From dd5b7bf8fda7446b4751c2eae6232b81323db1f5 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Thu, 26 Jun 2014 12:50:48 -0400
Subject: [PATCH] GUI: add load_buffers(), draw_rect()

---
 src/gui/GUI.cc | 34 ++++++++++++++++++++++++++++++++++
 src/gui/GUI.h  |  4 ++++
 2 files changed, 38 insertions(+)

diff --git a/src/gui/GUI.cc b/src/gui/GUI.cc
index ce56e2f..4f593f3 100644
--- a/src/gui/GUI.cc
+++ b/src/gui/GUI.cc
@@ -57,6 +57,9 @@ namespace jes
         if (!load_shaders())
             return false;
 
+        if (!load_buffers())
+            return false;
+
         return true;
     }
 
@@ -98,6 +101,25 @@ namespace jes
         return true;
     }
 
+    bool GUI::load_buffers()
+    {
+        static const GLint rect_coords[4][2] = {
+            {0, 0},
+            {1, 0},
+            {0, 1},
+            {1, 1},
+        };
+
+        m_rect_vbo = new GLBuffer();
+        if (!m_rect_vbo->create(GL_ARRAY_BUFFER, GL_STATIC_DRAW, &rect_coords, sizeof(rect_coords)))
+        {
+            std::cerr << "Failed to create rectangle VBO" << std::endl;
+            return false;
+        }
+
+        return true;
+    }
+
     int GUI::run()
     {
         resize();
@@ -148,4 +170,16 @@ namespace jes
         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
         SDL_GL_SwapWindow(m_window);
     }
+
+    void GUI::draw_rect(int x, int y, int width, int height, float r, float g, float b, float a)
+    {
+        m_programs[PROGRAM_RECT]->use();
+        glUniform2i(m_programs[PROGRAM_RECT]->get_uniform("position"), x, y);
+        glUniform2i(m_programs[PROGRAM_RECT]->get_uniform("size"), width, height);
+        glUniform4f(m_programs[PROGRAM_RECT]->get_uniform("color"), r, g, b, a);
+        m_rect_vbo->bind();
+        glEnableVertexAttribArray(0);
+        glVertexAttribIPointer(0, 2, GL_INT, 0, 0);
+        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+    }
 }
diff --git a/src/gui/GUI.h b/src/gui/GUI.h
index 45b36fa..cd6e501 100644
--- a/src/gui/GUI.h
+++ b/src/gui/GUI.h
@@ -5,6 +5,7 @@
 #include <SDL.h>
 #include "FontManager.h"
 #include "GLProgram.h"
+#include "GLBuffer.h"
 
 namespace jes
 {
@@ -22,12 +23,15 @@ namespace jes
         int run();
     protected:
         bool load_shaders();
+        bool load_buffers();
         void resize();
         void draw();
+        void draw_rect(int x, int y, int width, int height, float r, float g, float b, float a);
 
         SDL_Window * m_window;
         FontManagerRef m_font_manager;
         GLProgramRef m_programs[PROGRAM_COUNT];
+        GLBufferRef m_rect_vbo;
     };
 
     typedef Ref<GUI> GUIRef;