[Source] Need help restoring low detail modes (r_detail)

[drfrag]

Now that i think of it the algorithm doesn't take into accont that now lineto is four times the size of linefrom (was two times before), may be the problem is there but i don't know how to deal with it. By the way i wonder where the memory for lineto is reserved.

[drfrag]

Well, believe or not it's fixed now with a different approach. Seems like i'm not as bad as i thought, i plan to do a release soon.

[drfrag]

I've added a 3x3 low detail mode (4x2 was easy), it works but crashes on exit and i don't know why. I've traced the algorithm and it's right. The only way to prevent the crash is to stop the inner loop with x < rowsize-6 but then the rightmost part of the screen wouldn't be filled and would display junk. I've kept detailxshift and detailyshift at 1 since otherwise would be a mess but i think it doesn't matter. The problem is in ~DSimpleCanvas but the debug info is not useful. If someone wants to help i would appreciate it, i know Randi is the only one who knows well that part of the code.

Code: Select all

void R_DetailDouble ()
{

...

	case 5:		// x- and y-triple
		{
			int rowsize = viewwidth;
			int realpitch = RenderTarget->GetPitch();
			int pitch = realpitch << 1;
			int y,x;
			BYTE *linefrom, *lineto;
			BYTE c;
			int offset = viewwidth > 320 ? CPU.DataL1LineSize : 0;

			linefrom = dc_destorg;
			for (y = 0; y < viewheight; ++y, linefrom += pitch)
			{
				if (y > 0)
				{
					lineto = linefrom - viewwidth*3 - offset;
				}
				else
				{
					lineto = linefrom - viewwidth;
				}
				for (x = 0; x < rowsize-3; x=x+3)
				{
					c = linefrom[x];
					lineto[x*2] = c;
					lineto[x*2+1] = c;
					lineto[x*2+2] = c;
					c = linefrom[x+1];
					lineto[x*2+3] = c;
					lineto[x*2+4] = c;
					lineto[x*2+5] = c;
				}
				x = rowsize-1;
				if (viewwidth >= 200)
				{
					c = linefrom[x-2];
					lineto[x*2-2] = c;
					lineto[x*2-1] = c;
				}
				c = linefrom[x-1];
				lineto[x*2] = c;
				lineto[x*2+1] = c;
				if (y > 0)
				{
					memcpy (lineto+realpitch, lineto, rowsize*2);
					memcpy (lineto+realpitch*2, lineto, rowsize*2);
				}
				else
				{
					memcpy (lineto+realpitch, lineto, rowsize*2);
				}
			}
		}
		break;
}

Edit: rowsize is for instance 160 and screen width is 320. I've added the missing part but it crashes the same.
Edit2: it's fixed.

[drfrag]

It's fixed now. I wanted to do this mainly to prove myself that i was capable of doing it. I guess the compiler will optimize this and the y > 0 condition will not be checked on every iteration of the outer loop but i'm not sure.
There's a remaining problem, the image at high resolutions is displaced to the right and i think that's due to the CPU.DataL1LineSize cache optimization in DSimpleCanvas::DSimpleCanvas. I guess the pitch must be different but i don't know how to fix it, i've tried without luck.
Edit: fixed as well. Uploaded to gzdoomle.
Edit2: actually it's a 3x2 mode. I think 3x3 is impossible, i'd need to use linefrom += realpitch*3 but i get junk.
Same for 3x1, setting detailyshift to 0 makes the engine crash somewhere else.