[mutter/gbsneto/more-clutter-api: 1/3] clutter/paint-node: Add multitexture API

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit d5262f0f4db1e69a54bb8274cf9d84dc8d31ce1b
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Dec 26 23:09:17 2018 -0200

    clutter/paint-node: Add multitexture API
    
    The multitexture API is not a shortcut for multiple calls
    to the single texture API. It is meant to wrap calls to
    cogl_framebuffer_draw_multitexture_rectangle(), which
    uses the passed texture coordinates at different layers of
    the pipeline.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/405

 clutter/clutter/clutter-paint-node-private.h |  3 ++
 clutter/clutter/clutter-paint-node.c         | 68 +++++++++++++++++++++++++++-
 clutter/clutter/clutter-paint-node.h         |  6 +++
 clutter/clutter/clutter-paint-nodes.c        | 25 ++++++++++
 4 files changed, 101 insertions(+), 1 deletion(-)
---
diff --git a/clutter/clutter/clutter-paint-node-private.h b/clutter/clutter/clutter-paint-node-private.h
index 2945b78a4..feecdd811 100644
--- a/clutter/clutter/clutter-paint-node-private.h
+++ b/clutter/clutter/clutter-paint-node-private.h
@@ -77,6 +77,7 @@ struct _ClutterPaintNodeClass
 typedef enum {
   PAINT_OP_INVALID = 0,
   PAINT_OP_TEX_RECT,
+  PAINT_OP_MULTITEX_RECT,
   PAINT_OP_PATH,
   PAINT_OP_PRIMITIVE
 } PaintOpCode;
@@ -85,6 +86,8 @@ struct _ClutterPaintOperation
 {
   PaintOpCode opcode;
 
+  GArray *multitex_coords;
+
   union {
     float texrect[8];
 
diff --git a/clutter/clutter/clutter-paint-node.c b/clutter/clutter/clutter-paint-node.c
index 3dafca0f1..c31a0c702 100644
--- a/clutter/clutter/clutter-paint-node.c
+++ b/clutter/clutter/clutter-paint-node.c
@@ -761,6 +761,11 @@ clutter_paint_operation_clear (ClutterPaintOperation *op)
     case PAINT_OP_TEX_RECT:
       break;
 
+    case PAINT_OP_MULTITEX_RECT:
+      if (op->multitex_coords != NULL)
+        g_array_unref (op->multitex_coords);
+      break;
+
     case PAINT_OP_PATH:
       if (op->op.path != NULL)
         cogl_object_unref (op->op.path);
@@ -794,6 +799,27 @@ clutter_paint_op_init_tex_rect (ClutterPaintOperation *op,
   op->op.texrect[7] = y_2;
 }
 
+static inline void
+clutter_paint_op_init_multitex_rect (ClutterPaintOperation *op,
+                                     const ClutterActorBox *rect,
+                                     const float           *tex_coords,
+                                     unsigned int           tex_coords_len)
+{
+  clutter_paint_operation_clear (op);
+
+  op->opcode = PAINT_OP_MULTITEX_RECT;
+  op->multitex_coords = g_array_sized_new (FALSE, FALSE,
+                                           sizeof (float),
+                                           tex_coords_len);
+
+  g_array_append_vals (op->multitex_coords, tex_coords, tex_coords_len);
+
+  op->op.texrect[0] = rect->x1;
+  op->op.texrect[1] = rect->y1;
+  op->op.texrect[2] = rect->x2;
+  op->op.texrect[3] = rect->y2;
+}
+
 static inline void
 clutter_paint_op_init_path (ClutterPaintOperation *op,
                             CoglPath              *path)
@@ -881,6 +907,33 @@ clutter_paint_node_add_texture_rectangle (ClutterPaintNode      *node,
   g_array_append_val (node->operations, operation);
 }
 
+
+/**
+ * clutter_paint_node_add_multitexture_rectangle:
+ * @node: a #ClutterPaintNode
+ * @rect: a #ClutterActorBox
+ * @text_coords: array of multitexture values
+ * @text_coords_len: number of items of @text_coords
+ *
+ * Adds a rectangle region to the @node, with multitexture coordinates.
+ */
+void
+clutter_paint_node_add_multitexture_rectangle (ClutterPaintNode      *node,
+                                               const ClutterActorBox *rect,
+                                               const float           *text_coords,
+                                               unsigned int           text_coords_len)
+{
+  ClutterPaintOperation operation = PAINT_OP_INIT;
+
+  g_return_if_fail (CLUTTER_IS_PAINT_NODE (node));
+  g_return_if_fail (rect != NULL);
+
+  clutter_paint_node_maybe_init_operations (node);
+
+  clutter_paint_op_init_multitex_rect (&operation, rect, text_coords, text_coords_len);
+  g_array_append_val (node->operations, operation);
+}
+
 /**
  * clutter_paint_node_add_path: (skip)
  * @node: a #ClutterPaintNode
@@ -1006,7 +1059,7 @@ clutter_paint_node_to_json (ClutterPaintNode *node)
 
   if (node->operations != NULL)
     {
-      guint i;
+      guint i, j;
 
       for (i = 0; i < node->operations->len; i++)
         {
@@ -1031,6 +1084,19 @@ clutter_paint_node_to_json (ClutterPaintNode *node)
               json_builder_end_array (builder);
               break;
 
+            case PAINT_OP_MULTITEX_RECT:
+              json_builder_set_member_name (builder, "texrect");
+              json_builder_begin_array (builder);
+
+              for (j = 0; i < op->multitex_coords->len; j++)
+                {
+                  float coord = g_array_index (op->multitex_coords, float, j);
+                  json_builder_add_double_value (builder, coord);
+                }
+
+              json_builder_end_array (builder);
+              break;
+
             case PAINT_OP_PATH:
               json_builder_set_member_name (builder, "path");
               json_builder_add_int_value (builder, (gint64) op->op.path);
diff --git a/clutter/clutter/clutter-paint-node.h b/clutter/clutter/clutter-paint-node.h
index 779b15e35..e459e74ed 100644
--- a/clutter/clutter/clutter-paint-node.h
+++ b/clutter/clutter/clutter-paint-node.h
@@ -67,6 +67,12 @@ void                    clutter_paint_node_add_texture_rectangle        (Clutter
                                                                          float                  x_2,
                                                                          float                  y_2);
 
+CLUTTER_EXPORT
+void                   clutter_paint_node_add_multitexture_rectangle   (ClutterPaintNode       *node,
+                                                                        const ClutterActorBox  *rect,
+                                                                        const float            *text_coords,
+                                                                        unsigned int            
text_coords_len);
+
 CLUTTER_EXPORT
 void                    clutter_paint_node_add_path                     (ClutterPaintNode      *node,
                                                                          CoglPath              *path);
diff --git a/clutter/clutter/clutter-paint-nodes.c b/clutter/clutter/clutter-paint-nodes.c
index 2707dcf62..638ddb4a7 100644
--- a/clutter/clutter/clutter-paint-nodes.c
+++ b/clutter/clutter/clutter-paint-nodes.c
@@ -431,6 +431,17 @@ clutter_pipeline_node_draw (ClutterPaintNode *node)
                                               op->op.texrect[7]);
           break;
 
+        case PAINT_OP_MULTITEX_RECT:
+          cogl_framebuffer_draw_multitextured_rectangle (cogl_get_draw_framebuffer (),
+                                                         pnode->pipeline,
+                                                         op->op.texrect[0],
+                                                         op->op.texrect[1],
+                                                         op->op.texrect[2],
+                                                         op->op.texrect[3],
+                                                         (float*) op->multitex_coords->data,
+                                                         op->multitex_coords->len);
+          break;
+
         case PAINT_OP_PATH:
           cogl_path_fill (op->op.path);
           break;
@@ -827,6 +838,7 @@ clutter_text_node_draw (ClutterPaintNode *node)
             cogl_framebuffer_pop_clip (fb);
           break;
 
+        case PAINT_OP_MULTITEX_RECT:
         case PAINT_OP_PATH:
         case PAINT_OP_PRIMITIVE:
         case PAINT_OP_INVALID:
@@ -992,6 +1004,7 @@ clutter_clip_node_pre_draw (ClutterPaintNode *node)
           retval = TRUE;
           break;
 
+        case PAINT_OP_MULTITEX_RECT:
         case PAINT_OP_PRIMITIVE:
         case PAINT_OP_INVALID:
           break;
@@ -1025,6 +1038,7 @@ clutter_clip_node_post_draw (ClutterPaintNode *node)
           cogl_framebuffer_pop_clip (fb);
           break;
 
+        case PAINT_OP_MULTITEX_RECT:
         case PAINT_OP_PRIMITIVE:
         case PAINT_OP_INVALID:
           break;
@@ -1180,6 +1194,17 @@ clutter_layer_node_post_draw (ClutterPaintNode *node)
           cogl_pop_source ();
           break;
 
+        case PAINT_OP_MULTITEX_RECT:
+          cogl_framebuffer_draw_multitextured_rectangle (cogl_get_draw_framebuffer (),
+                                                         lnode->state,
+                                                         op->op.texrect[0],
+                                                         op->op.texrect[1],
+                                                         op->op.texrect[2],
+                                                         op->op.texrect[3],
+                                                         (float*) op->multitex_coords->data,
+                                                         op->multitex_coords->len);
+          break;
+
         case PAINT_OP_PATH:
           cogl_push_source (lnode->state);
           cogl_path_fill (op->op.path);