making initial code2 codebase diretory

code2/vefontcache/parser.odin

@@ -0,0 +1,196 @@
+package vefontcache
+
+/*
+Notes:
+This is a minimal wrapper I originally did incase a font parser other than stb_truetype is introduced in the future.
+Otherwise, its essentially 1:1 with it.
+
+Freetype isn't really supported and its not a high priority.
+~~Freetype will do memory allocations and has an interface the user can implement.~~
+~~That interface is not exposed from this parser but could be added to parser_init.~~
+
+STB_Truetype:
+* Added ability to set the stb_truetype allocator for STBTT_MALLOC and STBTT_FREE.
+* Changed procedure signatures to pass the font_info struct by immutable ptr (#by_ptr) 
+  when the C equivalent has their parameter as `const*`.
+*/
+
+import "core:c"
+import stbtt    "thirdparty:stb/truetype"
+// import freetype "thirdparty:freetype"
+
+Parser_Kind :: enum u32 {
+	STB_TrueType,
+	Freetype, // Currently not implemented.
+}
+
+Parser_Font_Info :: struct {
+	label : string,
+	kind  : Parser_Kind,
+	stbtt_info : stbtt.fontinfo,
+	// freetype_info : freetype.Face
+	data : []byte,
+}
+
+Glyph_Vert_Type :: enum u8 {
+	None,
+	Move = 1,
+	Line,
+	Curve,
+	Cubic,
+}
+
+// Based directly off of stb_truetype's vertex
+Parser_Glyph_Vertex :: struct {
+	x,          y          : i16,
+	contour_x0, contour_y0 : i16,
+	contour_x1, contour_y1 : i16,
+	type    : Glyph_Vert_Type,
+	padding : u8,
+}
+// A shape can be a dynamic array free_type or an opaque set of data handled by stb_truetype
+Parser_Glyph_Shape :: [dynamic]Parser_Glyph_Vertex
+
+Parser_Context :: struct {
+	lib_backing : Allocator,
+	kind        : Parser_Kind,
+	// ft_library : freetype.Library,
+}
+
+parser_stbtt_allocator_proc :: proc(
+	allocator_data : rawptr, 
+	type           : stbtt.zpl_allocator_type, 
+	size           : c.ssize_t, 
+	alignment      : c.ssize_t, 
+	old_memory     : rawptr, 
+	old_size       : c.ssize_t, 
+	flags          : c.ulonglong
+) -> rawptr
+{
+	allocator := transmute(^Allocator) allocator_data
+	result, error := allocator.procedure( allocator.data, cast(Allocator_Mode) type, cast(int) size, cast(int) alignment, old_memory, cast(int) old_size )
+	assert(error == .None)
+
+	if type == .Alloc || type == .Resize {
+		raw := transmute(Raw_Slice) result
+		// assert(raw.len > 0, "Allocation is 0 bytes?")
+		return transmute(rawptr) raw.data
+	}
+	else do return nil
+}
+
+parser_init :: proc( ctx : ^Parser_Context, kind : Parser_Kind, allocator := context.allocator )
+{
+	ctx.kind        = kind
+	ctx.lib_backing = allocator
+
+	stbtt_allocator := stbtt.zpl_allocator { parser_stbtt_allocator_proc, & ctx.lib_backing }
+	stbtt.SetAllocator( stbtt_allocator )
+}
+
+parser_reload :: proc( ctx : ^Parser_Context, allocator := context.allocator) {
+	ctx.lib_backing = allocator
+	stbtt_allocator := stbtt.zpl_allocator { parser_stbtt_allocator_proc, & ctx.lib_backing }
+	stbtt.SetAllocator( stbtt_allocator )
+}
+
+parser_shutdown :: proc( ctx : ^Parser_Context ) {
+	// Note: Not necesssary for stb_truetype
+}
+
+parser_load_font :: proc( ctx : ^Parser_Context, label : string, data : []byte ) -> (font : Parser_Font_Info, error : b32)
+{
+	error = ! stbtt.InitFont( & font.stbtt_info, raw_data(data), 0 )
+
+	font.label = label
+	font.data  = data
+	font.kind  = ctx.kind
+	return
+}
+
+parser_unload_font :: proc( font : ^Parser_Font_Info )
+{
+	// case .STB_TrueType:
+		// Do Nothing
+}
+
+parser_find_glyph_index :: #force_inline proc "contextless" ( font : Parser_Font_Info, codepoint : rune ) -> (glyph_index : Glyph)
+{
+	glyph_index = transmute(Glyph) stbtt.FindGlyphIndex( font.stbtt_info, codepoint )
+	return
+}
+
+parser_free_shape :: #force_inline proc( font : Parser_Font_Info, shape : Parser_Glyph_Shape )
+{
+	shape     := shape
+	shape_raw := transmute( ^Raw_Dynamic_Array) & shape
+	stbtt.FreeShape( font.stbtt_info, transmute( [^]stbtt.vertex) shape_raw.data )
+}
+
+parser_get_codepoint_horizontal_metrics :: #force_inline proc "contextless" ( font : Parser_Font_Info, codepoint : rune ) -> ( advance, to_left_side_glyph : i32 )
+{
+	stbtt.GetCodepointHMetrics( font.stbtt_info, codepoint, & advance, & to_left_side_glyph )
+	return
+}
+
+parser_get_codepoint_kern_advance :: #force_inline proc "contextless" ( font : Parser_Font_Info, prev_codepoint, codepoint : rune ) -> i32
+{
+	kern := stbtt.GetCodepointKernAdvance( font.stbtt_info, prev_codepoint, codepoint )
+	return kern
+}
+
+parser_get_font_vertical_metrics :: #force_inline proc "contextless" ( font : Parser_Font_Info ) -> (ascent, descent, line_gap : i32 )
+{
+	stbtt.GetFontVMetrics( font.stbtt_info, & ascent, & descent, & line_gap )
+	return
+}
+
+parser_get_bounds :: #force_inline proc "contextless" ( font : Parser_Font_Info, glyph_index : Glyph ) -> (bounds : Range2)
+{
+	// profile(#procedure)
+	bounds_0, bounds_1 : Vec2i
+
+	x0, y0, x1, y1 : i32
+	success := cast(bool) stbtt.GetGlyphBox( font.stbtt_info, i32(glyph_index), & x0, & y0, & x1, & y1 )
+
+	bounds_0 = { x0, y0 }
+	bounds_1 = { x1, y1 }
+	bounds = { vec2(bounds_0), vec2(bounds_1) }
+	return
+}
+
+parser_get_glyph_shape :: #force_inline proc ( font : Parser_Font_Info, glyph_index : Glyph ) -> (shape : Parser_Glyph_Shape, error : Allocator_Error)
+{
+	stb_shape : [^]stbtt.vertex
+	nverts    := stbtt.GetGlyphShape( font.stbtt_info, cast(i32) glyph_index, & stb_shape )
+
+	shape_raw          := transmute( ^Raw_Dynamic_Array) & shape
+	shape_raw.data      = stb_shape
+	shape_raw.len       = int(nverts)
+	shape_raw.cap       = int(nverts)
+	shape_raw.allocator = nil_allocator()
+	error = Allocator_Error.None
+	return
+}
+
+parser_is_glyph_empty :: #force_inline proc "contextless" ( font : Parser_Font_Info, glyph_index : Glyph ) -> b32
+{
+	return stbtt.IsGlyphEmpty( font.stbtt_info, cast(c.int) glyph_index )
+}
+
+parser_scale :: #force_inline proc "contextless" ( font : Parser_Font_Info, size : f32 ) -> f32
+{
+	// profile(#procedure)
+	size_scale := size > 0.0 ? parser_scale_for_mapping_em_to_pixels( font, size ) :  parser_scale_for_pixel_height( font, -size )
+	return size_scale
+}
+
+parser_scale_for_pixel_height :: #force_inline proc "contextless" ( font : Parser_Font_Info, size : f32 ) -> f32
+{
+	return stbtt.ScaleForPixelHeight( font.stbtt_info, size )
+}
+
+parser_scale_for_mapping_em_to_pixels :: #force_inline proc "contextless" ( font : Parser_Font_Info, size : f32 ) -> f32
+{
+	return stbtt.ScaleForMappingEmToPixels( font.stbtt_info, size )
+}