/// Inlcudes

 #include "VectorUtils4.h"
 #include "LittleOBJLoader.h"
 #include "LoadTGA.h"
 
 

 /// Generate terrain
 Model * GenerateTerrain(const char * filename)

 {

 	TextureData textureData;
 	if (!LoadTGATextureData(filename, &textureData))
 		return nullptr;
 
 	int vertexCount   =  textureData.width    *  textureData.height;
 	int triangleCount = (textureData.width-1) * (textureData.height-1) * 2;
 
 	vec3   * position = (vec3 *)  malloc(sizeof(GLfloat) * 3 * vertexCount);
 	vec3   * normal   = (vec3 *)  malloc(sizeof(GLfloat) * 3 * vertexCount);
 	vec2   * texCoord = (vec2 *)  malloc(sizeof(GLfloat) * 2 * vertexCount);
 	GLuint * indices  = (GLuint *)malloc(sizeof(GLuint)  * 3 * triangleCount);
 
 	int bytesPerPixel = textureData.bpp / 8;
 	for (unsigned int x = 0; x < textureData.width;  ++x)
 	for (unsigned int z = 0; z < textureData.height; ++z)
 	{
 		int indexBase = (x + z * textureData.width);
 		// Vertex array. You need to scale this properly.
 		GLubyte data = textureData.imageData[indexBase * bytesPerPixel];
 		position[indexBase].x = x    / 1.0;
 		position[indexBase].y = data / 100.0;
 		position[indexBase].z = z    / 1.0;
 		// Normal vectors. You need to calculate these.
 		normal[indexBase].x = 0.0;
 		normal[indexBase].y = 1.0;
 		normal[indexBase].z = 0.0;
 		// Texture coordinates. You may want to scale them.
 		texCoord[indexBase].x = x; // (float)x / textureData.width;
 		texCoord[indexBase].y = z; // (float)z / textureData.height;
 	}
 	for (unsigned int x = 0; x < textureData.width-1;  ++x)
 	for (unsigned int z = 0; z < textureData.height-1; ++z)
 	{
 		int indexBase = (x + z * (textureData.width-1))*6;

 		// Triangle 1

 		indices[indexBase + 0] = (x+0) + (z+0) * textureData.width;
 		indices[indexBase + 1] = (x+0) + (z+1) * textureData.width;
 		indices[indexBase + 2] = (x+1) + (z+0) * textureData.width;

 		// Triangle 2

 		indices[indexBase + 3] = (x+1) + (z+0) * textureData.width;
 		indices[indexBase + 4] = (x+0) + (z+1) * textureData.width;
 		indices[indexBase + 5] = (x+1) + (z+1) * textureData.width;
 	}

 	// Create Model and upload to GPU:
 	Model * model = LoadDataToModel(
 		position,
 		normal,
 		texCoord,
 		nullptr,
 		indices,
 		vertexCount,
 		triangleCount * 3
 	);
 
 	free(textureData.imageData);

 	return model;
 }