Terrain Question

OpenGL Development
#1

So i have spent 3 days looking for open source for heightmap/landscape/terrain loaders and cant find anything besides engines like Xith3D or JmonkeyEngine to load these. However i wish to create my own.

I need help with loading a the heightmap, if i could have a little help with this i would be forever grateful. This is one of my only problems i have had along the way.

#2

So… what bit are you having problems with? Are you loading from an existing heightmap file format, or do you want to make your own? Have you managed to get a flat terrain grid drawing (without loading any heights)? What kind of terrain are you aiming for?

#3

So… what bit are you having problems with?
I am having problems with getting the heightmap/terrain loaded.

Are you loading from an existing heightmap file format, or do you want to make your own?
I think i have my own, is a heightmap a 2d image? If not i can easily make a heightmap through a program.

Have you managed to get a flat terrain grid drawing (without loading any heights)?
Yes, i have a 3d system with a flat floor with 8x8 textures.

What kind of terrain are you aiming for?
Just a simple one for now with a few hills so i can test with it an later make a real one that will be used.
3D terrain i meant to add.

#4

Ok, so you want to store your heightmap as a greyscale image and convert colour to height?

If so that’s pretty simple - what’s causing you trouble? Load your image with ImageIO, then pull out the rgb value at each pixel, average the rgb to get a brightness, then convert the brightness into a height value.

#5

Its a 3D heightmap, what would be the commands for this. This is why i wanted an open source, i cant really find anything for heightmaps open source.

#6

There are no commands to make a heightmap, you have to make it yourself out of triangles. If you already have a flat floor then you know how to draw triangles - a heightmap is just a grid of triangles with different heights.

Maybe try and get a flat grid of triangles drawing first, with random colours at each point or something. Then adding heights from an image file will be easy.

#7 
floorDisplayList = glGenLists(1);
        glNewList(floorDisplayList, GL_COMPILE);
	        glBegin(GL_QUADS);
		        glTexCoord2f(0, 0);
		        	glVertex3f(-gridSize, floorHeight, -gridSize);
		        glTexCoord2f(0, gridSize * 10 * tileSize);
		        	glVertex3f(-gridSize, floorHeight, gridSize);
		        glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize);
		        	glVertex3f(gridSize, floorHeight, gridSize);
		        glTexCoord2f(gridSize * 10 * tileSize, 0);
		        	glVertex3f(gridSize, floorHeight, -gridSize);
	        glEnd();
        glEndList();

Is what im using.

#8

Ok, so that draws a single quad - have you tried changing that code so you get a grid of quads? What have you tried?

#9

No i havent, i got that piece of code from a tutorial which i have analyzed well. I am really despirate for this, is it possible we can communicate via a messenger?

#10

I think a heightmap may be a little beyond your abilities right now. I suggest you start from the beginning with the opengl red book: http://www.glprogramming.com/red/

#11

Thank you for this and i will study hard.

#12

just to add something for others searching how to render a highmap.

  • render a normal grid(like a chess board) where each grid point gets its Y(UP) value from some dataset(i.e. a texture which can be read from a vertex shader)
  • to get the normal for each grid point, calculate the sobel gradient(google it) from the height dataset around this point