MSDF Rewrite (#1)

- Wellspring is now a MSDF font rendering library, accepting output from msdf-atlas-gen for this purpose
- Renamed Wellspring_Draw to Wellspring_AddToTextBatch
- TextBounds and AddToTextBatch no longer accept position and depth values
- Removed Packer
- Removed CreatePacker, PackFontRanges, and GetPixelDataPointer. Font packing is now handled by msdf-atlas-gen
- Removed visualc solution in favor of CMake everywhere

Reviewed-on: #1

CMakeLists.txt

@@ -46,6 +46,7 @@ add_library(Wellspring
 	#Public header
 	include/Wellspring.h
 	#Source
+	lib/json.h
 	lib/stb_rect_pack.h
 	lib/stb_truetype.h
 	src/Wellspring.c

README.md

@@ -1,11 +1,21 @@
-This is Wellspring, an immediate mode font rendering system in C.
+This is Wellspring, an immediate mode multiple-channel signed distance field font rendering system in C.
 
 About Wellspring
 ----------------
 Wellspring is inspired by the design of Dear ImGui.
-It outputs pixel data that you can upload to a texture and vertex buffers that you can render anytime in your 3D application.
+It outputs buffer data that you can upload and render anytime in your 3D application.
 This means that you can integrate it easily using the graphics library of your choice.
-Wellspring uses stb_truetype to rasterize and pack fonts quickly.
+
+Wellspring uses JSON output from [msdf-atlas-gen](https://github.com/Chlumsky/msdf-atlas-gen) to generate buffers. It also uses [stb_truetype](https://github.com/nothings/stb/blob/master/stb_truetype.h) for additional kerning support. At render time, bind the image data from msdf-atlas-gen with buffers generated by Wellspring for beautiful MSDF font rendering.
+
+Using msdf-atlas-gen
+--------------
+A full explanation of msdf-atlas-gen is beyond the scope of this project, but note that Wellspring only accepts MSDF atlas types with JSON output.
+
+Your atlas generation might look like this:
+```sh
+msdf-atlas-gen -yorigin top -font ~/mygame/myfont.otf -imageout ~/mygame/content/forgotten_dream.png -json ~/mygame/content/forgotten_dream.json
+```
 
 Dependencies
 ------------
@@ -20,7 +30,7 @@ For *nix platforms, use CMake:
 	$ cmake ../
 	$ make
 
-For Windows, see the 'visualc/' directory.
+For Windows, you can use cmake-gui to generate a Visual Studio solution or use VSCode with the CMake and C/C++ Tools extensions.
 
 License
 -------

include/Wellspring.h

@@ -63,7 +63,6 @@ WELLSPRINGAPI uint32_t Wellspring_LinkedVersion(void);
 /* Type definitions */
 
 typedef struct Wellspring_Font Wellspring_Font;
-typedef struct Wellspring_Packer Wellspring_Packer;
 typedef struct Wellspring_TextBatch Wellspring_TextBatch;
 
 typedef struct Wellspring_FontRange
@@ -113,46 +112,25 @@ typedef enum Wellspring_VerticalAlignment
 
 WELLSPRINGAPI Wellspring_Font* Wellspring_CreateFont(
 	const uint8_t *fontBytes,
-	uint32_t fontBytesLength
+	uint32_t fontBytesLength,
-);
+	const uint8_t *atlasJsonBytes,
-
+	uint32_t atlasJsonBytesLength,
-WELLSPRINGAPI Wellspring_Packer* Wellspring_CreatePacker(
+	float *pPixelsPerEm,
-	Wellspring_Font *font,
+	float *pDistanceRange
-	float fontSize,
-	uint32_t width,
-	uint32_t height,
-	uint32_t strideInBytes, /* 0 means the buffer is tightly packed. */
-	uint32_t padding /* A sensible value here is 1 to allow bilinear filtering. */
-);
-
-WELLSPRINGAPI uint32_t Wellspring_PackFontRanges(
-	Wellspring_Packer *packer,
-	Wellspring_FontRange *ranges,
-	uint32_t numRanges
-);
-
-/* Returns a pointer to an array of rasterized pixels of the packed font.
- * This data must be uploaded to a texture before you render!
- * The pixel data becomes outdated if you call PackFontRanges.
- * Length is width * height.
- */
-WELLSPRINGAPI uint8_t* Wellspring_GetPixelDataPointer(
-	Wellspring_Packer *packer
 );
 
 /* Batches are not thread-safe, recommend one batch per thread. */
-WELLSPRINGAPI Wellspring_TextBatch* Wellspring_CreateTextBatch();
+WELLSPRINGAPI Wellspring_TextBatch* Wellspring_CreateTextBatch(void);
 
 /* Also restarts the batch */
 WELLSPRINGAPI void Wellspring_StartTextBatch(
 	Wellspring_TextBatch *textBatch,
-	Wellspring_Packer *packer
+	Wellspring_Font *font
 );
 
 WELLSPRINGAPI uint8_t Wellspring_TextBounds(
-	Wellspring_Packer* packer,
+	Wellspring_Font *font,
-	float x,
+	int pixelSize,
-	float y,
 	Wellspring_HorizontalAlignment horizontalAlignment,
 	Wellspring_VerticalAlignment verticalAlignment,
 	const uint8_t *strBytes,
@@ -160,11 +138,9 @@ WELLSPRINGAPI uint8_t Wellspring_TextBounds(
 	Wellspring_Rectangle *pRectangle
 );
 
-WELLSPRINGAPI uint8_t Wellspring_Draw(
+WELLSPRINGAPI uint8_t Wellspring_AddToTextBatch(
 	Wellspring_TextBatch *textBatch,
-	float x,
+	int pixelSize,
-	float y,
-	float depth,
 	Wellspring_Color *color,
 	Wellspring_HorizontalAlignment horizontalAlignment,
 	Wellspring_VerticalAlignment verticalAlignment,
@@ -182,7 +158,6 @@ WELLSPRINGAPI void Wellspring_GetBufferData(
 );
 
 WELLSPRINGAPI void Wellspring_DestroyTextBatch(Wellspring_TextBatch *textBatch);
-WELLSPRINGAPI void Wellspring_DestroyPacker(Wellspring_Packer *packer);
 WELLSPRINGAPI void Wellspring_DestroyFont(Wellspring_Font *font);
 
 #ifdef __cplusplus

src/Wellspring.c

@@ -95,6 +95,9 @@
 #define STBRP_SORT Wellspring_sort
 #define STBRP_ASSERT Wellspring_assert
 
+#define SHEREDOM_JSON_H_malloc Wellspring_malloc
+#define SHEREDOM_JSON_H_free Wellspring_free
+
 typedef uint8_t stbtt_uint8;
 typedef int8_t stbtt_int8;
 typedef uint16_t stbtt_uint16;
@@ -112,48 +115,54 @@ typedef int32_t stbtt_int32;
 #define STB_TRUETYPE_IMPLEMENTATION
 #include "stb_truetype.h"
 
+#include "json.h"
+
 #pragma GCC diagnostic warning "-Wunused-function"
 
 #define INITIAL_QUAD_CAPACITY 128
 
 /* Structs */
 
+typedef struct PackedChar
+{
+	float atlasLeft, atlasTop, atlasRight, atlasBottom;
+	float planeLeft, planeTop, planeRight, planeBottom;
+	float xAdvance;
+} PackedChar;
+
+typedef struct CharRange
+{
+	PackedChar *data;
+	uint32_t firstCodepoint;
+	uint32_t charCount;
+} CharRange;
+
+typedef struct Packer
+{
+	uint32_t width;
+	uint32_t height;
+
+	CharRange *ranges;
+	uint32_t rangeCount;
+} Packer;
+
 typedef struct Font
 {
 	uint8_t *fontBytes;
 	stbtt_fontinfo fontInfo;
 
-	int32_t ascent;
+	float ascender;
-	int32_t descent;
+	float descender;
-	int32_t lineGap;
+	float lineHeight;
+	float pixelsPerEm;
+	float distanceRange;
+
+	float scale;
+	float kerningScale; // kerning values from stb_tt are in a different scale
+
+	Packer packer;
 } Font;
 
-typedef struct CharRange
-{
-	stbtt_packedchar *data;
-	uint32_t firstCodepoint;
-	uint32_t charCount;
-	float fontSize;
-} CharRange;
-
-typedef struct Packer
-{
-	Font *font;
-	float fontSize;
-
-	stbtt_pack_context *context;
-	uint8_t *pixels;
-	uint32_t width;
-	uint32_t height;
-	uint32_t strideInBytes;
-	uint32_t padding;
-
-	float scale; /* precomputed at init */
-
-	CharRange *ranges;
-	uint32_t rangeCount;
-} Packer;
-
 typedef struct Batch
 {
 	Wellspring_Vertex *vertices;
@@ -164,9 +173,15 @@ typedef struct Batch
 	uint32_t indexCount;
 	uint32_t indexCapacity;
 
-	Packer *currentPacker;
+	Font *currentFont;
 } Batch;
 
+typedef struct Quad
+{
+   float x0,y0,s0,t0; // top-left
+   float x1,y1,s1,t1; // bottom-right
+} Quad;
+
 /* UTF-8 Decoder */
 
 /* Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
@@ -205,6 +220,126 @@ decode(uint32_t* state, uint32_t* codep, uint32_t byte) {
 	return *state;
 }
 
+/* JSON helpers */
+
+static uint8_t json_object_has_key(const json_object_t *object, const char* name)
+{
+	json_object_element_t *currentElement = object->start;
+	const char* currentName = currentElement->name->string;
+
+	while (SDL_strcmp(currentName, name) != 0)
+	{
+		if (currentElement->next == NULL)
+		{
+			return 0;
+		}
+
+		currentElement = currentElement->next;
+		currentName = currentElement->name->string;
+	}
+
+	return 1;
+}
+
+static json_object_element_t* json_object_get_element_by_name(const json_object_t *object, const char* name)
+{
+	json_object_element_t *currentElement = object->start;
+	const char* currentName = currentElement->name->string;
+
+	while (SDL_strcmp(currentName, name) != 0)
+	{
+		if (currentElement->next == NULL)
+		{
+			SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Key %s not found in JSON!", name);
+			return NULL;
+		}
+
+		currentElement = currentElement->next;
+		currentName = currentElement->name->string;
+	}
+
+	return currentElement;
+}
+
+static json_object_t* json_object_get_object(const json_object_t *object, const char* name)
+{
+	json_object_element_t *element = json_object_get_element_by_name(object, name);
+
+	if (element == NULL)
+	{
+		return NULL;
+	}
+
+	json_object_t *obj = json_value_as_object(element->value);
+
+	if (obj == NULL)
+	{
+		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Value with key %s was not an object!", name);
+	}
+
+	return obj;
+}
+
+static const char* json_object_get_string(const json_object_t *object, const char* name)
+{
+	json_object_element_t *element = json_object_get_element_by_name(object, name);
+
+	if (element == NULL)
+	{
+		return NULL;
+	}
+
+	json_string_t *str = json_value_as_string(element->value);
+
+	if (str == NULL)
+	{
+		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Value with key %s was not a string!", name);
+		return NULL;
+	}
+
+	return str->string;
+}
+
+static uint32_t json_object_get_uint(const json_object_t *object, const char* name)
+{
+	json_object_element_t *element = json_object_get_element_by_name(object, name);
+
+	if (element == NULL)
+	{
+		return 0;
+	}
+
+	json_number_t *num = json_value_as_number(element->value);
+
+	if (num == NULL)
+	{
+		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Value with key %s was not a number!", name);
+		return 0;
+	}
+
+	return (uint32_t) SDL_strtoul(num->number, NULL, 10);
+}
+
+static double json_object_get_double(const json_object_t *object, const char* name)
+{
+	json_object_element_t *element = json_object_get_element_by_name(object, name);
+
+	if (element == NULL)
+	{
+		return 0;
+	}
+
+	json_number_t *num = json_value_as_number(element->value);
+
+	if (num == NULL)
+	{
+		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Value with key %s was not a string!", name);
+		return 0;
+	}
+
+	return SDL_atof(num->number);
+}
+
 /* API */
 
 uint32_t Wellspring_LinkedVersion(void)
@@ -214,107 +349,146 @@ uint32_t Wellspring_LinkedVersion(void)
 
 Wellspring_Font* Wellspring_CreateFont(
 	const uint8_t* fontBytes,
-	uint32_t fontBytesLength
+	uint32_t fontBytesLength,
+	const uint8_t *atlasJsonBytes,
+	uint32_t atlasJsonBytesLength,
+	float *pPixelsPerEm,
+	float *pDistanceRange
 ) {
 	Font *font = Wellspring_malloc(sizeof(Font));
 
 	font->fontBytes = Wellspring_malloc(fontBytesLength);
 	Wellspring_memcpy(font->fontBytes, fontBytes, fontBytesLength);
 	stbtt_InitFont(&font->fontInfo, font->fontBytes, 0);
-	stbtt_GetFontVMetrics(&font->fontInfo, &font->ascent, &font->descent, &font->lineGap);
+	int stbAscender, stbDescender, stbLineHeight;
+	stbtt_GetFontVMetrics(&font->fontInfo, &stbAscender, &stbDescender, &stbLineHeight);
+
+	json_value_t *jsonRoot = json_parse(atlasJsonBytes, atlasJsonBytesLength);
+	json_object_t *jsonObject = jsonRoot->payload;
+
+	if (jsonObject == NULL)
+	{
+		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Atlas JSON is invalid! Bailing!");
+		Wellspring_free(font->fontBytes);
+		Wellspring_free(font);
+		return NULL;
+	}
+
+	if (SDL_strcmp(jsonObject->start->name->string, "atlas") != 0)
+	{
+		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Atlas JSON is invalid! Bailing!");
+		Wellspring_free(jsonRoot);
+		Wellspring_free(font->fontBytes);
+		Wellspring_free(font);
+		return NULL;
+	}
+
+	json_object_t *atlasObject = json_value_as_object(jsonObject->start->value);
+	json_object_t *metricsObject = json_value_as_object(jsonObject->start->next->value);
+	json_array_t *glyphsArray = json_value_as_array(jsonObject->start->next->next->value);
+
+	const char* atlasType = json_object_get_string(atlasObject, "type");
+
+	if (SDL_strcmp(atlasType, "msdf") != 0)
+	{
+		SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Atlas is not MSDF! Bailing!");
+		Wellspring_free(jsonRoot);
+		Wellspring_free(font->fontBytes);
+		Wellspring_free(font);
+		return NULL;
+	}
+
+	font->packer.width = json_object_get_uint(atlasObject, "width");
+	font->packer.height = json_object_get_uint(atlasObject, "height");
+	font->pixelsPerEm = json_object_get_double(atlasObject, "size");
+	font->distanceRange = json_object_get_double(atlasObject, "distanceRange");
+
+	font->ascender = json_object_get_double(metricsObject, "ascender");
+	font->descender = json_object_get_double(metricsObject, "descender");
+	font->lineHeight = json_object_get_double(metricsObject, "lineHeight");
+
+	font->scale = font->pixelsPerEm * 4 / 3; // converting from "points" (dpi) to pixels
+
+	/* Pack unicode ranges */
+
+	font->packer.ranges = Wellspring_malloc(sizeof(CharRange));
+	font->packer.rangeCount = 1;
+	font->packer.ranges[0].data = NULL;
+	font->packer.ranges[0].charCount = 0;
+
+	int32_t charRangeIndex = 0;
+
+	json_array_element_t *currentGlyphElement = glyphsArray->start;
+	while (currentGlyphElement != NULL)
+	{
+		json_object_t *currentGlyphObject = json_value_as_object(currentGlyphElement->value);
+
+		uint32_t codepoint = json_object_get_uint(currentGlyphObject, "unicode");
+
+		if (font->packer.ranges[charRangeIndex].charCount == 0)
+		{
+			// first codepoint on first range
+			font->packer.ranges[charRangeIndex].firstCodepoint = codepoint;
+		}
+		else if (codepoint != font->packer.ranges[charRangeIndex].firstCodepoint + font->packer.ranges[charRangeIndex].charCount)
+		{
+			// codepoint is not continuous, start a new range
+			charRangeIndex += 1;
+			font->packer.rangeCount += 1;
+
+			font->packer.ranges = Wellspring_realloc(font->packer.ranges, sizeof(PackedChar) * (charRangeIndex + 1));
+			font->packer.ranges[charRangeIndex].firstCodepoint = codepoint;
+		}
+
+		font->packer.ranges[charRangeIndex].charCount += 1;
+		font->packer.ranges[charRangeIndex].data = Wellspring_realloc(font->packer.ranges[charRangeIndex].data, sizeof(PackedChar) * font->packer.ranges[charRangeIndex].charCount);
+
+		PackedChar *packedChar = &font->packer.ranges[charRangeIndex].data[font->packer.ranges[charRangeIndex].charCount - 1];
+		packedChar->atlasLeft = 0;
+		packedChar->atlasRight = 0;
+		packedChar->atlasTop = 0;
+		packedChar->atlasBottom = 0;
+		packedChar->planeLeft = 0;
+		packedChar->planeRight = 0;
+		packedChar->planeTop = 0;
+		packedChar->planeBottom = 0;
+
+		packedChar->xAdvance = json_object_get_double(currentGlyphObject, "advance");
+
+		if (json_object_has_key(currentGlyphObject, "atlasBounds"))
+		{
+			json_object_t *boundsObject = json_object_get_object(currentGlyphObject, "atlasBounds");
+
+			packedChar->atlasLeft = json_object_get_double(boundsObject, "left");
+			packedChar->atlasRight = json_object_get_double(boundsObject, "right");
+			packedChar->atlasTop = json_object_get_double(boundsObject, "top");
+			packedChar->atlasBottom = json_object_get_double(boundsObject, "bottom");
+
+			json_object_t *planeObject = json_object_get_object(currentGlyphObject, "planeBounds");
+
+			packedChar->planeLeft = json_object_get_double(planeObject, "left");
+			packedChar->planeRight = json_object_get_double(planeObject, "right");
+			packedChar->planeTop = json_object_get_double(planeObject, "top");
+			packedChar->planeBottom = json_object_get_double(planeObject, "bottom");
+		}
+
+		currentGlyphElement = currentGlyphElement->next;
+	}
+
+	int advanceWidth, bearing;
+	stbtt_GetCodepointHMetrics(&font->fontInfo, font->packer.ranges[0].firstCodepoint, &advanceWidth, &bearing);
+
+	font->kerningScale = font->packer.ranges[0].data[0].xAdvance / advanceWidth;
+
+	Wellspring_free(jsonRoot);
+
+	*pPixelsPerEm = font->pixelsPerEm;
+	*pDistanceRange = font->distanceRange;
 
 	return (Wellspring_Font*) font;
 }
 
-Wellspring_Packer* Wellspring_CreatePacker(
+Wellspring_TextBatch* Wellspring_CreateTextBatch(void)
-	Wellspring_Font *font,
-	float fontSize,
-	uint32_t width,
-	uint32_t height,
-	uint32_t strideInBytes,
-	uint32_t padding
-) {
-	Packer *packer = Wellspring_malloc(sizeof(Packer));
-
-	packer->font = (Font*) font;
-	packer->fontSize = fontSize;
-
-	packer->context = Wellspring_malloc(sizeof(stbtt_pack_context));
-	packer->pixels = Wellspring_malloc(sizeof(uint8_t) * width * height);
-
-	packer->width = width;
-	packer->height = height;
-	packer->strideInBytes = strideInBytes;
-	packer->padding = padding;
-
-	packer->ranges = NULL;
-	packer->rangeCount = 0;
-
-	packer->scale = stbtt_ScaleForPixelHeight(&packer->font->fontInfo, fontSize);
-
-	stbtt_PackBegin(packer->context, packer->pixels, width, height, strideInBytes, padding, NULL);
-
-	return (Wellspring_Packer*) packer;
-}
-
-uint32_t Wellspring_PackFontRanges(
-	Wellspring_Packer *packer,
-	Wellspring_FontRange *ranges,
-	uint32_t numRanges
-) {
-	Packer *myPacker = (Packer*) packer;
-	Wellspring_FontRange *currentFontRange;
-	stbtt_pack_range* stbPackRanges = Wellspring_malloc(sizeof(stbtt_pack_range) * numRanges);
-	CharRange *currentCharRange;
-	uint32_t i;
-
-	for (i = 0; i < numRanges; i += 1)
-	{
-		currentFontRange = &ranges[i];
-		stbPackRanges[i].font_size = myPacker->fontSize;
-		stbPackRanges[i].first_unicode_codepoint_in_range = currentFontRange->firstCodepoint;
-		stbPackRanges[i].array_of_unicode_codepoints = NULL;
-		stbPackRanges[i].num_chars = currentFontRange->numChars;
-		stbPackRanges[i].h_oversample = currentFontRange->oversampleH;
-		stbPackRanges[i].v_oversample = currentFontRange->oversampleV;
-		stbPackRanges[i].chardata_for_range = Wellspring_malloc(sizeof(stbtt_packedchar) * currentFontRange->numChars);
-	}
-
-	if (!stbtt_PackFontRanges(myPacker->context, myPacker->font->fontBytes, 0, stbPackRanges, numRanges))
-	{
-		/* Font packing failed, time to bail */
-		for (i = 0; i < numRanges; i += 1)
-		{
-			Wellspring_free(stbPackRanges[i].chardata_for_range);
-		}
-		return 0;
-	}
-
-	myPacker->ranges = Wellspring_realloc(myPacker->ranges, sizeof(CharRange) * (myPacker->rangeCount + numRanges));
-
-	for (i = 0; i < numRanges; i += 1)
-	{
-		currentCharRange = &myPacker->ranges[myPacker->rangeCount + i];
-		currentCharRange->data = stbPackRanges[i].chardata_for_range;
-		currentCharRange->firstCodepoint = stbPackRanges[i].first_unicode_codepoint_in_range;
-		currentCharRange->charCount = stbPackRanges[i].num_chars;
-		currentCharRange->fontSize = stbPackRanges[i].font_size;
-	}
-
-	myPacker->rangeCount += numRanges;
-
-	Wellspring_free(stbPackRanges);
-	return 1;
-}
-
-uint8_t* Wellspring_GetPixelDataPointer(
-	Wellspring_Packer *packer
-) {
-	Packer* myPacker = (Packer*) packer;
-	return myPacker->pixels;
-}
-
-Wellspring_TextBatch* Wellspring_CreateTextBatch()
 {
 	Batch *batch = Wellspring_malloc(sizeof(Batch));
 
@@ -331,10 +505,10 @@ Wellspring_TextBatch* Wellspring_CreateTextBatch()
 
 void Wellspring_StartTextBatch(
 	Wellspring_TextBatch *textBatch,
-	Wellspring_Packer *packer
+	Wellspring_Font *font
 ) {
 	Batch *batch = (Batch*) textBatch;
-	batch->currentPacker = (Packer*) packer;
+	batch->currentFont = (Font*) font;
 	batch->vertexCount = 0;
 	batch->indexCount = 0;
 }
@@ -350,15 +524,15 @@ static float Wellspring_INTERNAL_GetVerticalAlignOffset(
 	}
 	else if (verticalAlignment == WELLSPRING_VERTICALALIGNMENT_TOP)
 	{
-		return scale * font->ascent;
+		return scale * font->ascender;
 	}
 	else if (verticalAlignment == WELLSPRING_VERTICALALIGNMENT_MIDDLE)
 	{
-		return scale * (font->ascent + font->descent) / 2.0f;
+		return scale * (font->ascender + font->descender) / 2.0f;
 	}
 	else /* BOTTOM */
 	{
-		return scale * font->descent;
+		return scale * font->descender;
 	}
 }
 
@@ -384,10 +558,40 @@ static inline uint32_t IsWhitespace(uint32_t codepoint)
 	}
 }
 
+static void GetPackedQuad(PackedChar *charData, float scale, int packerWidth, int packerHeight, int charIndex, float *xPos, float *yPos, Quad *q)
+{
+	float texelWidth = 1.0f / packerWidth, texelHeight = 1.0f / packerHeight;
+	PackedChar *b = charData + charIndex;
+
+	float pl, pb, pr, pt;
+	float il, ib, ir, it;
+
+	pl = *xPos + b->planeLeft * scale;
+	pb = *yPos + b->planeBottom * scale;
+	pr = *xPos + b->planeRight * scale;
+	pt = *yPos + b->planeTop * scale;
+
+	il = b->atlasLeft * texelWidth;
+	ib = b->atlasBottom * texelHeight;
+	ir = b->atlasRight * texelWidth;
+	it = b->atlasTop * texelHeight;
+
+	q->x0 = pl;
+	q->y0 = pt;
+	q->x1 = pr;
+	q->y1 = pb;
+
+	q->s0 = il;
+	q->t0 = it;
+	q->s1 = ir;
+	q->t1 = ib;
+
+	*xPos += b->xAdvance * scale;
+}
+
 static uint8_t Wellspring_Internal_TextBounds(
-	Packer* packer,
+	Font* font,
-	float x,
+	int pixelSize,
-	float y,
 	Wellspring_HorizontalAlignment horizontalAlignment,
 	Wellspring_VerticalAlignment verticalAlignment,
 	const uint8_t* strBytes,
@@ -397,20 +601,21 @@ static uint8_t Wellspring_Internal_TextBounds(
 	uint32_t decodeState = 0;
 	uint32_t codepoint;
 	int32_t glyphIndex;
-	int32_t previousGlyphIndex;
+	int32_t previousGlyphIndex = -1;
 	int32_t rangeIndex;
-	stbtt_packedchar* rangeData;
+	PackedChar* rangeData;
-	float rangeFontSize;
+	Quad charQuad;
-	stbtt_aligned_quad charQuad;
 	uint32_t i, j;
+	float x = 0, y = 0;
 	float minX = x;
 	float minY = y;
 	float maxX = x;
 	float maxY = y;
 	float startX = x;
 	float advance = 0;
+	float sizeFactor = pixelSize / font->pixelsPerEm;
 
-	y += Wellspring_INTERNAL_GetVerticalAlignOffset(packer->font, verticalAlignment, packer->scale);
+	y -= Wellspring_INTERNAL_GetVerticalAlignOffset(font, verticalAlignment, sizeFactor * font->scale);
 
 	for (i = 0; i < strLengthInBytes; i += 1)
 	{
@@ -425,17 +630,10 @@ static uint8_t Wellspring_Internal_TextBounds(
 			continue;
 		}
 
-		if (IsWhitespace(codepoint))
-		{
-			int32_t ws_adv, ws_bearing;
-			stbtt_GetCodepointHMetrics(&packer->font->fontInfo, codepoint, &ws_adv, &ws_bearing);
-			x += packer->scale * ws_adv;
-			maxX += packer->scale * ws_adv;
-			continue;
-		}
-
 		rangeData = NULL;
 
+		Packer *packer = &font->packer;
+
 		/* Find the packed char data */
 		for (j = 0; j < packer->rangeCount; j += 1)
 		{
@@ -445,7 +643,6 @@ static uint8_t Wellspring_Internal_TextBounds(
 			) {
 				rangeData = packer->ranges[j].data;
 				rangeIndex = codepoint - packer->ranges[j].firstCodepoint;
-				rangeFontSize = packer->ranges[j].fontSize;
 				break;
 			}
 		}
@@ -456,22 +653,31 @@ static uint8_t Wellspring_Internal_TextBounds(
 			return 0;
 		}
 
-		glyphIndex = stbtt_FindGlyphIndex(&packer->font->fontInfo, codepoint);
+		if (IsWhitespace(codepoint))
-
-		if (i > 0)
 		{
-			x += packer->scale * stbtt_GetGlyphKernAdvance(&packer->font->fontInfo, previousGlyphIndex, glyphIndex);
+			PackedChar *packedChar = rangeData + rangeIndex;
+			x += sizeFactor * font->scale * packedChar->xAdvance;
+			maxX += sizeFactor * font->scale * packedChar->xAdvance;
+			previousGlyphIndex = -1;
+			continue;
 		}
 
-		stbtt_GetPackedQuad(
+		glyphIndex = stbtt_FindGlyphIndex(&font->fontInfo, codepoint);
+
+		if (previousGlyphIndex != -1)
+		{
+			x += sizeFactor * font->kerningScale * font->scale * stbtt_GetGlyphKernAdvance(&font->fontInfo, previousGlyphIndex, glyphIndex);
+		}
+
+		GetPackedQuad(
 			rangeData,
+			sizeFactor * font->scale,
 			packer->width,
 			packer->height,
 			rangeIndex,
 			&x,
 			&y,
-			&charQuad,
+			&charQuad
-			0
 		);
 
 		if (charQuad.x0 < minX) { minX = charQuad.x0; }
@@ -504,9 +710,8 @@ static uint8_t Wellspring_Internal_TextBounds(
 }
 
 uint8_t Wellspring_TextBounds(
-	Wellspring_Packer* packer,
+	Wellspring_Font *font,
-	float x,
+	int pixelSize,
-	float y,
 	Wellspring_HorizontalAlignment horizontalAlignment,
 	Wellspring_VerticalAlignment verticalAlignment,
 	const uint8_t* strBytes,
@@ -514,9 +719,8 @@ uint8_t Wellspring_TextBounds(
 	Wellspring_Rectangle* pRectangle
 ) {
 	return Wellspring_Internal_TextBounds(
-		(Packer*) packer,
+		(Font*) font,
-		x,
+		pixelSize,
-		y,
 		horizontalAlignment,
 		verticalAlignment,
 		strBytes,
@@ -525,11 +729,9 @@ uint8_t Wellspring_TextBounds(
 	);
 }
 
-uint8_t Wellspring_Draw(
+uint8_t Wellspring_AddToTextBatch(
 	Wellspring_TextBatch *textBatch,
-	float x,
+	int pixelSize,
-	float y,
-	float depth,
 	Wellspring_Color *color,
 	Wellspring_HorizontalAlignment horizontalAlignment,
 	Wellspring_VerticalAlignment verticalAlignment,
@@ -537,26 +739,28 @@ uint8_t Wellspring_Draw(
 	uint32_t strLengthInBytes
 ) {
 	Batch *batch = (Batch*) textBatch;
-	Packer *myPacker = batch->currentPacker;
+	Font *font = batch->currentFont;
+	Packer *myPacker = &font->packer;
 	uint32_t decodeState = 0;
 	uint32_t codepoint;
 	int32_t glyphIndex;
-	int32_t previousGlyphIndex;
+	int32_t previousGlyphIndex = -1;
 	int32_t rangeIndex;
-	stbtt_packedchar *rangeData;
+	PackedChar *rangeData;
-	float rangeFontSize;
+	Quad charQuad;
-	stbtt_aligned_quad charQuad;
 	uint32_t vertexBufferIndex;
 	uint32_t indexBufferIndex;
 	Wellspring_Rectangle bounds;
 	uint32_t i, j;
+	float sizeFactor = pixelSize / font->pixelsPerEm;
+	float x = 0, y = 0;
 
-	y += Wellspring_INTERNAL_GetVerticalAlignOffset(myPacker->font, verticalAlignment, myPacker->scale);
+	y -= Wellspring_INTERNAL_GetVerticalAlignOffset(font, verticalAlignment, sizeFactor * font->scale);
 
 	/* FIXME: If we horizontally align, we have to decode and process glyphs twice, very inefficient. */
 	if (horizontalAlignment == WELLSPRING_HORIZONTALALIGNMENT_RIGHT)
 	{
-		if (!Wellspring_Internal_TextBounds(myPacker, x, y, horizontalAlignment, verticalAlignment, strBytes, strLengthInBytes, &bounds))
+		if (!Wellspring_Internal_TextBounds(font, pixelSize, horizontalAlignment, verticalAlignment, strBytes, strLengthInBytes, &bounds))
 		{
 			/* Something went wrong while calculating bounds. */
 			return 0;
@@ -566,7 +770,7 @@ uint8_t Wellspring_Draw(
 	}
 	else if (horizontalAlignment == WELLSPRING_HORIZONTALALIGNMENT_CENTER)
 	{
-		if (!Wellspring_Internal_TextBounds(myPacker, x, y, horizontalAlignment, verticalAlignment, strBytes, strLengthInBytes, &bounds))
+		if (!Wellspring_Internal_TextBounds(font, pixelSize, horizontalAlignment, verticalAlignment, strBytes, strLengthInBytes, &bounds))
 		{
 			/* Something went wrong while calculating bounds. */
 			return 0;
@@ -588,14 +792,6 @@ uint8_t Wellspring_Draw(
 			continue;
 		}
 
-		if (IsWhitespace(codepoint))
-		{
-			int32_t ws_adv, ws_bearing;
-			stbtt_GetCodepointHMetrics(&myPacker->font->fontInfo, codepoint, &ws_adv, &ws_bearing);
-			x += myPacker->scale * ws_adv;
-			continue;
-		}
-
 		rangeData = NULL;
 
 		/* Find the packed char data */
@@ -607,7 +803,6 @@ uint8_t Wellspring_Draw(
 			) {
 				rangeData = myPacker->ranges[j].data;
 				rangeIndex = codepoint - myPacker->ranges[j].firstCodepoint;
-				rangeFontSize = myPacker->ranges[j].fontSize;
 				break;
 			}
 		}
@@ -618,22 +813,30 @@ uint8_t Wellspring_Draw(
 			return 0;
 		}
 
-		glyphIndex = stbtt_FindGlyphIndex(&myPacker->font->fontInfo, codepoint);
+		if (IsWhitespace(codepoint))
-
-		if (i > 0)
 		{
-			x += myPacker->scale * stbtt_GetGlyphKernAdvance(&myPacker->font->fontInfo, previousGlyphIndex, glyphIndex);
+			PackedChar *packedChar = rangeData + rangeIndex;
+			x += sizeFactor * font->scale * packedChar->xAdvance;
+			previousGlyphIndex = -1;
+			continue;
 		}
 
-		stbtt_GetPackedQuad(
+		glyphIndex = stbtt_FindGlyphIndex(&font->fontInfo, codepoint);
+
+		if (previousGlyphIndex != -1)
+		{
+			x += sizeFactor * font->kerningScale * font->scale * stbtt_GetGlyphKernAdvance(&font->fontInfo, previousGlyphIndex, glyphIndex);
+		}
+
+		GetPackedQuad(
 			rangeData,
+			sizeFactor * font->scale,
 			myPacker->width,
 			myPacker->height,
 			rangeIndex,
 			&x,
 			&y,
-			&charQuad,
+			&charQuad
-			0
 		);
 
 		if (batch->vertexCount >= batch->vertexCapacity)
@@ -648,14 +851,12 @@ uint8_t Wellspring_Draw(
 			batch->indices = Wellspring_realloc(batch->indices, sizeof(uint32_t) * batch->indexCapacity);
 		}
 
-		/* TODO: kerning and alignment */
-
 		vertexBufferIndex = batch->vertexCount;
 		indexBufferIndex = batch->indexCount;
 
 		batch->vertices[vertexBufferIndex].x = charQuad.x0;
 		batch->vertices[vertexBufferIndex].y = charQuad.y0;
-		batch->vertices[vertexBufferIndex].z = depth;
+		batch->vertices[vertexBufferIndex].z = 0;
 		batch->vertices[vertexBufferIndex].u = charQuad.s0;
 		batch->vertices[vertexBufferIndex].v = charQuad.t0;
 		batch->vertices[vertexBufferIndex].r = color->r;
@@ -665,7 +866,7 @@ uint8_t Wellspring_Draw(
 
 		batch->vertices[vertexBufferIndex + 1].x = charQuad.x0;
 		batch->vertices[vertexBufferIndex + 1].y = charQuad.y1;
-		batch->vertices[vertexBufferIndex + 1].z = depth;
+		batch->vertices[vertexBufferIndex + 1].z = 0;
 		batch->vertices[vertexBufferIndex + 1].u = charQuad.s0;
 		batch->vertices[vertexBufferIndex + 1].v = charQuad.t1;
 		batch->vertices[vertexBufferIndex + 1].r = color->r;
@@ -675,7 +876,7 @@ uint8_t Wellspring_Draw(
 
 		batch->vertices[vertexBufferIndex + 2].x = charQuad.x1;
 		batch->vertices[vertexBufferIndex + 2].y = charQuad.y0;
-		batch->vertices[vertexBufferIndex + 2].z = depth;
+		batch->vertices[vertexBufferIndex + 2].z = 0;
 		batch->vertices[vertexBufferIndex + 2].u = charQuad.s1;
 		batch->vertices[vertexBufferIndex + 2].v = charQuad.t0;
 		batch->vertices[vertexBufferIndex + 2].r = color->r;
@@ -685,7 +886,7 @@ uint8_t Wellspring_Draw(
 
 		batch->vertices[vertexBufferIndex + 3].x = charQuad.x1;
 		batch->vertices[vertexBufferIndex + 3].y = charQuad.y1;
-		batch->vertices[vertexBufferIndex + 3].z = depth;
+		batch->vertices[vertexBufferIndex + 3].z = 0;
 		batch->vertices[vertexBufferIndex + 3].u = charQuad.s1;
 		batch->vertices[vertexBufferIndex + 3].v = charQuad.t1;
 		batch->vertices[vertexBufferIndex + 3].r = color->r;
@@ -733,27 +934,15 @@ void Wellspring_DestroyTextBatch(Wellspring_TextBatch *textBatch)
 	Wellspring_free(batch);
 }
 
-void Wellspring_DestroyPacker(Wellspring_Packer *packer)
-{
-	Packer* myPacker = (Packer*) packer;
-	uint32_t i;
-
-	stbtt_PackEnd(myPacker->context);
-
-	for (i = 0; i < myPacker->rangeCount; i += 1)
-	{
-		Wellspring_free(myPacker->ranges[i].data);
-	}
-
-	Wellspring_free(myPacker->ranges);
-	Wellspring_free(myPacker->context);
-	Wellspring_free(myPacker->pixels);
-}
-
 void Wellspring_DestroyFont(Wellspring_Font* font)
 {
 	Font *myFont = (Font*) font;
 
+	for (int i = 0; i < myFont->packer.rangeCount; i += 1)
+	{
+		Wellspring_free(myFont->packer.ranges[i].data);
+	}
+	Wellspring_free(myFont->packer.ranges);
 	Wellspring_free(myFont->fontBytes);
 	Wellspring_free(myFont);
 }

visualc/Wellspring.sln

@@ -1,31 +0,0 @@
-
-Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.0.30717.126
-MinimumVisualStudioVersion = 10.0.40219.1
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "Wellspring", "Wellspring.vcxproj", "{6DB15344-E000-45CB-A48A-1D72F7D6E945}"
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|x64 = Debug|x64
-		MinSizeRel|x64 = MinSizeRel|x64
-		Release|x64 = Release|x64
-		RelWithDebInfo|x64 = RelWithDebInfo|x64
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
-		{6DB15344-E000-45CB-A48A-1D72F7D6E945}.Debug|x64.ActiveCfg = Debug|x64
-		{6DB15344-E000-45CB-A48A-1D72F7D6E945}.Debug|x64.Build.0 = Debug|x64
-		{6DB15344-E000-45CB-A48A-1D72F7D6E945}.MinSizeRel|x64.ActiveCfg = MinSizeRel|x64
-		{6DB15344-E000-45CB-A48A-1D72F7D6E945}.MinSizeRel|x64.Build.0 = MinSizeRel|x64
-		{6DB15344-E000-45CB-A48A-1D72F7D6E945}.Release|x64.ActiveCfg = Release|x64
-		{6DB15344-E000-45CB-A48A-1D72F7D6E945}.Release|x64.Build.0 = Release|x64
-		{6DB15344-E000-45CB-A48A-1D72F7D6E945}.RelWithDebInfo|x64.ActiveCfg = RelWithDebInfo|x64
-		{6DB15344-E000-45CB-A48A-1D72F7D6E945}.RelWithDebInfo|x64.Build.0 = RelWithDebInfo|x64
-	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
-		HideSolutionNode = FALSE
-	EndGlobalSection
-	GlobalSection(ExtensibilityGlobals) = postSolution
-		SolutionGuid = {7B2DB465-0A55-3811-9EF4-A520B47653D2}
-	EndGlobalSection
-EndGlobal

visualc/Wellspring.vcxproj

@@ -1,84 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <ItemGroup Label="ProjectConfigurations">
-    <ProjectConfiguration Include="Debug|x64">
-      <Configuration>Debug</Configuration>
-      <Platform>x64</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release|x64">
-      <Configuration>Release</Configuration>
-      <Platform>x64</Platform>
-    </ProjectConfiguration>
-  </ItemGroup>
-  <PropertyGroup Label="Globals">
-    <ProjectGuid>{6DB15344-E000-45CB-A48A-1D72F7D6E945}</ProjectGuid>
-    <RootNamespace>FNA3D</RootNamespace>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
-  <PropertyGroup Condition="'$(Configuration)'=='Debug'" Label="Configuration">
-    <ConfigurationType>DynamicLibrary</ConfigurationType>
-    <UseDebugLibraries>true</UseDebugLibraries>
-    <CharacterSet>MultiByte</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)'=='Release'" Label="Configuration">
-    <ConfigurationType>DynamicLibrary</ConfigurationType>
-    <UseDebugLibraries>false</UseDebugLibraries>
-    <WholeProgramOptimization>true</WholeProgramOptimization>
-    <CharacterSet>MultiByte</CharacterSet>
-  </PropertyGroup>
-  <PropertyGroup Label="Configuration" Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
-    <PlatformToolset>v142</PlatformToolset>
-  </PropertyGroup>
-  <PropertyGroup Label="Configuration" Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
-    <PlatformToolset>v142</PlatformToolset>
-  </PropertyGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
-  <ImportGroup Label="ExtensionSettings">
-  </ImportGroup>
-  <ImportGroup Label="PropertySheets">
-    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
-  </ImportGroup>
-  <PropertyGroup Label="UserMacros" />
-  <PropertyGroup>
-    <IncludePath>..\lib\;..\..\SDL2\include;..\include;$(IncludePath)</IncludePath>
-    <LibraryPath>..\..\SDL2\lib\$(PlatformShortName);$(LibraryPath)</LibraryPath>
-  </PropertyGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)'=='Debug'">
-    <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
-      <Optimization>Disabled</Optimization>
-      <PreprocessorDefinitions>USE_SDL2;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-    </ClCompile>
-    <Link>
-      <GenerateDebugInformation>DebugFull</GenerateDebugInformation>
-      <AdditionalDependencies>SDL2.lib;%(AdditionalDependencies)</AdditionalDependencies>
-    </Link>
-  </ItemDefinitionGroup>
-  <ItemDefinitionGroup Condition="'$(Configuration)'=='Release'">
-    <ClCompile>
-      <WarningLevel>Level3</WarningLevel>
-      <Optimization>MaxSpeed</Optimization>
-      <PreprocessorDefinitions>USE_SDL2;%(PreprocessorDefinitions)</PreprocessorDefinitions>
-      <FunctionLevelLinking>true</FunctionLevelLinking>
-      <IntrinsicFunctions>true</IntrinsicFunctions>
-    </ClCompile>
-    <Link>
-      <GenerateDebugInformation>true</GenerateDebugInformation>
-      <OptimizeReferences>true</OptimizeReferences>
-      <AdditionalDependencies>SDL2.lib;%(AdditionalDependencies)</AdditionalDependencies>
-    </Link>
-  </ItemDefinitionGroup>
-  <ItemGroup>
-    <ClCompile Include="..\src\Wellspring.c" />
-  </ItemGroup>
-  <ItemGroup>
-    <ClCompile Include="..\lib\stb_rect_pack.h" />
-    <ClCompile Include="..\lib\stb_truetype.h" />
-  </ItemGroup>
-  <ItemGroup>
-    <ClInclude Include="..\include\Wellspring.h" />
-  </ItemGroup>
-  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
-  <ImportGroup Label="ExtensionTargets">
-  </ImportGroup>
-</Project>

visualc/Wellspring.vcxproj.user

@@ -1,4 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="Current" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
-  <PropertyGroup />
-</Project>