【DX11地形篇】9-16位高度图

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参考教程

Tutorial 8: RAW Height Maps

学习记录

  这篇文章中我们介绍使用16位高度图实现的较为精细的地形，本篇代码基于上一篇，无新增类。

  这篇中我们仅仅修改了 TerrainClass 类和 Setup.txt 文件，在 TerrainClass 中我们使用新的 LoadRawHeightMap() 方法来代替之前的 LoadBitmapHeightMap() ，由于我们新的高度图是一张存储高度的图片，所以读取的话只为 y 轴赋值，方法如下：

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bool TerrainClass::LoadRawHeightMap()
{
	int error, i, j, index;
	FILE* filePtr;
	unsigned long long imageSize, count;
	unsigned short* rawImage;


	// Create the float array to hold the height map data.
	m_heightMap = new HeightMapType[m_terrainWidth * m_terrainHeight];
	if (!m_heightMap)
	{
		return false;
	}

	// Open the 16 bit raw height map file for reading in binary.
	error = fopen_s(&filePtr, m_terrainFilename, "rb");
	if (error != 0)
	{
		return false;
	}

	// Calculate the size of the raw image data.
	imageSize = m_terrainHeight * m_terrainWidth;

	// Allocate memory for the raw image data.
	rawImage = new unsigned short[imageSize];
	if(!rawImage)
	{
		return false;
	}

	// Read in the raw image data.
	count = fread(rawImage, sizeof(unsigned short), imageSize, filePtr);
	if(count != imageSize)
	{
		return false;
	}

	// Close the file.
	error = fclose(filePtr);
	if(error != 0)
	{
		return false;
	}

	// Copy the image data into the height map array.
	for(j=0; j<m_terrainHeight; j++)
	{
		for(i=0; i<m_terrainWidth; i++)
		{
			index = (m_terrainWidth * j) + i;

			// Store the height at this point in the height map array.
			m_heightMap[index].y = (float)rawImage[index];
		}
	}

	// Release the bitmap image data.
	delete [] rawImage;
	rawImage = 0;

	// Release the terrain filename now that it has been read in.
	delete [] m_terrainFilename;
	m_terrainFilename = 0;

	return true;
}

  同时我们将修改 Setup.txt 文件，渲染一张更大的地图：

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Terrain Filename: ./data/heightmap.r16
Terrain Filename: ./data/colormap.bmp
Terrain Height: 1025
Terrain Width: 1025
Terrain Scaling: 300.0

  在 Initialize 方法里，使用 LoadRawHeightMap 代替 LoadBitmapHeightMap ：

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bool TerrainClass::Initialize(ID3D11Device* device , char* setupFileName)
{
	bool result;

	// Get the terrain filename , dimensions , and so forth from the setup file
	result = LoadSetupFile(setupFileName);
	if (!result) {
		return false;
	}

	// Initialize the terrain height map with the data from the raw file.
	result = LoadRawHeightMap();
	if(!result)
	{
		return false;
	}

//	result = LoadBitmapHeightMap();
//	if (!result) {
//		return false;
//	}

	SetTerrainCoordinates();

	// Calculate the normals for the terrain data.
	result = CalculateNormals();
	if(!result)
	{
		return false;
	}

	// Load in the color map for the terrain.
	result = LoadColorMap();
	if(!result)
	{
		return false;
	}

	result = BuildTerrainModel();
	if (!result) {
		return false;
	}

	// We can now release the height map since it is no longer needed in memory once the 3D terrain model has been built.
	ShutdownHeightMap();

	// Calculate the tangent and binormal for the terrain model.
	CalculateTerrainVectors();

	// Load the rendering buffers with the terrain data.
	result = InitializeBuffers(device);
	if(!result)
	{
		return false;
	}

	ShutdownTerrainModel();

	return true;
}

  最终效果：

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  源代码：DX11TerrainTutorial-RawHeightMaps

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