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graphics/opengl/context.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef GRAPHICS_OPENGL_CONTEXT_H
+#define GRAPHICS_OPENGL_CONTEXT_H
+
+#include "common/singleton.h"
+
+namespace OpenGL {
+
+enum ContextType {
+	kContextNone,
+	kContextGL,
+	kContextGLES,
+	kContextGLES2
+};
+
+/**
+ * Description structure of the OpenGL (ES) context.
+ */
+class Context : public Common::Singleton<Context> {
+public:
+	Context();
+
+	/**
+	 * Initialize the context description from currently active context.
+	 *
+	 * The extensions and features are marked as available according
+	 * to the current context capabilities.
+	 */
+	void initialize(ContextType contextType);
+
+	/**
+	 * Reset context.
+	 *
+	 * This marks all extensions as unavailable.
+	 */
+	void reset();
+
+	/** The type of the active context. */
+	ContextType type;
+
+	/** Helper function for checking the GL version supported by the context. */
+	inline bool isGLVersionOrHigher(int major, int minor) const {
+		return ((majorVersion > major) || ((majorVersion == major) && (minorVersion >= minor)));
+	}
+
+	/** The GL version supported by the context. */
+	int majorVersion, minorVersion;
+
+	/** The GLSL version supported by the context */
+	int glslVersion;
+
+	/** The maximum texture size supported by the context. */
+	int maxTextureSize;
+
+	/** Whether GL_ARB_texture_non_power_of_two is available or not. */
+	bool NPOTSupported;
+
+	/** Whether GL_ARB_imaging is available or not. */
+	bool imagingSupported;
+
+	/** Whether shader support is available or not. */
+	bool shadersSupported;
+
+	/** Whether shader support is good enough for engines or not. */
+	bool enginesShadersSupported;
+
+	/** Whether multi texture support is available or not. */
+	bool multitextureSupported;
+
+	/** Whether FBO support is available or not. */
+	bool framebufferObjectSupported;
+
+	/** Whether multisample FBO support is available or not */
+	bool framebufferObjectMultisampleSupported;
+
+	/**
+	 * Contains the maximum number of supported multisample samples
+	 * if multisample FBOs are supported. Contains -1 otherwise.
+	 */
+	int multisampleMaxSamples;
+
+	/** Whether BGRA support is available or not. */
+	bool bgraSupported;
+
+	/** Whether packed pixels support is available or not. */
+	bool packedPixelsSupported;
+
+	/** Whether packing the depth and stencil buffers is possible or not. */
+	bool packedDepthStencilSupported;
+
+	/** Whether specifying a pitch when uploading to textures is available or not */
+	bool unpackSubImageSupported;
+
+	/** Whether depth component 24 is supported or not */
+	bool OESDepth24;
+
+	/** Whether texture coordinate edge clamping is available or not. */
+	bool textureEdgeClampSupported;
+
+	/** Whether texture coordinate border clamping is available or not. */
+	bool textureBorderClampSupported;
+
+	/** Whether texture coordinate mirrored repeat is available or not. */
+	bool textureMirrorRepeatSupported;
+
+	/** Whether texture max level is available or not. */
+	bool textureMaxLevelSupported;
+
+	/** Texture lookup result precision. */
+	unsigned int textureLookupPrecision;
+
+private:
+	/**
+	 * Returns the native GLSL version supported by the driver.
+	 * This does NOT take shaders ARB extensions into account.
+	 */
+	int getGLSLVersion() const;
+};
+
+} // End of namespace OpenGL
+
+/** Shortcut for accessing the active OpenGL context. */
+#define OpenGLContext OpenGL::Context::instance()
+
+#endif