grimfang4 / sprig Goto Github PK

Alpha-blended or anti-aliased thick primitives are overlapped.

In some cases (rounding seems involved), a scaled image gains a black or
otherwise ruined line on one or more sides.

I most installs, SDL is found with #include <SDL/SDL.h> without having to 
manually add the SDL header search path. Sprig uses #include "SDL.h". It would 
be nice if it used the global search path instead ...

Using SPG_TransformX to draw to a negative x or y position draws nothing 
instead.

Using SPG_PolygonFade makes a polygon that is shaded with reference to only
the horizontal direction.  It seems to be due to the scanline approach with
spg_linefade.

The effect can be seen clearly when the polygon is animated, as in the
Polygons demo.

A solution may be to include the vertical scanlines in the calculation of
the colors, but this would probably require a pixel-by-pixel approach that
might be slow.

I'm trying to blit a PNG with transparency using SPG_Blit or SPG_QuadTex, but I 
get black instead of transparency and a blue hue. Using SDL_BlitSurface works 
fine, but I really want to be able to use the QuadTex. The image is loaded via 
SDL_image.

I can submit a small test app and the test image in question later on.

I've attached a patch to add a SPG_LinkedVersion() function, which returns
an SDL_version struct holding SPriG's version numbers. It's based on SDL's
SDL_Linked_Version() function.

I'm trying out SPriG using Ruby-FFI, which allows the Ruby programming
language to access C library functions directly, without a compiled
wrapper. But it can't see what the #defines were when the library was
compiled, so it needs a function to find out the version number. :)

SPG_BezierBlend has some pixels that are overdrawn, making them more opaque.

I am using SPG_Bezier and SPG_BezierBlend and it seems like it doesn't unlock 
the surface after drawing. Other primitives are drawn fine afterwards, but 
regular Blits fail and I get an EXC_BAD_ACCESS on shutdown when SDL calls 
SDL_VideoQuit.

Unlocking the surface manually via SDL_UnlockSurface after every bezier call 
fixes the issue.