+void Canvas::DrawRect(const glm::vec2 &p1, const glm::vec2 &p2, float width) {
+ glm::vec2 min(std::min(p1.x, p2.x), std::min(p1.y, p2.y));
+ glm::vec2 max(std::max(p1.x, p2.x), std::max(p1.y, p2.y));
+ glm::vec2 dg1(min.x, max.y);
+ glm::vec2 dg2(max.x, min.y);
+ glm::vec2 d(width * 0.5f, width * 0.5f);
+ glm::vec2 n(d.y, -d.x);
+ vao.Bind();
+ vao.BindAttributes();
+ {
+ auto attr = vao.MapAttributes(GL_WRITE_ONLY);
+ attr[0].position = min + d;
+ attr[1].position = min - d;
+ attr[2].position = dg1 + n;
+ attr[3].position = dg1 - n;
+ attr[4].position = max - d;
+ attr[5].position = max + d;
+ attr[6].position = dg2 - n;
+ attr[7].position = dg2 + n;
+ }
+ vao.BindElements();
+ {
+ auto elem = vao.MapElements(GL_WRITE_ONLY);
+ elem[0] = 0;
+ elem[1] = 1;
+ elem[2] = 2;
+ elem[3] = 3;
+ elem[4] = 4;
+ elem[5] = 5;
+ elem[6] = 6;
+ elem[7] = 7;
+ elem[8] = 0;
+ elem[9] = 1;
+ }
+ vao.DrawTriangleStrip(10);
+ vao.Unbind();