From 9f08819dc1f3fb630c221818c52515b6e39a0866 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Tue, 10 Jun 2014 14:44:35 -0400
Subject: [PATCH] successfully draw a letter

---
 freetype2gl3.cc | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/freetype2gl3.cc b/freetype2gl3.cc
index 9249789..732c81e 100644
--- a/freetype2gl3.cc
+++ b/freetype2gl3.cc
@@ -14,6 +14,7 @@ static FT_Library ft;
 static FT_Face face;
 static GLProgram program;
 static GLint uniform_tex;
+static GLint uniform_color;
 
 const char vertex_shader[] =
 "#version 120\n"
@@ -24,7 +25,7 @@ const char vertex_shader[] =
 "\n"
 "void main(void)\n"
 "{\n"
-"    gl_Position = vec4(coord.xy, 0, 1);\n"
+"    gl_Position = vec4(coord.xy * 2.0 / 500.0, 0, 1);\n"
 "    tex_coord_i = coord.zw;\n"
 "}\n";
 
@@ -44,9 +45,12 @@ void init(void)
     glClearColor (0.0, 0.0, 0.0, 0.0);
     program.create(vertex_shader, fragment_shader,
                    "coord", 0, NULL,
-                   "tex", NULL);
+                   "tex", "color", NULL);
     uniform_tex = program.uniform("tex");
+    uniform_color = program.uniform("color");
     program.use();
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 }
 
 void display(SDL_Window * window)
@@ -56,7 +60,6 @@ void display(SDL_Window * window)
     {
         cerr << "Failed to load character" << endl;
     }
-#if 0
     GLuint texture_id;
     glActiveTexture(GL_TEXTURE0);
     glGenTextures(1, &texture_id);
@@ -80,8 +83,17 @@ void display(SDL_Window * window)
     glEnableVertexAttribArray(0);
     glBindBuffer(GL_ARRAY_BUFFER, vbo);
     glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);
+    GLfloat color[4] = {1, 0.6, 0, 1.0};
     glUniform1i(uniform_tex, 0);
-#endif
+    glUniform4fv(uniform_color, 1, color);
+    GLfloat box[4][4] = {
+        {0, 0, 0, 0},
+        {face->glyph->bitmap.width, 0, 1, 0},
+        {0, -face->glyph->bitmap.rows, 0, 1},
+        {face->glyph->bitmap.width, -face->glyph->bitmap.rows, 1, 1}
+    };
+    glBufferData(GL_ARRAY_BUFFER, sizeof(box), box, GL_STATIC_DRAW);
+    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
     SDL_GL_SwapWindow(window);
 }