/**
 * @file llviewershadermgr.h
 * @brief Viewer Shader Manager
 *
 * $LicenseInfo:firstyear=2001&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_VIEWER_SHADER_MGR_H
#define LL_VIEWER_SHADER_MGR_H

#include "llshadermgr.h"
#include "llmaterial.h"

#define LL_DEFERRED_MULTI_LIGHT_COUNT 16

class LLViewerShaderMgr: public LLShaderMgr
{
public:
    static bool sInitialized;
    static bool sSkipReload;

    LLViewerShaderMgr();
    /* virtual */ ~LLViewerShaderMgr();

    // Add shaders to mShaderList for later uniform propagation
    // Will assert on redundant shader entries in debug builds
    void finalizeShaderList();

    // singleton pattern implementation
    static LLViewerShaderMgr * instance();
    static void releaseInstance();

    void initAttribsAndUniforms(void);
    void setShaders();
    void unloadShaders();
    S32  getShaderLevel(S32 type);

    // loadBasicShaders in case of a failure returns
    // name of a file error happened at, otherwise
    // returns an empty string
    std::string loadBasicShaders();
    bool loadShadersEffects();
    bool loadShadersDeferred();
    bool loadShadersObject();
    bool loadShadersAvatar();
    bool loadShadersWater();
    bool loadShadersInterface();

    std::vector<S32> mShaderLevel;
    S32 mMaxAvatarShaderLevel;

    enum EShaderClass
    {
        SHADER_LIGHTING,
        SHADER_OBJECT,
        SHADER_AVATAR,
        SHADER_ENVIRONMENT,
        SHADER_INTERFACE,
        SHADER_EFFECT,
        SHADER_WINDLIGHT,
        SHADER_WATER,
        SHADER_DEFERRED,
        SHADER_COUNT
    };

    // simple model of forward iterator
    // http://www.sgi.com/tech/stl/ForwardIterator.html
    class shader_iter
    {
    private:
        friend bool operator == (shader_iter const & a, shader_iter const & b);
        friend bool operator != (shader_iter const & a, shader_iter const & b);

        typedef std::vector<LLGLSLShader *>::const_iterator base_iter_t;
    public:
        shader_iter()
        {
        }

        shader_iter(base_iter_t iter) : mIter(iter)
        {
        }

        LLGLSLShader & operator * () const
        {
            return **mIter;
        }

        LLGLSLShader * operator -> () const
        {
            return *mIter;
        }

        shader_iter & operator++ ()
        {
            ++mIter;
            return *this;
        }

        shader_iter operator++ (int)
        {
            return mIter++;
        }

    private:
        base_iter_t mIter;
    };

    shader_iter beginShaders() const;
    shader_iter endShaders() const;

    /* virtual */ std::string getShaderDirPrefix(void);

    /* virtual */ void updateShaderUniforms(LLGLSLShader * shader);

private:
    // the list of shaders we need to propagate parameters to.
    std::vector<LLGLSLShader *> mShaderList;

}; //LLViewerShaderMgr

inline bool operator == (LLViewerShaderMgr::shader_iter const & a, LLViewerShaderMgr::shader_iter const & b)
{
    return a.mIter == b.mIter;
}

inline bool operator != (LLViewerShaderMgr::shader_iter const & a, LLViewerShaderMgr::shader_iter const & b)
{
    return a.mIter != b.mIter;
}

extern LLVector4            gShinyOrigin;

//utility shaders
extern LLGLSLShader         gOcclusionProgram;
extern LLGLSLShader         gOcclusionCubeProgram;
extern LLGLSLShader         gGlowCombineProgram;
extern LLGLSLShader         gReflectionMipProgram;
extern LLGLSLShader         gGaussianProgram;
extern LLGLSLShader         gRadianceGenProgram;
extern LLGLSLShader         gHeroRadianceGenProgram;
extern LLGLSLShader         gIrradianceGenProgram;
extern LLGLSLShader         gGlowCombineFXAAProgram;
extern LLGLSLShader         gDebugProgram;
enum NormalDebugShaderVariant : S32
{
    NORMAL_DEBUG_SHADER_DEFAULT,
    NORMAL_DEBUG_SHADER_WITH_TANGENTS,
    NORMAL_DEBUG_SHADER_COUNT
};
extern LLGLSLShader         gNormalDebugProgram[NORMAL_DEBUG_SHADER_COUNT];
extern LLGLSLShader         gSkinnedNormalDebugProgram[NORMAL_DEBUG_SHADER_COUNT];
extern LLGLSLShader         gClipProgram;
extern LLGLSLShader         gBenchmarkProgram;
extern LLGLSLShader         gReflectionProbeDisplayProgram;
extern LLGLSLShader         gCopyProgram;
extern LLGLSLShader         gCopyDepthProgram;
extern LLGLSLShader         gPBRTerrainBakeProgram;

//output tex0[tc0] - tex1[tc1]
extern LLGLSLShader         gTwoTextureCompareProgram;
//discard some fragments based on user-set color tolerance
extern LLGLSLShader         gOneTextureFilterProgram;


//object shaders
extern LLGLSLShader     gObjectPreviewProgram;
extern LLGLSLShader        gPhysicsPreviewProgram;
extern LLGLSLShader     gObjectBumpProgram;
extern LLGLSLShader        gSkinnedObjectBumpProgram;
extern LLGLSLShader     gObjectAlphaMaskNoColorProgram;

//environment shaders
extern LLGLSLShader         gWaterProgram;
extern LLGLSLShader         gWaterEdgeProgram;
extern LLGLSLShader         gUnderWaterProgram;
extern LLGLSLShader         gGlowProgram;
extern LLGLSLShader         gGlowExtractProgram;

//interface shaders
extern LLGLSLShader         gHighlightProgram;
extern LLGLSLShader         gHighlightNormalProgram;
extern LLGLSLShader         gHighlightSpecularProgram;

extern LLGLSLShader         gDeferredHighlightProgram;

extern LLGLSLShader         gPathfindingProgram;
extern LLGLSLShader         gPathfindingNoNormalsProgram;

// avatar shader handles
extern LLGLSLShader         gAvatarProgram;
extern LLGLSLShader         gAvatarEyeballProgram;
extern LLGLSLShader         gImpostorProgram;

// Post Process Shaders
extern LLGLSLShader         gPostScreenSpaceReflectionProgram;

// Deferred rendering shaders
extern LLGLSLShader         gDeferredImpostorProgram;
extern LLGLSLShader         gDeferredDiffuseProgram;
extern LLGLSLShader         gDeferredDiffuseAlphaMaskProgram;
extern LLGLSLShader         gDeferredNonIndexedDiffuseAlphaMaskProgram;
extern LLGLSLShader         gDeferredNonIndexedDiffuseAlphaMaskNoColorProgram;
extern LLGLSLShader         gDeferredNonIndexedDiffuseProgram;
extern LLGLSLShader         gDeferredBumpProgram;
extern LLGLSLShader         gDeferredTerrainProgram;
extern LLGLSLShader         gDeferredTreeProgram;
extern LLGLSLShader         gDeferredTreeShadowProgram;
extern LLGLSLShader         gDeferredLightProgram;
extern LLGLSLShader         gDeferredMultiLightProgram[LL_DEFERRED_MULTI_LIGHT_COUNT];
extern LLGLSLShader         gDeferredSpotLightProgram;
extern LLGLSLShader         gDeferredMultiSpotLightProgram;
extern LLGLSLShader         gDeferredSunProgram;
extern LLGLSLShader         gDeferredSunProbeProgram;
extern LLGLSLShader         gHazeProgram;
extern LLGLSLShader         gHazeWaterProgram;
extern LLGLSLShader         gDeferredBlurLightProgram;
extern LLGLSLShader         gDeferredAvatarProgram;
extern LLGLSLShader         gDeferredSoftenProgram;
extern LLGLSLShader         gDeferredShadowProgram;
extern LLGLSLShader         gDeferredShadowCubeProgram;
extern LLGLSLShader         gDeferredShadowAlphaMaskProgram;
extern LLGLSLShader         gDeferredShadowGLTFAlphaMaskProgram;
extern LLGLSLShader         gDeferredShadowGLTFAlphaBlendProgram;
extern LLGLSLShader         gDeferredShadowFullbrightAlphaMaskProgram;
extern LLGLSLShader         gDeferredPostProgram;
extern LLGLSLShader         gDeferredCoFProgram;
extern LLGLSLShader         gDeferredDoFCombineProgram;
extern LLGLSLShader         gFXAAProgram[4];
extern LLGLSLShader         gSMAAEdgeDetectProgram[4];
extern LLGLSLShader         gSMAABlendWeightsProgram[4];
extern LLGLSLShader         gSMAANeighborhoodBlendProgram[4];
extern LLGLSLShader         gCASProgram;
extern LLGLSLShader         gDeferredPostNoDoFProgram;
extern LLGLSLShader         gDeferredPostNoDoFNoiseProgram;
extern LLGLSLShader         gDeferredPostGammaCorrectProgram;
extern LLGLSLShader         gLegacyPostGammaCorrectProgram;
extern LLGLSLShader         gDeferredPostTonemapProgram;
extern LLGLSLShader         gNoPostTonemapProgram;
extern LLGLSLShader         gExposureProgram;
extern LLGLSLShader         gExposureProgramNoFade;
extern LLGLSLShader         gLuminanceProgram;
extern LLGLSLShader         gDeferredAvatarShadowProgram;
extern LLGLSLShader         gDeferredAvatarAlphaShadowProgram;
extern LLGLSLShader         gDeferredAvatarAlphaMaskShadowProgram;
extern LLGLSLShader         gDeferredAlphaProgram;
extern LLGLSLShader         gHUDAlphaProgram;
extern LLGLSLShader         gDeferredAlphaImpostorProgram;
extern LLGLSLShader         gDeferredFullbrightProgram;
extern LLGLSLShader         gHUDFullbrightProgram;
extern LLGLSLShader         gDeferredFullbrightAlphaMaskProgram;
extern LLGLSLShader         gHUDFullbrightAlphaMaskProgram;
extern LLGLSLShader         gDeferredFullbrightAlphaMaskAlphaProgram;
extern LLGLSLShader         gHUDFullbrightAlphaMaskAlphaProgram;
extern LLGLSLShader         gDeferredEmissiveProgram;
extern LLGLSLShader         gDeferredAvatarEyesProgram;
extern LLGLSLShader         gDeferredAvatarAlphaProgram;
extern LLGLSLShader         gEnvironmentMapProgram;
extern LLGLSLShader         gDeferredWLSkyProgram;
extern LLGLSLShader         gDeferredWLCloudProgram;
extern LLGLSLShader         gDeferredWLSunProgram;
extern LLGLSLShader         gDeferredWLMoonProgram;
extern LLGLSLShader         gDeferredStarProgram;
extern LLGLSLShader         gDeferredFullbrightShinyProgram;
extern LLGLSLShader         gHUDFullbrightShinyProgram;
extern LLGLSLShader         gNormalMapGenProgram;
extern LLGLSLShader         gDeferredGenBrdfLutProgram;
extern LLGLSLShader         gDeferredBufferVisualProgram;

// Deferred materials shaders
extern LLGLSLShader         gDeferredMaterialProgram[LLMaterial::SHADER_COUNT*2];

extern LLGLSLShader         gHUDPBROpaqueProgram;
extern LLGLSLShader         gPBRGlowProgram;
extern LLGLSLShader         gDeferredPBROpaqueProgram;
extern LLGLSLShader         gDeferredPBRAlphaProgram;
extern LLGLSLShader         gHUDPBRAlphaProgram;

// GLTF shaders
extern LLGLSLShader         gGLTFPBRMetallicRoughnessProgram;

// Encodes detail level for dropping textures, in accordance with the GLTF spec where possible
// 0 is highest detail, -1 drops emissive, etc
// Dropping metallic roughness is off-spec - Reserve for potato machines as needed
// https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#additional-textures
enum TerrainPBRDetail : S32
{
    TERRAIN_PBR_DETAIL_MAX                = 0,
    TERRAIN_PBR_DETAIL_EMISSIVE           = 0,
    TERRAIN_PBR_DETAIL_OCCLUSION          = -1,
    TERRAIN_PBR_DETAIL_NORMAL             = -2,
    TERRAIN_PBR_DETAIL_METALLIC_ROUGHNESS = -3,
    TERRAIN_PBR_DETAIL_BASE_COLOR         = -4,
    TERRAIN_PBR_DETAIL_MIN                = -4,
};
enum TerrainPaintType : U32
{
    // Use LLVLComposition::mDatap (heightmap) generated by generateHeights, plus noise from TERRAIN_ALPHARAMP
    TERRAIN_PAINT_TYPE_HEIGHTMAP_WITH_NOISE = 0,
    // Use paint map if PBR terrain, otherwise fall back to TERRAIN_PAINT_TYPE_HEIGHTMAP_WITH_NOISE
    TERRAIN_PAINT_TYPE_PBR_PAINTMAP         = 1,
    TERRAIN_PAINT_TYPE_COUNT                = 2,
};
extern LLGLSLShader         gDeferredPBRTerrainProgram[TERRAIN_PAINT_TYPE_COUNT];
#endif