Add OpenGL3 renderer and backends supporting the GLFW and SDL platfor…

…ms. Emscripten compilation supported on the SDL/GL3 backend.

Backends/RmlUi_Backend_GLFW_GL3.cpp

@@ -0,0 +1,258 @@
+/*
+ * This source file is part of RmlUi, the HTML/CSS Interface Middleware
+ *
+ * For the latest information, see http://github.com/mikke89/RmlUi
+ *
+ * Copyright (c) 2008-2010 CodePoint Ltd, Shift Technology Ltd
+ * Copyright (c) 2019 The RmlUi Team, and contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ */
+
+#include "RmlUi_Backend.h"
+#include "RmlUi_Platform_GLFW.h"
+#include "RmlUi_Renderer_GL3.h"
+#include <RmlUi/Core/Context.h>
+#include <RmlUi/Core/Input.h>
+#include <RmlUi/Core/Profiling.h>
+#include <GLFW/glfw3.h>
+
+static void SetupCallbacks(GLFWwindow* window);
+
+static void LogErrorFromGLFW(int error, const char* description)
+{
+	Rml::Log::Message(Rml::Log::LT_ERROR, "GLFW error (0x%x): %s", error, description);
+}
+
+/**
+    Global data used by this backend.
+
+    Lifetime governed by the calls to Backend::Initialize() and Backend::Shutdown().
+ */
+struct BackendData {
+	SystemInterface_GLFW system_interface;
+	RenderInterface_GL3 render_interface;
+	GLFWwindow* window = nullptr;
+	int glfw_active_modifiers = 0;
+	bool context_dimensions_dirty = true;
+
+	// Arguments set during event processing and nulled otherwise.
+	Rml::Context* context = nullptr;
+	KeyDownCallback key_down_callback = nullptr;
+};
+static Rml::UniquePtr<BackendData> data;
+
+bool Backend::Initialize(const char* name, int width, int height, bool allow_resize)
+{
+	RMLUI_ASSERT(!data);
+
+	glfwSetErrorCallback(LogErrorFromGLFW);
+
+	if (!glfwInit())
+		return false;
+
+	// Set window hints for OpenGL 3.3 Core context creation.
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+	glfwWindowHint(GLFW_DOUBLEBUFFER, GLFW_TRUE);
+
+	// Request stencil buffer of at least 8-bit size to supporting clipping on transformed elements.
+	glfwWindowHint(GLFW_STENCIL_BITS, 8);
+
+	// Enable MSAA for better-looking visuals, especially when transforms are applied.
+	glfwWindowHint(GLFW_SAMPLES, 2);
+
+	// Apply window properties and create it.
+	glfwWindowHint(GLFW_RESIZABLE, allow_resize ? GLFW_TRUE : GLFW_FALSE);
+	glfwWindowHint(GLFW_SCALE_TO_MONITOR, GLFW_TRUE);
+
+	GLFWwindow* window = glfwCreateWindow(width, height, name, nullptr, nullptr);
+	if (!window)
+		return false;
+
+	glfwMakeContextCurrent(window);
+	glfwSwapInterval(1);
+
+	// Load the OpenGL functions.
+	Rml::String renderer_message;
+	if (!RmlGL3::Initialize(&renderer_message))
+		return false;
+
+	// Construct the system and render interface, this includes compiling all the shaders. If this fails, it is likely an error in the shader code.
+	data = Rml::MakeUnique<BackendData>();
+	if (!data || !data->render_interface)
+		return false;
+
+	data->window = window;
+	data->system_interface.SetWindow(window);
+	data->system_interface.LogMessage(Rml::Log::LT_INFO, renderer_message);
+
+	// The window size may have been scaled by DPI settings, get the actual pixel size.
+	glfwGetFramebufferSize(window, &width, &height);
+	data->render_interface.SetViewport(width, height);
+
+	// Setup the input and window event callback functions.
+	SetupCallbacks(window);
+
+	return true;
+}
+
+void Backend::Shutdown()
+{
+	RMLUI_ASSERT(data);
+	glfwDestroyWindow(data->window);
+	data.reset();
+	RmlGL3::Shutdown();
+	glfwTerminate();
+}
+
+Rml::SystemInterface* Backend::GetSystemInterface()
+{
+	RMLUI_ASSERT(data);
+	return &data->system_interface;
+}
+
+Rml::RenderInterface* Backend::GetRenderInterface()
+{
+	RMLUI_ASSERT(data);
+	return &data->render_interface;
+}
+
+bool Backend::ProcessEvents(Rml::Context* context, KeyDownCallback key_down_callback)
+{
+	RMLUI_ASSERT(data && context);
+
+	// The initial window size may have been affected by system DPI settings, apply the actual pixel size and dp-ratio to the context.
+	if (data->context_dimensions_dirty)
+	{
+		data->context_dimensions_dirty = false;
+
+		Rml::Vector2i window_size;
+		float dp_ratio = 1.f;
+		glfwGetFramebufferSize(data->window, &window_size.x, &window_size.y);
+		glfwGetWindowContentScale(data->window, &dp_ratio, nullptr);
+
+		context->SetDimensions(window_size);
+		context->SetDensityIndependentPixelRatio(dp_ratio);
+	}
+
+	data->context = context;
+	data->key_down_callback = key_down_callback;
+
+	glfwPollEvents();
+
+	data->context = nullptr;
+	data->key_down_callback = nullptr;
+
+	return !glfwWindowShouldClose(data->window);
+}
+
+void Backend::RequestExit()
+{
+	RMLUI_ASSERT(data);
+	glfwSetWindowShouldClose(data->window, GLFW_TRUE);
+}
+
+void Backend::BeginFrame()
+{
+	RMLUI_ASSERT(data);
+	data->render_interface.BeginFrame();
+	data->render_interface.Clear();
+}
+
+void Backend::PresentFrame()
+{
+	RMLUI_ASSERT(data);
+	data->render_interface.EndFrame();
+	glfwSwapBuffers(data->window);
+
+	// Optional, used to mark frames during performance profiling.
+	RMLUI_FrameMark;
+}
+
+static void SetupCallbacks(GLFWwindow* window)
+{
+	RMLUI_ASSERT(data);
+
+	// Key input
+	glfwSetKeyCallback(window, [](GLFWwindow* /*window*/, int glfw_key, int /*scancode*/, int glfw_action, int glfw_mods) {
+		if (!data->context)
+			return;
+
+		// Store the active modifiers for later because GLFW doesn't provide them in the callbacks to the mouse input events.
+		data->glfw_active_modifiers = glfw_mods;
+
+		// Override the default key event callback to add global shortcuts for the samples.
+		Rml::Context* context = data->context;
+		KeyDownCallback key_down_callback = data->key_down_callback;
+
+		switch (glfw_action)
+		{
+		case GLFW_PRESS:
+		case GLFW_REPEAT:
+		{
+			const Rml::Input::KeyIdentifier key = RmlGLFW::ConvertKey(glfw_key);
+			const int key_modifier = RmlGLFW::ConvertKeyModifiers(glfw_mods);
+			float dp_ratio = 1.f;
+			glfwGetWindowContentScale(data->window, &dp_ratio, nullptr);
+
+			// See if we have any global shortcuts that take priority over the context.
+			if (key_down_callback && !key_down_callback(context, key, key_modifier, dp_ratio, true))
+				break;
+			// Otherwise, hand the event over to the context by calling the input handler as normal.
+			if (!RmlGLFW::ProcessKeyCallback(context, glfw_key, glfw_action, glfw_mods))
+				break;
+			// The key was not consumed by the context either, try keyboard shortcuts of lower priority.
+			if (key_down_callback && !key_down_callback(context, key, key_modifier, dp_ratio, false))
+				break;
+		}
+		break;
+		case GLFW_RELEASE:
+			RmlGLFW::ProcessKeyCallback(context, glfw_key, glfw_action, glfw_mods);
+			break;
+		}
+	});
+
+	glfwSetCharCallback(window, [](GLFWwindow* /*window*/, unsigned int codepoint) { RmlGLFW::ProcessCharCallback(data->context, codepoint); });
+
+	// Mouse input
+	glfwSetCursorPosCallback(window, [](GLFWwindow* /*window*/, double xpos, double ypos) {
+		RmlGLFW::ProcessCursorPosCallback(data->context, xpos, ypos, data->glfw_active_modifiers);
+	});
+
+	glfwSetMouseButtonCallback(window, [](GLFWwindow* /*window*/, int button, int action, int mods) {
+		data->glfw_active_modifiers = mods;
+		RmlGLFW::ProcessMouseButtonCallback(data->context, button, action, mods);
+	});
+
+	glfwSetScrollCallback(window, [](GLFWwindow* /*window*/, double /*xoffset*/, double yoffset) {
+		RmlGLFW::ProcessScrollCallback(data->context, yoffset, data->glfw_active_modifiers);
+	});
+
+	// Window events
+	glfwSetFramebufferSizeCallback(window, [](GLFWwindow* /*window*/, int width, int height) {
+		data->render_interface.SetViewport(width, height);
+		RmlGLFW::ProcessFramebufferSizeCallback(data->context, width, height);
+	});
+
+	glfwSetWindowContentScaleCallback(window,
+		[](GLFWwindow* /*window*/, float xscale, float /*yscale*/) { RmlGLFW::ProcessContentScaleCallback(data->context, xscale); });
+}