testing bitmap font generation and draw using stb_truetype

data/layout.xml

@@ -3,21 +3,24 @@
   <layout id="button">
     <border width="50" margin="0 5 0 0" color=".1" thickness="2" border-color=".5"></border>
   </layout>
+  <layout id="multi-button-item">
+    <border height="50%" width="50%" color=".1" thickness="2" border-color=".5" />
+  </layout>
   <layout id="multi-button">
     <node width="50" margin="0 5 0 0" dir="row" wrap="1">
-      <border height="50%" width="50%" color=".1" thickness="2" border-color=".5" />
-      <border height="50%" width="50%" color=".1" thickness="2" border-color=".5" />
-      <border height="50%" width="50%" color=".1" thickness="2" border-color=".5" />
-      <border height="50%" width="50%" color=".1" thickness="2" border-color=".5" />
+      <ref id="multi-button-item"/>
+      <ref id="multi-button-item"/>
+      <ref id="multi-button-item"/>
+      <ref id="multi-button-item"/>
     </node>
   </layout>
   <layout id="main">
     <node dir="col" wrap="0" width="100%" height="100%" pad="5">
       <!-- toolbar -->
       <border height="50" width="100%" pad="5" dir="row" color=".2">
-        <ref id="multi-button"></ref>
-        <ref id="multi-button"></ref>
-        <ref id="multi-button"></ref>
+        <ref id="multi-button"/>
+        <ref id="multi-button"/>
+        <ref id="multi-button"/>
         <ref id="button"></ref>
         <border width="50" margin="0 5 0 0" color=".1" thickness="2" border-color="1"></border>
         <border width="50" margin="0 5 0 0" color=".2" thickness="2" border-color="1"></border>

engine/app.cpp

@@ -52,6 +52,26 @@ void App::init()
         "void main(){"
         "   frag = col;"
         "}";
+    static const char* shader_font_v =
+        "#version 150\n"
+        "uniform mat4 mvp;"
+        "uniform vec2 texoff;"
+        "uniform vec2 texsz;"
+        "in vec4 pos;"
+        "in vec2 uvs;"
+        "out vec2 uv;"
+        "void main(){"
+        "   uv = texoff + uvs * texsz;"
+        "   gl_Position = mvp * vec4(pos.xyz, 1.f);"
+        "}";
+    static const char* shader_font_f =
+        "#version 150\n"
+        "uniform sampler2D tex;"
+        "in vec2 uv;"
+        "out vec4 frag;"
+        "void main(){"
+        "   frag = texture(tex, uv.xy);"
+        "}";
 
 #ifdef _WIN32
     static CONSOLE_SCREEN_BUFFER_INFO info;
@@ -77,15 +97,34 @@ void App::init()
     layout.load("data/layout.xml");
     //layout["main"].update(width, height);
 
-    sampler.create();
+    sampler.create(GL_NEAREST);
     ShaderManager::create(kShader::Texture, shader_v, shader_f);
     ShaderManager::create(kShader::Color, shader_color_v, shader_color_f);
     ShaderManager::create(kShader::UVs, shader_v, shader_uv_f);
+    ShaderManager::create(kShader::Font, shader_font_v, shader_font_f);
     WidgetBorder::m_plane.create<1>(1, 1);
 
     if (!tex.load("data/uvs.jpg"))
         printf("error loading image\n");
 
+    FILE* font_file = fopen("C:\\Windows\\Fonts\\arial.ttf", "rb");
+    if (font_file)
+    {
+        fseek(font_file, 0, SEEK_END);
+        long sz = ftell(font_file);
+        auto data = std::make_unique<uint8_t[]>(sz);
+        fseek(font_file, 0, SEEK_SET);
+        int bytes = fread(data.get(), 1, sz, font_file);
+        int w = 512;
+        int h = 512;
+        int num_chars = 96;
+        auto bitmap = std::make_unique<uint8_t[]>(w*h);
+        chars.resize(num_chars);
+        int ret = stbtt_BakeFontBitmap(data.get(), 0, 50, bitmap.get(), w, h, 32, num_chars, chars.data());
+        font_tex.create(w, h, GL_RED, bitmap.get());
+    }
+    plane.create<1>(400, 400);
+    
     glEnable(GL_TEXTURE_2D);
     glDisable(GL_DEPTH_TEST);
     glPointSize(5);
@@ -120,12 +159,6 @@ void App::update(float dt)
         layout[main_id].update(width, height);
     }
 
-    glActiveTexture(GL_TEXTURE0);
-    tex.bind();
-    sampler.bind(0);
-    ShaderManager::use(kShader::Texture);
-    ShaderManager::u_int(kShaderUniform::Tex, 0);
-
     glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
     glEnable(GL_SCISSOR_TEST);
     for (auto& n : layout[main_id])
@@ -138,7 +171,29 @@ void App::update(float dt)
         }
     }
     glDisable(GL_SCISSOR_TEST); 
-    tex.unbind();
+
+    glm::mat4 proj = glm::ortho(0.f, width, height, 0.f, -1.f, 1.f);
+    glm::mat4 tran = glm::translate(glm::vec3(200, 200, 0));
+
+    static int i = 0;
+    i = (i + 1) % 32;
+    auto c = chars["hgfrr56789opk0876ryuewighfcuisdbn"[i] - 32];
+    glm::vec2 a(c.x0, c.y0);
+    glm::vec2 b(c.x1, c.y1);
+    glm::vec2 s(512, 512);
+    glm::vec2 tof = a / s;
+    glm::vec2 tsz = (b - a) / s;
+
+    glActiveTexture(GL_TEXTURE0);
+    font_tex.bind();
+    sampler.bind(0);
+    ShaderManager::use(kShader::Font);
+    ShaderManager::u_int(kShaderUniform::Tex, 0);
+    ShaderManager::u_mat4(kShaderUniform::MVP, proj * tran);
+    ShaderManager::u_vec2(kShaderUniform::Tof, tof);
+    ShaderManager::u_vec2(kShaderUniform::Tsz, tsz);
+    plane.draw_fill();
+    font_tex.unbind();
     sampler.unbind();
 }
 

engine/app.h

@@ -10,6 +10,10 @@ class App
     Sampler sampler;
     Texture2D tex;
     LayoutManager layout;
+    stbtt_fontinfo font;
+    Texture2D font_tex;
+    std::vector<stbtt_bakedchar> chars;
+    Plane plane;
 public:
     static App I;
     float width;

engine/pch.h

@@ -32,5 +32,8 @@
 #include <glm/gtx/euler_angles.hpp>
 
 #include <tinyxml2.h>
-#include <yoga/Yoga.h>
 #endif
+
+#include <yoga/Yoga.h>
+#include <stb/stb_truetype.h>
+#include <stb/stb_image.h>

engine/shader.cpp

@@ -104,6 +104,12 @@ void Shader::u_vec4(kShaderUniform id, const glm::vec4& v)
 {
     glUniform4fv(m_umap[id], 1, glm::value_ptr(v));
 }
+
+void Shader::u_vec2(kShaderUniform id, const glm::vec2& v)
+{
+    glUniform2fv(m_umap[id], 1, glm::value_ptr(v));
+}
+
 void Shader::u_mat4(kShaderUniform id, const glm::mat4& m)
 {
     glUniformMatrix4fv(m_umap[id], 1, GL_FALSE, glm::value_ptr(m));
@@ -135,6 +141,11 @@ void ShaderManager::u_vec4(kShaderUniform id, const glm::vec4& v)
     m_current->u_vec4(id, v);
 }
 
+void ShaderManager::u_vec2(kShaderUniform id, const glm::vec2& v)
+{
+    m_current->u_vec2(id, v);
+}
+
 void ShaderManager::u_mat4(kShaderUniform id, const glm::mat4& m)
 {
     m_current->u_mat4(id, m);

engine/shader.h

@@ -6,6 +6,8 @@ enum class kShaderUniform : uint16_t
     MVP = const_hash("mvp"),
     Tex = const_hash("tex"),
     Col = const_hash("col"),
+    Tof = const_hash("texoff"),
+    Tsz = const_hash("texsz"),
 };
 
 class Shader
@@ -16,6 +18,7 @@ public:
     bool create(const char* vertex, const char* fragment);
     void use();
     void u_vec4(kShaderUniform id, const glm::vec4& v);
+    void u_vec2(kShaderUniform id, const glm::vec2& v);
     void u_mat4(kShaderUniform id, const glm::mat4& m);
     void u_int(kShaderUniform id, int i);
 };
@@ -25,6 +28,7 @@ enum class kShader : uint16_t
     Color       = const_hash("color"),
     Texture     = const_hash("texture"),
     UVs         = const_hash("uvs"),
+    Font        = const_hash("font"),
 };
 
 class ShaderManager
@@ -36,6 +40,7 @@ public:
     static void use(kShader id);
     static void use(const char* name);
     static void u_vec4(kShaderUniform id, const glm::vec4& v);
+    static void u_vec2(kShaderUniform id, const glm::vec2& v);
     static void u_mat4(kShaderUniform id, const glm::mat4& m);
     static void u_int(kShaderUniform id, int i);
 };