[retro-gtk/wip/aplazas/gl-display] draw the texture but geometry is wrong

[Adrien Plazas <aplazas src gnome org>]

commit 7a60230f3ad0465b68f4b9e31837a4fb76c03583
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Mon Nov 13 20:20:35 2017 +0100

    draw the texture but geometry is wrong

 retro-gtk/retro-gl-display.c |   85 ++++++++++++++++-------------------------
 1 files changed, 33 insertions(+), 52 deletions(-)
---
diff --git a/retro-gtk/retro-gl-display.c b/retro-gtk/retro-gl-display.c
index a54f6d8..e307814 100644
--- a/retro-gtk/retro-gl-display.c
+++ b/retro-gtk/retro-gl-display.c
@@ -15,7 +15,7 @@ struct _RetroGLDisplay
   gulong on_video_output_id;
 
   GLuint shader_program;
-  GLuint framebuffer;
+  GLuint texture;
 };
 
 G_DEFINE_TYPE (RetroGLDisplay, retro_gl_display, GTK_TYPE_GL_AREA)
@@ -78,20 +78,11 @@ typedef struct {
   } texture_coordinates;
 } RetroVertex;
 
-/* float vertices[] = { */
-/* //  Position      Texcoords */
-/*     -0.5f,  0.5f, 0.0f, 0.0f, // Top-left */
-/*      0.5f,  0.5f, 1.0f, 0.0f, // Top-right */
-/*      0.5f, -0.5f, 1.0f, 1.0f, // Bottom-right */
-/*     -0.5f, -0.5f, 0.0f, 1.0f, // Bottom-left */
-/* }; */
-
 float vertices[] = {
-//  Position      Texcoords
-    -0.5f,  0.5f, 0.0f, 0.0f, // Top-left
-     0.5f,  0.5f, 1.0f, 0.0f, // Top-right
-     0.5f, -0.5f, 1.0f, 1.0f, // Bottom-right
-    -0.5f, -0.5f, 0.0f, 1.0f, // Bottom-left
+  -1.0f,  1.0f, 0.0f, 0.0f, // Top-left
+   1.0f,  1.0f, 1.0f, 0.0f, // Top-right
+   1.0f, -1.0f, 1.0f, 1.0f, // Bottom-right
+  -1.0f, -1.0f, 0.0f, 1.0f, // Bottom-left
 };
 
 GLuint elements[] = {
@@ -157,6 +148,9 @@ retro_gl_display_realize (RetroGLDisplay *self)
                          sizeof (RetroVertex), offsetof (RetroVertex, texture_coordinates));
   glEnableVertexAttribArray (texture_coordinates_attrib);
 
+  glGenTextures (1, &self->texture);
+  glBindTexture (GL_TEXTURE_2D, self->texture);
+
   self->shader_program = shader_program;
 }
 
@@ -165,8 +159,10 @@ retro_gl_display_unrealize (RetroGLDisplay *self)
 {
   gtk_gl_area_make_current (GTK_GL_AREA (self));
 
-  glDeleteFramebuffers (1, &self->framebuffer);
+  glDeleteTextures (1, &self->texture);
+  self->texture = 0;
   glDeleteProgram (self->shader_program);
+  self->shader_program = 0;
 }
 
 static gboolean
@@ -195,17 +191,23 @@ retro_gl_display_render (RetroGLDisplay *self)
   }
 
   glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
-  GLint rect = glGetUniformLocation (self->shader_program, "rect");
-  glUniform4f (rect, x, y, w, h);
-
-  glBindFramebuffer (GL_READ_FRAMEBUFFER, self->framebuffer);
-  glBlitFramebuffer (0, 0,
-                     gdk_pixbuf_get_width (self->pixbuf),
-                     gdk_pixbuf_get_height (self->pixbuf),
-                     (GLint) x, (GLint) (y + h), (GLint) (x + w), (GLint) y,
-                     GL_COLOR_BUFFER_BIT,
-                     filter);
-  glBindFramebuffer (GL_READ_FRAMEBUFFER, 0);
+
+  if (self->pixbuf == NULL)
+    return FALSE;
+
+  glTexImage2D (GL_TEXTURE_2D,
+                0,
+                GL_RGB,
+                gdk_pixbuf_get_width (self->pixbuf),
+                gdk_pixbuf_get_height (self->pixbuf),
+                0,
+                GL_RGBA, GL_UNSIGNED_BYTE,
+                gdk_pixbuf_get_pixels (self->pixbuf));
+
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
+  glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
 
   glDrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
 
@@ -217,6 +219,10 @@ retro_gl_display_finalize (GObject *object)
 {
   RetroGLDisplay *self = (RetroGLDisplay *) object;
 
+  glDeleteTextures (1, &self->texture);
+  self->texture = 0;
+  glDeleteProgram (self->shader_program);
+  self->shader_program = 0;
   if (self->core != NULL)
     g_object_unref (self->core);
   if (self->pixbuf != NULL)
@@ -412,34 +418,9 @@ retro_gl_display_set_pixbuf (RetroGLDisplay *self,
 
   g_clear_object (&self->pixbuf);
 
-  if (pixbuf != NULL) {
+  if (pixbuf != NULL)
     self->pixbuf = g_object_ref (pixbuf);
 
-    GLuint tex = 0;
-    glGenTextures (1, &tex);
-    glBindTexture (GL_TEXTURE_2D, tex);
-
-    glTexImage2D (GL_TEXTURE_2D,
-                  0,
-                  GL_RGB,
-                  gdk_pixbuf_get_width (self->pixbuf),
-                  gdk_pixbuf_get_height (self->pixbuf),
-                  0,
-                  GL_RGBA, GL_UNSIGNED_BYTE,
-                  gdk_pixbuf_get_pixels (self->pixbuf));
-
-    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-
-    glGenFramebuffers (1, &self->framebuffer);
-    glBindFramebuffer (GL_READ_FRAMEBUFFER, self->framebuffer);
-    glFramebufferTexture2D (GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
-                            GL_TEXTURE_2D, tex, 0);
-    glBindFramebuffer (GL_READ_FRAMEBUFFER, 0);
-  }
-
   g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_PIXBUF]);
 }