From 44d829e5649b209126fb6a092d3a3761d29fdcfd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Steffen=20F=C3=BCndgens?= <steffen.fuendgens@rwth-aachen.de>
Date: Thu, 6 Nov 2014 19:21:24 +0100
Subject: [PATCH] added most of the functionallity to make a triangle strip
 from the heightmap

---
 terrain.cc | 87 +++++++++++++++++++++++++++++++++++++++++++++++-------
 terrain.hh |  6 ++++
 2 files changed, 82 insertions(+), 11 deletions(-)

diff --git a/terrain.cc b/terrain.cc
index 53f258d..9e655ea 100644
--- a/terrain.cc
+++ b/terrain.cc
@@ -9,26 +9,91 @@ Terrain::~Terrain() {
 
 void Terrain::load() {
     std::ifstream terrain_png(this->filePath);
-    unsigned int width, height, rowNum, columnNum;
+    unsigned int rowNum, columnNum;
 
-    terrain_png.seekg(16);			//skip part of the header
-    terrain_png.read((char *)&width, 4);	//read width
-    terrain_png.read((char *)&height, 4);	//read height
-    width = ntohl(width);			//convert from host to network byte order
-    height = ntohl(height);			
+    terrain_png.seekg(16);					//skip part of the header
+    terrain_png.read((char *)&this->heightmapWidth, 4);		//read width
+    terrain_png.read((char *)&this->heightmapHeight, 4);	//read height
+    this->heightmapWidth  = ntohl(this->heightmapWidth);	//convert from host to network byte order
+    this->heightmapHeight = ntohl(this->heightmapHeight);			
 
-    heightmap = new unsigned int*[height];	//initialize the heightmap
-    for(rowNum=0; rowNum<height; rowNum++){	//read in the heightmap
-	    heightmap[rowNum] = new unsigned int[width];
-        for(columnNum=0; columnNum<width; columnNum++){
+    heightmap = new unsigned int*[this->heightmapHeight];		//initialize the heightmap
+    for(rowNum = 0; rowNum < this->heightmapHeight; rowNum++){		//read in the heightmap
+	    heightmap[rowNum] = new unsigned int[this->heightmapWidth];
+        for(columnNum = 0; columnNum < this->heightmapWidth; columnNum++){
             terrain_png.read((char *)&heightmap[rowNum][columnNum], 1);
         }
     }
 
+    this->makeTriangleMesh();
+    heightmapChanged = false;
 
+    texture.load();
+}
 
-    
+void Terrain::makeTriangleMesh(){
+
+    ACGL::OpenGL::ArrayBuffer arrayBuffer = ACGL::OpenGL::ArrayBuffer();
+    arrayBuffer.defineAttribute("pos", GL_UNSIGNED_INT, 3);
+
+    unsigned int rowNum=0, columnNum=0;				//initializing:
+    bool movingRight = true, isUp = true;
+    while(rowNum < this->heightmapHeight){			//traversing the Triangle Strip!
+	unsigned int newPos[3];
+	newPos[0] = rowNum;
+	newPos[1] = columnNum;
+	newPos[2] = heightmap[rowNum][columnNum];
+        arrayBuffer.setDataElements(1, &newPos);
+	if (isUp){
+	    rowNum = rowNum + 1;
+	    isUp = false;
+	}else if (movingRight){
+	    if (columnNum = this->heightmapWidth - 1){
+		arrayBuffer.setDataElements(1, &newPos);
+		arrayBuffer.setDataElements(1, &newPos);
+		movingRight = false;
+		rowNum = rowNum + 1;
+	    } else{
+		rowNum = rowNum - 1;
+		columnNum = columnNum + 1;
+		isUp = true;
+	    }
+	}else{
+	    if (columnNum = 0){
+		arrayBuffer.setDataElements(1, &newPos);
+		arrayBuffer.setDataElements(1, &newPos);
+		movingRight = true;
+		rowNum = rowNum + 1;
+	    }else{
+		rowNum = rowNum - 1;
+		columnNum = columnNum - 1;
+		isUp = true;
+	    }
+	}
+    }
+
+    //this->triangleMesh = ACGL::OpenGL::VertexArrayObject();			//does not work since ACGL::OpenGL::VertexArrayObject is ACGL_NOT_COPYABLE
+    this->triangleMesh.bind();
+    this->triangleMesh.setMode(GL_TRIANGLE_STRIP);
+    //this->triangleMesh.attachAllAttributes(arrayBuffer);
+    //TODO unbind?
 }
 
 void Terrain::render() {
+    if (heightmapChanged)
+	this->makeTriangleMesh();
+    this->triangleMesh.render();
 }
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/terrain.hh b/terrain.hh
index 07a85be..481e2ed 100644
--- a/terrain.hh
+++ b/terrain.hh
@@ -6,6 +6,7 @@
 #include <fstream>
 //#include <winsock.h>		//on Windows
 #include <netinet/in.h>		//on Unix
+#include <ACGL/OpenGL/Objects/VertexArrayObject.hh>
 
 class Terrain {
     public:
@@ -17,7 +18,12 @@ class Terrain {
         float friction;
         Texture texture;
         std::string filePath;
+	unsigned int heightmapWidth, heightmapHeight;
 	unsigned int** heightmap;	//can be accessed like 'unsigned int[][]'
+	bool heightmapChanged;
+	ACGL::OpenGL::VertexArrayObject triangleMesh;
+
+	void makeTriangleMesh();
 };
 
 #endif