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#include "../../include/mgl/graphics/text.h"
#include "../../include/mgl/graphics/font.h"
#include "../../include/mgl/system/utf8.h"
#include "../../include/mgl/window/window.h"
#include "../../include/mgl/mgl.h"
#include <stdio.h>
/* TODO: Cache mgl_font_get_glyph */
#define TAB_WIDTH 4
/* Return false to stop the loop. |glyph| is not valid if codepoint is '\n' */
typedef bool (*codepoint_loop_callback)(size_t codepoint_index, uint32_t codepoint, const mgl_font_glyph *glyph, void *userdata);
static void mgl_text_for_each_codepoint(const mgl_text *self, codepoint_loop_callback callback, void *userdata) {
mgl_font_glyph glyph;
size_t codepoint_index = 0;
for(size_t i = 0; i < self->text_size;) {
unsigned char *cp = (unsigned char*)&self->text[i];
uint32_t codepoint;
size_t clen;
if(!mgl_utf8_decode(cp, self->text_size - i, &codepoint, &clen)) {
codepoint = *cp;
clen = 1;
}
if(codepoint == '\t') {
if(mgl_font_get_glyph(self->font, ' ', &glyph) == 0) {
if(!callback(codepoint_index, codepoint, &glyph, userdata))
return;
}
} else if(codepoint == '\n') {
if(!callback(codepoint_index, codepoint, &glyph, userdata))
return;
} else {
if(mgl_font_get_glyph(self->font, codepoint, &glyph) == 0) {
if(!callback(codepoint_index, codepoint, &glyph, userdata))
return;
}
}
i += clen;
++codepoint_index;
}
}
static float max_float(float a, float b) {
return a >= b ? a : b;
}
typedef struct {
mgl_vec2f bounds;
float line_width;
const mgl_font *font;
uint32_t prev_codepoint;
} CalculateBoundsUserdata;
static bool calculate_bounds_callback(size_t codepoint_index, uint32_t codepoint, const mgl_font_glyph *glyph, void *userdata) {
(void)codepoint_index;
CalculateBoundsUserdata *calculate_bounds_userdata = userdata;
if(codepoint == '\t') {
calculate_bounds_userdata->line_width += (glyph->advance * TAB_WIDTH) + mgl_font_get_kerning(calculate_bounds_userdata->font, calculate_bounds_userdata->prev_codepoint, codepoint);
calculate_bounds_userdata->bounds.x = max_float(calculate_bounds_userdata->bounds.x, calculate_bounds_userdata->line_width);
} else if(codepoint == '\n') {
calculate_bounds_userdata->line_width = 0.0f;
calculate_bounds_userdata->bounds.y += calculate_bounds_userdata->font->character_size;
calculate_bounds_userdata->prev_codepoint = 0;
} else {
calculate_bounds_userdata->line_width += glyph->advance + mgl_font_get_kerning(calculate_bounds_userdata->font, calculate_bounds_userdata->prev_codepoint, codepoint);
calculate_bounds_userdata->bounds.x = max_float(calculate_bounds_userdata->bounds.x, calculate_bounds_userdata->line_width);
}
calculate_bounds_userdata->prev_codepoint = codepoint;
return true;
}
static mgl_vec2f mgl_text_calculate_bounds(mgl_text *self) {
CalculateBoundsUserdata calculate_bounds_userdata;
calculate_bounds_userdata.bounds.x = 0.0f;
calculate_bounds_userdata.bounds.y = self->font->character_size;
calculate_bounds_userdata.line_width = 0.0f;
calculate_bounds_userdata.font = self->font;
calculate_bounds_userdata.prev_codepoint = 0;
mgl_text_for_each_codepoint(self, calculate_bounds_callback, &calculate_bounds_userdata);
return calculate_bounds_userdata.bounds;
}
void mgl_text_init(mgl_text *self, mgl_font *font, const char *str, size_t str_size) {
self->font = font;
self->color = (mgl_color){ 255, 255, 255, 255 };
self->position = (mgl_vec2f){ 0.0f, 0.0f };
self->text = NULL;
self->text_size = 0;
self->bounds_dirty = true;
mgl_text_set_string(self, str, str_size);
}
void mgl_text_deinit(mgl_text *self) {
self->font = NULL;
self->position = (mgl_vec2f){ 0.0f, 0.0f };
self->text = NULL;
self->text_size = 0;
self->bounds = (mgl_vec2f){ 0.0f, 0.0f };
}
void mgl_text_set_string(mgl_text *self, const char *str, size_t str_size) {
self->text = str;
self->text_size = str_size;
self->bounds_dirty = true;
}
void mgl_text_set_font(mgl_text *self, mgl_font *font) {
self->font = font;
self->bounds_dirty = true;
}
void mgl_text_set_position(mgl_text *self, mgl_vec2f position) {
self->position = position;
}
void mgl_text_set_color(mgl_text *self, mgl_color color) {
self->color = color;
}
mgl_vec2f mgl_text_get_bounds(mgl_text *self) {
if(self->bounds_dirty) {
self->bounds_dirty = false;
if(self->text && self->text_size > 0 && self->font)
self->bounds = mgl_text_calculate_bounds(self);
else if(self->font)
self->bounds = (mgl_vec2f){ 0.0f, (float)self->font->character_size };
else
self->bounds = (mgl_vec2f){ 0.0f, 0.0f };
}
return self->bounds;
}
typedef struct {
mgl_vec2f position;
const mgl_text *text;
size_t index;
uint32_t prev_codepoint;
} FindCharacterPosUserdata;
static bool find_character_pos_callback(size_t codepoint_index, uint32_t codepoint, const mgl_font_glyph *glyph, void *userdata) {
FindCharacterPosUserdata *find_character_pos_userdata = userdata;
if(codepoint_index >= find_character_pos_userdata->index)
return false;
if(codepoint == '\t') {
find_character_pos_userdata->position.x += (glyph->advance * TAB_WIDTH) + mgl_font_get_kerning(find_character_pos_userdata->text->font, find_character_pos_userdata->prev_codepoint, codepoint);
} else if(codepoint == '\n') {
find_character_pos_userdata->position.x = find_character_pos_userdata->text->position.x;
find_character_pos_userdata->position.y += find_character_pos_userdata->text->font->character_size;
find_character_pos_userdata->prev_codepoint = 0;
} else {
find_character_pos_userdata->position.x += glyph->advance + mgl_font_get_kerning(find_character_pos_userdata->text->font, find_character_pos_userdata->prev_codepoint, codepoint);
}
find_character_pos_userdata->prev_codepoint = codepoint;
return true;
}
mgl_vec2f mgl_text_find_character_pos(mgl_text *self, size_t index) {
FindCharacterPosUserdata find_character_pos_userdata;
find_character_pos_userdata.position = self->position;
find_character_pos_userdata.text = self;
find_character_pos_userdata.index = index;
find_character_pos_userdata.prev_codepoint = 0;
mgl_text_for_each_codepoint(self, find_character_pos_callback, &find_character_pos_userdata);
return (mgl_vec2f){ find_character_pos_userdata.position.x, find_character_pos_userdata.position.y };
}
static void mgl_text_draw_glyph(mgl_context *context, const mgl_font_glyph *glyph, mgl_vec2i position) {
context->gl.glTexCoord2f(glyph->texture_position.x, glyph->texture_position.y);
context->gl.glVertex3f(position.x + glyph->position.x, position.y + glyph->position.y, 0.0f);
context->gl.glTexCoord2f(glyph->texture_position.x + glyph->texture_size.x, glyph->texture_position.y);
context->gl.glVertex3f(position.x + glyph->position.x + glyph->size.x, position.y + glyph->position.y, 0.0f);
context->gl.glTexCoord2f(glyph->texture_position.x + glyph->texture_size.x, glyph->texture_position.y + glyph->texture_size.y);
context->gl.glVertex3f(position.x + glyph->position.x + glyph->size.x, position.y + glyph->position.y + glyph->size.y, 0.0f);
context->gl.glTexCoord2f(glyph->texture_position.x, glyph->texture_position.y + glyph->texture_size.y);
context->gl.glVertex3f(position.x + glyph->position.x, position.y + glyph->position.y + glyph->size.y, 0.0f);
}
typedef struct {
mgl_vec2f position;
const mgl_text *text;
mgl_context *context;
uint32_t prev_codepoint;
} TextDrawUserdata;
static bool text_draw_callback(size_t codepoint_index, uint32_t codepoint, const mgl_font_glyph *glyph, void *userdata) {
(void)codepoint_index;
TextDrawUserdata *text_draw_userdata = userdata;
if(codepoint == '\t') {
text_draw_userdata->position.x += (glyph->advance * TAB_WIDTH) + mgl_font_get_kerning(text_draw_userdata->text->font, text_draw_userdata->prev_codepoint, codepoint);
} else if(codepoint == '\n') {
text_draw_userdata->position.x = text_draw_userdata->text->position.x;
text_draw_userdata->position.y += text_draw_userdata->text->font->character_size;
text_draw_userdata->prev_codepoint = 0;
} else {
text_draw_userdata->position.x += mgl_font_get_kerning(text_draw_userdata->text->font, text_draw_userdata->prev_codepoint, codepoint);
mgl_text_draw_glyph(text_draw_userdata->context, glyph, (mgl_vec2i){ text_draw_userdata->position.x, text_draw_userdata->position.y });
text_draw_userdata->position.x += glyph->advance;
}
text_draw_userdata->prev_codepoint = codepoint;
return true;
}
/* TODO: Use opengl buffer object instead */
/* TODO: Cache texture bind to not bind texture if its already bound and do not bind texture 0 */
void mgl_text_draw(mgl_context *context, mgl_text *text) {
if(!text->text || text->text_size == 0 || !text->font)
return;
/* Calculate bounds beforehand if needed, which also generates glyphs because opengl outputs an error if that is done inside glBegin/glEnd */
/* TODO: Only run this on the new glyphs */
mgl_text_get_bounds(text);
TextDrawUserdata text_draw_userdata;
text_draw_userdata.position = (mgl_vec2f){ text->position.x, text->position.y };
text_draw_userdata.text = text;
text_draw_userdata.context = context;
text_draw_userdata.prev_codepoint = 0;
mgl_window_set_texture_blend_func(context->current_window);
context->gl.glColor4ub(text->color.r, text->color.g, text->color.b, text->color.a);
mgl_texture_use(&text->font->texture);
context->gl.glBegin(GL_QUADS);
mgl_text_for_each_codepoint(text, text_draw_callback, &text_draw_userdata);
context->gl.glEnd();
mgl_texture_use(NULL);
mgl_window_set_render_blend_func(context->current_window);
}
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