urho3d/Engine/Graphics/OpenGL/OGLTexture.h

//
// Urho3D Engine
// Copyright (c) 2008-2011 Lasse Öörni
//
// 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.
//

#pragma once

#include "Color.h"
#include "GPUObject.h"
#include "Image.h"
#include "GraphicsDefs.h"
#include "Resource.h"

static const int MAX_TEXTURE_QUALITY_LEVELS = 3;

class XMLFile;

/// Base class for texture resources
class Texture : public Resource, public GPUObject
{
public:
    /// Construct
    Texture(Context* context);
    /// Destruct
    virtual ~Texture();
    
    /// Set number of requested mipmap levels. Needs to be called before setting size
    void SetNumLevels(unsigned levels);
    /// Set filtering mode
    void SetFilterMode(TextureFilterMode filter);
    /// Set addressing mode by texture coordinate
    void SetAddressMode(TextureCoordinate coord, TextureAddressMode address);
    /// Set shadow compare mode, OpenGL only
    void SetShadowCompare(bool enable);
    /// Set border color for border addressing mode
    void SetBorderColor(const Color& color);
    /// Set backup texture to use when rendering to this texture
    void SetBackupTexture(Texture* texture);
    /// Dirty the parameters
    void SetParametersDirty();
    /// Clear data lost flag. No-op on OpenGL
    void ClearDataLost();
    /// Update changed parameters to OpenGL. Called by Graphics when binding the texture
    void UpdateParameters();
    
    /// Return texture usage type
    TextureUsage GetUsage() const;
    /// Return texture's OpenGL type
    unsigned GetTextureType() const { return textureType_; }
    /// Return texture format
    unsigned GetFormat() const { return format_; }
    /// Return number of mipmap levels
    unsigned GetLevels() const { return levels_; }
    /// Return OpenGL depth bits
    int GetDepthBits() const { return depthBits_; }
    /// Return width
    int GetWidth() const { return width_; }
    /// Return height
    int GetHeight() const { return height_; }
    /// Return whether data is lost. Always false on OpenGL
    bool IsDataLost() const { return false; }
    /// Return whether parameters are dirty
    bool GetParametersDirty() const { return parametersDirty_; }
    /// Return filtering mode
    TextureFilterMode GetFilterMode() const { return filterMode_; }
    /// Return addressing mode by texture coordinate
    TextureAddressMode GetAddressMode(TextureCoordinate coord) const { return addressMode_[coord]; }
    /// Return whether shadow compare is enabled, OpenGL only
    bool GetShadowCompare() const { return shadowCompare_; }
     /// Return border color
    const Color& GetBorderColor() const { return borderColor_; }
    /// Return backup texture
    Texture* GetBackupTexture() const { return backupTexture_; }
    /// Return API-specific compressed texture format
    static unsigned GetDXTFormat(CompressedFormat format);
    /// Return the non-internal texture format corresponding to an OpenGL internal format
    static unsigned GetExternalFormat(unsigned format);
    /// Return the data type corresponding to an OpenGL internal format
    static unsigned GetDataType(unsigned format);
    
protected:
    /// Load parameters
    void LoadParameters();
    /// Load parameters from an XML file
    void LoadParameters(XMLFile* xml);
    /// Check whether texture memory budget has been exceeded. Free unused materials in that case to release the texture references
    void CheckTextureBudget(ShortStringHash type);
    
    /// Texture's OpenGL type
    unsigned textureType_;
    /// Texture format
    unsigned format_;
    /// Current mipmap levels
    unsigned levels_;
    /// Requested mipmap levels
    unsigned requestedLevels_;
    /// Texture's OpenGL depth bits (depth textures only)
    int depthBits_;
    /// Texture width
    int width_;
    /// Texture height
    int height_;
    /// Dynamic flag
    bool dynamic_;
    /// Shadow compare mode, OpenGL only
    bool shadowCompare_;
    /// Parameters dirty flag
    bool parametersDirty_;
    /// Filtering mode
    TextureFilterMode filterMode_;
    /// Addressing mode
    TextureAddressMode addressMode_[MAX_COORDS];
    /// Mipmaps to skip when loading
    unsigned mipsToSkip_[MAX_TEXTURE_QUALITY_LEVELS];
    /// Border color
    Color borderColor_;
    /// Backup texture
    SharedPtr<Texture> backupTexture_;
};