Creating a custom image

[pippy]

I have a large map (of a Tile class), and I want to make a 'map preview'.

So far I have

Code: Select all

void Map::createMapPreview(){
	char chmapPreview[20];
	mapPreview = driver->addTexture(core::dimension2d<s32> (256,256),
		chmapPreview, video::ECF_A1R5G5B5);

}

Which is a no-brainer, but how would I set the individual pixels?

I noticed Iimage has a setPixel() function, so would I convert the texture a Iimage, set the map preview, and convert it back, or is there another way?

[vitek]

Not sure I understand what you want. Do you want a preview of what the image looks like, but smaller? If so, you can just load the image and display it into a smaller area using draw2DImage(). You might even be able to use the IGUIImage type to render the image also. You would create the texture with a simple call to driver->getTexture().

Travis

[pippy]

Surfing a while I found a way to do it. I'm still hammering out some of the bugs, but it works

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/**	createMapPreview - builds chmapPreview 
 * texture from the Scolor inTile class
 *
 *	@return void nothing
 */
void Map::createMapPreview(){
	// name of the map
	char chmapPreview[11] = "mapPreview";
	std::cout << "creating " << chmapPreview << std::endl;
	
	// dimensions of the minimap to be created 
	core::dimension2d<s32> minMapDim(128,128);

	// populate the texture
	video::SColor *dbuffer = new video::SColor[minMapDim.Height * minMapDim.Width];
	if(!dbuffer){
		std::cerr << "Error creating "<< chmapPreview << std::endl;
		return;
	}

	// fill the texture
	for(int i=0; i<minMapDim.Width; i++) {
		for(int j=0; j<minMapDim.Height; j++) {
			int index = (i * minMapDim.Width) + j;
			double mapposX = i/(minMapDim.Width/width);
			double mapposY = j/(minMapDim.Height/height);
			dbuffer[index] = getTile((int)(mapposX),(int)(mapposY))->getColor();
		}
	}

	// create an image
	video::IImage* image = driver->createImageFromData(
		video::ECF_A8R8G8B8, minMapDim, dbuffer, false);

	// create texture from image
	mapPreview = driver->addTexture(chmapPreview,image);
}

[arras]

With your code you created empty texture. To change its pixels you would use lock() function which return pointer in to pixel data. You need to call unlock() at the end to apply changes:

example:

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// create empty texture
	ITexture *txt = driver->addTexture(dimension2d<s32>(32,32), "texture", ECF_A8R8G8B8);
	
	// get pointer
	u32 *p = (u32*)txt->lock();
	
	// set all pixels to red
	SColor color(255,255,0,0);
	
	for(u32 j=0; j<txt->getSize().Height; j++)
	  for(u32 i=0; i<txt->getSize().Width; i++)
	  {// you need some simple math to calculate position in simple array from 
     //2D coordinates
     p[j * txt->getSize().Width + i] = color.color;
     }
	
	// set pixel 10,5 to green
	u32 xpos = 10;
	u32 ypos = 5;
	
	color = SColor(255,0,255,0);
	p[ypos * txt->getSize().Width + xpos] = color.color;
	
	// apply changes
	txt->unlock();

For 16bit textures you would use:

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...
u16 *p = (u16*) txt->lock();
...
p[ypos * txt->getSize().Width + xpos] = color.toA1R5G5B5();

Another possibility is to create IImage from array using IVideoDriver::createImageFromData() function. Than create ITexture from IImage with one of IVideoDriver::addTexture() functions.