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Code Issues Releases Activity

use native SDL functions when possible

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This commit is contained in:
Laserlicht
2025-07-31 01:06:00 +02:00
parent 23fe336048
commit 26b62b2655
1 changed files with 30 additions and 3 deletions
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31
client/renderSDL/SDL_Extensions.cpp
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@@ -761,13 +761,41 @@ SDL_Surface* CSDL_Ext::drawOutline(SDL_Surface* sourceSurface, const SDL_Color&
void applyAffineTransform(SDL_Surface* src, SDL_Surface* dst, double a, double b, double c, double d, double tx, double ty)
{
// Check if the transform is purely scaling (and optionally translation)
bool isPureScaling = vstd::isAlmostZero(b) && vstd::isAlmostZero(c);
if (isPureScaling)
{
// Calculate target dimensions
int scaledW = static_cast<int>(src->w * a);
int scaledH = static_cast<int>(src->h * d);
SDL_Rect srcRect = { 0, 0, src->w, src->h };
SDL_Rect dstRect = { static_cast<int>(tx), static_cast<int>(ty), scaledW, scaledH };
// Convert surfaces to same format if needed
if (src->format->format != dst->format->format)
{
SDL_Surface* converted = SDL_ConvertSurface(src, dst->format, 0);
if (!converted)
throw std::runtime_error("SDL_ConvertSurface failed!");
SDL_BlitScaled(converted, &srcRect, dst, &dstRect);
SDL_FreeSurface(converted);
}
else
SDL_BlitScaled(src, &srcRect, dst, &dstRect);
return;
}
// Lock surfaces for direct pixel access
if (SDL_MUSTLOCK(src)) SDL_LockSurface(src);
if (SDL_MUSTLOCK(dst)) SDL_LockSurface(dst);
// Calculate inverse matrix M_inv for mapping dst -> src
double det = a * d - b * c;
if (std::abs(det) < 1e-10)
if (vstd::isAlmostZero(det))
throw std::runtime_error("Singular transform matrix!");
double invDet = 1.0 / det;
double ia = d * invDet;
@@ -796,7 +824,6 @@ void applyAffineTransform(SDL_Surface* src, SDL_Surface* dst, double a, double b
// Check bounds
if (srcXi >= 0 && srcXi < src->w && srcYi >= 0 && srcYi < src->h)
{
Uint32 pixel = srcPixels[srcYi * src->w + srcXi];
dstPixels[y * dst->w + x] = pixel;
}