refactor layout.h into single file per Node* classes

engine/node_icon.cpp

@@ -0,0 +1,68 @@
+#include "pch.h"
+#include "log.h"
+#include "node_icon.h"
+#include "asset.h"
+#include "texture.h"
+
+std::map<std::string, glm::vec4> NodeIcon::m_icons;
+
+void NodeIcon::static_init()
+{
+    // spritesheet maker: https://draeton.github.io/stitches/
+    // icons: http://www.famfamfam.com/lab/icons/silk/
+    // regex css -> spritesheet.txt: \.([^{]+) {\s+width: (\d+)px;\s+height: (\d+)px;\s+.*: -(\d+)px -(\d+)px;\s+}\s+
+    // to: "\1",\2,\3,\4,\5\n
+    Asset file;
+    if (!(file.open("data/spritesheet.txt") && file.read_all()))
+        return;
+    char* data = (char*)file.m_data;
+    int size = file.m_len;
+    static char name[256];
+    int x, y, w, h;
+    char* s = strtok(data, "\n");
+    auto i = strlen(s) + 1;
+    while (i < size && sscanf(s, "%s %d %d %d %d", name, &w, &h, &x, &y) == 5)
+    {
+        m_icons[name] = glm::vec4(x, y, x + w, y + h);
+        s = strtok(nullptr, "\n");
+        i += strlen(s) + 1;
+    }
+    file.close();
+    TextureManager::load("data/spritesheet.png");
+}
+
+Node* NodeIcon::clone_instantiate() const
+{
+    return new NodeIcon();
+}
+
+void NodeIcon::clone_copy(Node* dest) const
+{
+    NodeImage::clone_copy(dest);
+    NodeIcon* n = static_cast<NodeIcon*>(dest);
+    n->m_icon_name = m_icon_name;
+}
+
+void NodeIcon::create()
+{
+    m_region = m_icons[m_icon_name];
+    m_path = "data/spritesheet.png";
+    m_tex_id = const_hash(m_path.c_str());
+    m_use_atlas = true;
+    NodeImage::create();
+    auto tex_sz = TextureManager::get(m_tex_id).size();
+    YGNodeStyleSetAspectRatio(y_node, tex_sz.x / tex_sz.y);
+}
+
+void NodeIcon::parse_attributes(kAttribute ka, const tinyxml2::XMLAttribute* attr)
+{
+    NodeImage::parse_attributes(ka, attr);
+    switch (ka)
+    {
+    case kAttribute::Icon:
+        m_icon_name = attr->Value();
+        break;
+    default:
+        break;
+    }
+}