opengles2 & batching = conjoined lines

[AntTheAlchemist]

I know I've been reporting some non-bugs recently, but I think I finally found one that's not a feature :-)

I'm getting 2 separate lines joined together in opengles2 when using batching. Reproduces on Android and Win10. Also happens if you try to draw each line using 2 points each with SDL_RenderDrawLinesF().

Simple code to repro:

#include <SDL.h>
int main(int argc, char** argv) {
	SDL_SetHint(SDL_HINT_RENDER_DRIVER, "opengles2");
	SDL_SetHint(SDL_HINT_RENDER_BATCHING, "1");
	SDL_Init(SDL_INIT_VIDEO);
	SDL_Window* w; SDL_Renderer* r;
	SDL_CreateWindowAndRenderer(640, 480, 0, &w, &r);
	SDL_RendererInfo info;
	SDL_GetRendererInfo(r, &info);
	SDL_SetWindowTitle(w, info.name);
	for (;;) {
		SDL_PumpEvents();
		SDL_Event event;
		while (SDL_PeepEvents(&event, 1, SDL_GETEVENT, 0, SDL_LASTEVENT) == 1) {
			switch (event.type) {
			case SDL_QUIT:
				SDL_Quit();
				return 0;
			}
		}
		SDL_SetRenderDrawColor(r, 0, 0, 0, 0xFF);
		SDL_RenderClear(r);
		SDL_SetRenderDrawColor(r, 0, 0xFF, 0, 0xFF);
		// these two lines are conjoined:
		SDL_RenderDrawLineF(r, 20, 20, 20, 460);
		SDL_RenderDrawLineF(r, 100, 20, 100, 460);
		SDL_RenderPresent(r);
	}
}

[1bsyl]

@AntTheAlchemist thanks good catch ! that was while optimizing batching

[1bsyl]

@AntTheAlchemist
I put back the original switch case, because there is not batch with groups with at least a joined lines.
but eventually we could batch if we detect groups of singles lines...

[1bsyl]

@AntTheAlchemist
ok, now gles2 batchs group of single lines ...
tested with "testdraw2" by only activating "DrawLines" in the code.
SDL_RENDER_DRIVER=opengles2 SDL_RENDER_BATCHING=1 ./testdraw2 --info render 50000
goes to 90fps
and 15fps before.

[icculus]

Okay to close this bug, then?

[icculus]

(I'd just to say how grateful I was to see a bug report about line drawing that wasn't about how it was one pixel off, lol)

[1bsyl]

yes, hope it didn't interfere with all the line + ending pixel issues ... which look quite un-resolvables ..
I think it's ok to close the bug!