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MCVE example
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@djowel
djowel committed Mar 16, 2024
1 parent 58024d0 commit eddca84
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Showing 2 changed files with 52 additions and 425 deletions.
165 changes: 52 additions & 113 deletions examples/host/linux/skia_app.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@
Distributed under the MIT License [ https://opensource.org/licenses/MIT ]
=============================================================================*/
#include "../../app.hpp"
#include <gtk/gtk.h>
#include <GL/gl.h>
#include <GL/glx.h>
Expand All @@ -14,94 +13,55 @@
#include "SkColorSpace.h"
#include "SkCanvas.h"
#include "SkSurface.h"
#include <chrono>

using namespace cycfi::artist;
float elapsed_ = 0; // rendering elapsed time

namespace
{
struct view_state
{
extent _size = {};
float _scale = 1.0;
bool _animate = false;
color _bkd = colors::white;
guint _timer_id = 0;

sk_sp<const GrGLInterface> _xface;
sk_sp<GrDirectContext> _ctx;
sk_sp<SkSurface> _surface;
};

void close_window(GtkWidget*, gpointer user_data)
{
view_state& state = *reinterpret_cast<view_state*>(user_data);
if (state._timer_id)
g_source_remove(state._timer_id);
}
sk_sp<const GrGLInterface> gl_interface;
sk_sp<GrDirectContext> gr_context;
sk_sp<SkSurface> skia_surface;

void realize(GtkGLArea* area, gpointer user_data)
{
gtk_gl_area_make_current (area);
if (gtk_gl_area_get_error (area) != NULL)
return;

view_state& state = *reinterpret_cast<view_state*>(user_data);
glClearColor(state._bkd.red, state._bkd.green, state._bkd.blue, state._bkd.alpha);
glClearColor(0, 0, 0, 1);
glClear(GL_COLOR_BUFFER_BIT);
state._xface = GrGLMakeNativeInterface();
state._ctx = GrDirectContext::MakeGL(state._xface);
gl_interface = GrGLMakeNativeInterface();
gr_context = GrDirectContext::MakeGL(gl_interface);
}

gboolean render(GtkGLArea* area, GdkGLContext* context, gpointer user_data)
{
view_state& state = *reinterpret_cast<view_state*>(user_data);
auto error = [](char const* msg) { throw std::runtime_error(msg); };

auto draw_f =
[&]()
{
if (!state._surface)
{
GrGLint buffer;
glGetIntegerv(GL_FRAMEBUFFER_BINDING, &buffer);
GrGLFramebufferInfo info;
info.fFBOID = (GrGLuint) buffer;
SkColorType colorType = kRGBA_8888_SkColorType;

info.fFormat = GL_RGBA8;
GrBackendRenderTarget target(
state._size.x*state._scale
, state._size.y*state._scale
, 0, 8, info
);

state._surface =
SkSurface::MakeFromBackendRenderTarget(
state._ctx.get(), target,
kBottomLeft_GrSurfaceOrigin, colorType, nullptr, nullptr
);

if (!state._surface)
error("Error: SkSurface::MakeRenderTarget returned null");
}

SkCanvas* gpu_canvas = state._surface->getCanvas();
gpu_canvas->save();
gpu_canvas->scale(state._scale, state._scale);
auto cnv = canvas{gpu_canvas};

draw(cnv);

gpu_canvas->restore();
state._surface->flush();
};

auto start = std::chrono::steady_clock::now();
draw_f();
auto stop = std::chrono::steady_clock::now();
elapsed_ = std::chrono::duration<double>{stop - start}.count();
if (!skia_surface)
{
GrGLint buffer;
glGetIntegerv(GL_FRAMEBUFFER_BINDING, &buffer);
GrGLFramebufferInfo info;
info.fFBOID = (GrGLuint) buffer;
SkColorType colorType = kRGBA_8888_SkColorType;

info.fFormat = GL_RGBA8;
GrBackendRenderTarget target(640, 480, 0, 8, info);

skia_surface =
SkSurface::MakeFromBackendRenderTarget(
gr_context.get(), target,
kBottomLeft_GrSurfaceOrigin, colorType, nullptr, nullptr
);

if (!skia_surface)
throw std::runtime_error("Error: SkSurface::MakeRenderTarget returned null");
}

SkCanvas* gpu_canvas = skia_surface->getCanvas();
gpu_canvas->save();

// Drawing here...

gpu_canvas->restore();
skia_surface->flush();

return true;
}
Expand All @@ -113,38 +73,41 @@ namespace
return true;
}

static auto proc = &glXGetProcAddress;

void activate(GtkApplication* app, gpointer user_data)
{
auto error = [](char const* msg) { throw std::runtime_error(msg); };
if (!proc)
error("Error: glXGetProcAddress is null");

view_state& state = *reinterpret_cast<view_state*>(user_data);
auto* window = gtk_application_window_new(app);
gtk_window_set_title(GTK_WINDOW(window), "Drawing Area");

g_signal_connect(window, "destroy", G_CALLBACK(close_window), user_data);

// create a GtkGLArea instance
auto* gl_area = gtk_gl_area_new();
gtk_container_add(GTK_CONTAINER(window), gl_area);

g_signal_connect(gl_area, "render", G_CALLBACK(render), user_data);
g_signal_connect(gl_area, "realize", G_CALLBACK(realize), user_data);

gtk_window_resize(GTK_WINDOW(window), state._size.x, state._size.y);
gtk_window_resize(GTK_WINDOW(window), 640, 480);
gtk_widget_show_all(window);

auto w = gtk_widget_get_window(GTK_WIDGET(window));
state._scale = gdk_window_get_scale_factor(w);

if (state._animate)
state._timer_id = g_timeout_add(1000 / 60, animate, gl_area);
}
}

int main(int argc, char const* argv[])
{
auto* app = gtk_application_new("org.gtk-skia.example", G_APPLICATION_FLAGS_NONE);
g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
int status = g_application_run(G_APPLICATION(app), argc, const_cast<char**>(argv));
g_object_unref(app);

return status;
}

#include <artist/resources.hpp>
#include <filesystem>
namespace fs = std::filesystem;

float elapsed_ = 0; // rendering elapsed time

namespace cycfi::artist
{
void init_paths()
Expand All @@ -159,28 +122,4 @@ namespace cycfi::artist
{
return fs::path(fs::current_path() / "resources/fonts");
}
}

int run_app(
int argc
, char const* argv[]
, extent window_size
, color background_color
, bool animate
)
{
view_state state;
state._size = window_size;
state._animate = animate;
state._bkd = background_color;

auto* app = gtk_application_new("org.gtk-skia.example", G_APPLICATION_FLAGS_NONE);
g_signal_connect(app, "activate", G_CALLBACK(activate), &state);
int status = g_application_run(G_APPLICATION(app), argc, const_cast<char**>(argv));
g_object_unref(app);

return status;
}



}
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