1 files changed, 106 insertions, 0 deletions
diff --git a/source/blender/draw/engines/image/image_batches.hh b/source/blender/draw/engines/image/image_batches.hh
new file mode 100644
index 00000000000..5f82504197a
--- /dev/null
+++ b/source/blender/draw/engines/image/image_batches.hh
@@ -0,0 +1,106 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Copyright 2021, Blender Foundation.
+ */
+
+/** \file
+ * \ingroup draw_engine
+ */
+
+#pragma once
+
+#include "image_texture_info.hh"
+
+/** \brief Create GPUBatch for a IMAGE_ScreenSpaceTextureInfo. */
+class BatchUpdater {
+  TextureInfo &info;
+
+  GPUVertFormat format = {0};
+  int pos_id;
+  int uv_id;
+
+ public:
+  BatchUpdater(TextureInfo &info) : info(info)
+  {
+  }
+
+  void update_batch()
+  {
+    ensure_clear_batch();
+    ensure_format();
+    init_batch();
+  }
+
+  void discard_batch()
+  {
+    GPU_BATCH_DISCARD_SAFE(info.batch);
+  }
+
+ private:
+  void ensure_clear_batch()
+  {
+    GPU_BATCH_CLEAR_SAFE(info.batch);
+    if (info.batch == nullptr) {
+      info.batch = GPU_batch_calloc();
+    }
+  }
+
+  void init_batch()
+  {
+    GPUVertBuf *vbo = create_vbo();
+    GPU_batch_init_ex(info.batch, GPU_PRIM_TRI_FAN, vbo, nullptr, GPU_BATCH_OWNS_VBO);
+  }
+
+  GPUVertBuf *create_vbo()
+  {
+    GPUVertBuf *vbo = GPU_vertbuf_create_with_format(&format);
+    GPU_vertbuf_data_alloc(vbo, 4);
+    float pos[4][2];
+    fill_tri_fan_from_rctf(pos, info.clipping_bounds);
+    float uv[4][2];
+    fill_tri_fan_from_rctf(uv, info.clipping_uv_bounds);
+
+    for (int i = 0; i < 4; i++) {
+      GPU_vertbuf_attr_set(vbo, pos_id, i, pos[i]);
+      GPU_vertbuf_attr_set(vbo, uv_id, i, uv[i]);
+    }
+
+    return vbo;
+  }
+
+  static void fill_tri_fan_from_rctf(float result[4][2], rctf &rect)
+  {
+    result[0][0] = rect.xmin;
+    result[0][1] = rect.ymin;
+    result[1][0] = rect.xmax;
+    result[1][1] = rect.ymin;
+    result[2][0] = rect.xmax;
+    result[2][1] = rect.ymax;
+    result[3][0] = rect.xmin;
+    result[3][1] = rect.ymax;
+  }
+
+  void ensure_format()
+  {
+    if (format.attr_len == 0) {
+      GPU_vertformat_attr_add(&format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
+      GPU_vertformat_attr_add(&format, "uv", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
+
+      pos_id = GPU_vertformat_attr_id_get(&format, "pos");
+      uv_id = GPU_vertformat_attr_id_get(&format, "uv");
+    }
+  }
+};