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text.cpp
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text.cpp
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#include <stdlib.h>
#include <malloc.h>
#include <string.h>
#include "cg2demo.h"
#include "text.h"
static const uint16_t text_combining_bit = 0x8000;
static const uint16_t text[] = {
// teapot
0x0BD8, 0xFFFF, 0xEFFE, 0xC4A0, 0,
// F L Y I N G
0x39A4, 0x4927, 0x5B52, 0x7497, 0x49AC, 0xC924, 0x3967, 0xC120, 0,
// T filler E A P O T
0x7492, 0x8000, 0x39A7, 0x3B7D, 0x3B74, 0x3927, 0xC920, 0x7492, 0,
// mushroom, mushroom
0x3E09, 0xCC00, 0x07C1, 0x8980, 0,
// [ M U S H R O O M ]
0x6926, 0x4D64, 0xAC92, 0x4927, 0xC920, 0x39C7, 0xE194, 0x49E4, 0xC924, 0x793C, 0x8904, 0x3927, 0xC920, 0x3927, 0xC920, 0x4D64, 0xAC92, 0x324B, 0,
};
static const size_t ntext = sizeof(text) / sizeof(*text);
static int kerndist(uint16_t prev, uint16_t next) {
if (next & text_combining_bit) {
return 3;
}
if (!prev || !next) {
return 0;
}
// maximum distance between edges is 6
// because each cell is 3px wide
int mindist = 6;
// each cell is 5 rows
// the rows are iterated backwards, i.e. upwards
// because it's easiest to do the checks
// to the last 3 bits
for (int i = 0; i < 5; i++) {
int dist = 0;
// check bits of prev from right to left
if (!(prev & 1)) {
dist++;
if (!(prev & 2)) {
dist++;
if (!(prev & 4)) {
dist++;
}
}
}
// check bits of next from left to right
if (!(next & 4)) {
dist++;
if (!(next & 2)) {
dist++;
if (!(next & 1)) {
dist++;
}
}
}
prev >>= 3;
next >>= 3;
if (dist < mindist) {
mindist = dist;
}
}
return 4 - mindist;
}
static void blitchar(uint8_t *img, int stride, uint16_t ch) {
for (int i = 0; i < 5; i++) {
img[0] = (ch & 0x4000) ? 0xFF : 0x00;
img[1] = (ch & 0x2000) ? 0xFF : 0x00;
img[2] = (ch & 0x1000) ? 0xFF : 0x00;
img += stride;
ch <<= 3;
}
}
static int pow2(int x) {
if (!(x & (x - 1))) {
return x;
}
while (x & (x - 1)) {
x = x & (x - 1);
}
return x << 1;
}
#if 0
static bool check_neighbour(uint8_t *mydist, uint8_t neighbourdist) {
if (neighbourdist == 255) {
return false;
}
if (*mydist > neighbourdist + 1) {
*mydist = neighbourdist + 1;
return true;
} else {
return false;
}
}
#endif
static const int line_height = 6;
int render_text(struct text_tex *tex) {
LOGF("Text bytes: %d", (int)sizeof(text));
int w = 0;
int h = 0;
size_t nlines = 0;
for (size_t i = 0; i < ntext; i++) {
int linew = 0;
uint16_t prev = 0;
for (; i < ntext && text[i]; i++) {
int dist = kerndist(prev, text[i]);
//LOGF("line %d, char %d-%d dist: %d", h, (int)(i - 1), (int)i, dist);
linew += dist;
prev = text[i];
}
linew += 3;
if (linew > w) {
w = linew;
}
h += line_height;
nlines++;
}
w = pow2(w);
h = pow2(h);
if (w < h) {
w = h;
}
if (h < w) {
h = w;
}
LOGF("Text texture width : %d; height: %d", w, h);
uint8_t *img = (uint8_t *)malloc(w * h);
if (!img) {
LOG("Error malloc");
return 0;
}
memset(img, 0, w * h);
for (size_t line = 0, i = 0; i < ntext && line < nlines; line++, i++) {
uint16_t prev = 0;
int linew = 0;
for (size_t j = i; j < ntext && text[j]; j++) {
linew += kerndist(prev, text[j]);
prev = text[j];
}
// 0x4924 - leftmost vertical bar
linew += kerndist(prev, 0x4924);
int x = (int)(w - linew + 1) / 2;
int y = (int)((h - nlines * line_height) / 2 + line * line_height);
prev = 0;
for (; i < ntext && text[i]; i++) {
int dist = kerndist(prev, text[i]);
x += dist;
blitchar(img + (h - y) * w + x, -w, text[i]);
prev = text[i];
}
}
#if 0
// unfortunately this is mostly bullshit
// now compute signed distance fields
bool changes = false;
do {
changes = false;
for (size_t y = 0; y < h; y++) {
for(size_t x = 0; x < w; x++) {
uint8_t *pmydist = img + y * w + x;
if (x > 0) {
changes = changes || check_neighbour(pmydist, img[y * w + (x - 1)]);
}
if (x < w) {
changes = changes || check_neighbour(pmydist, img[y * w + (x + 1)]);
}
if (y > 0) {
changes = changes || check_neighbour(pmydist, img[(y - 1) * w + x]);
}
if (y < h) {
changes = changes || check_neighbour(pmydist, img[(y + 1) * w + x]);
}
}
}
} while (changes);
#endif
// bloody awful hack for teapot lid
img[3103] = 0xFF;
#if !defined(NDEBUG)
FILE *imgraw = fopen("img.raw", "wb");
fwrite(img, 1, w * h, imgraw);
fclose(imgraw);
#endif
tex->width = w;
tex->height = h;
tex->data = img;
return 1;
}