Riemers3DXNA4advterrain01starting
Once again, we’ll not begin from scratch, as we already seen the very basics on terrain creation in the first series. We’ll start with the code presented below, which is tightly based on the code of the first series.
Because we would otherwise get a too lengthy LoadContent method, this method now calls a LoadVertices method where we will initialize all our vertices and indices.
For now, this LoadVertices method generates the vertices and indices for a terrain. These vertices contain both positional and color information. Next, we pass them to the CalculateNormals method, which generates the correct normals and adds them to the vertices. Finally, both vertices and indices are stored in a VertexBuffer and IndexBuffer for optimal speed.
In the Draw method, they are passed to the Colored technique, which is defined in the Series4Effects.fx file which is displayed below. This file will contain our HLSL code, so we’re going to extend it throughout the following chapters. You can also download the file here.
We’ll also be using a slightly bigger heightmap, which you can download here.
So create a new project and paste the code below into the Game1.cs file. Make sure the namespace in both the Game1.cs and Program.cs files are the same! Then create a file named Series4Effects.fx, and paste the HLSL code found below into it. We’re ready to go!
The Game1.cs contents:
using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Net;
using Microsoft.Xna.Framework.Storage;
namespace XNAseries4
{
public struct VertexPositionNormalColored
{
public Vector3 Position;
public Color Color;
public Vector3 Normal;
public static int SizeInBytes = 7 * 4;
public static VertexElement[] VertexElements = new VertexElement[]
{
new VertexElement( 0, 0, VertexElementFormat.Vector3, VertexElementMethod.Default, VertexElementUsage.Position, 0 ),
new VertexElement( 0, sizeof(float) * 3, VertexElementFormat.Color, VertexElementMethod.Default, VertexElementUsage.Color, 0 ),
new VertexElement( 0, sizeof(float) * 4, VertexElementFormat.Vector3, VertexElementMethod.Default, VertexElementUsage.Normal, 0 ),
};
}
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
GraphicsDevice device;
int terrainWidth;
int terrainLength;
float[,] heightData;
VertexBuffer terrainVertexBuffer;
IndexBuffer terrainIndexBuffer;
VertexDeclaration terrainVertexDeclaration;
Effect effect;
Matrix viewMatrix;
Matrix projectionMatrix;
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
}
protected override void Initialize()
{
graphics.PreferredBackBufferWidth = 500;
graphics.PreferredBackBufferHeight = 500;
graphics.ApplyChanges();
Window.Title = "Riemer's XNA Tutorials -- Series 4";
base.Initialize();
}
protected override void LoadContent()
{
device = GraphicsDevice;
effect = Content.Load<Effect> ("Series4Effects");
viewMatrix = Matrix.CreateLookAt(new Vector3(130, 30, -50), new Vector3(0,0,-40), new Vector3(0, 1, 0));
projectionMatrix = Matrix.CreatePerspectiveFieldOfView(MathHelper.PiOver4, device.Viewport.AspectRatio, 0.3f, 1000.0f);
LoadVertices();
}
private void LoadVertices()
{
Texture2D heightMap = Content.Load<Texture2D> ("heightmap"); LoadHeightData(heightMap);
VertexPositionNormalColored[] terrainVertices = SetUpTerrainVertices();
int[] terrainIndices = SetUpTerrainIndices();
terrainVertices = CalculateNormals(terrainVertices, terrainIndices);
CopyToTerrainBuffers(terrainVertices, terrainIndices);
terrainVertexDeclaration = new VertexDeclaration(device, VertexPositionNormalColored.VertexElements);
}
private void LoadHeightData(Texture2D heightMap)
{
float minimumHeight = float.MaxValue;
float maximumHeight = float.MinValue;
terrainWidth = heightMap.Width;
terrainLength = heightMap.Height;
Color[] heightMapColors = new Color[terrainWidth * terrainLength];
heightMap.GetData(heightMapColors);
heightData = new float[terrainWidth, terrainLength];
for (int x = 0; x < terrainWidth; x++)
for (int y = 0; y < terrainLength; y++)
{
heightData[x, y] = heightMapColors[x + y * terrainWidth].R;
if (heightData[x, y] < minimumHeight) minimumHeight = heightData[x, y];
if (heightData[x, y] > maximumHeight) maximumHeight = heightData[x, y];
}
for (int x = 0; x < terrainWidth; x++)
for (int y = 0; y < terrainLength; y++)
heightData[x, y] = (heightData[x, y] - minimumHeight) / (maximumHeight - minimumHeight) * 30.0f;
}
private VertexPositionNormalColored[] SetUpTerrainVertices()
{
VertexPositionNormalColored[] terrainVertices = new VertexPositionNormalColored[terrainWidth * terrainLength];
for (int x = 0; x < terrainWidth; x++)
{
for (int y = 0; y < terrainLength; y++)
{
terrainVertices[x + y * terrainWidth].Position = new Vector3(x, heightData[x, y], -y);
if (heightData[x, y] < 6)
terrainVertices[x + y * terrainWidth].Color = Color.Blue;
else if (heightData[x, y] < 15)
terrainVertices[x + y * terrainWidth].Color = Color.Green;
else if (heightData[x, y] < 25)
terrainVertices[x + y * terrainWidth].Color = Color.Brown;
else
terrainVertices[x + y * terrainWidth].Color = Color.White;
}
}
return terrainVertices;
}
private int[] SetUpTerrainIndices()
{
int[] indices = new int[(terrainWidth - 1) * (terrainLength - 1) * 6];
int counter = 0;
for (int y = 0; y < terrainLength - 1; y++)
{
for (int x = 0; x < terrainWidth - 1; x++)
{
int lowerLeft = x + y * terrainWidth;
int lowerRight = (x + 1) + y * terrainWidth;
int topLeft = x + (y + 1) * terrainWidth;
int topRight = (x + 1) + (y + 1) * terrainWidth;
indices[counter++] = topLeft;
indices[counter++] = lowerRight;
indices[counter++] = lowerLeft;
indices[counter++] = topLeft;
indices[counter++] = topRight;
indices[counter++] = lowerRight;
}
}
return indices;
}
private VertexPositionNormalColored[] CalculateNormals(VertexPositionNormalColored[] vertices, int[] indices)
{
for (int i = 0; i < vertices.Length; i++)
vertices[i].Normal = new Vector3(0, 0, 0);
for (int i = 0; i < indices.Length / 3; i++)
{
int index1 = indices[i * 3];
int index2 = indices[i * 3 + 1];
int index3 = indices[i * 3 + 2];
Vector3 side1 = vertices[index1].Position - vertices[index3].Position;
Vector3 side2 = vertices[index1].Position - vertices[index2].Position;
Vector3 normal = Vector3.Cross(side1, side2);
vertices[index1].Normal += normal;
vertices[index2].Normal += normal;
vertices[index3].Normal += normal;
}
for (int i = 0; i < vertices.Length; i++)
vertices[i].Normal.Normalize();
return vertices;
}
private void CopyToTerrainBuffers(VertexPositionNormalColored[] vertices, int[] indices)
{
terrainVertexBuffer = new VertexBuffer(device, vertices.Length * VertexPositionNormalColored.SizeInBytes, BufferUsage.WriteOnly);
terrainVertexBuffer.SetData(vertices);
terrainIndexBuffer = new IndexBuffer(device, typeof(int), indices.Length, BufferUsage.WriteOnly);
terrainIndexBuffer.SetData(indices);
}
protected override void UnloadContent()
{
}
protected override void Update(GameTime gameTime)
{
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
base.Update(gameTime);
}
protected override void Draw(GameTime gameTime)
{
float time = (float)gameTime.TotalGameTime.TotalMilliseconds / 100.0f;
device.RenderState.CullMode = CullMode.None;
device.Clear(ClearOptions.Target | ClearOptions.DepthBuffer, Color.Black, 1.0f, 0);
DrawTerrain(viewMatrix);
base.Draw(gameTime);
}
private void DrawTerrain(Matrix currentViewMatrix)
{
effect.CurrentTechnique = effect.Techniques["Colored"];
Matrix worldMatrix = Matrix.Identity;
effect.Parameters["xWorld"].SetValue(worldMatrix);
effect.Parameters["xView"].SetValue(currentViewMatrix);
effect.Parameters["xProjection"].SetValue(projectionMatrix);
effect.Parameters["xEnableLighting"].SetValue(true);
effect.Parameters["xAmbient"].SetValue(0.4f);
effect.Parameters["xLightDirection"].SetValue(new Vector3(-0.5f, -1, -0.5f));
effect.Begin();
foreach (EffectPass pass in effect.CurrentTechnique.Passes)
{
pass.Begin();
device.Vertices[0].SetSource(terrainVertexBuffer, 0, VertexPositionNormalColored.SizeInBytes);
device.Indices = terrainIndexBuffer;
device.VertexDeclaration = terrainVertexDeclaration;
int noVertices = terrainVertexBuffer.SizeInBytes / VertexPositionNormalColored.SizeInBytes;
int noTriangles = terrainIndexBuffer.SizeInBytes / sizeof(int)/3;
device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, noVertices, 0, noTriangles);
pass.End();
}
effect.End();
}
}
}And the contents of the Series4Effects.fx file:
//----------------------------------------------------
//-- --
//-- www.riemers.net --
//-- Series 4: Advanced terrain --
//-- Shader code --
//-- --
//----------------------------------------------------
//------- Constants --------
float4x4 xView;
float4x4 xProjection;
float4x4 xWorld;
float3 xLightDirection;
float xAmbient;
bool xEnableLighting;
//------- Texture Samplers --------
Texture xTexture;
sampler TextureSampler = sampler_state { texture = <xTexture> ; magfilter = LINEAR; minfilter = LINEAR; mipfilter=LINEAR; AddressU = mirror; AddressV = mirror;};
//------- Technique: Colored --------
struct ColVertexToPixel
{
float4 Position : POSITION;
float4 Color : COLOR0;
float LightingFactor: TEXCOORD0;
};
struct ColPixelToFrame
{
float4 Color : COLOR0;
};
ColVertexToPixel ColoredVS( float4 inPos : POSITION, float4 inColor: COLOR, float3 inNormal: NORMAL)
{
ColVertexToPixel Output = (ColVertexToPixel)0;
float4x4 preViewProjection = mul (xView, xProjection);
float4x4 preWorldViewProjection = mul (xWorld, preViewProjection);
Output.Position = mul(inPos, preWorldViewProjection);
Output.Color = inColor;
float3 Normal = normalize(mul(normalize(inNormal), xWorld));
Output.LightingFactor = 1;
if (xEnableLighting)
Output.LightingFactor = saturate(dot(Normal, -xLightDirection));
return Output;
}
ColPixelToFrame ColoredPS(ColVertexToPixel PSIn)
{
ColPixelToFrame Output = (ColPixelToFrame)0;
Output.Color = PSIn.Color;
Output.Color.rgb *= saturate(PSIn.LightingFactor + xAmbient);
return Output;
}
technique Colored
{
pass Pass0
{
VertexShader = compile vs_1_1 ColoredVS();
PixelShader = compile ps_1_1 ColoredPS();
}
}
//------- Technique: Textured --------
struct TexVertexToPixel
{
float4 Position : POSITION;
float4 Color : COLOR0;
float LightingFactor: TEXCOORD0;
float2 TextureCoords: TEXCOORD1;
};
struct TexPixelToFrame
{
float4 Color : COLOR0;
};
TexVertexToPixel TexturedVS( float4 inPos : POSITION, float3 inNormal: NORMAL, float2 inTexCoords: TEXCOORD0)
{
TexVertexToPixel Output = (TexVertexToPixel)0;
float4x4 preViewProjection = mul (xView, xProjection);
float4x4 preWorldViewProjection = mul (xWorld, preViewProjection);
Output.Position = mul(inPos, preWorldViewProjection);
Output.TextureCoords = inTexCoords;
float3 Normal = normalize(mul(normalize(inNormal), xWorld));
Output.LightingFactor = 1;
if (xEnableLighting)
Output.LightingFactor = saturate(dot(Normal, -xLightDirection));
return Output;
}
TexPixelToFrame TexturedPS(TexVertexToPixel PSIn)
{
TexPixelToFrame Output = (TexPixelToFrame)0;
Output.Color = tex2D(TextureSampler, PSIn.TextureCoords);
Output.Color.rgb *= saturate(PSIn.LightingFactor + xAmbient);
return Output;
}
technique Textured
{
pass Pass0
{
VertexShader = compile vs_1_1 TexturedVS();
PixelShader = compile ps_1_1 TexturedPS();
}
}