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text_renderer.c
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text_renderer.c
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#include "drawable.h"
#include "text_renderer.h"
#include "utf8.h"
static text_renderer_cell_p find_free_cell_or_revoke_unused_cell(text_renderer_p renderer, text_renderer_font_p font, uint32_t glyph_width, uint32_t glyph_height, uint32_t texture_width, uint32_t texture_height, size_t* line_idx, size_t* cell_idx);
void text_renderer_new(text_renderer_p renderer, size_t texture_width, size_t texture_height) {
FT_Error error = FT_Init_FreeType(&renderer->freetype);
if (error) {
printf("FT_Init_FreeType error\n");
return;
}
renderer->texture = texture_new(texture_width, texture_height, GL_R8);
size_t black_data_size = texture_width * texture_height;
void* black_data = malloc(black_data_size);
memset(black_data, 0, black_data_size);
texture_update(renderer->texture, GL_RED, black_data);
free(black_data);
glBindTexture(GL_TEXTURE_RECTANGLE, renderer->texture);
glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_RECTANGLE, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glBindTexture(GL_TEXTURE_RECTANGLE, 0);
renderer->fonts = hash_of(text_renderer_font_t);
renderer->lines = array_of(text_renderer_line_t);
}
void text_renderer_destroy(text_renderer_p renderer) {
texture_destroy(renderer->texture);
for(size_t i = 0; i < renderer->lines->length; i++)
array_destroy( array_elem(renderer->lines, text_renderer_line_t, i).cells );
array_destroy(renderer->lines);
for(hash_elem_t e = hash_start(renderer->fonts); e != NULL; e = hash_next(renderer->fonts, e))
text_renderer_font_destroy(renderer, hash_key(e));
hash_destroy(renderer->fonts);
FT_Error error = FT_Done_FreeType(renderer->freetype);
if (error)
printf("FT_Done_FreeType error\n");
}
int32_t text_renderer_font_new(text_renderer_p renderer, const char* font_path, size_t font_size) {
int32_t handle = renderer->fonts->length;
text_renderer_font_p font = hash_put_ptr(renderer->fonts, handle);
FT_Error error = FT_New_Face(renderer->freetype, font_path, 0, &font->face);
if (error) {
printf("FT_New_Face error\n");
goto failed_new_face;
}
error = FT_Set_Pixel_Sizes(font->face, 0, font_size);
if (error) {
printf("FT_Set_Pixel_Size error\n");
goto failed_set_pixel_size;
}
font->cell_refs = hash_of(text_renderer_cell_ref_t);
return handle;
failed_set_pixel_size:
FT_Done_Face(font->face);
failed_new_face:
hash_remove(renderer->fonts, handle);
return -1;
}
void text_renderer_font_destroy(text_renderer_p renderer, int32_t font_handle) {
text_renderer_font_p font = hash_get_ptr(renderer->fonts, font_handle);
if (!font)
return;
// TODO: mark all cells of this font as free
FT_Done_Face(font->face);
hash_destroy(font->cell_refs);
hash_remove(renderer->fonts, font_handle);
}
void text_renderer_prepare(text_renderer_p renderer, int32_t font_handle, uint32_t range_start, uint32_t range_end) {
text_renderer_font_p font = hash_get_ptr(renderer->fonts, font_handle);
if (!font)
return;
glBindTexture(GL_TEXTURE_RECTANGLE, renderer->texture);
// Lookup the size of our texture (needed by find_free_cell_or_revoke_unused_cell() for some checks)
GLint texture_width = 0, texture_height = 0;
glGetTexLevelParameteriv(GL_TEXTURE_RECTANGLE, 0, GL_TEXTURE_WIDTH, &texture_width);
glGetTexLevelParameteriv(GL_TEXTURE_RECTANGLE, 0, GL_TEXTURE_HEIGHT, &texture_height);
GLint unpack_alignment = 0;
glGetIntegerv(GL_UNPACK_ALIGNMENT, &unpack_alignment);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
for(uint32_t code_point = range_start; code_point <= range_end; code_point++) {
// Handle line break.
if (code_point == '\n') {
continue;
}
// Look if this glyph is present in the texture. If so this font has a cell reference
// for this code point.
text_renderer_cell_ref_p cell_ref = hash_get_ptr(font->cell_refs, code_point);
// Glyph not rendered yet, try to render it
if (!cell_ref) {
uint32_t glyph_index = FT_Get_Char_Index(font->face, code_point);
if (glyph_index == 0)
continue;
FT_Error error = FT_Load_Glyph(font->face, glyph_index, FT_LOAD_RENDER);
if (error)
continue;
// Look for a free cell to store the rendered glyph
uint32_t gw = font->face->glyph->bitmap.width, gh = font->face->glyph->bitmap.rows;
size_t line_idx = 0, cell_idx = 0;
text_renderer_cell_p free_cell = find_free_cell_or_revoke_unused_cell(renderer, font, gw, gh, texture_width, texture_height, &line_idx, &cell_idx);
if (free_cell == NULL)
continue;
free_cell->glyph_index = glyph_index;
free_cell->hori_bearing_x = font->face->glyph->metrics.horiBearingX / 64;
free_cell->hori_bearing_y = font->face->glyph->metrics.horiBearingY / 64;
free_cell->hori_advance = font->face->glyph->metrics.horiAdvance / 64;
/*
printf("%3u %c: %2ux%2u %3u bytes, pitch %2u, pos %3u/%3u hori_bearing: %2d/%2d, adv: %2d\n",
code_point, code_point, gw, gh, gw*gh, font->face->glyph->bitmap.pitch,
free_cell->x, free_cell->y, free_cell->hori_bearing_x, free_cell->hori_bearing_y, free_cell->hori_advance);
*/
glPixelStorei(GL_UNPACK_ROW_LENGTH, font->face->glyph->bitmap.pitch);
glTexSubImage2D(GL_TEXTURE_RECTANGLE, 0, free_cell->x, free_cell->y, gw, gh, GL_RED, GL_UNSIGNED_BYTE, font->face->glyph->bitmap.buffer);
cell_ref = hash_put_ptr(font->cell_refs, code_point);
cell_ref->line_idx = line_idx;
cell_ref->cell_idx = cell_idx;
}
}
glPixelStorei(GL_UNPACK_ALIGNMENT, unpack_alignment);
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
glBindTexture(GL_TEXTURE_RECTANGLE, 0);
}
size_t text_renderer_render(text_renderer_p renderer, int32_t font_handle, char* text, size_t x, size_t y, float* buffer_ptr, size_t buffer_size) {
text_renderer_font_p font = hash_get_ptr(renderer->fonts, font_handle);
if (!font)
return 0;
// The current position is the baseline of the text so start one line down
// from the position. Otherwise we would render above it.
size_t pos_x = x, pos_y = y + (font->face->size->metrics.height / 64);
float* p = buffer_ptr;
FT_UInt glyph_index = 0, prev_glyph_index = 0;
glBindTexture(GL_TEXTURE_RECTANGLE, renderer->texture);
// Lookup the size of our texture (needed by find_free_cell_or_revoke_unused_cell() for some checks)
GLint texture_width = 0, texture_height = 0;
glGetTexLevelParameteriv(GL_TEXTURE_RECTANGLE, 0, GL_TEXTURE_WIDTH, &texture_width);
glGetTexLevelParameteriv(GL_TEXTURE_RECTANGLE, 0, GL_TEXTURE_HEIGHT, &texture_height);
GLint unpack_alignment = 0;
glGetIntegerv(GL_UNPACK_ALIGNMENT, &unpack_alignment);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
for(utf8_iterator_t it = utf8_first(text); it.code_point != 0; it = utf8_next(it)) {
// Handle line break.
if (it.code_point == '\n') {
pos_y += font->face->size->metrics.height / 64;
pos_x = x;
// Don't do kerning at the next character after the line break.
prev_glyph_index = 0;
continue;
}
// Look if this glyph is present in the texture. If so this font has a cell reference
// for this code point.
text_renderer_cell_ref_p cell_ref = hash_get_ptr(font->cell_refs, it.code_point);
// Glyph not rendered yet, try to render it
if (!cell_ref) {
glyph_index = FT_Get_Char_Index(font->face, it.code_point);
if (glyph_index == 0)
goto render_error_glyph;
FT_Error error = FT_Load_Glyph(font->face, glyph_index, FT_LOAD_RENDER);
if (error)
goto render_error_glyph;
// Look for a free cell to store the rendered glyph
uint32_t gw = font->face->glyph->bitmap.width, gh = font->face->glyph->bitmap.rows;
size_t line_idx = 0, cell_idx = 0;
text_renderer_cell_p free_cell = find_free_cell_or_revoke_unused_cell(renderer, font, gw, gh, texture_width, texture_height, &line_idx, &cell_idx);
if (free_cell == NULL)
goto render_error_glyph;
free_cell->glyph_index = glyph_index;
free_cell->hori_bearing_x = font->face->glyph->metrics.horiBearingX / 64;
free_cell->hori_bearing_y = font->face->glyph->metrics.horiBearingY / 64;
free_cell->hori_advance = font->face->glyph->metrics.horiAdvance / 64;
/*
printf("%c: %2ux%2u %2u bytes, pitch %u, x: %u, y: %u hori_bearing: %2u/%2u, adv: %2u\n",
it.code_point, gw, gh, gw*gh, font->face->glyph->bitmap.pitch,
free_cell->x, free_cell->y, free_cell->hori_bearing_x, free_cell->hori_bearing_y, free_cell->hori_advance);
*/
glPixelStorei(GL_UNPACK_ROW_LENGTH, font->face->glyph->bitmap.pitch);
glTexSubImage2D(GL_TEXTURE_RECTANGLE, 0, free_cell->x, free_cell->y, gw, gh, GL_RED, GL_UNSIGNED_BYTE, font->face->glyph->bitmap.buffer);
cell_ref = hash_put_ptr(font->cell_refs, it.code_point);
cell_ref->line_idx = line_idx;
cell_ref->cell_idx = cell_idx;
}
// Glyph rendered successfully, do kerning and generate vertices for it
text_renderer_line_t line = array_elem(renderer->lines, text_renderer_line_t, cell_ref->line_idx);
text_renderer_cell_t cell = array_elem(line.cells, text_renderer_cell_t, cell_ref->cell_idx);
if (cell.glyph_index && prev_glyph_index) {
FT_Vector delta;
FT_Get_Kerning(font->face, prev_glyph_index, glyph_index, FT_KERNING_DEFAULT, &delta);
pos_x += delta.x / 64;
}
// We have the texture coordinates of the glyph, generate the vertex buffer
if ( (p + 6*4 - buffer_ptr) * sizeof(float) < buffer_size ) {
float w = cell.width, h = line.height;
float cx = pos_x + cell.hori_bearing_x;
float cy = pos_y - cell.hori_bearing_y;
float tl_x = cx + 0, tl_y = cy + 0, tl_u = cell.x, tl_v = cell.y;
float tr_x = cx + w, tr_y = cy + 0, tr_u = cell.x + w, tr_v = cell.y;
float bl_x = cx + 0, bl_y = cy + h, bl_u = cell.x, bl_v = cell.y + h;
float br_x = cx + w, br_y = cy + h, br_u = cell.x + w, br_v = cell.y + h;
*(p++) = tl_x; *(p++) = tl_y; *(p++) = tl_u; *(p++) = tl_v;
*(p++) = tr_x; *(p++) = tr_y; *(p++) = tr_u; *(p++) = tr_v;
*(p++) = bl_x; *(p++) = bl_y; *(p++) = bl_u; *(p++) = bl_v;
*(p++) = tr_x; *(p++) = tr_y; *(p++) = tr_u; *(p++) = tr_v;
*(p++) = br_x; *(p++) = br_y; *(p++) = br_u; *(p++) = br_v;
*(p++) = bl_x; *(p++) = bl_y; *(p++) = bl_u; *(p++) = bl_v;
pos_x += cell.hori_advance;
}
prev_glyph_index = glyph_index;
continue;
render_error_glyph:
// For now just output nothing when we fail to render a glyph.
// TODO: Figure out how to render a kind of error glyph.
prev_glyph_index = glyph_index;
continue;
}
glPixelStorei(GL_UNPACK_ALIGNMENT, unpack_alignment);
glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
glBindTexture(GL_TEXTURE_RECTANGLE, 0);
return (p - buffer_ptr) * sizeof(float);
}
static text_renderer_cell_p find_free_cell_or_revoke_unused_cell(text_renderer_p renderer, text_renderer_font_p font, uint32_t glyph_width, uint32_t glyph_height, uint32_t texture_width, uint32_t texture_height, size_t* line_idx, size_t* cell_idx) {
// Padding between the glyphs
const uint32_t padding = 1;
// Keep track of the texture coordinates so we know where our cell is on the texture
uint32_t x = 0, y = 0;
// First search for a line with the matching height
for(size_t i = 0; i < renderer->lines->length; i++) {
text_renderer_line_p line = &array_data(renderer->lines, text_renderer_line_t)[i];
if (line->height == glyph_height) {
// We found a line with matching height, now look if we can get our cell in there
x = 0;
for(size_t j = 0; j < line->cells->length; j++) {
text_renderer_cell_p current_cell = array_elem_ptr(line->cells, j);
x += current_cell->width + padding;
}
if (x + glyph_width <= texture_width) {
// There is space left at the end of this line, add our cell here
text_renderer_cell_p cell = array_append_ptr(line->cells);
memset(cell, 0, sizeof(text_renderer_cell_t));
cell->x = x;
cell->y = y;
cell->width = glyph_width;
*line_idx = i;
*cell_idx = line->cells->length - 1;
return cell;
}
// No space at end of line, search next line
}
y += line->height + padding;
}
// We haven't found a matching line or every matching line was full. Anyway add a new line
// if there is space left at the bottom of the texture and put the cell in there.
if (y + glyph_height + padding <= texture_height) {
text_renderer_line_p line = array_append_ptr(renderer->lines);
line->height = glyph_height;
line->cells = array_of(text_renderer_cell_t);
text_renderer_cell_p cell = array_append_ptr(line->cells);
memset(cell, 0, sizeof(text_renderer_cell_t));
cell->x = x;
cell->y = y;
cell->width = glyph_width;
*line_idx = renderer->lines->length - 1;
*cell_idx = 0;
return cell;
}
// We would like to add a new line but there is not enough free space at the bottom
// to the texture. For now just give up.
*line_idx = (size_t)-1;
*cell_idx = (size_t)-1;
return NULL;
}