pke: font rendering correct glyph transform

1 files changed, 72 insertions, 51 deletions

diff --git a/src/font.cpp b/src/font.cpp
index 96a93a6..1f97bf1 100644
--- a/src/font.cpp
+++ b/src/font.cpp
@@ -14,6 +14,8 @@
 const char *PKE_PROJECT_FONT_TITLE = "title: ";
 const char *PKE_PROJECT_FONT_TEXTURE_HANDLE = "texture_handle: ";
 const char *PKE_PROJECT_FONT_GLYPH_DETAILS_HANDLE = "glyph_details_handle: ";
+const char *PKE_PROJECT_FONT_MSDF_MIN_SCALE = "msdf_min_scale: ";
+const char *PKE_PROJECT_FONT_MSDF_PX_RANGE = "msdf_px_range: ";
 const char *PKE_PROJECT_FONT_SPACING_GEOMETRY_SCALE = "spacing_geometry_scale: ";
 const char *PKE_PROJECT_FONT_SPACING_EM_SIZE = "spacing_em_size: ";
 const char *PKE_PROJECT_FONT_SPACING_ASCENDER_Y = "spacing_ascender_y: ";
@@ -91,50 +93,48 @@ void FontType_Inner_CalcTransforms(const FontType *ft, FontRender *fr, FontInsta
 	FontGlyphChar *fgc;
 	FontInstanceBufferItem *buf_item;
 	uint32_t i;
-	float font_glyph_spacing_inverse;
+	float font_glyph_spacing;
 	float cursor_head, line_index, line_height;
-	float glyph_ratio, screen_ratio;
 	glm::vec2 glyph_size;
-	glm::vec2 translate;
-	glm::mat3 tr_scale_glyph = glm::mat3(1);
-	glm::mat3 tr_scale_screen = glm::mat3(1);
-	glm::mat3 tr_translate = glm::mat3(1);
-
-	font_glyph_spacing_inverse = (ft->spacing.em_size / ft->spacing.geometry_scale);
+	glm::vec3 translate;
+	glm::vec3 scale;
+
+	// TODO 2025-02-18 - JCB
+	// Trying to get pixel-perfect rendering with mannequin-7.
+	// Everything is now sized and positioned correctly.
+	// However, there is a ghost layer around the letter.
+	// Could be related to uv (set to a .5 value).
+	//
+	// Fonts are not aliased correctly - may or may not be related to ghosting.
+	//
+	// Letter spacing seems off.
+	// Digits and punctuation ',' '.' are the worst offenders.
+
+	font_glyph_spacing = ft->spacing.em_size * fr->settings.char_scale;
 	cursor_head = 0;
 	line_index = 0;
-	line_height = font_glyph_spacing_inverse * ft->spacing.line_height * fr->settings.char_scale;
+	line_height = font_glyph_spacing * ft->spacing.line_height * fr->settings.line_height_scale;
 
 	for (i = 0; i < fr->n_glyphs; ++i) {
-
+		translate = glm::vec3(0);
+		scale = glm::vec3(1);
 		fgc = &ft->glyphs[fr->glyph_indices[i]];
 
+		if (fgc->is_whitespace == true) {
+			cursor_head += fgc->advance * font_glyph_spacing;
+			continue;
+		}
+
 		// left, bottom, right, top
 		//    x,      y,     z,   w
-		glyph_size.x = fgc->baseline_bounding_box.z - fgc->baseline_bounding_box.x;
-		glyph_size.x *= font_glyph_spacing_inverse;
-		glyph_size.x *= fr->settings.char_scale;
-
-		glyph_size.y = fgc->baseline_bounding_box.w - fgc->baseline_bounding_box.y;
-		glyph_size.y *= font_glyph_spacing_inverse;
-		glyph_size.y *= fr->settings.char_scale;
-
-		glyph_ratio = glyph_size.x / glyph_size.y;
-
-		// this might break if the screen is vertical?
-		// scale the uniform box to the glyph ratio
-		if (glyph_ratio > 0) {
-			tr_scale_glyph[0][0] = glyph_ratio;
-			tr_scale_glyph[1][1] = 1;
-			screen_ratio = glyph_size.x / (float)Extent.width;
-		} else {
-			tr_scale_glyph[0][0] = 1;
-			tr_scale_glyph[1][1] = glyph_ratio;
-			screen_ratio = glyph_size.y / (float)Extent.height;
-		}
+		glyph_size.x = fgc->plane_bounds.z - fgc->plane_bounds.x;
+		glyph_size.x *= font_glyph_spacing;
+
+		glyph_size.y = fgc->plane_bounds.w - fgc->plane_bounds.y;
+		glyph_size.y *= font_glyph_spacing;
+
 		// shrink the correctly sized box to screen size
-		tr_scale_screen[0][0] = screen_ratio;
-		tr_scale_screen[1][1] = screen_ratio;
+		scale *= glm::vec3(glyph_size.x / (float)Extent.width, glyph_size.y / (float)Extent.height, 1.0);
 
 		// move to appropriate position + char placement
 
@@ -146,34 +146,34 @@ void FontType_Inner_CalcTransforms(const FontType *ft, FontRender *fr, FontInsta
 		// draw from top left [-1,-1], so add left
 		// (add because "left" from mtsdf is likely negative)
 		// (while testing, the char '#' had a negative "left")
-		translate.x += font_glyph_spacing_inverse * fgc->baseline_bounding_box.x;
+		translate.x += fgc->plane_bounds.x * font_glyph_spacing;
 		translate.x -= (Extent.width / 2.0);
 		translate.x /= (Extent.width / 2.0);
 
 		// ((val) - (width/2)) / (width/2)
 		// box position
 		translate.y = fr->settings.surface_area_pos.y;
-		// current line (+1 to not draw above the box)
-		translate.y += ((line_index + 1) * line_height);
-		// draw from top left [-1,-1], so subtract top
-		// (subtract because vulkan to go up)
-		translate.y -= (ft->spacing.em_size / ft->spacing.geometry_scale) * fgc->baseline_bounding_box.w;
-		translate.y -= (Extent.width / 2.0);
-		translate.y /= (Extent.width / 2.0);
-
-		tr_translate[2][0] = translate.x;
-		tr_translate[2][1] = translate.y;
+		// baseline - current line (+1 to not draw above the box)
+		translate.y -= ((line_index + 1) * line_height);
+		// places the top-left corner of the glyph on the baseline
+		translate.y += (font_glyph_spacing / 2.0) + (glyph_size.y / 2.0);
+		// move glyph to the height relative to the baseline (cursor)
+		translate.y -= (fgc->plane_bounds.w * font_glyph_spacing);
+		translate.y -= (Extent.height / 2.0);
+		translate.y /= (Extent.height / 2.0);
 
-		cursor_head += fgc->advance * font_glyph_spacing_inverse * fr->settings.char_scale;
+		cursor_head += fgc->advance * font_glyph_spacing;
 
 		buf_item = &ptr_dst[i];
-		buf_item->pos_scale = tr_translate * tr_scale_glyph * tr_scale_screen;
+		buf_item->pos_scale = glm::translate(glm::mat4(1), translate);
+		buf_item->pos_scale = glm::scale(buf_item->pos_scale, scale);
 		buf_item->fg_color = glm::vec4(0.4, 0.9, 0.5, 0.8);
 		buf_item->bg_color = glm::vec4(0.0, 0.0, 0.0, 0.0);
 		buf_item->sprite_region_min = fgc->sprite_region_min;
 		buf_item->sprite_region_max = fgc->sprite_region_max;
-		// TODO check me, not sure this is correct
-		buf_item->width = fr->settings.char_scale;
+		buf_item->width =
+			(ft->msdf_settings.minimum_scale / fr->settings.char_scale)
+			* ft->msdf_settings.px_range;
 	}
 }
 
@@ -263,6 +263,7 @@ void FontType_Tick(double delta) {
 
 void FontType_Serialize(std::ofstream &stream, FontType *ft) {
 	FontTypeSpacing sp{};
+	FontTypeMSDFSettings msdf{};
 	memset(&sp, 0, sizeof(sp));
 	NULL_CHAR_ARR(handleStr, AssetKeyLength + 2);
 	const Asset *txtr = AM_Get(ft->fontTextureAssetHandle);
@@ -272,6 +273,12 @@ void FontType_Serialize(std::ofstream &stream, FontType *ft) {
 	stream << PKE_PROJECT_FONT_TEXTURE_HANDLE << handleStr << std::endl;
 	snprintf(handleStr, AssetKeyLength + 1, "%s", glyphs->key);
 	stream << PKE_PROJECT_FONT_GLYPH_DETAILS_HANDLE << handleStr << std::endl;
+	if (ft->msdf_settings.minimum_scale != msdf.minimum_scale) {
+		stream << PKE_PROJECT_FONT_MSDF_MIN_SCALE << ft->msdf_settings.minimum_scale << std::endl;
+	}
+	if (ft->msdf_settings.px_range != msdf.px_range) {
+		stream << PKE_PROJECT_FONT_MSDF_PX_RANGE << ft->msdf_settings.px_range << std::endl;
+	}
 	if (ft->spacing.geometry_scale != sp.geometry_scale) {
 		stream << PKE_PROJECT_FONT_SPACING_GEOMETRY_SCALE << ft->spacing.geometry_scale << std::endl;
 	}
@@ -301,13 +308,14 @@ void FontType_Deserialize(std::ifstream &stream) {
 	uint64_t i;
 	NULL_CHAR_ARR(readLine, 128);
 	FontTypeSpacing sp{};
+	FontTypeMSDFSettings msdf{};
 	pk_cstr title;
 	AssetKey fontTextureKey;
 	AssetKey glyphDetailsKey;
 	memset(&sp, 0, sizeof(sp));
 	while (memset(readLine, 0, 128), stream.getline(readLine, 128)) {
 		if (strcmp("", readLine) == 0) {
-			FontType_RegisterFont(title, AM_GetHandle(fontTextureKey), AM_GetHandle(glyphDetailsKey), &sp);
+			FontType_RegisterFont(title, AM_GetHandle(fontTextureKey), AM_GetHandle(glyphDetailsKey), &msdf, &sp);
 			return;
 		}
 		if (strstr(readLine, PKE_PROJECT_FONT_TITLE)) {
@@ -332,6 +340,18 @@ void FontType_Deserialize(std::ifstream &stream) {
 			}
 			continue;
 		}
+		if (strstr(readLine, PKE_PROJECT_FONT_MSDF_MIN_SCALE)) {
+			uint64_t prefixLen = strlen(PKE_PROJECT_FONT_MSDF_MIN_SCALE);
+			auto result = pk_stn_float(&msdf.minimum_scale, readLine + prefixLen);
+			assert(result == PK_STN_RES_SUCCESS);
+			continue;
+		}
+		if (strstr(readLine, PKE_PROJECT_FONT_MSDF_PX_RANGE)) {
+			uint64_t prefixLen = strlen(PKE_PROJECT_FONT_MSDF_PX_RANGE);
+			auto result = pk_stn_float(&msdf.px_range, readLine + prefixLen);
+			assert(result == PK_STN_RES_SUCCESS);
+			continue;
+		}
 		if (strstr(readLine, PKE_PROJECT_FONT_SPACING_GEOMETRY_SCALE)) {
 			uint64_t prefixLen = strlen(PKE_PROJECT_FONT_SPACING_GEOMETRY_SCALE);
 			auto result = pk_stn_double(&sp.geometry_scale, readLine + prefixLen);
@@ -382,7 +402,7 @@ FontType* FontType_GetFonts(FontTypeIndex &count) {
 	return ftd.arr_ft;
 }
 
-FontTypeIndex FontType_RegisterFont(pk_cstr title, AssetHandle fontTextureHandle, AssetHandle glyphsHandle, FontTypeSpacing *spacing) {
+FontTypeIndex FontType_RegisterFont(pk_cstr title, AssetHandle fontTextureHandle, AssetHandle glyphsHandle, FontTypeMSDFSettings *msdf_settings, FontTypeSpacing *spacing) {
 	PKVK_TmpBufferDetails tmpBufferDetails{};
 	VkResult vkResult;
 	pk_arr arr_vert_mem_reqs;
@@ -396,6 +416,7 @@ FontTypeIndex FontType_RegisterFont(pk_cstr title, AssetHandle fontTextureHandle
 	constexpr VkDeviceSize startingGlyphCount = 4;
 	assert(fontTextureHandle != AssetHandle_MAX);
 	assert(glyphsHandle != AssetHandle_MAX);
+	assert(msdf_settings != nullptr);
 	assert(spacing != nullptr);
 
 	VkMemoryRequirements combined_vert_mem_reqs;
@@ -419,6 +440,7 @@ FontTypeIndex FontType_RegisterFont(pk_cstr title, AssetHandle fontTextureHandle
 	ft->glyphDetailsAssetHandle = glyphsHandle;
 	ft->renders = pk_new<FontRender>(startingGlyphCount);
 	ft->n_render = FontRenderIndex{startingGlyphCount};
+	ft->msdf_settings = *msdf_settings;
 	ft->spacing = *spacing;
 
 	const Asset *glyphs = AM_Get(glyphsHandle);
@@ -940,7 +962,6 @@ FontTypeIndex FontType_RegisterFont(pk_cstr title, AssetHandle fontTextureHandle
 void FontType_Unload(FontTypeIndex idx) {
 	FontType *ft = &ftd.arr_ft[(FontTypeIndex_T)idx];
 
-
 	// TODO specific bucket
 	if (ft->renders != nullptr) {
 		for (FontRenderIndex_T i = 0; i < (FontRenderIndex_T)ft->n_render; ++i) {