Opengl simple blending problem

[Hippogriff]

Stuck on things I shouldn't be stuck on as always :D.

I have been messing around with glBlendFunc to create a flashlight/spotlight effect on a tilemap, everything works exactly how I would expect apart from it always creates a white background color where no tiles exist (regardless of my glClearColor which is what I would expect it to show?).

Here is a picture to show what I mean http://puu.sh/2SS1C.png
(see the background above the trees is white whatever I seem to do, I am guessing my first blending call is wrong). I would like it to be black to match the texture without actually having to put tiles there.

http://puu.sh/2SSsN.png Texture to make everything darker
http://puu.sh/2SSu9.png "Light" texture (white square)

glLoadIdentity();
glClear(GL_COLOR_BUFFER_BIT);

glBlendFunc(GL_ONE, GL_ZERO);  // Might be the problem but not sure what else to set it as 

ApplySurface(0,0,Dark); 
ApplySurface(320,380,Light);
glBlendFunc(GL_DST_COLOR, GL_ZERO);
map.Show();

SDL_GL_SwapBuffers();

//map.Show Function
for(int j = (PlayerCamera.x) / 32; j < (PlayerCamera.x + PlayerCamera.w + 32) / 32; j++)
{
	for(int i = (PlayerCamera.y) / 32; i < (PlayerCamera.y + PlayerCamera.h + 32) / 32; i++)
	{
		if(i < Layers[a].size())
		{
			if(j < Layers[a][i].size())
			{
				if(Layers[a][i][j]->ID != -1)  // Tiles not shown
				{
					ApplySurface(Layers[a][i][j]->x -(PlayerCamera.x), Layers[a][i][j]->y - PlayerCamera.y, Layers[a][i][j]->image, &Layers[a][i][j]->B);
				}
			}

		}
	}
}

Of course I left a lot of other code out but none of it should influence that (let me know if you need to see anything else).

[xismn]

Might not do anything for you, but try doing something like this :

glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glAlphaFunc(GL_GREATER, 0.2f);

[Hippogriff]

Tried replacing my first blend function with that, didn't seem to change anything. Will try experimenting more with the AlphaFunc but I think it's a result of my dark texture reacting with the background...but not 100%.

Let me know if anyone has any more ideas as well, thanks.

[Hippogriff]

Seems to work fairly well basing everything off of alpha values instead of colors (so the background wont get involved). Thanks for the advice as well.

[xismn]

You're very welcome, glad it's working!