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/*
Copyright (c) 2017,2018 Regents of the University of Minnesota.
All Rights Reserved.
See corresponding header file for details.
*/
#include "text_shader.h"
#include "platform.h"
#include <fstream>
// disable warnings for this 3rd party code
#pragma warning (push, 0)
#define STB_RECT_PACK_IMPLEMENTATION
#include "stb_rect_pack.h"
#define STB_TRUETYPE_IMPLEMENTATION
#include <stb_truetype.h>
#pragma warning (pop)
namespace mingfx {
// Reference implementation: https://github.com/nothings/stb/blob/master/tests/oversample/main.c
TextShader::TextShader() : native_font_size_(0.0)
{
for (int i = 0; i < 128; i++) {
chardata_[i] = stbtt_packedchar();
}
}
TextShader::~TextShader() {
}
bool TextShader::Init(const std::string &filename, int font_size) {
// load shader
shader_.AddVertexShaderFromFile(Platform::FindMinGfxShaderFile("text.vert"));
shader_.AddFragmentShaderFromFile(Platform::FindMinGfxShaderFile("text.frag"));
shader_.LinkProgram();
// load font
native_font_size_ = (float)font_size;
std::ifstream is(filename.c_str(), std::ifstream::binary);
if (is) {
is.seekg(0, is.end);
int length = (int)is.tellg();
is.seekg(0, is.beg);
char *ttf_buffer = new char[length];
is.read(ttf_buffer, length);
if (is)
std::cout << "all characters read successfully.";
else
std::cout << "error: only " << is.gcount() << " could be read";
is.close();
// todo: calc an appropriate pow of 2 size given the font_size
int atlas_width = 1024;
int atlas_height = 1024;
stbtt_pack_context pc;
unsigned char *bitmap = new unsigned char[(size_t)atlas_width * atlas_height];
stbtt_PackBegin(&pc, bitmap, atlas_width, atlas_height, 0, 1, NULL);
stbtt_PackSetOversampling(&pc, 2, 2);
stbtt_PackFontRange(&pc, (unsigned char*)ttf_buffer, 0, (float)font_size, 32, 95, chardata_+32);
stbtt_PackEnd(&pc);
// convert to 4-channel since that is all that Texture2D currently supports
unsigned char *bitmap4D = new unsigned char[(size_t)4 * atlas_width * atlas_height];
for (int i=0; i < atlas_width * atlas_height; i++) {
bitmap4D[4*i + 0] = bitmap[i];
bitmap4D[4*i + 1] = bitmap[i];
bitmap4D[4*i + 2] = bitmap[i];
bitmap4D[4*i + 3] = bitmap[i];
}
atlas_.InitFromBytes(atlas_width, atlas_height, bitmap4D);
delete [] ttf_buffer;
delete [] bitmap;
delete [] bitmap4D;
return true;
}
else {
std::cerr << "TextShader: Error font file does not exist: " << filename << std::endl;
return false;
}
}
void TextShader::Draw3D(const Matrix4 &model, const Matrix4 &view, const Matrix4 &projection,
const std::string &text, TextFormat format, bool cache)
{
MeshData *md = NULL;
std::map<std::string, MeshData>::iterator it = cache_.find(text);
if (it != cache_.end()) {
// use an existing cached mesh
md = &(it->second);
}
else {
// need to create a new mesh, add a new one to the cache or use the tmp_mesh
if (cache) {
MeshData new_md;
cache_[text] = new_md;
md = &(cache_[text]);
}
else {
md = &tmp_md_;
}
// set appropriate vertices and texcoords for this text string
SetTextMesh(text, md);
}
Vector3 offset;
if (format.h_align == HorizAlign::HORIZ_ALIGN_LEFT) {
offset[0] = 0;
}
else if (format.h_align == HorizAlign::HORIZ_ALIGN_CENTER) {
offset[0] = -0.5f * (md->max[0] - md->min[0]);
}
else if (format.h_align == HorizAlign::HORIZ_ALIGN_RIGHT) {
offset[0] = -(md->max[0] - md->min[0]);
}
if (format.v_align == VertAlign::VERT_ALIGN_TOP) {
offset[1] = -md->max[1];
}
else if (format.v_align == VertAlign::VERT_ALIGN_CENTER) {
offset[1] = -0.5f * md->max[1];
}
else if (format.v_align == VertAlign::VERT_ALIGN_BASELINE) {
offset[1] = 0;
}
else if (format.v_align == VertAlign::VERT_ALIGN_BOTTOM) {
offset[1] = -md->min[1];
}
glDisable(GL_CULL_FACE);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
shader_.UseProgram();
Matrix4 mvp = projection * view * model;
shader_.SetUniform("mvp_matrix", mvp);
shader_.SetUniform("scale", format.size / native_font_size_);
shader_.SetUniform("offset", offset);
shader_.SetUniform("color", format.color);
shader_.BindTexture("font_atlas", atlas_);
md->mesh.Draw();
shader_.StopProgram();
glEnable(GL_CULL_FACE);
}
void TextShader::SetTextMesh(const std::string &text, MeshData *md) {
std::vector<Point3> verts;
std::vector<Point2> uvs;
std::vector<unsigned int> indices;
const char *c = text.c_str();
float x = 0.0;
float y = 0.0;
while (*c) {
stbtt_aligned_quad q;
stbtt_GetPackedQuad(chardata_, atlas_.width(), atlas_.height(), *c++, &x, &y, &q, 0);
// top left
verts.push_back(Point3(q.x0, -q.y0, 0.0));
uvs.push_back(Point2(q.s0, q.t0));
// top right
verts.push_back(Point3(q.x1, -q.y0, 0.0));
uvs.push_back(Point2(q.s1, q.t0));
// bot right
verts.push_back(Point3(q.x1, -q.y1, 0.0));
uvs.push_back(Point2(q.s1, q.t1));
// bot left
verts.push_back(Point3(q.x0, -q.y1, 0.0));
uvs.push_back(Point2(q.s0, q.t1));
indices.push_back((unsigned int)verts.size()-2);
indices.push_back((unsigned int)verts.size()-3);
indices.push_back((unsigned int)verts.size()-4);
indices.push_back((unsigned int)verts.size()-2);
indices.push_back((unsigned int)verts.size()-4);
indices.push_back((unsigned int)verts.size()-1);
}
md->mesh.SetVertices(verts);
md->mesh.SetTexCoords(0, uvs);
md->mesh.SetIndices(indices);
md->min = Point2(verts[0][0], verts[0][1]);
md->max = md->min;
for (int i=0; i<verts.size(); i++) {
Point3 p = verts[i];
if (p[0] < md->min[0]) md->min[0] = p[0];
if (p[0] > md->max[0]) md->max[0] = p[0];
if (p[1] < md->min[1]) md->min[1] = p[1];
if (p[1] > md->max[1]) md->max[1] = p[1];
}
}
Vector2 TextShader::TextExtents(const std::string &text, TextFormat format, bool cache) {
MeshData *md = NULL;
std::map<std::string, MeshData>::iterator it = cache_.find(text);
if (it != cache_.end()) {
// use an existing cached mesh
md = &(it->second);
}
else {
// need to create a new mesh, add a new one to the cache or use the tmp_mesh
if (cache) {
MeshData new_md;
cache_[text] = new_md;
md = &(cache_[text]);
}
else {
md = &tmp_md_;
}
// set appropriate vertices and texcoords for this text string
SetTextMesh(text, md);
}
return format.size / native_font_size_ * (md->max - md->min);
}
} // end namespace
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