[gtk+/wip/baedert/gl: 181/216] gl renderer: save on some frame buffers

[Timm Bäder <baedert src gnome org>]

commit 2c7942e91510ef6791d57335d84df661597975a4
Author: Timm Bäder <mail baedert org>
Date:   Thu Nov 16 09:47:19 2017 +0100

    gl renderer: save on some frame buffers
    
    If the child of a color matrix node is a texture, we can directly use
    that instead of drawing it to a texture first and then using that
    texture.

 gsk/gskglrenderer.c |   34 +++++++++++++++++++++++++++-------
 1 files changed, 27 insertions(+), 7 deletions(-)
---
diff --git a/gsk/gskglrenderer.c b/gsk/gskglrenderer.c
index 7b6ad9e..06649c3 100644
--- a/gsk/gskglrenderer.c
+++ b/gsk/gskglrenderer.c
@@ -656,7 +656,10 @@ render_item (GskGLRenderer    *self,
           float vec[4];
 
           glUniform1i (item->program->source_location, 0);
-          gsk_gl_driver_bind_source_texture (self->gl_driver, item->render_target);
+          if (item->render_target != 0)
+            gsk_gl_driver_bind_source_texture (self->gl_driver, item->render_target);
+          else
+            gsk_gl_driver_bind_source_texture (self->gl_driver, item->texture_id);
 
           graphene_matrix_to_float (&item->color_matrix_data.color_matrix, mat);
           glUniformMatrix4fv (item->program->color_matrix_location, 1, GL_FALSE, mat);
@@ -886,13 +889,30 @@ gsk_gl_renderer_add_render_item (GskGLRenderer           *self,
     case GSK_COLOR_MATRIX_NODE:
       {
         GskRenderNode *child = gsk_color_matrix_node_get_child (node);
-        graphene_matrix_t p;
-        graphene_matrix_t identity;
 
-        graphene_matrix_init_identity (&identity);
-        init_framebuffer_for_node (self, &item, node, projection, &p);
-        gsk_gl_renderer_add_render_item (self, &p, &identity, item.children, child,
-                                         item.render_target);
+        if (gsk_render_node_get_node_type (child) != GSK_TEXTURE_NODE)
+          {
+
+            graphene_matrix_t p;
+            graphene_matrix_t identity;
+
+            graphene_matrix_init_identity (&identity);
+            init_framebuffer_for_node (self, &item, node, projection, &p);
+            gsk_gl_renderer_add_render_item (self, &p, &identity, item.children, child,
+                                             item.render_target);
+          }
+        else
+          {
+            GdkTexture *texture = gsk_texture_node_get_texture (child);
+            int gl_min_filter = GL_NEAREST, gl_mag_filter = GL_NEAREST;
+
+            get_gl_scaling_filters (node, &gl_min_filter, &gl_mag_filter);
+
+            item.texture_id = gsk_gl_driver_get_texture_for_texture (self->gl_driver,
+                                                                     texture,
+                                                                     gl_min_filter,
+                                                                     gl_mag_filter);
+          }
 
         item.mode = MODE_COLOR_MATRIX;
         item.program = &self->color_matrix_program;