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backends/graphics/opengl/pipelines/pipeline.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 BACKENDS_GRAPHICS_OPENGL_PIPELINES_PIPELINE_H
+#define BACKENDS_GRAPHICS_OPENGL_PIPELINES_PIPELINE_H
+
+#include "graphics/opengl/system_headers.h"
+#include "graphics/opengl/texture.h"
+
+#include "math/matrix4.h"
+
+namespace OpenGL {
+
+class Framebuffer;
+
+/**
+ * Interface for OpenGL pipeline functionality.
+ *
+ * This encapsulates differences in various rendering pipelines used for
+ * OpenGL, OpenGL ES 1, and OpenGL ES 2.
+ */
+class Pipeline {
+public:
+	/**
+	 * Deactivate any pipeline.
+	 */
+	static void disable() { if (activePipeline) activePipeline->deactivate(); }
+
+	Pipeline();
+	virtual ~Pipeline() { if (isActive()) deactivate(); }
+
+	/**
+	 * Activate the pipeline.
+	 *
+	 * This sets the OpenGL state to make use of drawing with the given
+	 * OpenGL pipeline.
+	 */
+	void activate();
+
+	/**
+	 * Deactivate the pipeline.
+	 */
+	void deactivate();
+
+	/**
+	 * Set framebuffer to render to.
+	 *
+	 * Client is responsible for any memory management related to framebuffer.
+	 *
+	 * @param framebuffer Framebuffer to activate.
+	 * @return Formerly active framebuffer.
+	 */
+	Framebuffer *setFramebuffer(Framebuffer *framebuffer);
+
+	/**
+	 * Set modulation color.
+	 *
+	 * @param r Red component in [0,1].
+	 * @param g Green component in [0,1].
+	 * @param b Blue component in [0,1].
+	 * @param a Alpha component in [0,1].
+	 */
+	virtual void setColor(GLfloat r, GLfloat g, GLfloat b, GLfloat a) = 0;
+
+	/**
+	 * Draw a texture rectangle to the currently active framebuffer.
+	 *
+	 * @param texture     Texture to use for drawing.
+	 * @param coordinates x1, y1, x2, y2 coordinates where to draw the texture.
+	 */
+	inline void drawTexture(const Texture &texture, const GLfloat *coordinates, const GLfloat *texcoords) {
+		drawTextureInternal(texture, coordinates, texcoords);
+	}
+
+	inline void drawTexture(const Texture &texture, const GLfloat *coordinates) {
+		drawTextureInternal(texture, coordinates, texture.getTexCoords());
+	}
+
+	inline void drawTexture(const Texture &texture, GLfloat x, GLfloat y, GLfloat w, GLfloat h) {
+		const GLfloat coordinates[4*2] = {
+			x,     y,
+			x + w, y,
+			x,     y + h,
+			x + w, y + h
+		};
+		drawTextureInternal(texture, coordinates, texture.getTexCoords());
+	}
+
+	inline void drawTexture(const Texture &texture, GLfloat x, GLfloat y, GLfloat w, GLfloat h, const Common::Rect &clip) {
+		const GLfloat coordinates[4*2] = {
+			x,     y,
+			x + w, y,
+			x,     y + h,
+			x + w, y + h
+		};
+
+		const uint tw = texture.getWidth(),
+			  th = texture.getHeight();
+
+		if (tw == 0 || th == 0) {
+			// Nothing to display
+			return;
+		}
+
+		const GLfloat texcoords[4*2] = {
+			(float)clip.left  / tw, (float)clip.top    / th,
+			(float)clip.right / tw, (float)clip.top    / th,
+			(float)clip.left  / tw, (float)clip.bottom / th,
+			(float)clip.right / tw, (float)clip.bottom / th
+		};
+
+		drawTextureInternal(texture, coordinates, texcoords);
+	}
+
+	/**
+	 * Set the projection matrix.
+	 *
+	 * This is intended to be only ever be used by Framebuffer subclasses.
+	 */
+	virtual void setProjectionMatrix(const Math::Matrix4 &projectionMatrix) = 0;
+
+protected:
+	/**
+	 * Activate the pipeline.
+	 *
+	 * This sets the OpenGL state to make use of drawing with the given
+	 * OpenGL pipeline.
+	 */
+	virtual void activateInternal();
+
+	/**
+	 * Deactivate the pipeline.
+	 */
+	virtual void deactivateInternal();
+
+	virtual void drawTextureInternal(const Texture &texture, const GLfloat *coordinates, const GLfloat *texcoords) = 0;
+
+	bool isActive() const { return activePipeline == this; }
+
+	Framebuffer *_activeFramebuffer;
+
+private:
+	/** Currently active rendering pipeline. */
+	static Pipeline *activePipeline;
+};
+
+} // End of namespace OpenGL
+
+#endif