[gtk+] Add gdk_gl_texture_quad() helper

[Alexander Larsson <alexl src gnome org>]

commit 10a44e8f7ad4dd4fd4dd1ba3ef1e5f08ffcc6f87
Author: Alexander Larsson <alexl redhat com>
Date:   Wed Nov 5 15:42:06 2014 +0100

    Add gdk_gl_texture_quad() helper
    
    Right now this just centralizes the glBegin/glEnd code, but
    this will be replaced with buffer objects later.

 gdk/gdkgl.c                |   57 +++++++++++++++++++++++--------------------
 gdk/gdkinternals.h         |    4 +++
 gdk/x11/gdkglcontext-x11.c |   17 +++----------
 3 files changed, 38 insertions(+), 40 deletions(-)
---
diff --git a/gdk/gdkgl.c b/gdk/gdkgl.c
index c7c847a..f490330 100644
--- a/gdk/gdkgl.c
+++ b/gdk/gdkgl.c
@@ -35,6 +35,28 @@ gdk_cairo_surface_mark_as_direct (cairo_surface_t *surface,
                                g_object_ref (window),  g_object_unref);
 }
 
+void
+gdk_gl_texture_quad (float x1, float y1,
+                     float x2, float y2,
+                     float u1, float v1,
+                     float u2, float v2)
+{
+  glBegin (GL_QUADS);
+  glTexCoord2f (u1, v2);
+  glVertex2f (x1, y2);
+
+  glTexCoord2f (u2, v2);
+  glVertex2f (x2, y2);
+
+  glTexCoord2f (u2, v1);
+  glVertex2f (x2, y1);
+
+  glTexCoord2f (u1, v1);
+  glVertex2f (x1, y1);
+  glEnd();
+}
+
+
 /* x,y,width,height describes a rectangle in the gl render buffer
    coordinate space, and its top left corner is drawn at the current
    position according to the cairo translation. */
@@ -304,19 +326,10 @@ gdk_cairo_draw_from_gl (cairo_t              *cr,
               int clipped_src_x = x + (dest.x - dx * window_scale);
               int clipped_src_y = y + (height - dest.height - (dest.y - dy * window_scale));
 
-              glBegin (GL_QUADS);
-              glTexCoord2f (clipped_src_x / (float)texture_width, clipped_src_y / (float)texture_height);
-              glVertex2f (dest.x, FLIP_Y(dest.y + dest.height));
-
-              glTexCoord2f ((clipped_src_x + dest.width) / (float)texture_width, clipped_src_y / 
(float)texture_height);
-              glVertex2f (dest.x + dest.width, FLIP_Y(dest.y + dest.height));
-
-              glTexCoord2f ((clipped_src_x + dest.width) / (float)texture_width, (clipped_src_y + 
dest.height) / (float)texture_height);
-              glVertex2f (dest.x + dest.width, FLIP_Y(dest.y));
-
-              glTexCoord2f (clipped_src_x / (float)texture_width, (clipped_src_y + dest.height) / 
(float)texture_height);
-              glVertex2f (dest.x, FLIP_Y(dest.y));
-              glEnd();
+              gdk_gl_texture_quad (dest.x, FLIP_Y(dest.y),
+                                   dest.x + dest.width, FLIP_Y(dest.y + dest.height),
+                                   clipped_src_x / (float)texture_width, (clipped_src_y + dest.height) / 
(float)texture_height,
+                                   (clipped_src_x + dest.width) / (float)texture_width, clipped_src_y / 
(float)texture_height);
 
               if (impl_window->current_paint.flushed_region)
                 {
@@ -425,7 +438,6 @@ gdk_gl_texture_from_surface (cairo_surface_t *surface,
     return;
 
   /* Software fallback */
-
   use_texture_rectangle = gdk_gl_context_use_texture_rectangle (current);
 
   window = gdk_gl_context_get_window (current);
@@ -492,19 +504,10 @@ gdk_gl_texture_from_surface (cairo_surface_t *surface,
           vmax = 1.0;
         }
 
-      glBegin (GL_QUADS);
-      glTexCoord2f (0, vmax);
-      glVertex2f (rect.x * window_scale, FLIP_Y(rect.y + rect.height) * window_scale);
-
-      glTexCoord2f (umax, vmax);
-      glVertex2f ((rect.x + rect.width) * window_scale, FLIP_Y(rect.y + rect.height) * window_scale);
-
-      glTexCoord2f (umax, 0);
-      glVertex2f ((rect.x + rect.width) * window_scale, FLIP_Y(rect.y) * window_scale);
-
-      glTexCoord2f (0, 0);
-      glVertex2f (rect.x * window_scale, FLIP_Y(rect.y) * window_scale);
-      glEnd();
+      gdk_gl_texture_quad (rect.x * window_scale, FLIP_Y(rect.y) * window_scale,
+                           (rect.x + rect.width) * window_scale, FLIP_Y(rect.y + rect.height) * window_scale,
+                           0, 0,
+                           umax, vmax);
     }
 
   glDisable (target);
diff --git a/gdk/gdkinternals.h b/gdk/gdkinternals.h
index bb7b71a..69be704 100644
--- a/gdk/gdkinternals.h
+++ b/gdk/gdkinternals.h
@@ -341,6 +341,10 @@ gboolean        _gdk_cairo_surface_extents       (cairo_surface_t *surface,
                                                   GdkRectangle    *extents);
 void            gdk_gl_texture_from_surface      (cairo_surface_t *surface,
                                                   cairo_region_t  *region);
+void           gdk_gl_texture_quad               (float x1, float y1,
+                                                  float x2, float y2,
+                                                  float u1, float v1,
+                                                  float u2, float v2);
 void            gdk_cairo_surface_mark_as_direct (cairo_surface_t *surface,
                                                   GdkWindow       *window);
 cairo_region_t *gdk_cairo_region_from_clip       (cairo_t         *cr);
diff --git a/gdk/x11/gdkglcontext-x11.c b/gdk/x11/gdkglcontext-x11.c
index bc48d4d..7b86a72 100644
--- a/gdk/x11/gdkglcontext-x11.c
+++ b/gdk/x11/gdkglcontext-x11.c
@@ -469,19 +469,10 @@ gdk_x11_gl_context_texture_from_surface (GdkGLContext *context,
           vscale = 1.0 / cairo_xlib_surface_get_height (surface);
         }
 
-      glBegin (GL_QUADS);
-      glTexCoord2f (uscale * src_x, vscale * (src_y + src_height));
-      glVertex2f (rect.x * window_scale, FLIP_Y(rect.y + rect.height) * window_scale);
-
-      glTexCoord2f (uscale * (src_x + src_width), vscale * (src_y + src_height));
-      glVertex2f ((rect.x + rect.width) * window_scale, FLIP_Y(rect.y + rect.height) * window_scale);
-
-      glTexCoord2f (uscale * (src_x + src_width), vscale * src_y);
-      glVertex2f ((rect.x + rect.width) * window_scale, FLIP_Y(rect.y) * window_scale);
-
-      glTexCoord2f (uscale * src_x, vscale * src_y);
-      glVertex2f (rect.x * window_scale, FLIP_Y(rect.y) * window_scale);
-      glEnd();
+      gdk_gl_texture_quad (rect.x * window_scale, FLIP_Y(rect.y) * window_scale,
+                           (rect.x + rect.width) * window_scale, FLIP_Y(rect.y + rect.height) * window_scale,
+                           uscale * src_x, vscale * src_y,
+                           uscale * (src_x + src_width), vscale * (src_y + src_height));
     }
 
   glXReleaseTexImageEXT (glx_pixmap->display, glx_pixmap->drawable,