Add texture / image OpenGL helper.

CMakeLists.txt

@@ -59,6 +59,8 @@ PRIVATE
     ui/effects/slide_animation.h
     ui/gl/gl_detection.cpp
     ui/gl/gl_detection.h
+    ui/gl/gl_image.cpp
+    ui/gl/gl_image.h
     ui/gl/gl_surface.cpp
     ui/gl/gl_surface.h
     ui/image/image_prepare.cpp

ui/gl/gl_image.cpp

@@ -0,0 +1,85 @@
+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#include "ui/gl/gl_image.h"
+
+#include <QtGui/QOpenGLFunctions>
+
+namespace Ui::GL {
+namespace details {
+
+void GenerateTextures(QOpenGLFunctions &f, gsl::span<GLuint> values) {
+	Expects(!values.empty());
+
+	f.glGenTextures(values.size(), values.data());
+	for (const auto texture : values) {
+		f.glBindTexture(GL_TEXTURE_2D, texture);
+		const auto clamp = GL_CLAMP_TO_EDGE;
+		f.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, clamp);
+		f.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, clamp);
+		f.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+		f.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+	}
+}
+
+void DestroyTextures(QOpenGLFunctions &f, gsl::span<GLuint> values) {
+	Expects(!values.empty());
+
+	f.glDeleteTextures(values.size(), values.data());
+	ranges::fill(values, 0);
+}
+
+} // namespace details
+void Image::setImage(QImage image) {
+	_image = std::move(image);
+}
+
+const QImage &Image::image() const {
+	return _image;
+}
+
+QImage Image::takeImage() {
+	return _image.isNull() ? base::take(_storage) : base::take(_image);
+}
+
+void Image::invalidate() {
+	_storage = base::take(_image);
+}
+
+void Image::bind(QOpenGLFunctions &f) {
+	Expects(!_image.isNull());
+
+	_textures.ensureCreated(f);
+	const auto cacheKey = _image.cacheKey();
+	const auto upload = (_cacheKey != cacheKey);
+	if (upload) {
+		_cacheKey = cacheKey;
+		_index = 1 - _index;
+	}
+	_textures.bind(f, _index);
+	const auto error = f.glGetError();
+	if (upload) {
+		f.glPixelStorei(GL_UNPACK_ROW_LENGTH, _image.bytesPerLine() / 4);
+		f.glTexImage2D(
+			GL_TEXTURE_2D,
+			0,
+			GL_RGBA,
+			_image.width(),
+			_image.height(),
+			0,
+			GL_RGBA,
+			GL_UNSIGNED_BYTE,
+			_image.constBits());
+		f.glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
+	}
+}
+
+void Image::destroy(QOpenGLFunctions &f) {
+	_textures.destroy(f);
+	_cacheKey = 0;
+}
+
+} // namespace Ui::GL

ui/gl/gl_image.h

@@ -0,0 +1,73 @@
+// This file is part of Desktop App Toolkit,
+// a set of libraries for developing nice desktop applications.
+//
+// For license and copyright information please follow this link:
+// https://github.com/desktop-app/legal/blob/master/LEGAL
+//
+#pragma once
+
+#include <QtGui/QOpenGLFunctions>
+
+namespace Ui::GL {
+namespace details {
+
+void GenerateTextures(QOpenGLFunctions &f, gsl::span<GLuint> values);
+void DestroyTextures(QOpenGLFunctions &f, gsl::span<GLuint> values);
+
+} // namespace details
+
+template <size_t Count>
+class Textures final {
+public:
+	static_assert(Count > 0);
+
+	void ensureCreated(QOpenGLFunctions &f) {
+		if (!created()) {
+			details::GenerateTextures(f, gsl::make_span(_values));
+		}
+	}
+	void destroy(QOpenGLFunctions &f) {
+		if (created()) {
+			details::DestroyTextures(f, gsl::make_span(_values));
+		}
+	}
+
+	[[nodiscard]] void bind(QOpenGLFunctions &f, int index) const {
+		Expects(index >= 0 && index < Count);
+
+		f.glBindTexture(GL_TEXTURE_2D, _values[index]);
+	}
+
+	[[nodiscard]] bool created() const {
+		return (_values[0] != 0);
+	}
+
+private:
+	std::array<GLuint, Count> _values = { { 0 } };
+
+};
+
+class Image final {
+public:
+	void setImage(QImage image);
+	[[nodiscard]] const QImage &image() const;
+	[[nodiscard]] QImage takeImage();
+	void invalidate();
+
+	void bind(QOpenGLFunctions &f);
+	void destroy(QOpenGLFunctions &f);
+
+	explicit operator bool() const {
+		return !_image.isNull();
+	}
+
+private:
+	QImage _image;
+	QImage _storage;
+	Textures<2> _textures;
+	qint64 _cacheKey = 0;
+	int _index = 0;
+
+};
+
+} // namespace Ui::GL

ui/gl/gl_surface.cpp

@@ -71,15 +71,15 @@ void SurfaceOpenGL::initializeGL() {
 		context,
 		&QOpenGLContext::aboutToBeDestroyed,
 		[=] { callDeInit(); });
-	_renderer->init(this, context->functions());
+	_renderer->init(this, *context->functions());
 }
 
 void SurfaceOpenGL::resizeGL(int w, int h) {
-	_renderer->resize(this, context()->functions(), w, h);
+	_renderer->resize(this, *context()->functions(), w, h);
 }
 
 void SurfaceOpenGL::paintGL() {
-	_renderer->paint(this, context()->functions());
+	_renderer->paint(this, *context()->functions());
 }
 
 void SurfaceOpenGL::callDeInit() {
@@ -91,7 +91,7 @@ void SurfaceOpenGL::callDeInit() {
 	Assert(surface != nullptr);
 	const auto context = this->context();
 	context->makeCurrent(surface);
-	_renderer->deinit(this, context->functions());
+	_renderer->deinit(this, *context->functions());
 }
 
 SurfaceRaster::SurfaceRaster(
@@ -109,7 +109,7 @@ void SurfaceRaster::paintEvent(QPaintEvent *e) {
 
 void Renderer::paint(
 		not_null<QOpenGLWidget*> widget,
-		not_null<QOpenGLFunctions*> f) {
+		QOpenGLFunctions &f) {
 	paintFallback(Painter(widget.get()), widget->rect(), Backend::OpenGL);
 }
 

ui/gl/gl_surface.h

@@ -28,24 +28,24 @@ class Renderer {
 public:
     virtual void init(
         not_null<QOpenGLWidget*> widget,
-        not_null<QOpenGLFunctions*> f) {
+        QOpenGLFunctions &f) {
     }
 
     virtual void deinit(
         not_null<QOpenGLWidget*> widget,
-        not_null<QOpenGLFunctions*> f) {
+        QOpenGLFunctions &f) {
     }
 
     virtual void resize(
         not_null<QOpenGLWidget*> widget,
-        not_null<QOpenGLFunctions*> f,
+        QOpenGLFunctions &f,
         int w,
         int h) {
     }
 
     virtual void paint(
         not_null<QOpenGLWidget*> widget,
-        not_null<QOpenGLFunctions*> f);
+        QOpenGLFunctions &f);
 
     virtual void paintFallback(
         Painter &&p,