Getting Average Color of DXTCompressed Texture

Graphics and GPU Programming Programming

Started by HenriqueRocha June 24, 2012 03:58 AM

2 comments, last by HenriqueRocha 11 years, 10 months ago

145

Author

June 24, 2012 03:58 AM

Hello again.

I am trying to Implement a Minimap for my game and for each Texture I want the avg color to paint the minimap.

so far I've this:



		public Color GetAvgColor(Texture2D tex)

		{

			Color[] data = new Color[tex.Width*tex.Height];

			Color sum = Color.Black;

			int amount = 0;

			tex.GetData<Color>(data);

			foreach (Color c in data)

			{

				sum.R += c.R;

				sum.G += c.G;

				sum.B += c.B;

				++amount;

			}

			return new Color(sum.R / amount, sum.G / amount, sum.B / amount); ;

		}

I didn't tested with Colored Textures because my terrain textures are DXTCompressed and MipMapped.

The problem is with GetData:



{"The type you are using for T in this method is an invalid size for this resource."}

Is that possible to Get the Average Color of a DXTCompressed Texture?

Thanks ;-)

AmzBee

485

June 24, 2012 08:30 AM

Another excuse to use System.Linq



public Color GetAvgColor(Texture2D tex, Rectangle rect, int mipLevel = 0)

{

	Color[] data = new Color[rect.Width * rect.Height];

	if (data.Length == 0) return Color.White;

	tex.GetData<Color>(mipLevel, rect, data, 0, data.Length);

	int r = data.Sum(t => t.R) / data.Length;

	int g = data.Sum(t => t.G) / data.Length;

	int b = data.Sum(t => t.B) / data.Length;

	int a = data.Sum(t => t.A) / data.Length;

	return new Color(r, g, b, a);

}

edit with a bit of explanation: the 3rd overload of the GetData allows you to specify a rectangle to retrieve colours from, so you simply have to make sure your data array is the same size as what your after returning.

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21st Century Moose

13,459

June 24, 2012 11:51 AM

Why not just sample the textures from the smallest mip level? That will give you an average colour and won't require anything CPU-side.

Direct3D has need of instancing, but we do not. We have plenty of glVertexAttrib calls.

HenriqueRocha

145

Author

June 26, 2012 08:50 AM

Another excuse to use System.Linq

public Color GetAvgColor(Texture2D tex, Rectangle rect, int mipLevel = 0) { Color[] data = new Color[rect.Width * rect.Height]; if (data.Length == 0) return Color.White; tex.GetData<Color>(mipLevel, rect, data, 0, data.Length); int r = data.Sum(t => t.R) / data.Length; int g = data.Sum(t => t.G) / data.Length; int b = data.Sum(t => t.B) / data.Length; int a = data.Sum(t => t.A) / data.Length; return new Color(r, g, b, a); }

edit with a bit of explanation: the 3rd overload of the GetData allows you to specify a rectangle to retrieve colours from, so you simply have to make sure your data array is the same size as what your after returning.

It's not working... The problem is the DXTcompression.

Getting Average Color of DXTCompressed Texture

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Getting Average Color of DXTCompressed Texture

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