From ecba8247bfdfa0f477c99a7a313e7b166d785527 Mon Sep 17 00:00:00 2001
From: LandaMm <qwer.009771@gmail.com>
Date: Sat, 18 Oct 2025 17:55:26 +0200
Subject: [PATCH] feat: rendering improvemenets

---
 engine/include/engine/components/batch.h |  1 +
 engine/src/components/batch.cpp          | 17 ++++++++++++++---
 engine/src/renderer/renderer.cpp         | 13 ++++++-------
 sandbox/src/main.cpp                     |  4 ++--
 4 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/engine/include/engine/components/batch.h b/engine/include/engine/components/batch.h
index efc2f55..afe609f 100644
--- a/engine/include/engine/components/batch.h
+++ b/engine/include/engine/components/batch.h
@@ -21,6 +21,7 @@ protected:
 private:
     unsigned int m_id;
     unsigned int m_instance_vbo { 0 };
+    unsigned int m_instance_count { 0 };
 private:
     void prepare(glm::mat4 *instances, unsigned int count);
 };
diff --git a/engine/src/components/batch.cpp b/engine/src/components/batch.cpp
index 632c643..8952898 100644
--- a/engine/src/components/batch.cpp
+++ b/engine/src/components/batch.cpp
@@ -11,9 +11,20 @@ batch::batch() {
 void batch::prepare(glm::mat4 *instances, unsigned int count) {
     if (m_instance_vbo == 0) {
         glGenBuffers(1, &m_instance_vbo);
+        glBindBuffer(GL_ARRAY_BUFFER, m_instance_vbo);
+        // Allocate *once*, no data yet — just reserve space
+        glBufferData(GL_ARRAY_BUFFER, sizeof(glm::mat4) * count, nullptr, GL_DYNAMIC_DRAW);
+        m_instance_count = count;
+    } else if (count > m_instance_count) {
+        // Optional: reallocate only if you *really* have more instances than before
+        glBindBuffer(GL_ARRAY_BUFFER, m_instance_vbo);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(glm::mat4) * count, nullptr, GL_DYNAMIC_DRAW);
+        m_instance_count = count;
+    } else {
+        glBindBuffer(GL_ARRAY_BUFFER, m_instance_vbo);
     }
-    
-    glBindBuffer(GL_ARRAY_BUFFER, m_instance_vbo);
-        glBufferData(GL_ARRAY_BUFFER, sizeof(glm::mat4) * count, reinterpret_cast<void*>(instances), GL_DYNAMIC_DRAW);
+
+    // Just update the data region — much cheaper
+    glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(glm::mat4) * count, instances);
     glBindBuffer(GL_ARRAY_BUFFER, 0);
 }
\ No newline at end of file
diff --git a/engine/src/renderer/renderer.cpp b/engine/src/renderer/renderer.cpp
index 3c57ec9..5b1285b 100644
--- a/engine/src/renderer/renderer.cpp
+++ b/engine/src/renderer/renderer.cpp
@@ -205,12 +205,9 @@ void Renderer::GenerateShadowMaps() {
 void Renderer::Render() {
     m_depthShader.use();
 
-    glEnable(GL_DEPTH_TEST);
-    glEnable(GL_CULL_FACE);
-
     glCullFace(GL_FRONT);
 
-    auto lights = m_registry.view<light, transform>();
+    const auto lights = m_registry.view<light, transform>();
 
     for (auto [_, l, t] : lights.each()) {
         // TODO: support other light types when ready
@@ -218,10 +215,10 @@ void Renderer::Render() {
 
         EnsureShadowResources(l);
 
-        float near_plane = 0.1f, far_plane = 20.0f;
+        // float near_plane = 0.1f, far_plane = 50.0f;
         glm::vec3 target   = glm::vec3(0.0f, 0.5f, 0.0f);
         glm::mat4 lightView = glm::lookAt(t.position, target, glm::vec3(0.0f, 1.0f, 0.0f));
-        glm::mat4 lightProjection = glm::ortho(-6.0f, 6.0f, -6.0f, 6.0f, near_plane, far_plane);
+        glm::mat4 lightProjection = glm::ortho(-6.0f, 6.0f, -6.0f, 6.0f, 1.0f, 20.0f);
         glm::mat4 lightSpaceMatrix = lightProjection * lightView;
 
         m_depthShader.setMat4("u_lightSpace", lightSpaceMatrix);
@@ -237,6 +234,8 @@ void Renderer::Render() {
 
         RenderScene(m_depthShader);
 
+        // glDisable(GL_POLYGON_OFFSET_FILL);
+
         glBindFramebuffer(GL_FRAMEBUFFER, 0);
     }
 
@@ -246,7 +245,7 @@ void Renderer::Render() {
     glViewport(0, 0, Window::GetWidth(), Window::GetHeight());
     glClearColor(0x18/255.0f, 0x18/255.0f, 0x18/255.0f, 1);
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-    
+
     m_shader.use();
     ApplyLights(m_shader);
     UpdateView();
diff --git a/sandbox/src/main.cpp b/sandbox/src/main.cpp
index c4fb424..3016b75 100644
--- a/sandbox/src/main.cpp
+++ b/sandbox/src/main.cpp
@@ -35,9 +35,9 @@ public:
         m_registry.emplace<transform>(cameraEntity, glm::vec3(0.f, 2.f, 2.f));
         m_registry.emplace<camera>(cameraEntity);
 
-        Object* targetObj = Object::LoadFile("./assets/wizard/wizard.obj");
+        Object* targetObj = Object::LoadFile("./assets/car/car.obj");
         const auto targetEntity = m_registry.create();
-        m_registry.emplace<transform>(targetEntity, glm::vec3(0.f, 0.0f, 0.f), glm::vec3(0.f, 0.0f, 0.f), glm::vec3(0.5f, 0.5f, 0.5f));
+        m_registry.emplace<transform>(targetEntity, glm::vec3(0.f, 0.0f, 0.f));
         m_registry.emplace<mesh>(targetEntity, std::shared_ptr<Object>(targetObj));
         m_registry.emplace<rotate>(targetEntity);