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1

General / Re: Need Advices for performances + shaders

« on: January 19, 2020, 02:20:36 pm »

Thanks,

I think this is exactly what I needed to hear.

You're right, I'll now start to do all the rendering part with OpenGL. (still using SFML for window and input management etc...).

Thanks again

2

General / Need Advices for performances + shaders

« on: January 18, 2020, 02:52:58 pm »

Hi,

I'm a roguelike enthusiastic working on a small ASCII game on my free time, and I need advice.

First of all, let me show you the "game":

https://imgur.com/a/HaddYPf

(The distortion effect is here just for the test...)

To achieve the 3d effect :
My game map is a 2D array of cells (position (x,y), glyph + color, "height")
Each frame :
    -I generate quads based on the 2d array (each cell is the "center" of a quad).
    -I use mvp matrices with glm to calculate the position of each vertices of each quads, on the CPU, and project them to 2D.
    -Once this is done. I put them in a vertex Array and render them with one draw().
    -For the distortion effect : I render another quad using another shader (and use the screen drawn before as a texture) and do another draw().

All you see here are 2D quads.
I only use the SFML api, I don't have the level to do OpenGL stuff at the moment...

Let me show you how it looks like without the textures :
https://imgur.com/a/wODRyf8

But there's two drawback :
-The first is permormance in debug, I can draw like 200 sprite on screen at 60fps without too much problems, but I already see that having like 800 quads seem to put a single core of my CPU at 100%. (I don't do mutli-threading at the moment , maybe I should ?)
https://imgur.com/a/pvDBpPf

(spriteFromCell is the code who generate a quad (4 points) from a cell and do the billboarding/rotation based from the camera view; And "mProjection*points" apply the projection matrice to these points )

The glm projection is quite slow without compiler optimisations and I'm afraid that will be a problem when I will have more effects in the game. I would love to do the MVP multiplication within the vertex shader, but it's not possible as I can only send 2D points with the draw() function. 
Should I use some optimisation, even in debug, to have the debug binary more smooth ?


-The second is shaders : I wanted to have shaders like some heaze heat effect applied to some glyph. But I don't know how to hide these effect if the glyph is behind another glyph, using only one draw call. (The "easiest" way I think is that I would have to stop the batch rendering technique, and render the quad one by one, that way, the heat effect can be partially "hidden" by a glyph.)

As anyone worked on this type of project, and have some tips/advice to manage these thing ?
That will be so useful ! 

Thanks for you help, anyways