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feat(rendering): stroked text

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maelstrom 2025-07-13 16:12:28 +02:00
parent acc1f93f27
commit a75119a8c2
2 changed files with 64 additions and 31 deletions
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92
core/src/rendering/font.cpp
View file

@ -10,6 +10,7 @@
#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_STROKER_H
// https://learnopengl.com/In-Practice/Text-Rendering
@ -52,6 +53,34 @@ void fontFinish() {
}
}
static void loadCharTexture(FT_Face& face, FT_BitmapGlyph& glyph_bitmap, Character& character) {
// Generate texture
unsigned int texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(
GL_TEXTURE_2D,
0,
GL_RED,
glyph_bitmap->bitmap.width,
glyph_bitmap->bitmap.rows,
0,
GL_RED,
GL_UNSIGNED_BYTE,
glyph_bitmap->bitmap.buffer
);
// set texture options
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// now store character for later use
character.ID = texture;
character.size = glm::ivec2(glyph_bitmap->bitmap.width, glyph_bitmap->bitmap.rows);
character.bearing = glm::ivec2(glyph_bitmap->left, glyph_bitmap->top);
character.advance = (unsigned int)face->glyph->advance.x;
}
std::shared_ptr<Font> loadFont(std::string fontName) {
std::string fontPath = "assets/font/" + fontName;
@ -66,50 +95,53 @@ std::shared_ptr<Font> loadFont(std::string fontName) {
FT_Set_Pixel_Sizes(face, 0, 16);
font->height = face->size->metrics.y_ppem;
FT_Stroker stroker;
FT_Stroker_New(freetype, &stroker);
FT_Stroker_Set(stroker, 2 * 64, FT_STROKER_LINECAP_ROUND, FT_STROKER_LINEJOIN_ROUND, 0);
// Load each glyph
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
for (unsigned char c = 0; c < 128; c++) {
// load character glyph
if (FT_Error err = FT_Load_Char(face, c, FT_LOAD_RENDER)) {
if (FT_Error err = FT_Load_Char(face, c, FT_LOAD_DEFAULT)) {
Logger::errorf("Failed to load glyph %d in font '%s': [%d]", c, fontName.c_str(), err);
continue;
}
// Generate texture
unsigned int texture;
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(
GL_TEXTURE_2D,
0,
GL_RED,
face->glyph->bitmap.width,
face->glyph->bitmap.rows,
0,
GL_RED,
GL_UNSIGNED_BYTE,
face->glyph->bitmap.buffer
);
// set texture options
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// now store character for later use
FT_Glyph glyph;
FT_BitmapGlyph glyph_bitmap;
Character character;
character.ID = texture;
character.size = glm::ivec2(face->glyph->bitmap.width, face->glyph->bitmap.rows);
character.bearing = glm::ivec2(face->glyph->bitmap_left, face->glyph->bitmap_top);
character.advance = (unsigned int)face->glyph->advance.x;
font->characters[c] = character;
}
// Render base
FT_Get_Glyph(face->glyph, &glyph);
FT_Glyph_To_Bitmap(&glyph, FT_RENDER_MODE_NORMAL, nullptr, true);
glyph_bitmap = (FT_BitmapGlyph)glyph;
loadCharTexture(face, glyph_bitmap, character);
font->characters[c] = character;
FT_Done_Glyph(glyph);
// TODO: Find out how to clear FT_BitmapGlyph... I cant import FT_Bitmap_Done for some reason
// Render stroked
// https://stackoverflow.com/a/28078293/16255372
FT_Get_Glyph(face->glyph, &glyph);
FT_Glyph_StrokeBorder(&glyph, stroker, false, true);
FT_Glyph_To_Bitmap(&glyph, FT_RENDER_MODE_NORMAL, nullptr, true);
glyph_bitmap = reinterpret_cast<FT_BitmapGlyph>(glyph);
loadCharTexture(face, glyph_bitmap, character);
font->strokeCharacters[c] = character;
FT_Done_Glyph(glyph);
}
FT_Stroker_Done(stroker);
FT_Done_Face(face);
return font;
}
void drawText(std::shared_ptr<Font> font, std::string text, float x, float y, float scale, glm::vec3 color) {
void drawText(std::shared_ptr<Font> font, std::string text, float x, float y, float scale, glm::vec3 color, bool drawStroke) {
// activate corresponding render state
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
@ -129,7 +161,7 @@ void drawText(std::shared_ptr<Font> font, std::string text, float x, float y, fl
// iterate through all characters
for (size_t i = 0; i < text.size(); i++) {
unsigned char c = text[i];
Character ch = font->characters[c];
Character ch = drawStroke ? font->strokeCharacters[c] : font->characters[c];
float xpos = x + ch.bearing.x * scale;
float ypos = viewportHeight - y - font->height - (ch.size.y - ch.bearing.y) * scale;

3
core/src/rendering/font.h
View file

@ -16,10 +16,11 @@ struct Character {
struct Font {
unsigned int height;
Character characters[128];
Character strokeCharacters[128];
};
void fontInit();
void fontFinish();
std::shared_ptr<Font> loadFont(std::string fontName);
void drawText(std::shared_ptr<Font> font, std::string text, float x, float y, float scale=1.f, glm::vec3 color = glm::vec3(1,1,1));
void drawText(std::shared_ptr<Font> font, std::string text, float x, float y, float scale=1.f, glm::vec3 color = glm::vec3(1,1,1), bool drawStroke = false);
float calcTextWidth(std::shared_ptr<Font> font, std::string text, float scale = 1.f);