So, I've been searching the internet for a while and I still didn't understand how to create a flashlight's "circle" in front of the camera over other objects.
I found the following links:
forum question about multiple passes and multiple effects;
shader example with multiple lights (which I can't open because its an old project).
And they give me examples and solutions about how to draw lights or other effects on objects.
But it's not clear to me yet. I'm newbie with HLSL (and still a little with XNA itself) and I don't get what should I do. I need help with the steps I should take to modify my HLSL effect* of the voxel engine to draw a white circle where the cursor points and shine the light around the camera position as the flashlight is on.
*I created a voxel engine that uses a effect (modified a little) I found in a project called TechCraft. It changes the light on the map depending of the time of the day and the sun position. But I'm not sure how it works neither, I just read a little but I'm not used to HLSL as I said. (Where could I find good HLSL tutorials?)
Do I need to make many passes and make a pixel shader and a vertex shader for each one? Or should I create many techniques? What's the difference?
Or is that a bad idea? Should I create another effect and draw again the voxel with its technique and pass?
And maybe it's not only one light. If I'm able to create a multiplayer someday, or NPCs, the game will have more than one light on at the same time. How to draw more than one circle?
I'm really lost with this, and I have no idea where should I start from. I appreciate any help; even showing already answered questions is helpful to me.