pipeline.h

/* 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;

class Pipeline {
public:
    static void disable() { if (activePipeline) activePipeline->deactivate(); }

    Pipeline();
    virtual ~Pipeline() { if (isActive()) deactivate(); }

    void activate();

    void deactivate();

    Framebuffer *setFramebuffer(Framebuffer *framebuffer);

    virtual void setColor(GLfloat r, GLfloat g, GLfloat b, GLfloat a) = 0;

    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);
    }

    virtual void setProjectionMatrix(const Math::Matrix4 &projectionMatrix) = 0;

protected:
    virtual void activateInternal();

    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:
    static Pipeline *activePipeline;
};

} // End of namespace OpenGL

#endif