#include "New3D.h"
#include "Texture.h"
#include "Vec.h"
#include <cmath>
#include <algorithm>
#include <limits>
#include <string.h>
#include "R3DFloat.h"

#define MAX_RAM_VERTS 300000	
#define MAX_ROM_VERTS 1500000

#define BYTE_TO_FLOAT(B)	((2.0f * (B) + 1.0f) * (1.0F/255.0f))

namespace New3D {

CNew3D::CNew3D(const Util::Config::Node &config, std::string gameName)
	: m_r3dShader(config),
	  m_r3dScrollFog(config),
	  m_gameName(gameName)
{
	m_cullingRAMLo	= nullptr;
	m_cullingRAMHi	= nullptr;
	m_polyRAM		= nullptr;
	m_vrom			= nullptr;
	m_textureRAM	= nullptr;
	m_sunClamp		= true;
	m_shadeIsSigned = true;
	m_numPolyVerts	= 3;			
	m_primType		= GL_TRIANGLES;

	if (config["QuadRendering"].ValueAs<bool>()) {
		m_numPolyVerts	= 4;
		m_primType		= GL_LINES_ADJACENCY;
	}
}

CNew3D::~CNew3D()
{
	m_vbo.Destroy();
}

void CNew3D::AttachMemory(const UINT32 *cullingRAMLoPtr, const UINT32 *cullingRAMHiPtr, const UINT32 *polyRAMPtr, const UINT32 *vromPtr, const UINT16 *textureRAMPtr)
{
	m_cullingRAMLo	= cullingRAMLoPtr;
	m_cullingRAMHi	= cullingRAMHiPtr;
	m_polyRAM		= polyRAMPtr;
	m_vrom			= vromPtr;
	m_textureRAM	= textureRAMPtr;
}

void CNew3D::SetStepping(int stepping)
{
	m_step = stepping;

	if ((m_step != 0x10) && (m_step != 0x15) && (m_step != 0x20) && (m_step != 0x21)) {
		m_step = 0x10;
	}

	if (m_step > 0x10) {
		m_offset = 0;							// culling nodes are 10 words
		m_vertexFactor = (1.0f / 2048.0f);		// vertices are in 13.11 format
	}
	else {
		m_offset = 2;							// 8 words
		m_vertexFactor = (1.0f / 128.0f);		// 17.7
	}

	m_vbo.Create(GL_ARRAY_BUFFER, GL_DYNAMIC_DRAW, sizeof(FVertex) * (MAX_RAM_VERTS + MAX_ROM_VERTS));
}

bool CNew3D::Init(unsigned xOffset, unsigned yOffset, unsigned xRes, unsigned yRes, unsigned totalXResParam, unsigned totalYResParam)
{
	// Resolution and offset within physical display area
	m_xRatio	= xRes / 496.0f;
	m_yRatio	= yRes / 384.0f;
	m_xOffs		= xOffset;
	m_yOffs		= yOffset;
	m_xRes    = xRes;
	m_yRes    = yRes;
	m_totalXRes	= totalXResParam;
	m_totalYRes = totalYResParam;

	m_r3dShader.LoadShader();

	m_r3dFrameBuffers.CreateFBO(totalXResParam, totalYResParam);

	glUseProgram(0);

	return OKAY;	// OKAY ? wtf ..
}

void CNew3D::UploadTextures(unsigned level, unsigned x, unsigned y, unsigned width, unsigned height)
{
	if (level == 0) {
		m_texSheet.Invalidate(x, y, width, height);		// base textures only
	} 
	else if (level == 1) {
		// we want to work out what the base level is, and invalidate the entire texture
		// the mipmap data in some cases is being sent later

		int page = y / 1024;
		y -= (page * 1024);	// remove page from tex y

		int xPos = (x - 1024) * 2;
		int yPos = (y - 512) * 2;

		yPos += page * 1024;
		width *= 2;
		height *= 2;

		m_texSheet.Invalidate(xPos, yPos, width, height);
	}
}

void CNew3D::DrawScrollFog()
{
	// ths is my best guess at the logic based upon what games are doing
	//
	// ocean hunter		- every viewport has scroll fog values set. Must start with lowest priority layers as the higher ones sometimes are garbage
	// scud race		- first viewports in priority layer missing scroll values. The latter ones all contain valid scroll values.
	// daytona			- doesn't seem to use scroll fog at all. Will set scroll values for the first viewports, the end ones contain no scroll values
	// vf3				- first viewport only has it set. But set with highest select value ?? Rest of the viewports in priority layer contain a lower select value
	// sega bassfishing	- first viewport in priority 1 sets scroll value. The rest all contain the wrong value + a higher select value ..
	// spikeout final	- 2nd viewport in the priority layer has scroll values set, none of the others do. It also uses the highest select value

	// known bug (vf3)	- if you complete the game on a stage that has fogging, that fogging gets carried over into the credits. I did a binary diff on the viewport, it's never updated from the previous stage, neither is the data it's pointing at. Either a game or emulation bug.

	for (int i = 0; i < 4; i++) {

		Viewport *vp = nullptr;

		for (auto &n : m_nodes) {

			if (n.viewport.priority == i) {
				if (!vp && n.viewport.scrollFog) {
					vp = &n.viewport;		// only start grabbing viewports if there is a scroll value
				}
				else if(vp && n.viewport.select == vp->select) {
					vp = &n.viewport;		// grab the last viewport with the same select value ??
				}
			}
		}

		if (vp && vp->scrollFog) {

			float rgba[4] = { vp->fogParams[0], vp->fogParams[1], vp->fogParams[2], vp->scrollFog };

			glViewport(0, 0, m_totalXRes, m_totalYRes);		// fill the whole viewport
			m_r3dScrollFog.DrawScrollFog(rgba, vp->scrollAtt, vp->fogParams[6], vp->spotFogColor, vp->spotEllipse);
			return;
		}
	}
}

bool CNew3D::RenderScene(int priority, bool renderOverlay, Layer layer)
{
	bool hasOverlay = false;		// (high priority polys)

	for (auto &n : m_nodes) {

		if (n.viewport.priority != priority || n.models.empty()) {
			continue;
		}

		std::shared_ptr<Texture> tex1;

		CalcViewport(&n.viewport, std::abs(m_nfPairs[priority].zNear*0.99f), std::abs(m_nfPairs[priority].zFar*1.05f));	// make planes 5% bigger
		glViewport(n.viewport.x, n.viewport.y, n.viewport.width, n.viewport.height);

		m_r3dShader.SetViewportUniforms(&n.viewport);

		for (auto &m : n.models) {

			bool matrixLoaded = false;

			if (m.meshes->empty()) {
				continue;
			}

			for (auto &mesh : *m.meshes) {

				if (mesh.highPriority) {
					hasOverlay = true;
				}

				if (!mesh.Render(layer)) continue;
				if (mesh.highPriority != renderOverlay) continue;

				if (!matrixLoaded) {
					m_r3dShader.SetModelStates(&m);
					matrixLoaded = true;		// do this here to stop loading matrices we don't need. Ie when rendering non transparent etc
				}
				
				if (mesh.textured) {

					int x, y;
					CalcTexOffset(m.textureOffsetX, m.textureOffsetY, m.page, mesh.x, mesh.y, x, y);

					if (tex1 && tex1->Compare(x, y, mesh.width, mesh.height, mesh.format)) {
						// texture already bound
					}
					else {
						tex1 = m_texSheet.BindTexture(m_textureRAM, mesh.format, x, y, mesh.width, mesh.height);
						if (tex1) {
							tex1->BindTexture();
						}
					}

					if (mesh.microTexture) {

						int mX, mY;
						glActiveTexture(GL_TEXTURE1);
						m_texSheet.GetMicrotexPos(y / 1024, mesh.microTextureID, mX, mY);
						auto tex2 = m_texSheet.BindTexture(m_textureRAM, 0, mX, mY, 128, 128);
						if (tex2) {
							tex2->BindTexture();
						}
						glActiveTexture(GL_TEXTURE0);
					}
				}
				
				m_r3dShader.SetMeshUniforms(&mesh);
				glDrawArrays(m_primType, mesh.vboOffset, mesh.vertexCount);
			}
		}
	}

	return hasOverlay;
}

bool CNew3D::SkipLayer(int layer)
{
	for (const auto &n : m_nodes) {
		if (n.viewport.priority == layer) {
			if (n.models.size()) {
				return false;
			}
		}
	}

	return true;
}

void CNew3D::SetRenderStates()
{
	m_vbo.Bind(true);
	m_r3dShader.SetShader(true);

	glEnableVertexAttribArray(0);
	glEnableVertexAttribArray(1);
	glEnableVertexAttribArray(2);
	glEnableVertexAttribArray(3);
	glEnableVertexAttribArray(4);
	glEnableVertexAttribArray(5);

	// before draw, specify vertex and index arrays with their offsets, offsetof is maybe evil ..
	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inVertex"), 4, GL_FLOAT, GL_FALSE, sizeof(FVertex), 0);
	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inNormal"), 3, GL_FLOAT, GL_FALSE, sizeof(FVertex), (void*)offsetof(FVertex, normal));
	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inTexCoord"), 2, GL_FLOAT, GL_FALSE, sizeof(FVertex), (void*)offsetof(FVertex, texcoords));
	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inColour"), 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(FVertex), (void*)offsetof(FVertex, faceColour));
	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inFaceNormal"), 3, GL_FLOAT, GL_FALSE, sizeof(FVertex), (void*)offsetof(FVertex, faceNormal));
	glVertexAttribPointer(m_r3dShader.GetVertexAttribPos("inFixedShade"), 1, GL_FLOAT, GL_FALSE, sizeof(FVertex), (void*)offsetof(FVertex, fixedShade));

	glDepthFunc		(GL_LEQUAL);
	glEnable		(GL_DEPTH_TEST);
	glDepthMask		(GL_TRUE);
	glActiveTexture	(GL_TEXTURE0);
	glDisable		(GL_CULL_FACE);					// we'll emulate this in the shader		
	glDisable		(GL_BLEND);

	glStencilFunc	(GL_EQUAL, 0, 0xFF);			// basically stencil test passes if the value is zero
	glStencilOp		(GL_KEEP, GL_INCR, GL_INCR);	// if the stencil test passes, we incriment the value
	glStencilMask	(0xFF);
}

void CNew3D::DisableRenderStates()
{
	m_vbo.Bind(false);
	m_r3dShader.SetShader(false);

	glDisable(GL_STENCIL_TEST);

	glDisableVertexAttribArray(0);
	glDisableVertexAttribArray(1);
	glDisableVertexAttribArray(2);
	glDisableVertexAttribArray(3);
	glDisableVertexAttribArray(4);
	glDisableVertexAttribArray(5);
}

void CNew3D::RenderFrame(void)
{
	for (int i = 0; i < 4; i++) {
		m_nfPairs[i].zNear = -std::numeric_limits<float>::max();
		m_nfPairs[i].zFar  =  std::numeric_limits<float>::max();
	}

	for (int i = 0; i < 4; i++) {
		m_lineOfSight[i] = 0;
	}

	// release any resources from last frame
	m_polyBufferRam.clear();		// clear dyanmic model memory buffer
	m_nodes.clear();				// memory will grow during the object life time, that's fine, no need to shrink to fit
	m_modelMat.Release();			// would hope we wouldn't need this but no harm in checking
	m_nodeAttribs.Reset();

	RenderViewport(0x800000);						// build model structure
	DrawScrollFog();								// fog layer if applicable must be drawn here
	
	m_vbo.Bind(true);
	m_vbo.BufferSubData(MAX_ROM_VERTS*sizeof(FVertex), m_polyBufferRam.size()*sizeof(FVertex), m_polyBufferRam.data());	// upload all the dynamic data to GPU in one go

	if (m_polyBufferRom.size()) {

		// sync rom memory with vbo
		int romBytes	= (int)m_polyBufferRom.size() * sizeof(FVertex);
		int vboBytes	= m_vbo.GetSize();
		int size		= romBytes - vboBytes;

		if (size) {
			//check we haven't blown up the memory buffers
			//we will lose rom models for 1 frame is this happens, not the end of the world, as probably won't ever happen anyway
			if (m_polyBufferRom.size() >= MAX_ROM_VERTS) {
				m_polyBufferRom.clear();
				m_romMap.clear();
				m_vbo.Reset();
			}
			else {
				m_vbo.AppendData(size, &m_polyBufferRom[vboBytes / sizeof(FVertex)]);
			}
		}
	}

	m_r3dFrameBuffers.SetFBO(Layer::trans12);
	glClear(GL_COLOR_BUFFER_BIT);					// wipe both trans layers

	for (int pri = 0; pri <= 3; pri++) {

		//==============
		bool hasOverlay;
		//==============

		if (SkipLayer(pri)) continue;

		for (int i = 0; i < 2; i++) {

			bool renderOverlay = (i == 1);

			m_r3dFrameBuffers.SetFBO(Layer::colour);
			glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
			
			SetRenderStates();

			m_r3dShader.DiscardAlpha(true);						// discard all translucent pixels in opaque pass
			m_r3dFrameBuffers.SetFBO(Layer::colour);
			hasOverlay = RenderScene(pri, renderOverlay, Layer::colour);

			if (!renderOverlay && ProcessLos(pri)) {
				ProcessLos(pri);
			}

			DisableRenderStates();

			m_r3dFrameBuffers.DrawOverTransLayers();			// mask trans layer with opaque pixels
			m_r3dFrameBuffers.CompositeBaseLayer();				// copy opaque pixels to back buffer

			SetRenderStates();
			
			glDepthFunc(GL_LESS);								// alpha polys seem to use gl_less (ocean hunter)

			m_r3dShader.DiscardAlpha		(false);			// render only translucent pixels
			m_r3dFrameBuffers.StoreDepth	();					// save depth buffer for 1st trans pass
			m_r3dFrameBuffers.SetFBO		(Layer::trans1);
			RenderScene						(pri, renderOverlay, Layer::trans1);

			m_r3dFrameBuffers.RestoreDepth	();					// restore depth buffer, trans layers don't seem to depth test against each other
			m_r3dFrameBuffers.SetFBO		(Layer::trans2);
			RenderScene						(pri, renderOverlay, Layer::trans2);

			DisableRenderStates();

			if (!hasOverlay) break;								// no high priority polys						
		}
	}

	m_r3dFrameBuffers.CompositeAlphaLayer();
}

void CNew3D::BeginFrame(void)
{
}

void CNew3D::EndFrame(void)
{
}

/******************************************************************************
Real3D Address Translation

Functions that interpret word-granular Real3D addresses and return pointers.
******************************************************************************/

// Translates 24-bit culling RAM addresses
const UINT32* CNew3D::TranslateCullingAddress(UINT32 addr)
{
	addr &= 0x00FFFFFF;	// caller should have done this already

	if ((addr >= 0x800000) && (addr < 0x840000)) {
		return &m_cullingRAMHi[addr & 0x3FFFF];
	}
	else if (addr < 0x100000) {
		return &m_cullingRAMLo[addr];
	}

	return NULL;
}

// Translates model references
const UINT32* CNew3D::TranslateModelAddress(UINT32 modelAddr)
{
	modelAddr &= 0x00FFFFFF;	// caller should have done this already

	if (modelAddr < 0x100000) {
		return &m_polyRAM[modelAddr];
	}
	else {
		return &m_vrom[modelAddr];
	}
}

bool CNew3D::DrawModel(UINT32 modelAddr)
{
	const UINT32*	modelAddress;
	bool			cached = false;
	Model*			m;

	modelAddress = TranslateModelAddress(modelAddr);

	// create a new model to push onto the vector
	m_nodes.back().models.emplace_back();

	// get the last model in the array
	m = &m_nodes.back().models.back();

	if (IsVROMModel(modelAddr) && !IsDynamicModel((UINT32*)modelAddress)) {

		// try to find meshes in the rom cache

		m->meshes = m_romMap[modelAddr];	// will create an entry with a null pointer if empty

		if (m->meshes) {
			cached = true;
		}
		else {
			m->meshes = std::make_shared<std::vector<Mesh>>();
			m_romMap[modelAddr] = m->meshes;		// store meshes in our rom map here
		}

		m->dynamic = false;
	}
	else {
		m->meshes = std::make_shared<std::vector<Mesh>>();
	}

	// copy current model matrix
	for (int i = 0; i < 16; i++) {
		m->modelMat[i] = m_modelMat.currentMatrix[i];
	}

	// update texture offsets
	m->textureOffsetX = m_nodeAttribs.currentTexOffsetX;
	m->textureOffsetY = m_nodeAttribs.currentTexOffsetY;
	m->page = m_nodeAttribs.currentPage;
	m->scale = m_nodeAttribs.currentModelScale;

	if (!cached) {
		CacheModel(m, modelAddress);
	}

	if (m_nodeAttribs.currentClipStatus != Clip::INSIDE) {
		ClipModel(m);	// not storing clipped values, only working out the Z range
	}

	return true;
}

// Descends into a 10-word culling node
void CNew3D::DescendCullingNode(UINT32 addr)
{
	const UINT32	*node, *lodTable;
	UINT32			matrixOffset, child1Ptr, sibling2Ptr;
	BBox			bbox;
	UINT16			uCullRadius;
	float			fCullRadius;
	UINT16			uBlendRadius;
	float			fBlendRadius;
	UINT8			lodTablePointer;

	if (m_nodeAttribs.StackLimit()) {
		return;
	}

	node = TranslateCullingAddress(addr);

	if (NULL == node) {
		return;
	}

	// Extract known fields
	child1Ptr		= node[0x07 - m_offset] & 0x7FFFFFF;	// mask colour table bits
	sibling2Ptr		= node[0x08 - m_offset] & 0x1FFFFFF;	// mask colour table bits
	matrixOffset	= node[0x03 - m_offset] & 0xFFF;
	lodTablePointer = (node[0x03 - m_offset] >> 12) & 0x7F;

	// parse siblings 
	if ((node[0x00] & 0x07) != 0x06) {						// colour table seems to indicate no siblings
		if (!(sibling2Ptr & 0x1000000) && sibling2Ptr) {
			DescendCullingNode(sibling2Ptr);				// no need to mask bit, would already be zero
		}
	}

	if ((node[0x00] & 0x04)) {
		m_colorTableAddr = ((node[0x03 - m_offset] >> 19) << 0) | ((node[0x07 - m_offset] >> 28) << 13) | ((node[0x08 - m_offset] >> 25) << 17);
		m_colorTableAddr &= 0x000FFFFF; // clamp to 4MB (in words) range
	}

	m_nodeAttribs.Push();	// save current attribs

	if (!m_offset) {		// Step 1.5+
		
		float modelScale = *(float *)&node[1];
		if (modelScale > std::numeric_limits<float>::min()) {
			m_nodeAttribs.currentModelScale = modelScale;
		}

		// apply texture offsets, else retain current ones
		if ((node[0x02] & 0x8000))	{
			int tx = 32 * ((node[0x02] >> 7) & 0x3F);
			int ty = 32 * (node[0x02] & 0x1F);
			m_nodeAttribs.currentTexOffsetX	= tx;
			m_nodeAttribs.currentTexOffsetY = ty;
			m_nodeAttribs.currentPage = (node[0x02] & 0x4000) >> 14;
		}
	}

	// Apply matrix and translation
	m_modelMat.PushMatrix();

	// apply translation vector
	if (node[0x00] & 0x10) {
		float x = *(float *)&node[0x04 - m_offset];
		float y = *(float *)&node[0x05 - m_offset];
		float z = *(float *)&node[0x06 - m_offset];
		m_modelMat.Translate(x, y, z);
	}
	// multiply matrix, if specified
	else if (matrixOffset) {
		MultMatrix(matrixOffset,m_modelMat);
	}

	uCullRadius = node[9 - m_offset] & 0xFFFF;
	fCullRadius = R3DFloat::GetFloat16(uCullRadius);

	uBlendRadius = node[9 - m_offset] >> 16;
	fBlendRadius = R3DFloat::GetFloat16(uBlendRadius);

	if (m_nodeAttribs.currentClipStatus != Clip::INSIDE) {

		if (uCullRadius != R3DFloat::Pro16BitMax) {

			CalcBox(fCullRadius, bbox);
			TransformBox(m_modelMat, bbox);

			m_nodeAttribs.currentClipStatus = ClipBox(bbox, m_planes);

			if (m_nodeAttribs.currentClipStatus == Clip::INSIDE) {
				CalcBoxExtents(bbox);
			}
		}
		else {
			m_nodeAttribs.currentClipStatus = Clip::NOT_SET;
		}
	}

	if (m_nodeAttribs.currentClipStatus != Clip::OUTSIDE && fCullRadius > R3DFloat::Pro16BitFltMin) {

		// Descend down first link
		if ((node[0x00] & 0x08))	// 4-element LOD table
		{
			lodTable = TranslateCullingAddress(child1Ptr);

			if (NULL != lodTable) {
				if ((node[0x03 - m_offset] & 0x20000000)) {
					DescendCullingNode(lodTable[0] & 0xFFFFFF);
				}
				else {
					DrawModel(lodTable[0] & 0xFFFFFF);	//TODO
				}
			}
		}
		else {
			DescendNodePtr(child1Ptr);
		}

	}

	m_modelMat.PopMatrix();

	// Restore old texture offsets
	m_nodeAttribs.Pop();
}

void CNew3D::DescendNodePtr(UINT32 nodeAddr)
{
	// Ignore null links
	if ((nodeAddr & 0x00FFFFFF) == 0) {
		return;
	}

	switch ((nodeAddr >> 24) & 0xFF)	// pointer type encoded in upper 8 bits
	{
	case 0x00:	// culling node
		DescendCullingNode(nodeAddr & 0xFFFFFF);
		break;
	case 0x01:	// model (perhaps bit 2 is a flag in this case?)
	case 0x03:
		DrawModel(nodeAddr & 0xFFFFFF);
		break;
	case 0x04:	// pointer list
		DescendPointerList(nodeAddr & 0xFFFFFF);
		break;
	default:
		break;
	}
}

void CNew3D::DescendPointerList(UINT32 addr)
{
	const UINT32*	list;
	UINT32			nodeAddr;
	int				index;

	list = TranslateCullingAddress(addr);

	if (NULL == list) {
		return;
	}

	index = 0;

	while (true) {

		if (list[index] & 0x01000000) {
			break;	// empty list
		}

		nodeAddr = list[index] & 0x00FFFFFF;	// clear upper 8 bits to ensure this is processed as a culling node

		DescendCullingNode(nodeAddr);

		if (list[index] & 0x02000000) {
			break;	// list end
		}

		index++;
	}
}


/******************************************************************************
Matrix Stack
******************************************************************************/

// Macro to generate column-major (OpenGL) index from y,x subscripts
#define CMINDEX(y,x)	(x*4+y)

/*
* MultMatrix():
*
* Multiplies the matrix stack by the specified Real3D matrix. The matrix
* index is a 12-bit number specifying a matrix number relative to the base.
* The base matrix MUST be set up before calling this function.
*/
void CNew3D::MultMatrix(UINT32 matrixOffset, Mat4& mat)
{
	GLfloat		m[4*4];
	const float	*src = &m_matrixBasePtr[matrixOffset * 12];

	if (m_matrixBasePtr == NULL)	// LA Machineguns
		return;

	m[CMINDEX(0, 0)] = src[3];
	m[CMINDEX(0, 1)] = src[4];
	m[CMINDEX(0, 2)] = src[5];
	m[CMINDEX(0, 3)] = src[0];
	m[CMINDEX(1, 0)] = src[6];
	m[CMINDEX(1, 1)] = src[7];
	m[CMINDEX(1, 2)] = src[8];
	m[CMINDEX(1, 3)] = src[1];
	m[CMINDEX(2, 0)] = src[9];
	m[CMINDEX(2, 1)] = src[10];
	m[CMINDEX(2, 2)] = src[11];
	m[CMINDEX(2, 3)] = src[2];
	m[CMINDEX(3, 0)] = 0.0;
	m[CMINDEX(3, 1)] = 0.0;
	m[CMINDEX(3, 2)] = 0.0;
	m[CMINDEX(3, 3)] = 1.0;

	mat.MultMatrix(m);
}

/*
* InitMatrixStack():
*
* Initializes the modelview (model space -> view space) matrix stack and
* Real3D coordinate system. These are the last transforms to be applied (and
* the first to be defined on the stack) before projection.
*
* Model 3 games tend to define the following unusual base matrix:
*
*		0	0	-1	0
*		1	0	0	0
*		0	-1	0	0
*		0	0	0	1
*
* When this is multiplied by a column vector, the output is:
*
*		-Z
*		X
*		-Y
*		1
*
* My theory is that the Real3D GPU accepts vectors in Z,X,Y order. The games
* store everything as X,Y,Z and perform the translation at the end. The Real3D
* also has Y and Z coordinates opposite of the OpenGL convention. This
* function inserts a compensating matrix to undo these things.
*
* NOTE: This function assumes we are in GL_MODELVIEW matrix mode.
*/

void CNew3D::InitMatrixStack(UINT32 matrixBaseAddr, Mat4& mat)
{
	GLfloat m[4 * 4];

	// This matrix converts vectors back from the weird Model 3 Z,X,Y ordering
	// and also into OpenGL viewspace (-Y,-Z)
	m[CMINDEX(0, 0)] = 0.0;	m[CMINDEX(0, 1)] = 1.0;	m[CMINDEX(0, 2)] = 0.0;	m[CMINDEX(0, 3)] = 0.0;
	m[CMINDEX(1, 0)] = 0.0;	m[CMINDEX(1, 1)] = 0.0;	m[CMINDEX(1, 2)] =-1.0; m[CMINDEX(1, 3)] = 0.0;
	m[CMINDEX(2, 0)] =-1.0; m[CMINDEX(2, 1)] = 0.0;	m[CMINDEX(2, 2)] = 0.0;	m[CMINDEX(2, 3)] = 0.0;
	m[CMINDEX(3, 0)] = 0.0;	m[CMINDEX(3, 1)] = 0.0;	m[CMINDEX(3, 2)] = 0.0;	m[CMINDEX(3, 3)] = 1.0;

	mat.LoadMatrix(m);

	// Set matrix base address and apply matrix #0 (coordinate system matrix)
	m_matrixBasePtr = (float *)TranslateCullingAddress(matrixBaseAddr);
	MultMatrix(0, mat);
}

// Draws viewports of the given priority
void CNew3D::RenderViewport(UINT32 addr)
{
	static const GLfloat	color[8][3] =
	{											// RGB1 color translation
		{ 0.0, 0.0, 0.0 },	// off
		{ 0.0, 0.0, 1.0 },	// blue
		{ 0.0, 1.0, 0.0 },	// green
		{ 0.0, 1.0, 1.0 },	// cyan
		{ 1.0, 0.0, 0.0 }, 	// red
		{ 1.0, 0.0, 1.0 },	// purple
		{ 1.0, 1.0, 0.0 },	// yellow
		{ 1.0, 1.0, 1.0 }	// white
	};

	// Translate address and obtain pointer
	const uint32_t *vpnode = TranslateCullingAddress(addr);

	if (NULL == vpnode) {
		return;
	}

	if (vpnode[0x01] == 0) {		// memory probably hasn't been set up yet, abort
		return;
	}

	if (!(vpnode[0] & 0x20)) {	// only if viewport enabled

		// create node object 
		m_nodes.emplace_back(Node());
		m_nodes.back().models.reserve(2048);				// create space for models

		// get pointer to its viewport
		Viewport *vp = &m_nodes.back().viewport;

		vp->priority	= (vpnode[0] >> 3) & 0x3;
		vp->select		= (vpnode[0] >> 8) & 0x3;
		vp->number		= (vpnode[0] >> 10);

		m_currentPriority = vp->priority;

		// Fetch viewport parameters (TO-DO: would rounding make a difference?)
		vp->vpX			= (int)(((vpnode[0x1A] & 0xFFFF) / 16.0f) + 0.5f);		// viewport X (12.4 fixed point)
		vp->vpY			= (int)(((vpnode[0x1A] >> 16) / 16.0f) + 0.5f);			// viewport Y (12.4)
		vp->vpWidth		= (int)(((vpnode[0x14] & 0xFFFF) / 4.0f) + 0.5f);		// width (14.2)
		vp->vpHeight	= (int)(((vpnode[0x14] >> 16) / 4.0f) + 0.5f);			// height (14.2)

		uint32_t matrixBase	= vpnode[0x16] & 0xFFFFFF;							// matrix base address

		m_LODBlendTable = (LODBlendTable*)TranslateCullingAddress(vpnode[0x17] & 0xFFFFFF);

		/*
		vp->angle_left		= -atan2(*(float *)&vpnode[12],  *(float *)&vpnode[13]);	// These values work out as the normals for the clipping planes.
		vp->angle_right		=  atan2(*(float *)&vpnode[16], -*(float *)&vpnode[17]);	// Sometimes these values (dirt devils,lost world) are totally wrong
		vp->angle_top		=  atan2(*(float *)&vpnode[14],  *(float *)&vpnode[15]);	// and don't work for the frustum values exactly.
		vp->angle_bottom	= -atan2(*(float *)&vpnode[18], -*(float *)&vpnode[19]);	// Perhaps they are just used for culling and not rendering.
		*/

		float cv = *(float *)&vpnode[0x8];	// 1/(left-right)
		float cw = *(float *)&vpnode[0x9];	// 1/(top-bottom)
		float io = *(float *)&vpnode[0xa];	// top / bottom (ratio) - ish
		float jo = *(float *)&vpnode[0xb];	// left / right (ratio)

		vp->angle_left		= (1.0f / cv) * (0.0f - jo);
		vp->angle_right		= (1.0f / cv) * (1.0f - jo);
		vp->angle_bottom	= (1.0f / cw) * -(1.0f - io);
		vp->angle_top		= (1.0f / cw) * -(0.0f - io);

		// calculate the frustum shape, near/far pair are dummy values
		CalcViewport(vp, 1, 1000);

		// calculate frustum planes
		CalcFrustumPlanes(m_planes, vp->projectionMatrix);	// we need to calc a 'projection matrix' to get the correct frustum planes for clipping

		// Lighting (note that sun vector points toward sun -- away from vertex)
		vp->lightingParams[0] =  *(float *)&vpnode[0x05];								// sun X
		vp->lightingParams[1] = -*(float *)&vpnode[0x06];								// sun Y (- to convert to ogl cordinate system)
		vp->lightingParams[2] = -*(float *)&vpnode[0x04];								// sun Z (- to convert to ogl cordinate system)
		vp->lightingParams[3] = std::max(0.f, std::min(*(float *)&vpnode[0x07], 1.0f));	// sun intensity (clamp to 0-1)
		vp->lightingParams[4] = (float)((vpnode[0x24] >> 8) & 0xFF) * (1.0f / 255.0f);	// ambient intensity
		vp->lightingParams[5] = 0.0;	// reserved
		
		vp->sunClamp		= m_sunClamp;
		vp->intensityClamp	= (m_step == 0x10);		// just step 1.0 ?
		vp->hardwareStep	= m_step;
		
		// Spotlight
		int spotColorIdx = (vpnode[0x20] >> 11) & 7;									// spotlight color index
		int spotFogColorIdx = (vpnode[0x20] >> 8) & 7;									// spotlight on fog color index
		vp->spotEllipse[0] = (float)(INT16)(vpnode[0x1E] & 0xFFFF) / 8.0f;				// spotlight X position (13.3 fixed point)
		vp->spotEllipse[1] = (float)(INT16)(vpnode[0x1D] & 0xFFFF) / 8.0f;				// spotlight Y
		vp->spotEllipse[2] = (float)((vpnode[0x1E] >> 16) & 0xFFFF);					// spotlight X size (16-bit)
		vp->spotEllipse[3] = (float)((vpnode[0x1D] >> 16) & 0xFFFF);					// spotlight Y size

		vp->spotRange[0] = 1.0f / (*(float *)&vpnode[0x21]);							// spotlight start
		vp->spotRange[1] = *(float *)&vpnode[0x1F];										// spotlight extent

		vp->spotColor[0] = color[spotColorIdx][0];										// spotlight color
		vp->spotColor[1] = color[spotColorIdx][1];
		vp->spotColor[2] = color[spotColorIdx][2];

		vp->spotFogColor[0] = color[spotFogColorIdx][0];								// spotlight color on fog
		vp->spotFogColor[1] = color[spotFogColorIdx][1];
		vp->spotFogColor[2] = color[spotFogColorIdx][2];

		// spotlight is specified in terms of physical resolution
		vp->spotEllipse[1] = 384.0f - vp->spotEllipse[1];								// flip Y position

		// Avoid division by zero
		vp->spotEllipse[2] = std::max(1.0f, vp->spotEllipse[2]);
		vp->spotEllipse[3] = std::max(1.0f, vp->spotEllipse[3]);

		vp->spotEllipse[2] = std::roundf(2047.0f / vp->spotEllipse[2]);
		vp->spotEllipse[3] = std::roundf(2047.0f / vp->spotEllipse[3]);

		// Scale the spotlight to the OpenGL viewport
		vp->spotEllipse[0] = vp->spotEllipse[0] * m_xRatio + m_xOffs;
		vp->spotEllipse[1] = vp->spotEllipse[1] * m_yRatio + m_yOffs;
		vp->spotEllipse[2] *= m_xRatio;
		vp->spotEllipse[3] *= m_yRatio;

		// Line of sight position
		vp->losPosX = (int)(((vpnode[0x1c] & 0xFFFF) / 16.0f) + 0.5f);					// x position
		vp->losPosY = (int)(((vpnode[0x1c] >> 16) / 16.0f) + 0.5f);						// y position 0 starts from the top

		// Fog
		vp->fogParams[0] = (float)((vpnode[0x22] >> 16) & 0xFF) * (1.0f / 255.0f);	// fog color R
		vp->fogParams[1] = (float)((vpnode[0x22] >> 8) & 0xFF) * (1.0f / 255.0f);	// fog color G
		vp->fogParams[2] = (float)((vpnode[0x22] >> 0) & 0xFF) * (1.0f / 255.0f);	// fog color B
		vp->fogParams[3] = std::abs(*(float *)&vpnode[0x23]);						// fog density	- ocean hunter uses negative values, but looks the same
		vp->fogParams[4] = (float)(INT16)(vpnode[0x25] & 0xFFFF)*(1.0f / 255.0f);	// fog start

		// Avoid Infinite and NaN values for Star Wars Trilogy
		if (std::isinf(vp->fogParams[3]) || std::isnan(vp->fogParams[3])) {
			for (int i = 0; i < 7; i++) vp->fogParams[i] = 0.0f;
		}

		vp->fogParams[5] = (float)((vpnode[0x24] >> 16) & 0xFF) * (1.0f / 255.0f);	// fog attenuation
		vp->fogParams[6] = (float)((vpnode[0x25] >> 16) & 0xFF) * (1.0f / 255.0f);	// fog ambient

		vp->scrollFog = (float)(vpnode[0x20] & 0xFF) * (1.0f / 255.0f);				// scroll fog
		vp->scrollAtt = (float)(vpnode[0x24] & 0xFF) * (1.0f / 255.0f);				// scroll attenuation

		// Clear texture offsets before proceeding
		m_nodeAttribs.Reset();

		// Set up coordinate system and base matrix
		InitMatrixStack(matrixBase, m_modelMat);

		// Safeguard: weird coordinate system matrices usually indicate scenes that will choke the renderer
		if (NULL != m_matrixBasePtr)
		{
			float	m21, m32, m13;

			// Get the three elements that are usually set and see if their magnitudes are 1
			m21 = m_matrixBasePtr[6];
			m32 = m_matrixBasePtr[10];
			m13 = m_matrixBasePtr[5];

			m21 *= m21;
			m32 *= m32;
			m13 *= m13;

			if ((m21>1.05) || (m21<0.95))
				return;
			if ((m32>1.05) || (m32<0.95))
				return;
			if ((m13>1.05) || (m13<0.95))
				return;
		}

		// Descend down the node link: Use recursive traversal
		DescendNodePtr(vpnode[0x02]);
	}

	// render next viewport
	if (vpnode[0x01] != 0x01000000) {
		RenderViewport(vpnode[0x01]);
	}
}

void CNew3D::CopyVertexData(const R3DPoly& r3dPoly, std::vector<FVertex>& vertexArray)
{
	// both lemans 24 and dirt devils are rendering some totally transparent polys as the first object in each viewport
	// in dirt devils it's parallel to the camera so is completel invisible, but breaks our depth calculation
	// in lemans 24 its a sort of diamond shape, but never leaves a hole in the transparent geometry so must be being skipped by the h/w
	if (r3dPoly.faceColour[3] == 0) {
		return;
	}

	if (m_numPolyVerts==4) {
		if (r3dPoly.number == 4) {
			vertexArray.emplace_back(r3dPoly, 0);		// construct directly inside container without copy
			vertexArray.emplace_back(r3dPoly, 1);
			vertexArray.emplace_back(r3dPoly, 2);
			vertexArray.emplace_back(r3dPoly, 3);

			// check for identical points (ie forced triangle) and replace with average point
			// if we don't do this our quad code falls apart
			FVertex* v = (&vertexArray.back()) - 3;

			for (int i = 0; i < 4; i++) {

				int next1 = (i + 1) % 4;
				int next2 = (i + 2) % 4;

				if (FVertex::Equal(v[i], v[next1])) {
					FVertex::Average(v[i], v[next1], v[next2]);
				}
			}
		}
		else {
			vertexArray.emplace_back(r3dPoly, 0);	
			vertexArray.emplace_back(r3dPoly, 1);
			vertexArray.emplace_back(r3dPoly, 2);
			vertexArray.emplace_back(r3dPoly, 0, 2);	// last point is an average of 0 and 2
		}
	}
	else {
		vertexArray.emplace_back(r3dPoly, 0);
		vertexArray.emplace_back(r3dPoly, 1);
		vertexArray.emplace_back(r3dPoly, 2);

		if (r3dPoly.number == 4) {
			vertexArray.emplace_back(r3dPoly, 0);
			vertexArray.emplace_back(r3dPoly, 2);
			vertexArray.emplace_back(r3dPoly, 3);
		}
	}
}

void CNew3D::SetMeshValues(SortingMesh *currentMesh, PolyHeader &ph)
{
	//copy attributes
	currentMesh->textured		= ph.TexEnabled();
	currentMesh->alphaTest		= ph.AlphaTest();
	currentMesh->textureAlpha	= ph.TextureAlpha();
	currentMesh->polyAlpha		= ph.PolyAlpha();
	currentMesh->lighting		= ph.LightEnabled();
	currentMesh->fixedShading	= ph.FixedShading() && !ph.SmoothShading();
	currentMesh->highPriority	= ph.HighPriority();
	currentMesh->transLSelect	= ph.TranslucencyPatternSelect();
	currentMesh->layered		= ph.Layered();
	currentMesh->specular		= ph.SpecularEnabled();
	currentMesh->shininess		= ph.Shininess();
	currentMesh->specularValue	= ph.SpecularValue();
	currentMesh->fogIntensity	= ph.LightModifier();

	if (currentMesh->textured) {

		currentMesh->format = m_texSheet.GetTexFormat(ph.TexFormat(), ph.AlphaTest());

		if (currentMesh->format == 7) {
			currentMesh->alphaTest = false;	// alpha test is a 1 bit test, this format needs a lower threshold, since it has 16 levels of transparency
		}

		currentMesh->x				= ph.X();
		currentMesh->y				= ph.Y();
		currentMesh->width			= ph.TexWidth();
		currentMesh->height			= ph.TexHeight();
		currentMesh->microTexture	= ph.MicroTexture();
		currentMesh->inverted		= ph.TranslatorMapOffset() == 2;

		{
			bool smoothU = ph.TexSmoothU();
			bool smoothV = ph.TexSmoothV();

			if (ph.AlphaTest()) {
				smoothU = false;	// smooth wrap makes no sense for alpha tested polys with pixel dilate
				smoothV = false;
			}

			if (ph.TexUMirror()) {
				if (smoothU)	currentMesh->wrapModeU = Mesh::TexWrapMode::mirror;
				else			currentMesh->wrapModeU = Mesh::TexWrapMode::mirrorClamp;
			}
			else {
				if (smoothU)	currentMesh->wrapModeU = Mesh::TexWrapMode::repeat;
				else			currentMesh->wrapModeU = Mesh::TexWrapMode::repeatClamp;
			}

			if (ph.TexVMirror()) {
				if (smoothV)	currentMesh->wrapModeV = Mesh::TexWrapMode::mirror;
				else			currentMesh->wrapModeV = Mesh::TexWrapMode::mirrorClamp;
			}
			else {
				if (smoothV)	currentMesh->wrapModeV = Mesh::TexWrapMode::repeat;
				else			currentMesh->wrapModeV = Mesh::TexWrapMode::repeatClamp;
			}
		}

		if (currentMesh->microTexture) {

			float microTexScale[] = { 2, 4, 16, 256 };

			currentMesh->microTextureID = ph.MicroTextureID();
			currentMesh->microTextureScale = microTexScale[ph.MicroTextureMinLOD()];
		}
	}
}

void CNew3D::CacheModel(Model *m, const UINT32 *data)
{
	UINT16			texCoords[4][2];
	PolyHeader		ph;
	UINT64			lastHash	= -1;
	SortingMesh*	currentMesh = nullptr;
	
	std::map<UINT64, SortingMesh> sMap;

	if (data == NULL)
		return;

	ph = data; 
	int numTriangles = ph.NumTrianglesTotal();

	// Cache all polygons
	do {

		R3DPoly		p;					// current polygon
		float		uvScale;
		int			i, j;

		if (ph.header[6] == 0) {
			break;
		}

		// create a hash value based on poly attributes -todo add more attributes
		auto hash = ph.Hash();

		if (hash != lastHash) {

			if (sMap.count(hash) == 0) {

				sMap[hash] = SortingMesh();

				currentMesh = &sMap[hash];

				//make space for our vertices
				currentMesh->verts.reserve(numTriangles * 3);

				//set mesh values
				SetMeshValues(currentMesh, ph);
			}

			currentMesh = &sMap[hash];
		}

		// Obtain basic polygon parameters
		p.number	= ph.NumVerts();
		uvScale		= ph.UVScale();

		ph.FaceNormal(p.faceNormal);

		// Fetch reused vertices according to bitfield, then new verts
		i = 0;
		j = 0;
		for (i = 0; i < 4; i++)		// up to 4 reused vertices
		{
			if (ph.SharedVertex(i))
			{
				p.v[j] = m_prev[i];

				texCoords[j][0] = m_prevTexCoords[i][0];
				texCoords[j][1] = m_prevTexCoords[i][1];

				//check if we need to recalc tex coords - will only happen if tex tiles are different + sharing vertices
				if (hash != lastHash) {
					if (currentMesh->textured) {
						Texture::GetCoordinates(currentMesh->width, currentMesh->height, texCoords[j][0], texCoords[j][1], uvScale, p.v[j].texcoords[0], p.v[j].texcoords[1]);
					}
				}

				j++;
			}
		}

		lastHash = hash;

		// copy face attributes

		if (!ph.PolyColor()) {
			int colorIdx = ph.ColorIndex();
			p.faceColour[2] = (m_polyRAM[m_colorTableAddr + colorIdx] & 0xFF);
			p.faceColour[1] = ((m_polyRAM[m_colorTableAddr + colorIdx] >> 8) & 0xFF);
			p.faceColour[0] = ((m_polyRAM[m_colorTableAddr + colorIdx] >> 16) & 0xFF);
		}
		else {

			p.faceColour[0] = ((ph.header[4] >> 24));
			p.faceColour[1] = ((ph.header[4] >> 16) & 0xFF);
			p.faceColour[2] = ((ph.header[4] >> 8) & 0xFF);

			if (ph.TranslatorMap()) {
				p.faceColour[0] = (p.faceColour[0] * 255) / 16;		// When the translator map is enabled, max colour seems
				p.faceColour[1] = (p.faceColour[1] * 255) / 16;		// to be 16. Scaling these up gives the correct colours.
				p.faceColour[2] = (p.faceColour[2] * 255) / 16;		// Not sure why didn't allow 32 colours with 4 bits?
			}
		}

		p.faceColour[3] = ph.Transparency();

		if (ph.Discard1() && !ph.Discard2()) {
			p.faceColour[3] /= 2;
		}

		// if we have flat shading, we can't re-use normals from shared vertices
		for (i = 0; i < p.number && !ph.SmoothShading(); i++) {
			p.v[i].normal[0] = p.faceNormal[0];
			p.v[i].normal[1] = p.faceNormal[1];
			p.v[i].normal[2] = p.faceNormal[2];
		}

		UINT32* vData = ph.StartOfData();	// vertex data starts here

		// remaining vertices are new and defined here
		for (; j < p.number; j++)	
		{
			// Fetch vertices
			UINT32 ix = vData[0];
			UINT32 iy = vData[1];
			UINT32 iz = vData[2];
			UINT32 it = vData[3];

			// Decode vertices
			p.v[j].pos[0] = (((INT32)ix) >> 8) * m_vertexFactor;
			p.v[j].pos[1] = (((INT32)iy) >> 8) * m_vertexFactor;
			p.v[j].pos[2] = (((INT32)iz) >> 8) * m_vertexFactor;
			p.v[j].pos[3] = 1.0f;

			// Per vertex normals
			if (ph.SmoothShading()) {
				p.v[j].normal[0] = BYTE_TO_FLOAT((INT8)(ix & 0xFF));
				p.v[j].normal[1] = BYTE_TO_FLOAT((INT8)(iy & 0xFF));
				p.v[j].normal[2] = BYTE_TO_FLOAT((INT8)(iz & 0xFF));
			}

			if (ph.FixedShading() && !ph.SmoothShading()) {			// fixed shading seems to be disabled if actual normals are set

				//==========
				float shade;
				//==========

				if (!m_shadeIsSigned) {
					shade = (ix & 0xFF) / 255.f;
				}
				else {
					shade = BYTE_TO_FLOAT((INT8)(ix & 0xFF));
				}
				
				p.v[j].fixedShade = shade;
			}

			float texU = 0;
			float texV = 0;

			// tex coords
			if (currentMesh->textured) {
				Texture::GetCoordinates(currentMesh->width, currentMesh->height, (UINT16)(it >> 16), (UINT16)(it & 0xFFFF), uvScale, texU, texV);
			}

			p.v[j].texcoords[0] = texU;
			p.v[j].texcoords[1] = texV;

			//cache un-normalised tex coordinates
			texCoords[j][0] = (UINT16)(it >> 16);
			texCoords[j][1] = (UINT16)(it & 0xFFFF);

			vData += 4;
		}

		// check if we need to double up vertices for two sided lighting
		if (ph.DoubleSided() && !ph.Discard()) {

			R3DPoly tempP = p;

			// flip normals
			V3::inverse(tempP.faceNormal);

			for (int i = 0; i < tempP.number; i++) {
				V3::inverse(tempP.v[i].normal);
			}

			CopyVertexData(tempP, currentMesh->verts);
		}

		// Copy this polygon into the model buffer
		if (!ph.Discard()) {
			CopyVertexData(p, currentMesh->verts);
		}
		
		// Copy current vertices into previous vertex array
		for (i = 0; i < 4; i++) {
			m_prev[i] = p.v[i];
			m_prevTexCoords[i][0] = texCoords[i][0];
			m_prevTexCoords[i][1] = texCoords[i][1];
		}

	} while (ph.NextPoly());

	//sorted the data, now copy to main data structures

	// we know how many meshes we have so reserve appropriate space
	m->meshes->reserve(sMap.size());

	for (auto& it : sMap) {

		if (m->dynamic) {

			// calculate VBO values for current mesh
			it.second.vboOffset		= (int)m_polyBufferRam.size() + MAX_ROM_VERTS;
			it.second.vertexCount	= (int)it.second.verts.size();

			// copy poly data to main buffer
			m_polyBufferRam.insert(m_polyBufferRam.end(), it.second.verts.begin(), it.second.verts.end());
		}
		else {
			// calculate VBO values for current mesh
			it.second.vboOffset		= (int)m_polyBufferRom.size();
			it.second.vertexCount	= (int)it.second.verts.size();

			// copy poly data to main buffer
			m_polyBufferRom.insert(m_polyBufferRom.end(), it.second.verts.begin(), it.second.verts.end());
		}

		//copy the temp mesh into the model structure
		//this will lose the associated vertex data, which is now copied to the main buffer anyway
		m->meshes->push_back(it.second);
	}
}

bool CNew3D::IsDynamicModel(UINT32 *data)
{
	if (data == NULL) {
		return false;
	}

	PolyHeader p(data);

	do {

		if ((p.header[1] & 2) == 0) {		// model has rgb colour palette 
			return true;
		}

		if (p.header[6] == 0) {
			break;
		}

	} while (p.NextPoly());

	return false;
}

bool CNew3D::IsVROMModel(UINT32 modelAddr)
{
	return modelAddr >= 0x100000;
}

void CNew3D::CalcTexOffset(int offX, int offY, int page, int x, int y, int& newX, int& newY)
{
	newX = (x + offX) & 2047;	// wrap around 2048, shouldn't be required

	int oldPage = y / 1024;

	y -= (oldPage * 1024);	// remove page from tex y

	// calc newY with wrap around, wraps around in the same sheet, not into another memory sheet

	newY = (y + offY) & 1023;

	// add page to Y

	newY += ((oldPage + page) & 1) * 1024;		// max page 0-1
}

void CNew3D::CalcFrustumPlanes(Plane p[4], const float* matrix)
{
	// Left Plane
	p[0].a = matrix[3] + matrix[0];
	p[0].b = matrix[7] + matrix[4];
	p[0].c = matrix[11] + matrix[8];
	p[0].d = matrix[15] + matrix[12];
	p[0].Normalise();

	// Right Plane
	p[1].a = matrix[3] - matrix[0];
	p[1].b = matrix[7] - matrix[4];
	p[1].c = matrix[11] - matrix[8];
	p[1].d = matrix[15] - matrix[12];
	p[1].Normalise();

	// Bottom Plane
	p[2].a = matrix[3] + matrix[1];
	p[2].b = matrix[7] + matrix[5];
	p[2].c = matrix[11] + matrix[9];
	p[2].d = matrix[15] + matrix[13];
	p[2].Normalise();

	// Top Plane
	p[3].a = matrix[3] - matrix[1];
	p[3].b = matrix[7] - matrix[5];
	p[3].c = matrix[11] - matrix[9];
	p[3].d = matrix[15] - matrix[13];
	p[3].Normalise();
}

void CNew3D::CalcBox(float distance, BBox& box)
{
	//bottom left front
	box.points[0][0] = -distance;
	box.points[0][1] = -distance;
	box.points[0][2] = distance;
	box.points[0][3] = 1;

	//bottom left back
	box.points[1][0] = -distance;
	box.points[1][1] = -distance;
	box.points[1][2] = -distance;
	box.points[1][3] = 1;

	//bottom right back
	box.points[2][0] = distance;
	box.points[2][1] = -distance;
	box.points[2][2] = -distance;
	box.points[2][3] = 1;

	//bottom right front
	box.points[3][0] = distance;
	box.points[3][1] = -distance;
	box.points[3][2] = distance;
	box.points[3][3] = 1;

	//top left front
	box.points[4][0] = -distance;
	box.points[4][1] = distance;
	box.points[4][2] = distance;
	box.points[4][3] = 1;

	//top left back
	box.points[5][0] = -distance;
	box.points[5][1] = distance;
	box.points[5][2] = -distance;
	box.points[5][3] = 1;

	//top right back
	box.points[6][0] = distance;
	box.points[6][1] = distance;
	box.points[6][2] = -distance;
	box.points[6][3] = 1;

	//top right front
	box.points[7][0] = distance;
	box.points[7][1] = distance;
	box.points[7][2] = distance;
	box.points[7][3] = 1;
}

void CNew3D::MultVec(const float matrix[16], const float in[4], float out[4]) 
{
	for (int i = 0; i < 4; i++) {
		out[i] =
			in[0] * matrix[0 * 4 + i] +
			in[1] * matrix[1 * 4 + i] +
			in[2] * matrix[2 * 4 + i] +
			in[3] * matrix[3 * 4 + i];
	}
}

void CNew3D::TransformBox(const float *m, BBox& box)
{
	for (int i = 0; i < 8; i++) {
		float v[4];
		MultVec(m, box.points[i], v);
		box.points[i][0] = v[0];
		box.points[i][1] = v[1];
		box.points[i][2] = v[2];
	}
}

Clip CNew3D::ClipBox(BBox& box, Plane planes[4])
{
	int count = 0;

	for (int i = 0; i < 8; i++) {

		int temp = 0;

		for (int j = 0; j < 4; j++) {
			if (planes[j].DistanceToPoint(box.points[i]) >= 0) {
				temp++;
			}
		}

		if (temp == 4) count++;		// point is inside all 4 frustum planes
	}

	if (count == 8)	return Clip::INSIDE;
	if (count > 0)	return Clip::INTERCEPT;
	
	//if we got here all points are outside of the view frustum
	//check for all points being side same of any plane, means box outside of view

	for (int i = 0; i < 4; i++) {

		int temp = 0;

		for (int j = 0; j < 8; j++) {
			if (planes[i].DistanceToPoint(box.points[j]) >= 0) {
				temp++;
			}
		}

		if (temp == 0) {
			return Clip::OUTSIDE;
		}
	}

	//if we got here, box is traversing view frustum

	return Clip::INTERCEPT;
}

void CNew3D::CalcBoxExtents(const BBox& box)
{
	for (int i = 0; i < 8; i++) {
		if (box.points[i][2] < 0) {
			m_nfPairs[m_currentPriority].zNear = std::max(box.points[i][2], m_nfPairs[m_currentPriority].zNear);
			m_nfPairs[m_currentPriority].zFar  = std::min(box.points[i][2], m_nfPairs[m_currentPriority].zFar);
		}
	}
}

void CNew3D::ClipPolygon(ClipPoly& clipPoly, Plane planes[4])
{
	//============
	ClipPoly temp;
	ClipPoly *in;
	ClipPoly *out;
	//============

	in = &clipPoly;
	out = &temp;

	for (int i = 0; i < 4; i++) {

		//=================
		bool	currentIn;
		bool	nextIn;
		float	currentDot;
		float	nextDot;
		//=================

		currentDot	= planes[i].DotProduct(in->list[0].pos);
		currentIn	= (currentDot + planes[i].d) >= 0;

		for (int j = 0; j < in->count; j++) {

			if (currentIn) {
				out->list[out->count] = in->list[j];
				out->count++;
			}

			int nextIndex = j + 1;
			if (nextIndex >= in->count) {
				nextIndex = 0;
			}

			nextDot = planes[i].DotProduct(in->list[nextIndex].pos);
			nextIn	= (nextDot + planes[i].d) >= 0;

			// we have an intersection
			if (currentIn != nextIn) {

				float u = (currentDot + planes[i].d) / (currentDot - nextDot);

				float* p1 = in->list[j].pos;
				float* p2 = in->list[nextIndex].pos;

				out->list[out->count].pos[0] = p1[0] + ((p2[0] - p1[0]) * u);
				out->list[out->count].pos[1] = p1[1] + ((p2[1] - p1[1]) * u);
				out->list[out->count].pos[2] = p1[2] + ((p2[2] - p1[2]) * u);
				out->count++;
			}

			currentDot = nextDot;
			currentIn = nextIn;
		}

		std::swap(in, out);
		out->count = 0;
	}
}

void CNew3D::ClipModel(const Model *m)
{
	//===============================
	ClipPoly				clipPoly;
	std::vector<FVertex>*	vertices;
	int						offset;
	//===============================

	if (m->dynamic) {
		vertices = &m_polyBufferRam;
		offset = MAX_ROM_VERTS;
	}
	else {
		vertices = &m_polyBufferRom;
		offset = 0;
	}

	for (const auto &mesh : *m->meshes) {

		int start = mesh.vboOffset - offset;
		
		for (int i = 0; i < mesh.vertexCount; i += m_numPolyVerts) {							// inc to next poly

			for (int j = 0; j < m_numPolyVerts; j++) {
				MultVec(m->modelMat, (*vertices)[start + i + j].pos, clipPoly.list[j].pos);		// copy all 3 of 4  our transformed vertices into our clip poly struct
			}

			clipPoly.count = m_numPolyVerts;

			ClipPolygon(clipPoly, m_planes);

			for (int j = 0; j < clipPoly.count; j++) {
				if (clipPoly.list[j].pos[2] < 0) {
					m_nfPairs[m_currentPriority].zNear = std::max(clipPoly.list[j].pos[2], m_nfPairs[m_currentPriority].zNear);
					m_nfPairs[m_currentPriority].zFar  = std::min(clipPoly.list[j].pos[2], m_nfPairs[m_currentPriority].zFar);
				}
			}
		}
	}
}

void CNew3D::CalcViewport(Viewport* vp, float near, float far)
{
	if (near < far / 1000000) {
		near = far / 1000000;				// if we get really close to zero somehow, we will have almost no depth precision
	}

	float l = near * vp->angle_left;	// we need to calc the shape of the projection frustum for culling
	float r = near * vp->angle_right;
	float t = near * vp->angle_top;
	float b = near * vp->angle_bottom;

	vp->projectionMatrix.LoadIdentity();	// reset matrix

	if ((vp->vpX == 0) && (vp->vpWidth >= 495) && (vp->vpY == 0) && (vp->vpHeight >= 383)) {

		/*
		 * Compute aspect ratio correction factor. "Window" refers to the full GL
		 * viewport (i.e., totalXRes x totalYRes). "Viewable area" is the effective
		 * Model 3 screen (xRes x yRes). In non-wide-screen, non-stretch mode, this
		 * is intended to replicate the 496x384 display and may in general be 
		 * smaller than the window. The rest of the window appears to have a
		 * border, which is created by a scissor box.
		 *
		 * In wide-screen mode, we want to expand the frustum horizontally to fill
		 * the window. We want the aspect ratio to be correct. To accomplish this,
		 * the viewable area is set *the same* as in non-wide-screen mode (e.g.,
		 * often smaller than the window) but glScissor() is set by the OSD layer's
		 * screen setup code to reveal the entire window.
		 *
		 * In stretch mode, the window and viewable area are both set the same,
		 * which means there will be no aspect ratio correction and the display
		 * will stretch to fill the entire window while keeping the view frustum
		 * the same as a 496x384 Model 3 display. The display will be distorted.
		 */
		float windowAR = (float)m_totalXRes / (float)m_totalYRes;
		float viewableAreaAR = (float)m_xRes / (float)m_yRes;
		
		// Will expand horizontal frustum planes only in non-stretch mode (wide-
		// screen and non-wide-screen modes have identical resolution parameters
		// and only their scissor box differs)
		float correction = windowAR / viewableAreaAR;

		vp->x		= 0;
		vp->y		= m_yOffs + (int)((384 - (vp->vpY + vp->vpHeight))*m_yRatio);
		vp->width	= m_totalXRes;
		vp->height = (int)(vp->vpHeight*m_yRatio);

		vp->projectionMatrix.Frustum(l*correction, r*correction, b, t, near, far);
	}
	else {

		vp->x		= m_xOffs + (int)(vp->vpX*m_xRatio);
		vp->y		= m_yOffs + (int)((384 - (vp->vpY + vp->vpHeight))*m_yRatio);
		vp->width	= (int)(vp->vpWidth*m_xRatio);
		vp->height	= (int)(vp->vpHeight*m_yRatio);

		vp->projectionMatrix.Frustum(l, r, b, t, near, far);
	}
}

void CNew3D::SetSunClamp(bool enable)
{
	m_sunClamp = enable;
}

void CNew3D::SetSignedShade(bool enable)
{
	m_shadeIsSigned = enable;
}

float CNew3D::GetLosValue(int layer)
{
	return m_lineOfSight[layer];
}

void CNew3D::TranslateLosPosition(int inX, int inY, int& outX, int& outY)
{
	// remap real3d 496x384 to our new viewport
	inY = 384 - inY;

	outX = m_xOffs + int(inX * m_xRatio);
	outY = m_yOffs + int(inY * m_yRatio);
}

bool CNew3D::ProcessLos(int priority)
{
	for (const auto &n : m_nodes) {
		if (n.viewport.priority == priority) {
			if (n.viewport.losPosX || n.viewport.losPosY) {

				int losX, losY;
				TranslateLosPosition(n.viewport.losPosX, n.viewport.losPosY, losX, losY);

				float depth;
				glReadPixels(losX, losY, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &depth);

				if (depth < 0.99f || depth == 1.0f) {		// kinda guess work but when depth = 1, haven't drawn anything, when 0.99~ drawing sky somewhere far
					return false;
				}

				depth = 2.0f * depth - 1.0f;

				float zNear = m_nfPairs[priority].zNear;
				float zFar	= m_nfPairs[priority].zFar;
				float zVal	= 2.0f * zNear * zFar / (zFar + zNear - depth * (zFar - zNear));

				m_lineOfSight[priority] = zVal;
				return true;
			}
		}
	}

	return false;
}

} // New3D