This adds a new parameter `blend` to `gfx_draw_glyph()`. When `blend` is
true, the function performs normal alpha blending (same as
`gfx_draw_glyph_to_pmap()`).
If `blend` is false, the resulting pixel color will be the text color
and the alpha value will be copied from the glyph texture. However, if
the alpha value is less than 0.01, the pixel will not be written.
If you are drawing on a transparent texture (which will later be blended
into another texture), `blend` should be false. If you are drawing on top
of an image, `blend` should be true.
`gfx_draw_glyph()` used to fill transparent pixels with text color, but
this step is no longer needed and has been removed.
SDL_ttf isn't really designed to be used with OpenGL. It caches glyph
bitmaps in memory, whereas we want to cache glyph textures on the GPU.
By using FreeType directly we avoid creating and destroying a new
texture every time a glyph is rendered.
Additionally, all glyph textures (including fnl-derived glyphs) now use
the GL_RED internal format instead of GL_RGBA.
Only unscaled glyph bitmaps are now cached in regular memory. Scaled
glyphs are stored as textures on the GPU. Only the alpha channel on
glyph textures is used, with the color being provided as an input to the
shader.
Outline and bold rendering is improved by using a simple dilate shader.
This looks okay but could be improved (the result is a bit blurry
still).
kichikuou