added dev/MinGfx/

1 files changed, 238 insertions, 0 deletions

diff --git a/dev/MinGfx/src/text_shader.cc b/dev/MinGfx/src/text_shader.cc
new file mode 100644
index 0000000..ca99953
--- /dev/null
+++ b/dev/MinGfx/src/text_shader.cc
@@ -0,0 +1,238 @@
+/*
+ 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
\ No newline at end of file