/*
===========================================================================
Copyright (C) 2022-2024 Gian 'myT' Schellenbaum

This file is part of Challenge Quake 3 (CNQ3).

Challenge Quake 3 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.

Challenge Quake 3 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 Challenge Quake 3. If not, see <https://www.gnu.org/licenses/>.
===========================================================================
*/
// Gameplay Rendering Pipeline - private declarations


#pragma once


#include "srp_local.h"


#pragma pack(push, 4)

struct WorldVertexRC
{
	float modelViewMatrix[16];
	float projectionMatrix[16];
	float clipPlane[4];
};

struct WorldPixelRC
{
	// general
	uint32_t stageIndices[8]; // sampler: 16 - texture: 16
	float greyscale;

	// r_shaderTrace - dynamically enabled
	uint32_t shaderTrace; // shader index: 14 - frame index: 2 - enable: 1
	uint16_t centerPixelX;
	uint16_t centerPixelY;

	// r_depthFade - statically enabled
	uint16_t hFadeDistance;
	uint16_t hFadeOffset;
	uint32_t depthFadeColorTex; // texture index: 12 - color bias: 4 - color scale: 4

	// r_dither - statically enabled
	uint16_t hFrameSeed;
	uint16_t hNoiseScale;
	uint16_t hInvGamma;
	uint16_t hInvBrightness;
};

#pragma pack(pop)

struct VertexBuffers : BufferBase
{
	enum BaseId
	{
		BasePosition,
		BaseNormal,
		BaseCount
	};

	enum StageId
	{
		StageTexCoords,
		StageColors,
		StageCount
	};

	void Create(const char* name, MemoryUsage::Id memoryUsage, uint32_t vertexCount);
	void BeginUpload();
	void EndUpload();
	void Upload(uint32_t firstStage, uint32_t stageCount);

	static const uint32_t BufferCount = BaseCount + StageCount * MAX_SHADER_STAGES;
	HBuffer buffers[BufferCount] = {};
	uint32_t strides[BufferCount] = {};
	uint8_t* mapped[BufferCount] = {};
};

struct GeometryBuffers
{
	void Rewind()
	{
		vertexBuffers.Rewind();
		indexBuffer.Rewind();
	}

	VertexBuffers vertexBuffers;
	IndexBuffer indexBuffer;
};

struct StaticGeometryChunk
{
	uint32_t vertexCount;
	uint32_t indexCount;
	uint32_t firstGPUVertex;
	uint32_t firstGPUIndex;
	uint32_t firstCPUIndex;
};

struct BatchType
{
	enum Id
	{
		Standard,
		DynamicLight,
		DepthFade,
		Count
	};
};

struct World
{
	void Init();
	void BeginFrame();
	void EndFrame();
	void Begin();
	void End();
	void DrawPrePass(const drawSceneViewCommand_t& cmd);
	void BeginBatch(const shader_t* shader, bool hasStaticGeo, BatchType::Id batchType);
	void EndBatch();
	void EndSkyBatch();
	void RestartBatch();
	void DrawGUI();
	void ProcessWorld(world_t& world);
	void DrawSceneView(const drawSceneViewCommand_t& cmd);
	void BindVertexBuffers(bool staticGeo, uint32_t firstStage, uint32_t stageCount);
	void BindIndexBuffer(bool staticGeo);
	void DrawFog();
	void DrawLitSurfaces(dlight_t* dl, bool opaque);
	void DrawDynamicLights(bool opaque);
	void DrawSkyBox();
	void DrawClouds();

	typedef uint32_t Index;
	const IndexType::Id indexType = IndexType::UInt32;

	HTexture depthTexture;
	uint32_t depthTextureIndex;

	float clipPlane[4];

	struct BufferFamily
	{
		enum Id
		{
			Invalid,
			PrePass,
			Static,
			Dynamic
		};
	};

	// Z pre-pass
	HRootSignature zppRootSignature;
	HDescriptorTable zppDescriptorTable;
	HPipeline zppPipeline;
	GeometryBuffer zppVertexBuffer;

	// shared
	BufferFamily::Id boundVertexBuffers;
	BufferFamily::Id boundIndexBuffer;
	uint32_t boundStaticVertexBuffersFirst;
	uint32_t boundStaticVertexBuffersCount;
	HPipeline batchPSO;
	BatchType::Id batchType;
	bool batchHasStaticGeo;
	int psoChangeCount;
	bool batchDepthHack;
	bool batchOldDepthHack;
	ShadingRate::Id batchShadingRate;
	ShadingRate::Id batchOldShadingRate;

	// dynamic
	GeometryBuffers dynBuffers[FrameCount];

	// static
	GeometryBuffers statBuffers;
	StaticGeometryChunk statChunks[32768];
	uint32_t statChunkCount;
	uint32_t statIndices[1 << 20];
	uint32_t statIndexCount;

	// fog
	HRootSignature fogRootSignature;
	HDescriptorTable fogDescriptorTable;
	HPipeline fogOutsidePipeline;
	HPipeline fogInsidePipeline;
	HBuffer boxVertexBuffer;
	HBuffer boxIndexBuffer;

	// dynamic lights
	HRootSignature dlRootSignature;
	HPipeline dlPipelines[CT_COUNT * 2 * 2]; // { cull type, polygon offset, depth test }
	bool dlOpaque;
	float dlIntensity; // 1 for most surfaces, but can be scaled down for liquids etc.
	bool dlDepthTestEqual;
	// quick explanation on why dlOpaque is useful in the first place:
	// - opaque surfaces can have a diffuse texture whose alpha isn't 255 everywhere
	// - when that happens and we multiply the color by the the alpha (DL uses additive blending),
	//   we get "light holes" in opaque surfaces, which is not what we want
};

#pragma pack(push, 1)

struct PSODesc
{
	cullType_t cullType;
	bool polygonOffset;
	bool clampDepth;
	bool depthFade;
};

#pragma pack(pop)

struct CachedPSO
{
#if defined(_DEBUG)
	// lets us know which Q3 shader
	// triggered the creation of this PSO
	char name[MAX_QPATH];
#endif
	PSODesc desc;
	uint32_t stageStateBits[MAX_SHADER_STAGES];
	uint32_t stageCount;
	HPipeline pipeline;
};

struct PostProcess
{
	void Init();
	void Draw(const char* renderPassName, HTexture renderTarget);
	void ToneMap();
	void InverseToneMap(int colorFormat);
	void SetToneMapInput(HTexture toneMapInput);
	void SetInverseToneMapInput(HTexture inverseToneMapInput);

private:
	HPipeline toneMapPipeline;
	HRootSignature toneMapRootSignature;
	HDescriptorTable toneMapDescriptorTable;

	HPipeline inverseToneMapPipelines[RTCF_COUNT];
	HRootSignature inverseToneMapRootSignature;
	HDescriptorTable inverseToneMapDescriptorTable;
};

struct SMAA
{
	void Init();
	void Update();
	void Draw(const viewParms_t& parms);

	// matches r_smaa
	struct Mode
	{
		enum Id
		{
			Disabled,
			Low,
			Medium,
			High,
			Ultra,
			Count
		};
	};

private:
	// fixed
	HTexture areaTexture;
	HTexture searchTexture;
	HRootSignature rootSignature;
	HDescriptorTable descriptorTable;

	// depends on render target resolution
	HTexture edgeTexture;
	HTexture blendTexture;
	HTexture stencilTexture;
	HTexture inputTexture;  // tone mapped
	HTexture outputTexture; // tone mapped

	// depends on selected preset/mode
	// SMAA has 3 passes:
	// 1. edge detection
	// 2. blend weight computation
	// 3. neighborhood blending
	HPipeline firstPassPipeline;
	HPipeline secondPassPipeline;
	HPipeline thirdPassPipeline;

	Mode::Id mode = Mode::Disabled;
	int width = -1;
	int height = -1;
	bool fixedLoaded = false;
};

struct GRP : IRenderPipeline
{
	void Init() override;
	void ShutDown(bool fullShutDown) override;
	void CreateTexture(image_t* image, int mipCount, int width, int height) override;
	void UpoadTextureAndGenerateMipMaps(image_t* image, const byte* data) override;
	void BeginTextureUpload(MappedTexture& mappedTexture, image_t* image) override;
	void EndTextureUpload() override;
	void ProcessWorld(world_t& world) override;
	void ProcessModel(model_t& model) override;
	void ProcessShader(shader_t& shader) override;

	void ExecuteRenderCommands(const byte* data, bool readbackRequested) override;
	void TessellationOverflow() override { world.RestartBatch(); }
	void DrawSkyBox() override { world.DrawSkyBox(); }
	void DrawClouds() override { world.DrawClouds(); }
	void ReadPixels(int w, int h, int alignment, colorSpace_t colorSpace, void* out) override;

	uint32_t GetSamplerDescriptorIndexFromBaseIndex(uint32_t baseIndex) override { return baseIndex; }

	void BeginFrame();
	void EndFrame();

	uint32_t RegisterTexture(HTexture htexture);

	uint32_t CreatePSO(CachedPSO& cache, const char* name);

	void UpdateReadbackTexture();

	UI ui;
	World world;
	MipMapGenerator mipMapGen;
	ImGUI imgui;
	PostProcess post;
	SMAA smaa;
	Nuklear nuklear;
	float frameSeed;
	bool updateReadbackTexture;

	HTexture renderTarget;
	TextureFormat::Id renderTargetFormat;
	HTexture readbackRenderTarget;
	RootSignatureDesc rootSignatureDesc;
	HRootSignature rootSignature;
	HDescriptorTable descriptorTable;
	uint32_t textureIndex;
	HSampler samplers[BASE_SAMPLER_COUNT]; // all base samplers

	CachedPSO psos[1024];
	uint32_t psoCount;
	HRootSignature uberRootSignature;
};

extern GRP grp;