[retro-gtk/wip/aplazas/gl-display] From triangle to square

[Adrien Plazas <aplazas src gnome org>]

commit 8fb767052cf047b2a49675bce68191093c6a8d6d
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Fri Nov 10 11:15:45 2017 +0100

    From triangle to square

 retro-gtk/retro-gl-display.c |   11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)
---
diff --git a/retro-gtk/retro-gl-display.c b/retro-gtk/retro-gl-display.c
index b5ca8b2..db48b4b 100644
--- a/retro-gtk/retro-gl-display.c
+++ b/retro-gtk/retro-gl-display.c
@@ -81,9 +81,12 @@ retro_gl_display_get_video_box (RetroGLDisplay *self,
 
 // From Antons's OpenGL 4 Tutorial
 float points[] = {
-   0.0f,  0.5f,  0.0f,
+  -0.5f,  0.5f,  0.0f,
+   0.5f,  0.5f,  0.0f,
+  -0.5f, -0.5f,  0.0f,
+   0.5f,  0.5f,  0.0f,
+  -0.5f, -0.5f,  0.0f,
    0.5f, -0.5f,  0.0f,
-  -0.5f, -0.5f,  0.0f
 };
 
 static void
@@ -102,7 +105,7 @@ retro_gl_display_realize (RetroGLDisplay *self)
   // Prepare the vertex buffer
   glGenBuffers (1, &vertex_buffer_object);
   glBindBuffer (GL_ARRAY_BUFFER, vertex_buffer_object);
-  glBufferData (GL_ARRAY_BUFFER, 9 * sizeof(float), points, GL_STATIC_DRAW);
+  glBufferData (GL_ARRAY_BUFFER, 18 * sizeof (float), points, GL_STATIC_DRAW);
 
   // Prepare the vertex array
   glGenVertexArrays (1, &vertex_array_object);
@@ -152,7 +155,7 @@ retro_gl_display_render (RetroGLDisplay *self)
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   glUseProgram(self->shader_program);
   glBindVertexArray(self->vertex_array_object);
-  glDrawArrays(GL_TRIANGLES, 0, 3);
+  glDrawArrays(GL_TRIANGLES, 0, 6);
 
   return FALSE;
 }