dolphin/Source/Plugins/Plugin_VideoSoftware/Src/Rasterizer.cpp

// Copyright (C) 2003-2009 Dolphin Project.

// This program 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, version 2.0.

// This program 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 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

#include "Common.h"

#include "Rasterizer.h"
#include "HwRasterizer.h"
#include "EfbInterface.h"
#include "BPMemLoader.h"
#include "XFMemLoader.h"
#include "Tev.h"
#include "Statistics.h"
#include "VideoConfig.h"


#define BLOCK_SIZE 2

#define CLAMP(x, a, b) (x>b)?b:(x<a)?a:x

// returns approximation of log2(f) in s28.4
// results are close enough to use for LOD
static inline s32 FixedLog2(float f)
{
	u32 *x = (u32*)&f;
	s32 logInt = ((*x & 0x7F800000) >> 19) - 2032; // integer part
	s32 logFract = (*x & 0x007fffff) >> 19; // approximate fractional part

	return logInt + logFract;
}

namespace Rasterizer
{
Slope ZSlope;
Slope WSlope;
Slope ColorSlopes[2][4];
Slope TexSlopes[8][3];

s32 vertex0X;
s32 vertex0Y;
float vertexOffsetX;
float vertexOffsetY;

s32 scissorLeft = 0;
s32 scissorTop = 0;
s32 scissorRight = 0;
s32 scissorBottom = 0;

Tev tev;
RasterBlock rasterBlock;

void Init()
{
     tev.Init();
}

inline int iround(float x)
{
    int t;

#if defined(_WIN32) && !defined(_M_X64)
    __asm
    {
        fld  x
        fistp t
    }
#else
	t = (int)x;
	if((x - t) >= 0.5)
		return t + 1;
#endif

    return t;
}

void SetScissor()
{
    int xoff = bpmem.scissorOffset.x * 2 - 342;
    int yoff = bpmem.scissorOffset.y * 2 - 342;

	scissorLeft = bpmem.scissorTL.x - xoff - 342;
	if (scissorLeft < 0) scissorLeft = 0;

	scissorTop = bpmem.scissorTL.y - yoff - 342;
	if (scissorTop < 0) scissorTop = 0;
    
	scissorRight = bpmem.scissorBR.x - xoff - 341;
	if (scissorRight > EFB_WIDTH) scissorRight = EFB_WIDTH;

	scissorBottom = bpmem.scissorBR.y - yoff - 341;
	if (scissorBottom > EFB_HEIGHT) scissorBottom = EFB_HEIGHT;
}

void SetTevReg(int reg, int comp, bool konst, s16 color)
{
    tev.SetRegColor(reg, comp, konst, color);
}

inline void Draw(s32 x, s32 y, s32 xi, s32 yi)
{
    INCSTAT(stats.thisFrame.rasterizedPixels);

	float dx = vertexOffsetX + (float)(x - vertex0X);
	float dy = vertexOffsetY + (float)(y - vertex0Y);

	float zFloat = 1.0f + ZSlope.GetValue(dx, dy);
	if (zFloat < 0.0f || zFloat > 1.0f)
		return;

	s32 z = (s32)(zFloat * 0x00ffffff);

	if (bpmem.zcontrol.zcomploc && bpmem.zmode.testenable)
	{
		// early z
		if (!EfbInterface::ZCompare(x, y, z))
			return;
	}

	RasterBlockPixel& pixel = rasterBlock.Pixel[xi][yi];

	tev.Position[0] = x;
	tev.Position[1] = y;
	tev.Position[2] = z;

	//  colors
	for (unsigned int i = 0; i < bpmem.genMode.numcolchans; i++)
	{
		for(int comp = 0; comp < 4; comp++)
			tev.Color[i][comp] = (u8)ColorSlopes[i][comp].GetValue(dx, dy);
	}

	// tex coords
	for (unsigned int i = 0; i < bpmem.genMode.numtexgens; i++)
	{
		// multiply by 128 because TEV stores stores UVs as s17.7
		tev.Uv[i].s = (s32)(pixel.Uv[i][0] * 128);
		tev.Uv[i].t = (s32)(pixel.Uv[i][1] * 128);
	}

	for (unsigned int i = 0; i < bpmem.genMode.numindstages; i++)
	{
		tev.IndirectLod[i] = rasterBlock.IndirectLod[i];
		tev.IndirectLinear[i] = rasterBlock.IndirectLinear[i];
	}

	for (unsigned int i = 0; i <= bpmem.genMode.numtevstages; i++)
	{
		tev.TextureLod[i] = rasterBlock.TextureLod[i];
		tev.TextureLinear[i] = rasterBlock.TextureLinear[i];
	}
   
    tev.Draw();
}

void InitTriangle(float X1, float Y1, s32 xi, s32 yi)
{
	vertex0X = xi;
    vertex0Y = yi;

	// adjust a little less than 0.5
	const float adjust = 0.495f;

	vertexOffsetX = ((float)xi - X1) + adjust;
	vertexOffsetY = ((float)yi - Y1) + adjust;
}

void InitSlope(Slope *slope, float f1, float f2, float f3, float DX31, float DX12, float DY12, float DY31)
{
	float DF31 = f3 - f1;
    float DF21 = f2 - f1;
    float a = DF31 * -DY12 - DF21 * DY31;
    float b = DX31 * DF21 + DX12 * DF31;    
    float c = -DX12 * DY31 - DX31 * -DY12;
    slope->dfdx = -a / c;
    slope->dfdy = -b / c;
    slope->f0 = f1;
}

inline void CalculateLOD(s32 &lod, bool &linear, u32 texmap, u32 texcoord)
{
	FourTexUnits& texUnit = bpmem.tex[(texmap >> 2) & 1];
	u8 subTexmap = texmap & 3;

	// LOD calculation requires data from the texture mode for bias, etc.
	// it does not seem to use the actual texture size
	TexMode0& tm0 = texUnit.texMode0[subTexmap];
	TexMode1& tm1 = texUnit.texMode1[subTexmap];

	float sDelta, tDelta;
	if (tm0.diag_lod)
	{
		float *uv0 = rasterBlock.Pixel[0][0].Uv[texcoord];
		float *uv1 = rasterBlock.Pixel[1][1].Uv[texcoord];

		sDelta = abs(uv0[0] - uv1[0]);
		tDelta = abs(uv0[1] - uv1[1]);
	}
	else
	{
		float *uv0 = rasterBlock.Pixel[0][0].Uv[texcoord];
		float *uv1 = rasterBlock.Pixel[1][0].Uv[texcoord];
		float *uv2 = rasterBlock.Pixel[0][1].Uv[texcoord];

		sDelta = max(abs(uv0[0] - uv1[0]), abs(uv0[0] - uv2[0]));
		tDelta = max(abs(uv0[1] - uv1[1]), abs(uv0[1] - uv2[1]));
	}

	// get LOD in s28.4
	lod = FixedLog2(max(sDelta, tDelta));

	// bias is s2.5
	int bias = tm0.lod_bias;
	bias >>= 1;
	lod += bias;

	linear = ((lod > 0 && (tm0.min_filter & 4)) || (lod <= 0 && tm0.mag_filter));

	// order of checks matters
	// should be:
	// if lod > max then max
	// else if lod < min then min
	lod = CLAMP(lod, (s32)tm1.min_lod, (s32)tm1.max_lod);
}

void BuildBlock(s32 blockX, s32 blockY)
{
	for (s32 yi = 0; yi < BLOCK_SIZE; yi++)
	{
		for (s32 xi = 0; xi < BLOCK_SIZE; xi++)
		{
			RasterBlockPixel& pixel = rasterBlock.Pixel[xi][yi];

			float dx = vertexOffsetX + (float)(xi + blockX - vertex0X);
			float dy = vertexOffsetY + (float)(yi + blockY - vertex0Y);

			float invW = 1.0f / WSlope.GetValue(dx, dy);
			pixel.InvW = invW;

			// tex coords
			for (unsigned int i = 0; i < bpmem.genMode.numtexgens; i++)
			{
				float projection;
				if (xfregs.texMtxInfo[i].projection)
				{
					float q = TexSlopes[i][2].GetValue(dx, dy) * invW;
					projection = invW / q;
				}
				else
					projection = invW;

				pixel.Uv[i][0] = TexSlopes[i][0].GetValue(dx, dy) * projection;
				pixel.Uv[i][1] = TexSlopes[i][1].GetValue(dx, dy) * projection;
			}
		}
	}

	u32 indref = bpmem.tevindref.hex;
	for (unsigned int i = 0; i < bpmem.genMode.numindstages; i++)
	{
		u32 texmap = indref & 3;
		indref >>= 3;
		u32 texcoord = indref & 3;
		indref >>= 3;

		CalculateLOD(rasterBlock.IndirectLod[i], rasterBlock.IndirectLinear[i], texmap, texcoord);
	}

	for (unsigned int i = 0; i <= bpmem.genMode.numtevstages; i++)
	{
		int stageOdd = i&1;
		TwoTevStageOrders &order = bpmem.tevorders[i >> 1];
		if(order.getEnable(stageOdd))
		{
			u32 texmap = order.getTexMap(stageOdd);
			u32 texcoord = order.getTexCoord(stageOdd);

			CalculateLOD(rasterBlock.TextureLod[i], rasterBlock.TextureLinear[i], texmap, texcoord);
		}
	}
}

void DrawTriangleFrontFace(OutputVertexData *v0, OutputVertexData *v1, OutputVertexData *v2)
{
    INCSTAT(stats.thisFrame.numTrianglesDrawn);

    if (g_Config.bHwRasterizer)
    {
        HwRasterizer::DrawTriangleFrontFace(v0, v1, v2);
        return;
    }

    // adapted from http://www.devmaster.net/forums/showthread.php?t=1884

    // 28.4 fixed-pou32 coordinates. rounded to nearest and adjusted to match hardware output
	// could also take floor and adjust -8
	const s32 Y1 = iround(16.0f * v0->screenPosition[1]) - 9;
	const s32 Y2 = iround(16.0f * v1->screenPosition[1]) - 9;
	const s32 Y3 = iround(16.0f * v2->screenPosition[1]) - 9;

	const s32 X1 = iround(16.0f * v0->screenPosition[0]) - 9;
	const s32 X2 = iround(16.0f * v1->screenPosition[0]) - 9;
	const s32 X3 = iround(16.0f * v2->screenPosition[0]) - 9;

    // Deltas
    const s32 DX12 = X1 - X2;
    const s32 DX23 = X2 - X3;
    const s32 DX31 = X3 - X1;

    const s32 DY12 = Y1 - Y2;
    const s32 DY23 = Y2 - Y3;
    const s32 DY31 = Y3 - Y1;

    // Fixed-pos32 deltas
    const s32 FDX12 = DX12 << 4;
    const s32 FDX23 = DX23 << 4;
    const s32 FDX31 = DX31 << 4;

    const s32 FDY12 = DY12 << 4;
    const s32 FDY23 = DY23 << 4;
    const s32 FDY31 = DY31 << 4;

    // Bounding rectangle
    s32 minx = (min(min(X1, X2), X3) + 0xF) >> 4;
    s32 maxx = (max(max(X1, X2), X3) + 0xF) >> 4;
    s32 miny = (min(min(Y1, Y2), Y3) + 0xF) >> 4;
    s32 maxy = (max(max(Y1, Y2), Y3) + 0xF) >> 4;

    // scissor
    minx = max(minx, scissorLeft);
    maxx = min(maxx, scissorRight);
    miny = max(miny, scissorTop);
    maxy = min(maxy, scissorBottom);

    if (minx >= maxx || miny >= maxy)
        return;

    // Setup slopes
    float fltx1 = v0->screenPosition.x;
    float flty1 = v0->screenPosition.y;
    float fltdx31 = v2->screenPosition.x - fltx1;
    float fltdx12 = fltx1 - v1->screenPosition.x;
    float fltdy12 = flty1 - v1->screenPosition.y;
    float fltdy31 = v2->screenPosition.y - flty1;

	InitTriangle(fltx1, flty1, (X1 + 0xF) >> 4, (Y1 + 0xF) >> 4);

    float w[3] = { 1.0f / v0->projectedPosition.w, 1.0f / v1->projectedPosition.w, 1.0f / v2->projectedPosition.w };
    InitSlope(&WSlope, w[0], w[1], w[2], fltdx31, fltdx12, fltdy12, fltdy31);

    InitSlope(&ZSlope, v0->screenPosition[2], v1->screenPosition[2], v2->screenPosition[2], fltdx31, fltdx12, fltdy12, fltdy31);

    for(unsigned int i = 0; i < bpmem.genMode.numcolchans; i++)
    {
        for(int comp = 0; comp < 4; comp++)
            InitSlope(&ColorSlopes[i][comp], v0->color[i][comp], v1->color[i][comp], v2->color[i][comp], fltdx31, fltdx12, fltdy12, fltdy31);
    }

    for(unsigned int i = 0; i < bpmem.genMode.numtexgens; i++)
    {
        for(int comp = 0; comp < 3; comp++)
            InitSlope(&TexSlopes[i][comp], v0->texCoords[i][comp] * w[0], v1->texCoords[i][comp] * w[1], v2->texCoords[i][comp] * w[2], fltdx31, fltdx12, fltdy12, fltdy31);
    }

    // Start in corner of 8x8 block
    minx &= ~(BLOCK_SIZE - 1);
    miny &= ~(BLOCK_SIZE - 1);
    
    // Half-edge constants
    s32 C1 = DY12 * X1 - DX12 * Y1;
    s32 C2 = DY23 * X2 - DX23 * Y2;
    s32 C3 = DY31 * X3 - DX31 * Y3;

    // Correct for fill convention
    if(DY12 < 0 || (DY12 == 0 && DX12 > 0)) C1++;
    if(DY23 < 0 || (DY23 == 0 && DX23 > 0)) C2++;
    if(DY31 < 0 || (DY31 == 0 && DX31 > 0)) C3++;

    // Loop through blocks
    for(s32 y = miny; y < maxy; y += BLOCK_SIZE)
    {
        for(s32 x = minx; x < maxx; x += BLOCK_SIZE)
        {
            // Corners of block
            s32 x0 = x << 4;
            s32 x1 = (x + BLOCK_SIZE - 1) << 4;
            s32 y0 = y << 4;
            s32 y1 = (y + BLOCK_SIZE - 1) << 4;

            // Evaluate half-space functions
            bool a00 = C1 + DX12 * y0 - DY12 * x0 > 0;
            bool a10 = C1 + DX12 * y0 - DY12 * x1 > 0;
            bool a01 = C1 + DX12 * y1 - DY12 * x0 > 0;
            bool a11 = C1 + DX12 * y1 - DY12 * x1 > 0;
            int a = (a00 << 0) | (a10 << 1) | (a01 << 2) | (a11 << 3);
    
            bool b00 = C2 + DX23 * y0 - DY23 * x0 > 0;
            bool b10 = C2 + DX23 * y0 - DY23 * x1 > 0;
            bool b01 = C2 + DX23 * y1 - DY23 * x0 > 0;
            bool b11 = C2 + DX23 * y1 - DY23 * x1 > 0;
            int b = (b00 << 0) | (b10 << 1) | (b01 << 2) | (b11 << 3);
    
            bool c00 = C3 + DX31 * y0 - DY31 * x0 > 0;
            bool c10 = C3 + DX31 * y0 - DY31 * x1 > 0;
            bool c01 = C3 + DX31 * y1 - DY31 * x0 > 0;
            bool c11 = C3 + DX31 * y1 - DY31 * x1 > 0;
            int c = (c00 << 0) | (c10 << 1) | (c01 << 2) | (c11 << 3);

            // Skip block when outside an edge
            if(a == 0x0 || b == 0x0 || c == 0x0) continue;

			BuildBlock(x, y);

            // Accept whole block when totally covered
            if(a == 0xF && b == 0xF && c == 0xF)
            {
                for(s32 iy = 0; iy < BLOCK_SIZE; iy++)
                {
                    for(s32 ix = 0; ix < BLOCK_SIZE; ix++)
                    {                        
                        Draw(x + ix, y + iy, ix, iy);
                    }
                }
            }
            else // Partially covered block
            {
                s32 CY1 = C1 + DX12 * y0 - DY12 * x0;
                s32 CY2 = C2 + DX23 * y0 - DY23 * x0;
                s32 CY3 = C3 + DX31 * y0 - DY31 * x0;

                for(s32 iy = 0; iy < BLOCK_SIZE; iy++)
                {
                    s32 CX1 = CY1;
                    s32 CX2 = CY2;
                    s32 CX3 = CY3;

                    for(s32 ix = 0; ix < BLOCK_SIZE; ix++)
                    {
                        if(CX1 > 0 && CX2 > 0 && CX3 > 0)
                        {
                            Draw(x + ix, y + iy, ix, iy);
                        }

                        CX1 -= FDY12;
                        CX2 -= FDY23;
                        CX3 -= FDY31;
                    }

                    CY1 += FDX12;
                    CY2 += FDX23;
                    CY3 += FDX31;
                }
            }
        }
    }

}



}