Messing around with when to do glGen, solving a memory leak because of that, and rewriting Scene::spawn to use the instancing stuff.

27-instancing/src/config.hpp

@@ -1,6 +1,6 @@
 #pragma once
 
-#define INSTANCE_COUNT 100
+#define INSTANCE_COUNT 5
 
 const unsigned int SCR_WIDTH = 1792;
 const unsigned int SCR_HEIGHT = 1008;

27-instancing/src/main.cpp

@@ -76,8 +76,8 @@ void process_input(GLFWwindow *window, Scene& scene) {
   }
 
   if(glfwGetKey(window, GLFW_KEY_M) == GLFW_PRESS) {
-    components::Rotation rotation{90.0f, {1.0f, 0.0f, 0.0f}};
+    components::Rotation rotation{0.0f, {1.0f, 1.0f, 1.0f}};
-    scene.spawn("grass", scene.camera.position, rotation);
+    scene.spawn("marble_cube", scene.camera.position, rotation);
   }
 
   if(glfwGetKey(window, GLFW_KEY_L) == GLFW_PRESS) {

27-instancing/src/mesh.cpp

@@ -2,13 +2,13 @@
 #include "dbc.hpp"
 #include "config.hpp"
 
-void Mesh::draw(Shader &shader, bool with_textures) {
+void Mesh::draw(Shader &shader, bool with_textures, unsigned int count) {
   if(with_textures) {
     apply_textures(shader);
   }
 
   glBindVertexArray(VAO);
-  glDrawElementsInstanced(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0, INSTANCE_COUNT);
+  glDrawElementsInstanced(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0, count);
   glBindVertexArray(0);
   glActiveTexture(GL_TEXTURE0);
 }

27-instancing/src/mesh.hpp

@@ -66,7 +66,7 @@ struct Mesh {
     setup_mesh();
   }
 
-  void draw(Shader &shader, bool with_textures);
+  void draw(Shader &shader, bool with_textures, unsigned int count);
   void setup_mesh();
   void apply_textures(const Shader& shader);
 };

27-instancing/src/model.cpp

@@ -83,9 +83,9 @@ unsigned int texture_from_file(const std::string& directory, const std::string&
   return textureID;
 }
 
-void Model::draw(Shader &shader, bool with_textures) {
+void Model::draw(Shader &shader, bool with_textures, unsigned int count) {
   for(auto& mesh : meshes) {
-    mesh.draw(shader, with_textures);
+    mesh.draw(shader, with_textures, count);
   }
 }
 

27-instancing/src/model.hpp

@@ -32,7 +32,7 @@ struct Model {
     load_model();
   }
 
-  void draw(Shader &shader, bool with_textures=true);
+  void draw(Shader &shader, bool with_textures, unsigned int count);
 
   void load_model();
   void process_node(const aiScene *scene, aiNode *node);

27-instancing/src/scene.cpp

@@ -33,7 +33,7 @@ void Scene::draw_thing(Shader& with_shader, Thing& thing)
   with_shader.setMat4("model", model);
 
   // !reflect_on turns it on? yeah weird
-  thing.model.draw(with_shader, !reflect_on);
+  thing.model.draw(with_shader, !reflect_on, translations.size());
 }
 
 void Scene::render(GLFWwindow* window) {
@@ -72,13 +72,7 @@ void Scene::cleanup() {
 
 void Scene::spawn(const std::string& name, components::Position& position, components::Rotation& rotation) {
   if(models.contains(name)) {
-    things.emplace_back(
+    translations.push_back(position);
-          name,
-          models.at(name),
-          materials.at("default"),
-          position,
-          rotation,
-          1.0f);
   } else {
     dbc::log($F("No model named: {}", name));
   }
@@ -86,7 +80,7 @@ void Scene::spawn(const std::string& name, components::Position& position, compo
 
 void Scene::time_warp() {
   float time = glfwGetTime();
-  for(size_t i = 0; i < INSTANCE_COUNT; i++) {
+  for(size_t i = 0; i < translations.size(); i++) {
     auto& t = translations[i];
     float factor = (float)i / 3.0f;
     t.y = cos((time + i)) * factor;
@@ -94,9 +88,8 @@ void Scene::time_warp() {
     t.x = sin((time + i)) * factor;
   }
 
-  glGenBuffers(1, &instanceVBO);
   glBindBuffer(GL_ARRAY_BUFFER, instanceVBO);
-  glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec3) * INSTANCE_COUNT, &translations[0], GL_STATIC_DRAW);
+  glBufferData(GL_ARRAY_BUFFER, sizeof(glm::vec3) * translations.size(), translations.data(), GL_STATIC_DRAW);
   glBindBuffer(GL_ARRAY_BUFFER, 0);
 
   for(auto& mesh : things[0].model.meshes) {
@@ -111,17 +104,13 @@ void Scene::time_warp() {
 
 void Scene::setup_instancing() {
   for(size_t i = 0; i < INSTANCE_COUNT; i++) {
-    translations[i].x = (float)i;
+    translations.emplace_back((float)i, (float)i, (float)i);
-    translations[i].z = (float)i;
-    translations[i].y = (float)i;
   }
 
   time_warp();
 }
 
 void Scene::init_skybox() {
-  glGenVertexArrays(1, &skyboxVAO);
-  glGenBuffers(1, &skyboxVBO);
   glBindVertexArray(skyboxVAO);
   glBindBuffer(GL_ARRAY_BUFFER, skyboxVBO);
   glBufferData(GL_ARRAY_BUFFER, sizeof(skyboxVertices), &skyboxVertices, GL_STATIC_DRAW);
@@ -138,7 +127,6 @@ void Scene::load_skybox_textures() {
   int nrChannels = 0;
   size_t face_i = 0;
 
-  glGenTextures(1, &skybox_texture_id);
   glBindTexture(GL_TEXTURE_CUBE_MAP, skybox_texture_id);
 
   for(const auto& face : skybox_faces) {

27-instancing/src/scene.hpp

@@ -34,7 +34,6 @@ struct Scene {
   Screen screen;
   FrameBuffer framebuffer;
 
-
   std::unordered_map<std::string, components::Material> materials;
   Camera camera;
   components::Lighting light;
@@ -47,7 +46,7 @@ struct Scene {
   unsigned int skybox_texture_id = 0;
   bool reflect_on = false;
 
-  glm::vec3 translations[INSTANCE_COUNT];
+  std::vector<glm::vec3> translations;
   unsigned int instanceVBO = 0;
 
   Scene(components::Scene& config):
@@ -80,6 +79,11 @@ struct Scene {
           thing.scale);
     }
 
+    glGenVertexArrays(1, &skyboxVAO);
+    glGenBuffers(1, &skyboxVBO);
+    glGenTextures(1, &skybox_texture_id);
+    glGenBuffers(1, &instanceVBO);
+
     shader.use();
     shader.setInt("texture1", 0);
     shader.apply_lighting(light);

27-instancing/tests/model_tests.cpp

@@ -14,13 +14,13 @@ namespace model_tests {
     Shader shader({"shaders/14-vert.glsl", "shaders/14-frag.glsl", ""});
 
     Model popcorn{"assets", "popcorn_model_a.glb"};
-    popcorn.draw(shader);
+    popcorn.draw(shader, true, 1);
 
     Model crate_glb{"assets", "crate.glb"};
-    crate_glb.draw(shader);
+    crate_glb.draw(shader, true, 1);
 
     Model crate_obj{"assets", "crate.obj"};
-    crate_obj.draw(shader);
+    crate_obj.draw(shader, true, 1);
   }
 
   void test_failures() {