1 files changed, 60 insertions, 0 deletions
diff --git a/src/model_instance.cpp b/src/model_instance.cpp
new file mode 100644
index 0000000..db28243
--- /dev/null
+++ b/src/model_instance.cpp
@@ -0,0 +1,60 @@
+#include "model_instance.hpp"
+#include "scene.hpp"
+#include <tuple>
+
+ModelInstance::ModelInstance(std::shared_ptr<Mesh> mesh, FIXED scale,
+                             VECTOR rotation, VECTOR position)
+    : m_mesh(mesh), m_scale(scale), m_rot(rotation), m_pos(position) {}
+
+VECTOR rotate(VECTOR v, VECTOR rot) {
+  FIXED sin_theta_x, sin_theta_y, sin_theta_z;
+  FIXED cos_theta_x, cos_theta_y, cos_theta_z;
+
+  VECTOR res = {v.x, v.y, v.z};
+
+  if (rot.x != 0) {
+    sin_theta_x = float2fx(0.707); // lu_sin(rot.x) >> 4;
+    cos_theta_x = float2fx(0.707); // lu_cos(rot.x) >> 4;
+    res.y = fxmul(res.y, cos_theta_x) - fxmul(res.z, sin_theta_x);
+    res.z = fxmul(res.z, cos_theta_x) + fxmul(res.y, sin_theta_x);
+  }
+
+  if (rot.y != 0) {
+    sin_theta_y = lu_sin(rot.y) >> 4;
+    cos_theta_y = lu_cos(rot.y) >> 4;
+    res.x = fxmul(res.x, cos_theta_y) + fxmul(res.z, sin_theta_y);
+    res.z = fxmul(res.z, cos_theta_y) - fxmul(res.x, sin_theta_y);
+  }
+
+  if (rot.z != 0) {
+    sin_theta_z = lu_sin(rot.z) >> 4;
+    cos_theta_z = lu_cos(rot.z) >> 4;
+    res.x = fxmul(res.x, cos_theta_z) - fxmul(res.y, sin_theta_z);
+    res.y = fxmul(res.z, cos_theta_z) + fxmul(res.x, sin_theta_z);
+  }
+
+  return res;
+}
+
+void ModelInstance::render(std::shared_ptr<Scene> scene_context) {
+  usu::vector<POINT> projected(m_mesh->vertices.size());
+
+  for (std::uint32_t i = 0; i < projected.size(); i++) {
+    VECTOR transformed = rotate(m_mesh->vertices[i], m_rot);
+    vec_add(&transformed, &transformed, &m_pos);
+
+    projected[i] = scene_context->project_2d(transformed);
+  }
+
+  for (const TRIANGLE triangle : m_mesh->triangles) {
+    POINT v0 = projected[std::get<0>(triangle.vertex_indices)];
+    POINT v1 = projected[std::get<1>(triangle.vertex_indices)];
+    POINT v2 = projected[std::get<2>(triangle.vertex_indices)];
+
+    scene_context->draw_line(v0, v1, triangle.color_idx);
+    scene_context->draw_line(v1, v2, triangle.color_idx);
+    scene_context->draw_line(v2, v0, triangle.color_idx);
+  }
+}
+
+void ModelInstance::add_pos(VECTOR d_pos) { vec_add(&m_pos, &m_pos, &d_pos); }