Started on terrain, created a plane

Author: Cheng Xie

src/meshutility.cpp

@@ -81,3 +81,79 @@ Mesh *MeshUtility::loadObjModel(string filename)
 
     return mesh;
 }
+
+Mesh *MeshUtility::createPlane(int tessellationLevel, float size)
+{
+    assert(tessellationLevel > 0);
+    assert(size > 0);
+    
+    vector<SimpleVertex> vertexBuffer;
+    IndexBuffer indexBuffer;
+    
+    vec3 normal = {0, 1, 0};
+    
+    vec3 upperleft = {-size, 0, -size};
+    vec3 lowerleft = {-size, 0, size};
+    vec3 lowerright = {size, 0, size};
+    
+    vec3 dy = (upperleft - lowerleft) / tessellationLevel;
+    
+    float width = (lowerright - lowerleft).length();
+    float height = (upperleft - lowerleft).length();
+    
+    // build vertices
+    for (int row = 0; row <= tessellationLevel; row++) {
+        vector<vec3> result;
+        tessellate(lowerleft + dy * row, lowerright + dy * row, tessellationLevel, result);
+        for (const vec3& point : result) {
+            SimpleVertex v;
+            v.position = point;
+            v.normal = normal;
+            v.uv.setX(vec3::dotProduct(point - lowerleft, (lowerright - lowerleft).normalized()) / width);
+            v.uv.setY(vec3::dotProduct(point - lowerleft, (upperleft - lowerleft).normalized()) / height);
+            vertexBuffer.push_back(v);
+        }
+    }
+    
+    // build faces
+    for (int l = 0; l < tessellationLevel; l++) {
+        for (int s = 0; s < tessellationLevel; s++) {
+            uint16_t i1 = l * (tessellationLevel+1) + s;
+            uint16_t i2 = i1 + 1;
+            uint16_t i3 = i1 + tessellationLevel+1;
+            uint16_t i4 = i2 + tessellationLevel+1;
+            
+            indexBuffer.push_back(i1);
+            indexBuffer.push_back(i2);
+            indexBuffer.push_back(i3);
+            
+            indexBuffer.push_back(i4);
+            indexBuffer.push_back(i3);
+            indexBuffer.push_back(i2);
+        }
+    }
+    
+    Mesh* mesh = new Mesh;
+    VertexBufferDesc desc;
+    desc.bufferData = vertexBuffer.data();
+    desc.bufferSize = vertexBuffer.size() * sizeof(SimpleVertex);
+    desc.vertexElementSizes = {3, 3, 2};
+    desc.stride = sizeof(SimpleVertex);
+    
+    mesh->setVertexBuffer(desc, PrimitiveType::Triangles);
+    mesh->setIndexBuffer(indexBuffer);
+    
+    return mesh;
+    
+}
+
+void MeshUtility::tessellate(vec3 p1, vec3 p2, int level, vector<vec3> &result)
+{
+    assert(level > 0);
+    
+    auto delta = (p2 - p1) / level;
+    for (int i = 0; i <= level; i++)
+    {
+        result.push_back(p1 + delta * i);
+    }
+}

src/meshutility.h

@@ -2,11 +2,16 @@
 #define MESHUTILITY_H
 
 #include "common.h"
+#include "geometry.h"
 
 class MeshUtility
 {
 public:
     static Mesh* loadObjModel(string filename);
+    
+    static Mesh* createPlane(int tessellationLevel, float size);
+    
+    static void tessellate(vec3 p1, vec3 p2, int level, vector<vec3>& result);
 };
 
 #endif // MESHUTILITY_H

src/scene.cpp

@@ -10,6 +10,7 @@
 #include "particlesystem.h"
 #include "skybox.h"
 #include "skyboxmaterial.h"
+#include "terrain.h"
 
 Scene::Scene()
 {
@@ -88,6 +89,10 @@ void Scene::initialize()
 
     // Skybox
     skybox_ = new Skybox("cloudy");
+    
+    // Terrain
+    Terrain* terrain = new Terrain();
+    sceneObjects_.push_back(terrain);
 }
 
 void Scene::render(DrawContext &context)

src/terrain.cpp

@@ -1,5 +1,27 @@
 #include "terrain.h"
+#include "meshutility.h"
+#include "phongmaterial.h"
+#include "mesh.h"
 
 Terrain::Terrain()
 {
+    buildMesh();
+}
+
+Terrain::~Terrain()
+{
+    delete mesh_;
+}
+
+void Terrain::buildMesh()
+{
+    mesh_ = MeshUtility::createPlane(200, 500);
+    
+    PhongMaterial* material = new PhongMaterial;
+    material->setAmbient({0.2, 0.2, 0.2});
+    material->setDiffuse({0.7, 0.7, 0.2});
+    
+    setMaterial(material);
+    
+    transform().translate(0, -20, 0);
 }

src/terrain.h

@@ -7,9 +7,10 @@ class Terrain : public SceneObject
 {
 public:
     Terrain();
+    virtual ~Terrain();
 
 private:
-    void buildMesh() {}
+    void buildMesh();
 };
 
 #endif // TERRAIN_H