From 4a53c24e9c1aa2882c2b2f98d50385283575d150 Mon Sep 17 00:00:00 2001
From: SeanOMik <seanomik@gmail.com>
Date: Sat, 15 Oct 2022 23:39:20 -0400
Subject: [PATCH] Implement transform interpolation for slower TPS than FPS

---
 src/gfx/renderer.cpp | 12 +-----------
 src/scene.cpp        | 10 ++++++++--
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/src/gfx/renderer.cpp b/src/gfx/renderer.cpp
index 514ec33..764e07a 100644
--- a/src/gfx/renderer.cpp
+++ b/src/gfx/renderer.cpp
@@ -154,20 +154,10 @@ namespace simpleengine::gfx {
     bool Renderer::render_job(const float& interpolate_alpha, const RenderingJob &job) {
         Mesh *mesh = job.rendering_mesh;
 
-        /* glm::mat4 transform_mat = job.transform_mat * interpolate_alpha +
-            job.last_transform_mat * (1.f - interpolate_alpha); */
-
-        //glm::mat4 transform_mat = lerp(job.transform_mat, job.last_transform_mat, interpolate_alpha);
+        // Iterpolate between transforms
         glm::mat4 transform_mat = lerp(job.last_transform_mat, job.transform_mat, interpolate_alpha);
 
-        std::cout << "Last transform: " << glm::to_string(job.last_transform_mat) << std::endl <<
-            "Current Transform: " << glm::to_string(job.transform_mat) << std::endl <<
-            "Lerp: " << glm::to_string(transform_mat) << std::endl << std::endl;
-
-        //std::cout << "Current: " << job.transform_mat[3]
-
         shader.set_uniform_matrix_4f("u_transform_matrix", transform_mat);
-        //shader.set_uniform_matrix_4f("u_transform_matrix", job.transform_mat);
 
         std::optional<Material> &material = mesh->material;
 
diff --git a/src/scene.cpp b/src/scene.cpp
index 875acd8..20630ff 100644
--- a/src/scene.cpp
+++ b/src/scene.cpp
@@ -6,6 +6,9 @@
 #include "ecs/entity.h"
 #include "gfx/renderer.h"
 
+#include <glm/gtx/string_cast.hpp>
+#include <stdexcept>
+
 namespace simpleengine {
     Scene::Scene(std::shared_ptr<gfx::Renderer> renderer) : renderer(renderer) {
         
@@ -16,6 +19,11 @@ namespace simpleengine {
     }
 
     void Scene::update(const float& delta_time) {
+        // Update the last transform matrix 
+        registry.view<TransformComponent>().each([this, &delta_time](TransformComponent& transform) {
+            transform.last_transform_matrix = transform.transform_matrix;
+        });
+
         // Rotate the model
         registry.view<TransformComponent, RotatingComponent>().each([this, &delta_time](TransformComponent& transform, RotatingComponent& rotating) {
             transform.rotate(rotating.rate * delta_time, rotating.rotation_axis);
@@ -32,7 +40,6 @@ namespace simpleengine {
                 }
 
                 renderer->queue_job(gfx::RenderingJob(rendering_type, mesh, transform.last_transform_matrix, transform.transform_matrix));
-                transform.last_transform_matrix = transform.transform_matrix; // Update last transform
             }
         });
 
@@ -43,7 +50,6 @@ namespace simpleengine {
             }
 
             renderer->queue_job(gfx::RenderingJob(rendering_type, mesh_component.mesh, transform.last_transform_matrix, transform.transform_matrix));
-            transform.last_transform_matrix = transform.transform_matrix; // Update last transform
         });
 
         renderer->render(interpolate_alpha, frame_time);