Index Rendering

src/engine/layer/GameLayer.cpp

@@ -13,15 +13,18 @@ GameLayer::GameLayer() :model(0,0) //Platzhalter, echtes Model kommt in onAttach
 void GameLayer::onAttach()
 {
     std::vector<float> vertices = {
-        -0.5f, 0.5f, 0.f,
+        -0.5f, 0.5f, 0.f,//v0
-        -0.5f, -0.5f, 0.f,
+                        -0.5f, -0.5f, 0.f,//v1
-        0.5f, -0.5f, 0.f,
+                        0.5f, -0.5f, 0.f,//v2
-        0.5f, -0.5f, 0.f,
+                        0.5f, 0.5f, 0.f,//v3
-        0.5f, 0.5f, 0.f,
-        -0.5f, 0.5f, 0.f
     };
 
-    model = loader.loadToVAO(vertices);
+    std::vector<int> indices = {
+        0,1,3,
+        3,1,2
+    };
+
+    model = loader.loadToVAO(vertices, indices);
 }
 
 void GameLayer::onDetach()

src/engine/renderer/Renderer.cpp

@@ -19,7 +19,7 @@ void Renderer::renderFrame(const RawModel& model) {
 void Renderer::renderRawModel(const RawModel& model) {
     glBindVertexArray(model.vaoID);
     glEnableVertexAttribArray(0);
-    glDrawArrays(GL_TRIANGLES,0 , model.vertexCount);
+    glDrawElements(GL_TRIANGLES , model.vertexCount, GL_UNSIGNED_INT, 0);
     glDisableVertexAttribArray(0);
     glBindVertexArray(0);
 

src/engine/renderer/model/Loader.cpp

@@ -4,11 +4,12 @@
 
 #include "Loader.h"
 
-RawModel Loader::loadToVAO(std::vector<float> vertices){
+RawModel Loader::loadToVAO(const std::vector<float>& vertices, const std::vector<int>& indices){
     GLuint vaoID = createVAO();
     storeDataInAttributeList(0, vertices);
+    bindIndicesBuffer(indices);
     unbindVAO();
-    return {vaoID, static_cast<int>(vertices.size() / 3)};
+    return {vaoID, static_cast<int>(indices.size())};
 }
 
 Loader::~Loader() {
@@ -44,6 +45,16 @@ void Loader::storeDataInAttributeList(int attributeNumber, const std::vector<flo
     glBindBuffer(GL_ARRAY_BUFFER, 0);
 }
 
+void Loader::bindIndicesBuffer(const std::vector<int>& indices) {
+    GLuint vboID;
+    glGenBuffers(1, &vboID);
+    vboIDs.push_back(vboID);
+
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vboID);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(int), indices.data(), GL_STATIC_DRAW);
+
+}
+
 void Loader::unbindVAO() {
     glBindVertexArray(0);
 }

src/engine/renderer/model/Loader.h

@@ -13,13 +13,14 @@
 class Loader
 {
 public:
-    RawModel loadToVAO(std::vector<float> vertices);
+    RawModel loadToVAO(const std::vector<float>& vertices, const std::vector<int>& indices);
     ~Loader();
     void cleanUp();
 
 private:
     GLuint createVAO();
     void storeDataInAttributeList(int attributeNumber, const std::vector<float> &data);
+    void bindIndicesBuffer(const std::vector<int> &indices);
     void unbindVAO();
 
     std::vector<GLuint> vaoIDs;