1 files changed, 144 insertions, 0 deletions
diff --git a/src/ui/widget/canvas/glgraphics.h b/src/ui/widget/canvas/glgraphics.h
new file mode 100644
index 0000000..7cb6ecf
--- /dev/null
+++ b/src/ui/widget/canvas/glgraphics.h
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * OpenGL display backend.
+ * Copyright (C) 2022 PBS <pbs3141@gmail.com>
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#ifndef INKSCAPE_UI_WIDGET_CANVAS_GLGRAPHICS_H
+#define INKSCAPE_UI_WIDGET_CANVAS_GLGRAPHICS_H
+
+#include <mutex>
+#include <epoxy/gl.h>
+#include "graphics.h"
+#include "texturecache.h"
+
+namespace Inkscape {
+namespace UI {
+namespace Widget {
+class Stores;
+class Prefs;
+class PixelStreamer;
+
+template <GLuint type>
+struct Shader : boost::noncopyable
+{
+    GLuint id;
+    Shader(char const *src) { id = glCreateShader(type); glShaderSource(id, 1, &src, nullptr); glCompileShader(id); }
+    ~Shader() { glDeleteShader(id); }
+};
+using GShader = Shader<GL_GEOMETRY_SHADER>;
+using VShader = Shader<GL_VERTEX_SHADER>;
+using FShader = Shader<GL_FRAGMENT_SHADER>;
+
+struct Program : boost::noncopyable
+{
+    GLuint id = 0;
+    void create(VShader const &v,                   FShader const &f) { id = glCreateProgram(); glAttachShader(id, v.id);                           glAttachShader(id, f.id); glLinkProgram(id); }
+    void create(VShader const &v, const GShader &g, FShader const &f) { id = glCreateProgram(); glAttachShader(id, v.id); glAttachShader(id, g.id); glAttachShader(id, f.id); glLinkProgram(id); }
+    auto loc(char const *str) const { return glGetUniformLocation(id, str); }
+    ~Program() { glDeleteProgram(id); }
+};
+
+class VAO
+{
+public:
+    GLuint vao = 0;
+    GLuint vbuf;
+
+    VAO() = default;
+    VAO(GLuint vao, GLuint vbuf) : vao(vao), vbuf(vbuf) {}
+    VAO(VAO &&other) noexcept { movefrom(other); }
+    VAO &operator=(VAO &&other) noexcept { reset(); movefrom(other); return *this; }
+    ~VAO() { reset(); }
+
+private:
+    void reset() noexcept { if (vao) { glDeleteVertexArrays(1, &vao); glDeleteBuffers(1, &vbuf); } }
+    void movefrom(VAO &other) noexcept { vao = other.vao; vbuf = other.vbuf; other.vao = 0; }
+};
+
+struct GLFragment
+{
+    Texture texture;
+    Texture outline_texture;
+};
+
+class GLGraphics : public Graphics
+{
+public:
+    GLGraphics(Prefs const &prefs, Stores const &stores, PageInfo const &pi);
+    ~GLGraphics() override;
+
+    void set_scale_factor(int scale) override { scale_factor = scale; }
+    void set_outlines_enabled(bool) override;
+    void set_background_in_stores(bool enabled) override { background_in_stores = enabled; }
+    void set_colours(uint32_t p, uint32_t d, uint32_t b) override { page = p; desk = d; border = b; }
+
+    void recreate_store(Geom::IntPoint const &dimensions) override;
+    void shift_store(Fragment const &dest) override;
+    void swap_stores() override;
+    void fast_snapshot_combine() override;
+    void snapshot_combine(Fragment const &dest) override;
+    void invalidate_snapshot() override;
+
+    bool is_opengl() const override { return true; }
+    void invalidated_glstate() override { state = State::None; }
+
+    Cairo::RefPtr<Cairo::ImageSurface> request_tile_surface(Geom::IntRect const &rect, bool nogl) override;
+    void draw_tile(Fragment const &fragment, Cairo::RefPtr<Cairo::ImageSurface> surface, Cairo::RefPtr<Cairo::ImageSurface> outline_surface) override;
+    void junk_tile_surface(Cairo::RefPtr<Cairo::ImageSurface> surface) override;
+
+    void paint_widget(Fragment const &view, PaintArgs const &args, Cairo::RefPtr<Cairo::Context> const &cr) override;
+
+private:
+    // Drawn content.
+    GLFragment store, snapshot;
+
+    // OpenGL objects.
+    VAO rect; // Rectangle vertex data.
+    Program checker, shadow, texcopy, texcopydouble, outlineoverlay, xray, outlineoverlayxray; // Shaders
+    GLuint fbo; // Framebuffer object for rendering to stores.
+
+    // Pixel streamer and texture cache for uploading pixel data to GPU.
+    std::unique_ptr<PixelStreamer> pixelstreamer;
+    std::unique_ptr<TextureCache> texturecache;
+    std::mutex ps_mutex;
+
+    // For preventing unnecessary pipeline recreation.
+    enum class State { None, Widget, Stores, Tiles };
+    State state;
+    void setup_stores_pipeline();
+    void setup_tiles_pipeline();
+    void setup_widget_pipeline(Fragment const &view);
+
+    // For caching frequently-used uniforms.
+    GLuint mat_loc, trans_loc, subrect_loc, tex_loc, texoutline_loc;
+
+    // Dependency objects in canvas.
+    Prefs const &prefs;
+    Stores const &stores;
+    PageInfo const &pi;
+
+    // Backend-agnostic state.
+    int scale_factor = 1;
+    bool outlines_enabled = false;
+    bool background_in_stores = false;
+    uint32_t page, desk, border;
+};
+
+} // namespace Widget
+} // namespace UI
+} // namespace Inkscape
+
+#endif // INKSCAPE_UI_WIDGET_CANVAS_GLGRAPHICS_H
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :