const noexcept {
+        auto h = [](float f) -> size_t {
+            uint32_t b;
+            static_assert(sizeof(float) == sizeof(uint32_t));
+            std::memcpy(&b, &f, sizeof(float));
+            // splitmix64-like mixing (simple)
+            uint64_t x = b;
+            x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9ULL;
+            x = (x ^ (x >> 27)) * 0x94d049bb133111ebULL;
+            x ^= x >> 31;
+            return static_cast<size_t>(x);
+        };
+
+        size_t res = 1469598103934665603ULL;
+        res ^= h(v.position.x) + 0x9e3779b97f4a7c15ULL + (res<<6) + (res>>2);
+        res ^= h(v.position.y) + 0x9e3779b97f4a7c15ULL + (res<<6) + (res>>2);
+        res ^= h(v.position.z) + 0x9e3779b97f4a7c15ULL + (res<<6) + (res>>2);
+
+        res ^= h(v.normal.x) + 0x9e3779b97f4a7c15ULL + (res<<6) + (res>>2);
+        res ^= h(v.normal.y) + 0x9e3779b97f4a7c15ULL + (res<<6) + (res>>2);
+        res ^= h(v.normal.z) + 0x9e3779b97f4a7c15ULL + (res<<6) + (res>>2);
+
+        res ^= h(v.uv.x) + 0x9e3779b97f4a7c15ULL + (res<<6) + (res>>2);
+        res ^= h(v.uv.y) + 0x9e3779b97f4a7c15ULL + (res<<6) + (res>>2);
+        return res;
+    }
+};
+
+}