TerritoryTexture.h

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/* Copyright (C) 2011 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. 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 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. 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 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "lib/ogl.h"

#include "maths/Matrix3D.h"
#include "simulation2/helpers/Grid.h"

class CSimulation2;

/**
 * Maintains the territory boundary texture, used for
 * rendering and for the minimap.
 */
class CTerritoryTexture
{
    NONCOPYABLE(CTerritoryTexture);

public:
    CTerritoryTexture(CSimulation2& simulation);
    ~CTerritoryTexture();

    /**
     * Recomputes the territory texture if necessary, and binds it to the requested
     * texture unit.
     * Also switches the current active texture unit, and enables texturing on it.
     * The texture is in 32-bit BGRA format.
     */
    void BindTexture(int unit);

    /**
     * Recomputes the territory texture if necessary, and returns the texture handle.
     * Also potentially switches the current active texture unit, and enables texturing on it.
     * The texture is in 32-bit BGRA format.
     */
    GLuint GetTexture();

    /**
     * Returns a matrix to map (x,y,z) world coordinates onto (u,v) texture
     * coordinates, in the form expected by glLoadMatrixf.
     * This must only be called after BindTexture.
     */
    const float* GetTextureMatrix();

    /**
     * Returns a matrix to map (0,0)-(1,1) texture coordinates onto texture
     * coordinates, in the form expected by glLoadMatrixf.
     * This must only be called after BindTexture.
     */
    const float* GetMinimapTextureMatrix();

private:
    /**
     * Returns true if the territory state has changed since the last call to this function
     */
    bool UpdateDirty();

    void DeleteTexture();
    void ConstructTexture(int unit);
    void RecomputeTexture(int unit);

    void GenerateBitmap(const Grid<u8>& territories, u8* bitmap, ssize_t w, ssize_t h);

    CSimulation2& m_Simulation;

    size_t m_DirtyID;

    GLuint m_Texture;

    ssize_t m_MapSize; // tiles per side
    GLsizei m_TextureSize; // texels per side

    CMatrix3D m_TextureMatrix;
    CMatrix3D m_MinimapTextureMatrix;
};