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add letterboxing and pillarboxing instead of streching #7

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Merged
iProgramMC merged 1 commit into from
May 27, 2026
Merged

add letterboxing and pillarboxing instead of streching #7

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69 changes: 41 additions & 28 deletions src/sw/sw_renderer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,7 @@ typedef struct
bool viewActive;
int viewX, viewY, viewW, viewH;
int portX, portY, portW, portH;
int gameW, gameH;
int gameW, gameH, maxX, maxY;
}
SWRenderer;

Expand Down Expand Up @@ -437,14 +437,25 @@ static void SWRenderer_beginView(Renderer* renderer, int32_t viewX, int32_t view
UNIMP();
xratio = 1.0f;
yratio = 1.0f;
portX = (int)(portX * xratio);
portY = (int)(portY * yratio);
}
else {
xratio = (float) swr->width / swr->gameW;
yratio = (float) swr->height / swr->gameH;
}
float scaleX = (float) swr->width / swr->gameW;
float scaleY = (float) swr->height / swr->gameH;
float scale = (scaleX < scaleY) ? scaleX : scaleY;

int32_t scaledW = (int32_t)(swr->gameW * scale);
int32_t scaledH = (int32_t)(swr->gameH * scale);
int32_t offsetX = (swr->width - scaledW) / 2;
int32_t offsetY = (swr->height - scaledH) / 2;

portX = (int)(portX * xratio);
portY = (int)(portY * yratio);
xratio = scale;
yratio = scale;

portX = (int)(portX * xratio) + offsetX;
portY = (int)(portY * yratio) + offsetY;
}
portW = (int)(portW * xratio);
portH = (int)(portH * yratio);

Expand All @@ -457,6 +468,8 @@ static void SWRenderer_beginView(Renderer* renderer, int32_t viewX, int32_t view
swr->portY = portY;
swr->portW = portW;
swr->portH = portH;
swr->maxX = portX + portW;
swr->maxY = portY + portH;
}

static void SWRenderer_endView(Renderer* renderer)
Expand Down Expand Up @@ -577,8 +590,8 @@ FORCE_INLINE void swrPlotPixel(Renderer* renderer, int x, int y, uintpixel_t col
{
SWRenderer* swr = (SWRenderer*) renderer;

if (x < 0 || y < 0) return;
if (x >= swr->width || y >= swr->height) return;
if (x < swr->portX || y < swr->portY) return;
if (x >= swr->maxX || y >= swr->maxY) return;

alphaBlend(&swr->fb[y * swr->fbPitch + x], color, alpha);
}
Expand All @@ -587,10 +600,10 @@ static void swrDrawHLineInt(Renderer* renderer, int dx, int dy, int dw, uintpixe
{
SWRenderer *swr = (SWRenderer*) renderer;

if (dy < 0) return;
if (dy >= swr->height) return;
if (dx < 0) { dw += dx; dx = 0; }
if (dx + dw >= swr->width) dw = swr->width - dx;
if (dy < swr->portY) return;
if (dy >= swr->maxY) return;
if (dx < swr->portX) { dw += dx; dx = swr->portX; }
if (dx + dw >= swr->maxX) dw = swr->maxX - dx;
if (dw <= 0) return;

#if PIXEL_SIZE == 32
Expand Down Expand Up @@ -650,10 +663,10 @@ static void swrDrawVLineInt(Renderer* renderer, int dx, int dy, int dh, uintpixe
{
SWRenderer *swr = (SWRenderer*) renderer;

if (dx < 0) return;
if (dx >= swr->width) return;
if (dy < 0) { dh += dy; dy = 0; }
if (dy + dh >= swr->height) dh = swr->height - dy;
if (dx < swr->portX) return;
if (dx >= swr->maxX) return;
if (dy < swr->portY) { dh += dy; dy = swr->portY; }
if (dy + dh >= swr->maxY) dh = swr->maxY - dy;
if (dh <= 0) return;

#if PIXEL_SIZE == 32
Expand Down Expand Up @@ -885,10 +898,10 @@ static void swrDrawSpriteInternal(
if (dw == 0 || dh == 0) return;
if (sw == 0) sw = 1;
if (sh == 0) sh = 1;
if (dx + dw <= 0) return;
if (dy + dh <= 0) return;
if (dx >= swr->width) return;
if (dy >= swr->height) return;
if (dx + dw <= swr->portX) return;
if (dy + dh <= swr->portY) return;
if (dx >= swr->maxX) return;
if (dy >= swr->maxY) return;

int odw = dw, odh = dh;
int osw = sw, osh = sh;
Expand Down Expand Up @@ -1057,10 +1070,10 @@ static void swrDrawSpriteRotatedInternal(
int maxY = swrCeiling(maxYf);

// basic out-of-bound checks
if (maxX < 0) return;
if (maxY < 0) return;
if (minX >= swr->width) return;
if (minY >= swr->height) return;
if (maxX < swr->portX) return;
if (maxY < swr->portY) return;
if (minX >= swr->maxX) return;
if (minY >= swr->maxY) return;

// however, we'll need to clip it against out of bounds first
int minXc = minX, minYc = minY, maxXc = maxX, maxYc = maxY;
Expand Down Expand Up @@ -1378,10 +1391,10 @@ static void swrDrawTriangleInternal(SWRenderer* swr, int xup, int yup, int xleft
x2 = tmp;
}

if (x1 < 0) x1 = 0;
if (x1 >= swr->width) continue;
if (x2 < 0) continue;
if (x2 >= swr->width) x2 = swr->width - 1;
if (x1 < swr->portX) x1 = swr->portX;
if (x1 >= swr->maxX) continue;
if (x2 < swr->portX) continue;
if (x2 >= swr->maxX) x2 = swr->maxX - 1;
if (x1 > x2) continue;

uintpixel_t* line = &swr->fb[y * swr->width];
Expand Down