/*
 * 86Box    A hypervisor and IBM PC system emulator that specializes in
 *          running old operating systems and software designed for IBM
 *          PC systems and compatibles from 1981 through fairly recent
 *          system designs based on the PCI bus.
 *
 *          This file is part of the 86Box distribution.
 *
 *          3DFX Voodoo emulation.
 *
 *
 *
 * Authors: Sarah Walker, <https://pcem-emulator.co.uk/>
 *
 *          Copyright 2008-2020 Sarah Walker.
 */
#include <stdarg.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <stddef.h>
#include <wchar.h>
#include <math.h>
#define HAVE_STDARG_H
#include <86box/86box.h>
#include "cpu.h"
#include <86box/machine.h>
#include <86box/device.h>
#include <86box/mem.h>
#include <86box/timer.h>
#include <86box/device.h>
#include <86box/plat.h>
#include <86box/thread.h>
#include <86box/video.h>
#include <86box/vid_svga.h>
#include <86box/vid_voodoo_common.h>
#include <86box/vid_voodoo_regs.h>
#include <86box/vid_voodoo_render.h>
#include <86box/vid_voodoo_setup.h>

#ifdef ENABLE_VOODOO_SETUP_LOG
int voodoo_setup_do_log = ENABLE_VOODOO_SETUP_LOG;

static void
voodoo_setup_log(const char *fmt, ...)
{
    va_list ap;

    if (voodoo_setup_do_log) {
        va_start(ap, fmt);
        pclog_ex(fmt, ap);
        va_end(ap);
    }
}
#else
#    define voodoo_setup_log(fmt, ...)
#endif

void
voodoo_triangle_setup(voodoo_t *voodoo)
{
    float  dxAB;
    float  dxBC;
    float  dyAB;
    float  dyBC;
    float  area;
    int    va = 0;
    int    vb = 1;
    int    vc = 2;
    vert_t verts[3];

    verts[0] = voodoo->verts[0];
    verts[1] = voodoo->verts[1];
    verts[2] = voodoo->verts[2];

    if (verts[0].sVy < verts[1].sVy) {
        if (verts[1].sVy < verts[2].sVy) {
            /* V1>V0, V2>V1, V2>V1>V0*/
            va = 0; /*OK*/
            vb = 1;
            vc = 2;
        } else {
            /* V1>V0, V1>V2*/
            if (verts[0].sVy < verts[2].sVy) {
                /* V1>V0, V1>V2, V2>V0, V1>V2>V0*/
                va = 0;
                vb = 2;
                vc = 1;
            } else {
                /* V1>V0, V1>V2, V0>V2, V1>V0>V2*/
                va = 2;
                vb = 0;
                vc = 1;
            }
        }
    } else {
        if (verts[1].sVy < verts[2].sVy) {
            /* V0>V1, V2>V1*/
            if (verts[0].sVy < verts[2].sVy) {
                /* V0>V1, V2>V1, V2>V0, V2>V0>V1*/
                va = 1;
                vb = 0;
                vc = 2;
            } else {
                /* V0>V1, V2>V1, V0>V2, V0>V2>V1*/
                va = 1;
                vb = 2;
                vc = 0;
            }
        } else {
            /*V0>V1>V2*/
            va = 2;
            vb = 1;
            vc = 0;
        }
    }

    dxAB = verts[0].sVx - verts[1].sVx;
    dxBC = verts[1].sVx - verts[2].sVx;
    dyAB = verts[0].sVy - verts[1].sVy;
    dyBC = verts[1].sVy - verts[2].sVy;

    area = dxAB * dyBC - dxBC * dyAB;

    if (area == 0.0)
        return;

    if (voodoo->sSetupMode & SETUPMODE_CULLING_ENABLE) {
        int cull_sign = voodoo->sSetupMode & SETUPMODE_CULLING_SIGN;
        int sign      = (area < 0.0);

        if ((voodoo->sSetupMode & (SETUPMODE_CULLING_ENABLE | SETUPMODE_DISABLE_PINGPONG))
                == SETUPMODE_CULLING_ENABLE
            && voodoo->cull_pingpong)
            cull_sign = !cull_sign;

        if (cull_sign && sign)
            return;
        if (!cull_sign && !sign)
            return;
    }

    dxAB = verts[va].sVx - verts[vb].sVx;
    dxBC = verts[vb].sVx - verts[vc].sVx;
    dyAB = verts[va].sVy - verts[vb].sVy;
    dyBC = verts[vb].sVy - verts[vc].sVy;

    area = dxAB * dyBC - dxBC * dyAB;

    dxAB /= area;
    dxBC /= area;
    dyAB /= area;
    dyBC /= area;

    voodoo->params.vertexAx = (int32_t) (int16_t) ((int32_t) (verts[va].sVx * 16.0f) & 0xffff);
    voodoo->params.vertexAy = (int32_t) (int16_t) ((int32_t) (verts[va].sVy * 16.0f) & 0xffff);
    voodoo->params.vertexBx = (int32_t) (int16_t) ((int32_t) (verts[vb].sVx * 16.0f) & 0xffff);
    voodoo->params.vertexBy = (int32_t) (int16_t) ((int32_t) (verts[vb].sVy * 16.0f) & 0xffff);
    voodoo->params.vertexCx = (int32_t) (int16_t) ((int32_t) (verts[vc].sVx * 16.0f) & 0xffff);
    voodoo->params.vertexCy = (int32_t) (int16_t) ((int32_t) (verts[vc].sVy * 16.0f) & 0xffff);

    if (voodoo->params.vertexAy > voodoo->params.vertexBy || voodoo->params.vertexBy > voodoo->params.vertexCy) {
        voodoo_setup_log("triangle_setup wrong order %d %d %d\n", voodoo->params.vertexAy, voodoo->params.vertexBy, voodoo->params.vertexCy);
        return;
    }

    if (voodoo->sSetupMode & SETUPMODE_RGB) {
        voodoo->params.startR = (int32_t) (verts[va].sRed * 4096.0f);
        voodoo->params.dRdX   = (int32_t) (((verts[va].sRed - verts[vb].sRed) * dyBC - (verts[vb].sRed - verts[vc].sRed) * dyAB) * 4096.0f);
        voodoo->params.dRdY   = (int32_t) (((verts[vb].sRed - verts[vc].sRed) * dxAB - (verts[va].sRed - verts[vb].sRed) * dxBC) * 4096.0f);
        voodoo->params.startG = (int32_t) (verts[va].sGreen * 4096.0f);
        voodoo->params.dGdX   = (int32_t) (((verts[va].sGreen - verts[vb].sGreen) * dyBC - (verts[vb].sGreen - verts[vc].sGreen) * dyAB) * 4096.0f);
        voodoo->params.dGdY   = (int32_t) (((verts[vb].sGreen - verts[vc].sGreen) * dxAB - (verts[va].sGreen - verts[vb].sGreen) * dxBC) * 4096.0f);
        voodoo->params.startB = (int32_t) (verts[va].sBlue * 4096.0f);
        voodoo->params.dBdX   = (int32_t) (((verts[va].sBlue - verts[vb].sBlue) * dyBC - (verts[vb].sBlue - verts[vc].sBlue) * dyAB) * 4096.0f);
        voodoo->params.dBdY   = (int32_t) (((verts[vb].sBlue - verts[vc].sBlue) * dxAB - (verts[va].sBlue - verts[vb].sBlue) * dxBC) * 4096.0f);
    }
    if (voodoo->sSetupMode & SETUPMODE_ALPHA) {
        voodoo->params.startA = (int32_t) (verts[va].sAlpha * 4096.0f);
        voodoo->params.dAdX   = (int32_t) (((verts[va].sAlpha - verts[vb].sAlpha) * dyBC - (verts[vb].sAlpha - verts[vc].sAlpha) * dyAB) * 4096.0f);
        voodoo->params.dAdY   = (int32_t) (((verts[vb].sAlpha - verts[vc].sAlpha) * dxAB - (verts[va].sAlpha - verts[vb].sAlpha) * dxBC) * 4096.0f);
    }
    if (voodoo->sSetupMode & SETUPMODE_Z) {
        voodoo->params.startZ = (int32_t) (verts[va].sVz * 4096.0f);
        voodoo->params.dZdX   = (int32_t) (((verts[va].sVz - verts[vb].sVz) * dyBC - (verts[vb].sVz - verts[vc].sVz) * dyAB) * 4096.0f);
        voodoo->params.dZdY   = (int32_t) (((verts[vb].sVz - verts[vc].sVz) * dxAB - (verts[va].sVz - verts[vb].sVz) * dxBC) * 4096.0f);
    }
    if (voodoo->sSetupMode & SETUPMODE_Wb) {
        voodoo->params.startW        = (int64_t) (verts[va].sWb * 4294967296.0f);
        voodoo->params.dWdX          = (int64_t) (((verts[va].sWb - verts[vb].sWb) * dyBC - (verts[vb].sWb - verts[vc].sWb) * dyAB) * 4294967296.0f);
        voodoo->params.dWdY          = (int64_t) (((verts[vb].sWb - verts[vc].sWb) * dxAB - (verts[va].sWb - verts[vb].sWb) * dxBC) * 4294967296.0f);
        voodoo->params.tmu[0].startW = voodoo->params.tmu[1].startW = voodoo->params.startW;
        voodoo->params.tmu[0].dWdX   = voodoo->params.tmu[1].dWdX = voodoo->params.dWdX;
        voodoo->params.tmu[0].dWdY   = voodoo->params.tmu[1].dWdY = voodoo->params.dWdY;
    }
    if (voodoo->sSetupMode & SETUPMODE_W0) {
        voodoo->params.tmu[0].startW = (int64_t) (verts[va].sW0 * 4294967296.0f);
        voodoo->params.tmu[0].dWdX   = (int64_t) (((verts[va].sW0 - verts[vb].sW0) * dyBC - (verts[vb].sW0 - verts[vc].sW0) * dyAB) * 4294967296.0f);
        voodoo->params.tmu[0].dWdY   = (int64_t) (((verts[vb].sW0 - verts[vc].sW0) * dxAB - (verts[va].sW0 - verts[vb].sW0) * dxBC) * 4294967296.0f);
        voodoo->params.tmu[1].startW = voodoo->params.tmu[0].startW;
        voodoo->params.tmu[1].dWdX   = voodoo->params.tmu[0].dWdX;
        voodoo->params.tmu[1].dWdY   = voodoo->params.tmu[0].dWdY;
    }
    if (voodoo->sSetupMode & SETUPMODE_S0_T0) {
        voodoo->params.tmu[0].startS = (int64_t) (verts[va].sS0 * 4294967296.0f);
        voodoo->params.tmu[0].dSdX   = (int64_t) (((verts[va].sS0 - verts[vb].sS0) * dyBC - (verts[vb].sS0 - verts[vc].sS0) * dyAB) * 4294967296.0f);
        voodoo->params.tmu[0].dSdY   = (int64_t) (((verts[vb].sS0 - verts[vc].sS0) * dxAB - (verts[va].sS0 - verts[vb].sS0) * dxBC) * 4294967296.0f);
        voodoo->params.tmu[0].startT = (int64_t) (verts[va].sT0 * 4294967296.0f);
        voodoo->params.tmu[0].dTdX   = (int64_t) (((verts[va].sT0 - verts[vb].sT0) * dyBC - (verts[vb].sT0 - verts[vc].sT0) * dyAB) * 4294967296.0f);
        voodoo->params.tmu[0].dTdY   = (int64_t) (((verts[vb].sT0 - verts[vc].sT0) * dxAB - (verts[va].sT0 - verts[vb].sT0) * dxBC) * 4294967296.0f);
        voodoo->params.tmu[1].startS = voodoo->params.tmu[0].startS;
        voodoo->params.tmu[1].dSdX   = voodoo->params.tmu[0].dSdX;
        voodoo->params.tmu[1].dSdY   = voodoo->params.tmu[0].dSdY;
        voodoo->params.tmu[1].startT = voodoo->params.tmu[0].startT;
        voodoo->params.tmu[1].dTdX   = voodoo->params.tmu[0].dTdX;
        voodoo->params.tmu[1].dTdY   = voodoo->params.tmu[0].dTdY;
    }
    if (voodoo->sSetupMode & SETUPMODE_W1) {
        voodoo->params.tmu[1].startW = (int64_t) (verts[va].sW1 * 4294967296.0f);
        voodoo->params.tmu[1].dWdX   = (int64_t) (((verts[va].sW1 - verts[vb].sW1) * dyBC - (verts[vb].sW1 - verts[vc].sW1) * dyAB) * 4294967296.0f);
        voodoo->params.tmu[1].dWdY   = (int64_t) (((verts[vb].sW1 - verts[vc].sW1) * dxAB - (verts[va].sW1 - verts[vb].sW1) * dxBC) * 4294967296.0f);
    }
    if (voodoo->sSetupMode & SETUPMODE_S1_T1) {
        voodoo->params.tmu[1].startS = (int64_t) (verts[va].sS1 * 4294967296.0f);
        voodoo->params.tmu[1].dSdX   = (int64_t) (((verts[va].sS1 - verts[vb].sS1) * dyBC - (verts[vb].sS1 - verts[vc].sS1) * dyAB) * 4294967296.0f);
        voodoo->params.tmu[1].dSdY   = (int64_t) (((verts[vb].sS1 - verts[vc].sS1) * dxAB - (verts[va].sS1 - verts[vb].sS1) * dxBC) * 4294967296.0f);
        voodoo->params.tmu[1].startT = (int64_t) (verts[va].sT1 * 4294967296.0f);
        voodoo->params.tmu[1].dTdX   = (int64_t) (((verts[va].sT1 - verts[vb].sT1) * dyBC - (verts[vb].sT1 - verts[vc].sT1) * dyAB) * 4294967296.0f);
        voodoo->params.tmu[1].dTdY   = (int64_t) (((verts[vb].sT1 - verts[vc].sT1) * dxAB - (verts[va].sT1 - verts[vb].sT1) * dxBC) * 4294967296.0f);
    }

    voodoo->params.sign = (area < 0.0);

    if (voodoo->ncc_dirty[0])
        voodoo_update_ncc(voodoo, 0);
    if (voodoo->ncc_dirty[1])
        voodoo_update_ncc(voodoo, 1);
    voodoo->ncc_dirty[0] = voodoo->ncc_dirty[1] = 0;

    voodoo_queue_triangle(voodoo, &voodoo->params);
}