1 files changed, 130 insertions, 0 deletions
diff --git a/intern/cycles/app/opengl/display_driver.h b/intern/cycles/app/opengl/display_driver.h
new file mode 100644
index 00000000000..7645d7905b4
--- /dev/null
+++ b/intern/cycles/app/opengl/display_driver.h
@@ -0,0 +1,130 @@
+/*
+ * Copyright 2011-2022 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <atomic>
+
+#include "app/opengl/shader.h"
+
+#include "session/display_driver.h"
+
+#include "util/function.h"
+#include "util/unique_ptr.h"
+
+CCL_NAMESPACE_BEGIN
+
+class OpenGLDisplayDriver : public DisplayDriver {
+ public:
+  /* Callbacks for enabling and disabling the OpenGL context. Must be provided to support enabling
+   * the context on the Cycles render thread independent of the main thread. */
+  OpenGLDisplayDriver(const function<bool()> &gl_context_enable,
+                      const function<void()> &gl_context_disable);
+  ~OpenGLDisplayDriver();
+
+  virtual void graphics_interop_activate() override;
+  virtual void graphics_interop_deactivate() override;
+
+  virtual void clear() override;
+
+  void set_zoom(float zoom_x, float zoom_y);
+
+ protected:
+  virtual void next_tile_begin() override;
+
+  virtual bool update_begin(const Params &params, int texture_width, int texture_height) override;
+  virtual void update_end() override;
+
+  virtual half4 *map_texture_buffer() override;
+  virtual void unmap_texture_buffer() override;
+
+  virtual GraphicsInterop graphics_interop_get() override;
+
+  virtual void draw(const Params &params) override;
+
+  /* Make sure texture is allocated and its initial configuration is performed. */
+  bool gl_texture_resources_ensure();
+
+  /* Ensure all runtime GPU resources needed for drawing are allocated.
+   * Returns true if all resources needed for drawing are available. */
+  bool gl_draw_resources_ensure();
+
+  /* Destroy all GPU resources which are being used by this object. */
+  void gl_resources_destroy();
+
+  /* Update GPU texture dimensions and content if needed (new pixel data was provided).
+   *
+   * NOTE: The texture needs to be bound. */
+  void texture_update_if_needed();
+
+  /* Update vertex buffer with new coordinates of vertex positions and texture coordinates.
+   * This buffer is used to render texture in the viewport.
+   *
+   * NOTE: The buffer needs to be bound. */
+  void vertex_buffer_update(const Params &params);
+
+  /* Texture which contains pixels of the render result. */
+  struct {
+    /* Indicates whether texture creation was attempted and succeeded.
+     * Used to avoid multiple attempts of texture creation on GPU issues or GPU context
+     * misconfiguration. */
+    bool creation_attempted = false;
+    bool is_created = false;
+
+    /* OpenGL resource IDs of the texture itself and Pixel Buffer Object (PBO) used to write
+     * pixels to it.
+     *
+     * NOTE: Allocated on the engine's context. */
+    uint gl_id = 0;
+    uint gl_pbo_id = 0;
+
+    /* Is true when new data was written to the PBO, meaning, the texture might need to be resized
+     * and new data is to be uploaded to the GPU. */
+    bool need_update = false;
+
+    /* Content of the texture is to be filled with zeroes. */
+    std::atomic<bool> need_clear = true;
+
+    /* Dimensions of the texture in pixels. */
+    int width = 0;
+    int height = 0;
+
+    /* Dimensions of the underlying PBO. */
+    int buffer_width = 0;
+    int buffer_height = 0;
+  } texture_;
+
+  OpenGLShader display_shader_;
+
+  /* Special track of whether GPU resources were attempted to be created, to avoid attempts of
+   * their re-creation on failure on every redraw. */
+  bool gl_draw_resource_creation_attempted_ = false;
+  bool gl_draw_resources_created_ = false;
+
+  /* Vertex buffer which hold vertices of a triangle fan which is textures with the texture
+   * holding the render result. */
+  uint vertex_buffer_ = 0;
+
+  void *gl_render_sync_ = nullptr;
+  void *gl_upload_sync_ = nullptr;
+
+  float2 zoom_ = make_float2(1.0f, 1.0f);
+
+  function<bool()> gl_context_enable_ = nullptr;
+  function<void()> gl_context_disable_ = nullptr;
+};
+
+CCL_NAMESPACE_END