add triangle vcm shape - 'tri'

src/coders/vcm.cpp

@@ -71,6 +71,39 @@ static void perform_rect(const xmlelement& root, model::Model& model) {
     );
 }
 
+static void perform_triangle(const xmlelement& root, model::Model& model) {
+    auto pointA = root.attr("a").asVec3();
+    auto pointB = root.attr("b").asVec3();
+    auto pointC = root.attr("c").asVec3();
+
+    float uvs[6] {0, 0, 1, 0, 1, 1};
+
+    bool shading = true;
+    if (root.has("shading")) {
+        shading = to_boolean(root.attr("shading"));
+    }
+    if (root.has("uv")) {
+        root.attr("uv").asNumbers(uvs, sizeof(uvs) / sizeof(float));
+    }
+    
+    glm::vec3 ba = pointB - pointA;
+    glm::vec3 ca = pointC - pointA;
+    glm::vec3 normal = glm::normalize(glm::cross(ba, ca));
+
+    std::string texture = root.attr("texture", "$0").getText();
+    auto& mesh = model.addMesh(texture, shading);
+
+    mesh.addTriangle(
+        pointA,
+        pointB,
+        pointC,
+        normal,
+        {uvs[0], uvs[1]},
+        {uvs[2], uvs[3]},
+        {uvs[4], uvs[5]}
+    );
+}
+
 static void perform_box(const xmlelement& root, model::Model& model) {
     auto from = root.attr("from").asVec3();
     auto to = root.attr("to").asVec3();
@@ -181,6 +214,8 @@ static std::unique_ptr<model::Model> load_model(const xmlelement& root) {
             perform_rect(*elem, model);
         } else if (tag == "box") {
             perform_box(*elem, model);
+        } else if (tag == "tri") {
+            perform_triangle(*elem, model);
         }
     }
 

src/coders/xml.cpp

@@ -105,6 +105,19 @@ glm::vec4 Attribute::asColor() const {
     }
 }
 
+int Attribute::asNumbers(float* dst, size_t dstSize) const {
+    size_t pos = 0;
+    size_t count = 0;
+    while (pos < text.length() && count < dstSize) {
+        size_t end = text.find(',', pos);
+        dst[count++] = util::parse_double(
+            text, pos, std::min<size_t>(end - pos, text.length() - pos)
+        );
+        pos = end + 1;
+    }
+    return count;
+}
+
 Node::Node(std::string tag) : tag(std::move(tag)) {
 }
 

src/coders/xml.hpp

@@ -29,6 +29,7 @@ namespace xml {
         glm::vec3 asVec3() const;
         glm::vec4 asVec4() const;
         glm::vec4 asColor() const;
+        int asNumbers(float* dst, size_t dstSize) const;
     };
 
     /// @brief XML element class. Text element has tag 'text' and attribute

src/graphics/commons/Model.cpp

@@ -41,6 +41,20 @@ void Mesh::addPlane(
     );
 }
 
+void Mesh::addTriangle(
+    const glm::vec3& a,
+    const glm::vec3& b,
+    const glm::vec3& c,
+    const glm::vec3& norm,
+    const glm::vec2& uvA,
+    const glm::vec2& uvB,
+    const glm::vec2& uvC
+) {
+    vertices.push_back({a, uvA, norm});
+    vertices.push_back({b, uvB, norm});
+    vertices.push_back({c, uvC, norm});
+}
+
 void Mesh::addRect(
     const glm::vec3& pos,
     const glm::vec3& right,

src/graphics/commons/Model.hpp

@@ -39,6 +39,15 @@ namespace model {
             const glm::vec3& up,
             const glm::vec3& norm,
             const UVRegion& region
+        ); 
+        void addTriangle(
+            const glm::vec3& a,
+            const glm::vec3& b,
+            const glm::vec3& c,
+            const glm::vec3& norm,
+            const glm::vec2& uvA,
+            const glm::vec2& uvB,
+            const glm::vec2& uvC
         );
         void addBox(const glm::vec3& pos, const glm::vec3& size);
         void addBox(