offset circle & arc lines by half a pixel to improve alignment

This commit is contained in:
2024-03-10 20:54:16 +11:00
parent 18afba5e5d
commit 96d1ae11f7

View File

@ -59,6 +59,9 @@ void DrawLine(int x1, int y1, int x2, int y2)
void DrawCircleSteps(int x, int y, int r, int steps)
{
const float fx = (float)x - 0.5f;
const float fy = (float)y - 0.5f;
const float stepsz = (float)TAU / steps;
const float mag = (float)r;
float lastx = mag;
@ -69,8 +72,8 @@ void DrawCircleSteps(int x, int y, int r, int steps)
float ofsy = sinf(stepsz * i) * mag;
SDL_RenderLine(rend,
x + lastx, y + lasty,
x + ofsx, y + ofsy);
fx + lastx, fy + lasty,
fx + ofsx, fy + ofsy);
lastx = ofsx;
lasty = ofsy;
@ -79,6 +82,9 @@ void DrawCircleSteps(int x, int y, int r, int steps)
void DrawArcSteps(int x, int y, int r, int startAng, int endAng, int steps)
{
const float fx = (float)x - 0.5f;
const float fy = (float)y - 0.5f;
const float fstart = (float)startAng * (float)DEG2RAD;
const float fstepSz = (float)(endAng - startAng) / abs(steps) * (float)DEG2RAD;
const float mag = (float)r;
@ -92,8 +98,8 @@ void DrawArcSteps(int x, int y, int r, int startAng, int endAng, int steps)
float ofsy = -sinf(theta) * mag;
SDL_RenderLine(rend,
x + lastx, y + lasty,
x + ofsx, y + ofsy);
fx + lastx, fy + lasty,
fx + ofsx, fy + ofsy);
lastx = ofsx;
lasty = ofsy;