+
+OutlineModel::OutlineModel()
+: vertices()
+, colors()
+, handle{}
+, dirty(false) {
+ glGenBuffers(ATTRIB_COUNT, handle);
+}
+
+OutlineModel::~OutlineModel() {
+ glDeleteBuffers(ATTRIB_COUNT, handle);
+}
+
+
+void OutlineModel::Clear() {
+ vertices.clear();
+ colors.clear();
+ Invalidate();
+}
+
+void OutlineModel::Reserve(int s) {
+ vertices.reserve(s);
+ colors.reserve(s);
+}
+
+
+void OutlineModel::Update() {
+ glBindBuffer(GL_ARRAY_BUFFER, handle[ATTRIB_VERTEX]);
+ glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(glm::vec3), vertices.data(), GL_STATIC_DRAW);
+
+#ifndef NDEBUG
+ if (colors.size() < vertices.size()) {
+ std::cerr << "OutlineModel: not enough colors!" << std::endl;
+ colors.resize(vertices.size(), { 1, 0, 1 });
+ }
+#endif
+ glBindBuffer(GL_ARRAY_BUFFER, handle[ATTRIB_COLOR]);
+ glBufferData(GL_ARRAY_BUFFER, colors.size() * sizeof(glm::vec3), colors.data(), GL_STATIC_DRAW);
+
+ dirty = false;
+}
+
+
+void OutlineModel::Draw() {
+ if (dirty) {
+ Update();
+ }
+
+ glEnableVertexAttribArray(ATTRIB_VERTEX);
+ glBindBuffer(GL_ARRAY_BUFFER, handle[ATTRIB_VERTEX]);
+ glVertexAttribPointer(
+ ATTRIB_VERTEX, // location (for shader)
+ 3, // size
+ GL_FLOAT, // type
+ GL_FALSE, // normalized
+ 0, // stride
+ nullptr // offset
+ );
+
+ glEnableVertexAttribArray(ATTRIB_COLOR);
+ glBindBuffer(GL_ARRAY_BUFFER, handle[ATTRIB_COLOR]);
+ glVertexAttribPointer(
+ ATTRIB_COLOR, // location (for shader)
+ 3, // size
+ GL_FLOAT, // type
+ GL_FALSE, // normalized
+ 0, // stride
+ nullptr // offset
+ );
+
+ glLineWidth(2.0f);
+
+ glDrawArrays(
+ GL_LINES, // how
+ 0, // start
+ vertices.size() // len
+ );
+
+ glDisableVertexAttribArray(ATTRIB_COLOR);
+ glDisableVertexAttribArray(ATTRIB_VERTEX);
+}
+