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#include "font.h"
#include <stdio.h>
#define STB_TRUETYPE_IMPLEMENTATION
#include "3rdparty/stb/stb_truetype.h"
#include "color.h"
namespace jin
{
namespace render
{
#define BITMAP_WIDTH 512
#define BITMAP_HEIGHT 512
#define PIXEL_HEIGHT 32
Font::Font():Drawable()
{
}
// ttf file read buffer
static unsigned char ttf_buffer[1 << 20];
// bitmap for saving font data
static unsigned char temp_bitmap[BITMAP_WIDTH * BITMAP_HEIGHT];
void Font::loadf(const char* path)
{
fread(ttf_buffer, 1, 1 << 20, fopen(path, "rb"));
loadb(ttf_buffer);
}
/**
* load from memory
*/
void Font::loadb(const unsigned char* data)
{
stbtt_BakeFontBitmap(data, 0, PIXEL_HEIGHT, temp_bitmap, BITMAP_WIDTH, BITMAP_HEIGHT, 32, 96, cdata);
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, BITMAP_WIDTH,
BITMAP_HEIGHT, 0, GL_ALPHA, GL_UNSIGNED_BYTE, temp_bitmap);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glBindTexture(GL_TEXTURE_2D, 0);
}
/**
* get texture quad
*/
static Quad getCharQuad(const stbtt_bakedchar* chardata, int pw, int ph, int char_index)
{
float ipw = 1.0f / pw, iph = 1.0f / ph;
const stbtt_bakedchar *b = chardata + char_index;
Quad q;
q.x = b->x0 * ipw;
q.y = b->y0 * iph;
q.w = b->x1 * ipw - b->x0 * ipw;
q.h = b->y1 * iph - b->y0 * iph;
return q;
}
/**
* render function draw mutiple times
* in loop
*/
void Font::render(
const char* text, // rendered text
float x, float y, // render position
int fheight, // font height
int spacing, // font spacing
int lheight) // line height
{
float _x = x,
_y = y;
int len = strlen(text);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
// for saving clip quad
stbtt_aligned_quad q;
// render every given character
int xc = x;
int yc = y;
float factor = fheight / (float)PIXEL_HEIGHT;
for (int i = 0; i < len; ++i)
{
char c = text[i];
if (c == '\n')
{
xc = x;
yc += lheight;
continue;
}
// only support ASCII
Quad q = getCharQuad(cdata, 512, 512, c - 32);
float s0 = q.x,
s1 = q.x + q.w,
t0 = q.y,
t1 = q.y + q.h;
// texture quad
float tc[] = {
s0, t1,
s1, t1,
s1, t0,
s0, t0
};
// character bound box
stbtt_bakedchar box = cdata[c - 32];
float width = factor * (box.x1 - box.x0);
float height = factor * (box.y1 - box.y0);
float xoffset = factor * box.xoff;
// I don't know why add PIXEL_HEIGHT to box.yoff, but
// it works.
float yoffset = factor * (box.yoff + PIXEL_HEIGHT);
float xadvance = factor * box.xadvance;
// render quad
float vc[] = {
xc + xoffset, yc + height + yoffset,
xc + width + xoffset, yc + height + yoffset,
xc + width + xoffset, yc + yoffset,
xc + xoffset, yc + yoffset
};
// forward to next character
xc += xadvance + spacing;
glTexCoordPointer(2, GL_FLOAT, 0, tc);
glVertexPointer(2, GL_FLOAT, 0, vc);
glDrawArrays(GL_QUADS, 0, 4);
}
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
glBindTexture(GL_TEXTURE_2D, 0);
glDisable(GL_TEXTURE_2D);
}
void Font::box(const char* str, int fheight, int spacing, int lheight, int* w, int * h)
{
int len = strlen(str);
float xc = 0;
int yc = len ? lheight: 0;
int maxX = 0;
float factor = fheight / (float)PIXEL_HEIGHT;
for (int i = 0; i < len; ++i)
{
char c = str[i];
if (c == '\n')
{
yc += lheight;
xc = 0;
continue;
}
stbtt_bakedchar box = cdata[c - 32];
xc += factor * box.xadvance + spacing;
if (xc > maxX) maxX = xc;
}
*w = maxX;
*h = yc;
}
}
}
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