SDL_RenderGeometry & SDL_HINT_RENDER_SCALE_QUALITY

Game Development
1

Hi, thank you SDL team for adding the SDL_RenderGeometry() function,

I didn’t manage to change the render quality, it’s like the hint SDL_HINT_RENDER_SCALE_QUALITY as no effect.

And, yes, I put it before loading the surface and create the texture.

2

You mean jagged lines vs antialiasing? On my system I’m getting smooth diagonal lines. it seems to depend on the hardware and renderer. I can influence the outcome by changing the NVIDIA Control Panel settings. I’m surprised more people aren’t having smooth lines out of the box.

3

I probably make a mistake somewhere in my code, cause I just create a sample to demonstrate the bug, and… there is no bug. :no_mouth:

#include <SDL2/SDL.h>

#define W 0xffffffff
#define B 0x000000ff

int main(int argc,char *argv[])
{
	SDL_Init(SDL_INIT_VIDEO);
	SDL_Window *w=SDL_CreateWindow("test",SDL_WINDOWPOS_UNDEFINED,SDL_WINDOWPOS_UNDEFINED,400,200,SDL_WINDOW_RESIZABLE);
	SDL_Renderer *r=SDL_CreateRenderer(w,-1,SDL_RENDERER_ACCELERATED);
	SDL_RenderSetIntegerScale(r,SDL_TRUE);
	SDL_RenderSetLogicalSize(r,400,200);
	SDL_SetRenderDrawColor(r,127,0,63,255);

	// create a checkboard texture
	SDL_Texture *t=SDL_CreateTexture(r,SDL_PIXELFORMAT_RGBA8888,SDL_TEXTUREACCESS_STATIC,8,8);
	Uint32 pixels[8*8] = {
		W, B, W, B, W, B, W, B,
		B, W, B, W, B, W, B, W,
		W, B, W, B, W, B, W, B,
		B, W, B, W, B, W, B, W,
		W, B, W, B, W, B, W, B,
		B, W, B, W, B, W, B, W,
		W, B, W, B, W, B, W, B,
		B, W, B, W, B, W, B, W
	};
	SDL_Rect c={0,0,8,8};
	SDL_UpdateTexture(t,&c,static_cast<void*>(&pixels[0]),8*sizeof(Uint32));

	// for the left rectangle
	SDL_Rect d={25,25,150,150};

	// for the right rectangle: setup vertices and indices
	SDL_Vertex v[4] = {
		{ {225,25}, {255,255,255,255}, {0,0} },
		{ {225+150,25}, {255,255,255,255}, {1,0} },
		{ {225+150,25+150}, {255,255,255,255}, {1,1} },
		{ {225,25+150}, {255,255,255,255}, {0,1} }
	};
	int i[6]={3,0,1,1,2,3};

	SDL_Event e;
	bool o=true;
	while(o)
	{
		while(SDL_PollEvent(&e)) switch(e.type)
		{
			case SDL_QUIT: o=false; break;
		}
		SDL_RenderClear(r);

		// render using copy
		SDL_RenderCopy(r,t,&c,&d);

		// render using geometry
		SDL_RenderGeometry(r,t,&v[0],4,&i[0],6);

		SDL_RenderPresent(r);
	}

	SDL_DestroyRenderer(r);
	SDL_DestroyWindow(w);
	SDL_Quit();
}