[text] Review LoadTTF() spritefont generation

[raysan5]

Right now using a basic font baking mechanism, no proper texture-packing just aligning characters one after the other, no sub-pixel oversampling for better font quality.

This function can be improved...

[raysan5]

Just for record, I've been working on this issue (along with SDF font generation) for some time now.

Current LoadTTF() implementation uses stbtt_BakeFontBitmap() from stb_truetype library. That function packs characters in an image, one after another. After that, texture is loaded from image and font.chars info data is filled. LoadTTF() is not versatile at all, neither optimum in packing terms, I needed something better.

After some time working in an improved implementation for image font atlas generation, I came to different approximations:

1. Generate Image font atlas but also fill CharInfo *chars; data in a single function (instead of just returning an opaque Font structure:

Image GenImageFont(const char *fileName, int fontSize, int *fontChars, CharInfo *chars, int charsCount);

This method give us an Image font atlas and the CharInfo data separately that later can be used to fill Font data. It works ok but Font loading is a bit cumbersome and counter-intuitive:

Font font = { 0 };
font.baseSize = 36;
font.charsCount = 96;
font.chars = (CharInfo *)malloc(font.charsCount*sizeof(CharInfo));
Image atlas = GenImageFont("fonts/Inconsolata.ttf", font.baseSize, NULL, font.chars, font.charsCount);
font.texture = LoadTextureFromImage(atlas);

2. Generate CharInfo *chars data from TTF file, store every character pixel data in a first pass (requires CharInfo.data added to CharInfo struct) . After that, use that data to generate the image font atlas:

CharInfo *LoadFontData(const char *fileName, int fontSize, int *fontChars, int charsCount, bool sdf);
Image GenImageFontAtlas(CharInfo *chars, int charsCount, int fontSize, int packMethod);

I think those methods are more intuitive and give us more control over the full system, including packing mechanism inside GenImageFontAtlas(). Font loading is a bit more intuitive:

Font font = { 0 };
font.baseSize = 36;
font.charsCount = 96;
font.chars = LoadFontData("fonts/Inconsolata.ttf", font.baseSize, NULL, font.charsCount, false);
Image atlas = GenImageFontAtlas(font.chars, font.charsCount, font.baseSize, 0);
font.texture = LoadTextureFromImage(atlas);

I keep thinking on this API improvement, really need a versatile and intuitive system for future related projects. Comments are welcome!

[raysan5]

Improvements implemented in commit 75ba5ac

Still some things to review:

• SDF generation chars padding --> Should be configurable? Other SDF generation params?
• Image font packaging chars padding --> Should be passed as parameter?

[raysan5]

Reviewed on commit 0e13511.

For now I consider this implementation complete... only SDF example left. Working on it.

[iva0410217]

... (edited by @raysan5)

[raysan5]

@iva0410217 why this issue is linked to 401?

EDIT: I'll assume it was an error. Editing your post.