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/*

 * Copyright (c) 1999, 2000, 2001 Greg Haerr <greg@censoft.com>

 *

 * 8bpp Linear Video Driver for Microwindows

 *      00/01/26 added alpha blending with lookup tables (64k total)

 *

 * Inspired from Ben Pfaff's BOGL <pfaffben@debian.org>

 */

/*#define NDEBUG*/

#include <assert.h>

/* We want to do string copying fast, so inline assembly if possible */

#ifndef __OPTIMIZE__

#define __OPTIMIZE__

#endif

#include <string.h>

#include "device.h"

#include "fb.h"

#if ALPHABLEND

/*

 * Alpha lookup tables for 256 color palette systems

 * A 5 bit alpha value is used to keep tables smaller.

 *

 * Two tables are created.  The first, alpha_to_rgb contains 15 bit RGB

 * values for each alpha value for each color: 32*256 short words.

 * RGB values can then be blended.  The second, rgb_to_palindex contains

 * the closest color (palette index) for each of the 5-bit

 * R, G, and B values: 32*32*32 bytes.

 */

static unsigned short *alpha_to_rgb = NULL;

static unsigned char  *rgb_to_palindex = NULL;

void init_alpha_lookup(void);

#endif

/* Calc linelen and mmap size, return 0 on fail*/

static int

linear8_init(PSD psd)

{

        if (!psd->size)

                psd->size = psd->yres * psd->linelen;

        /* linelen in bytes for bpp 1, 2, 4, 8 so no change*/

        return 1;

}

/* Set pixel at x, y, to pixelval c*/

static void

linear8_drawpixel(PSD psd, MWCOORD x, MWCOORD y, MWPIXELVAL c)

{

        ADDR8   addr = psd->addr;

        assert (addr != 0);

        assert (x >= 0 && x < psd->xres);

        assert (y >= 0 && y < psd->yres);

        assert (c < psd->ncolors);

        DRAWON;

        if(gr_mode == MWMODE_COPY)

                addr[x + y * psd->linelen] = c;

        else

                applyOp(gr_mode, c, &addr[ x + y * psd->linelen], ADDR8);

        DRAWOFF;

}

/* Read pixel at x, y*/

static MWPIXELVAL

linear8_readpixel(PSD psd, MWCOORD x, MWCOORD y)

{

        ADDR8   addr = psd->addr;

        assert (addr != 0);

        assert (x >= 0 && x < psd->xres);

        assert (y >= 0 && y < psd->yres);

        return addr[x + y * psd->linelen];

}

/* Draw horizontal line from x1,y to x2,y including final point*/

static void

linear8_drawhorzline(PSD psd, MWCOORD x1, MWCOORD x2, MWCOORD y, MWPIXELVAL c)

{

        ADDR8   addr = psd->addr;

        assert (addr != 0);

        assert (x1 >= 0 && x1 < psd->xres);

        assert (x2 >= 0 && x2 < psd->xres);

        assert (x2 >= x1);

        assert (y >= 0 && y < psd->yres);

        assert (c < psd->ncolors);

        DRAWON;

        addr += x1 + y * psd->linelen;

        if(gr_mode == MWMODE_COPY)

                memset(addr, c, x2 - x1 + 1);

        else {

                while(x1++ <= x2) {

                        applyOp(gr_mode, c, addr, ADDR8);

                        ++addr;

                }

        }

        DRAWOFF;

}

/* Draw a vertical line from x,y1 to x,y2 including final point*/

static void

linear8_drawvertline(PSD psd, MWCOORD x, MWCOORD y1, MWCOORD y2, MWPIXELVAL c)

{

        ADDR8   addr = psd->addr;

        int     linelen = psd->linelen;

        assert (addr != 0);

        assert (x >= 0 && x < psd->xres);

        assert (y1 >= 0 && y1 < psd->yres);

        assert (y2 >= 0 && y2 < psd->yres);

        assert (y2 >= y1);

        assert (c < psd->ncolors);

        DRAWON;

        addr += x + y1 * linelen;

        if(gr_mode == MWMODE_COPY) {

                while(y1++ <= y2) {

                        *addr = c;

                        addr += linelen;

                }

        } else {

                while(y1++ <= y2) {

                        applyOp(gr_mode, c, addr, ADDR8);

                        addr += linelen;

                }

        }

        DRAWOFF;

}

/* srccopy bitblt*/

static void

linear8_blit(PSD dstpsd, MWCOORD dstx, MWCOORD dsty, MWCOORD w, MWCOORD h,

        PSD srcpsd, MWCOORD srcx, MWCOORD srcy, long op)

{

        ADDR8   dst;

        ADDR8   src;

        int     dlinelen = dstpsd->linelen;

        int     slinelen = srcpsd->linelen;

#if ALPHABLEND

        unsigned int srcalpha, dstalpha;

#endif

        assert (dstpsd->addr != 0);

        assert (dstx >= 0 && dstx < dstpsd->xres);

        assert (dsty >= 0 && dsty < dstpsd->yres);

        assert (w > 0);

        assert (h > 0);

        assert (srcpsd->addr != 0);

        assert (srcx >= 0 && srcx < srcpsd->xres);

        assert (srcy >= 0 && srcy < srcpsd->yres);

        assert (dstx+w <= dstpsd->xres);

        assert (dsty+h <= dstpsd->yres);

        assert (srcx+w <= srcpsd->xres);

        assert (srcy+h <= srcpsd->yres);

        DRAWON;

        dst = dstpsd->addr + dstx + dsty * dlinelen;

        src = srcpsd->addr + srcx + srcy * slinelen;

#if ALPHABLEND

        if((op & MWROP_EXTENSION) != MWROP_BLENDCONSTANT)

                goto stdblit;

        srcalpha = op & 0xff;

        /* FIXME create lookup table after palette is stabilized...*/

        if(!rgb_to_palindex || !alpha_to_rgb) {

                init_alpha_lookup();

                if(!rgb_to_palindex || !alpha_to_rgb)

                        goto stdblit;

        }

        /* Create 5 bit alpha value index for 256 color indexing*/

        /* destination alpha is (1 - source) alpha*/

        dstalpha = ((srcalpha>>3) ^ 31) << 8;

        srcalpha = (srcalpha>>3) << 8;

        while(--h >= 0) {

            int i;

            for(i=0; i<w; ++i) {

                /* Get source RGB555 value for source alpha value*/

                unsigned short s = alpha_to_rgb[srcalpha + *src++];

                /* Get destination RGB555 value for dest alpha value*/

                unsigned short d = alpha_to_rgb[dstalpha + *dst];

                /* Add RGB values together and get closest palette index to it*/

                *dst++ = rgb_to_palindex[s + d];

            }

            dst += dlinelen - w;

            src += slinelen - w;

        }

        DRAWOFF;

        return;

stdblit:

#endif

        if (op == MWROP_COPY) {

                /* copy from bottom up if dst in src rectangle*/

                /* memmove is used to handle x case*/

                if (srcy < dsty) {

                        src += (h-1) * slinelen;

                        dst += (h-1) * dlinelen;

                        slinelen *= -1;

                        dlinelen *= -1;

                }

                while(--h >= 0) {

                        /* a _fast_ memcpy is a _must_ in this routine*/

                        memmove(dst, src, w);

                        dst += dlinelen;

                        src += slinelen;

                }

        } else {

                while (--h >= 0) {

                        int i;

                        for (i=0; i<w; i++) {

                                applyOp(MWROP_TO_MODE(op), *src, dst, ADDR8);

                                ++src;

                                ++dst;

                        }

                        dst += dlinelen - w;

                        src += slinelen - w;

                }

        }

        DRAWOFF;

}

/* srccopy stretchblt*/

static void

linear8_stretchblit(PSD dstpsd, MWCOORD dstx, MWCOORD dsty, MWCOORD dstw,

        MWCOORD dsth, PSD srcpsd, MWCOORD srcx, MWCOORD srcy, MWCOORD srcw,

        MWCOORD srch, long op)

{

        ADDR8   dst;

        ADDR8   src;

        int     dlinelen = dstpsd->linelen;

        int     slinelen = srcpsd->linelen;

        int     i, ymax;

        int     row_pos, row_inc;

        int     col_pos, col_inc;

        unsigned char pixel = 0;

        assert (dstpsd->addr != 0);

        assert (dstx >= 0 && dstx < dstpsd->xres);

        assert (dsty >= 0 && dsty < dstpsd->yres);

        assert (dstw > 0);

        assert (dsth > 0);

        assert (srcpsd->addr != 0);

        assert (srcx >= 0 && srcx < srcpsd->xres);

        assert (srcy >= 0 && srcy < srcpsd->yres);

        assert (srcw > 0);

        assert (srch > 0);

        assert (dstx+dstw <= dstpsd->xres);

        assert (dsty+dsth <= dstpsd->yres);

        assert (srcx+srcw <= srcpsd->xres);

        assert (srcy+srch <= srcpsd->yres);

        DRAWON;

        row_pos = 0x10000;

        row_inc = (srch << 16) / dsth;

        /* stretch blit using integer ratio between src/dst height/width*/

        for (ymax = dsty+dsth; dsty<ymax; ++dsty) {

                /* find source y position*/

                while (row_pos >= 0x10000L) {

                        ++srcy;

                        row_pos -= 0x10000L;

                }

                dst = dstpsd->addr + dstx + dsty*dlinelen;

                src = srcpsd->addr + srcx + (srcy-1)*slinelen;

                /* copy a row of pixels*/

                col_pos = 0x10000;

                col_inc = (srcw << 16) / dstw;

                for (i=0; i<dstw; ++i) {

                        /* get source x pixel*/

                        while (col_pos >= 0x10000L) {

                                pixel = *src++;

                                col_pos -= 0x10000L;

                        }

                        *dst++ = pixel;

                        col_pos += col_inc;

                }

                row_pos += row_inc;

        }

        DRAWOFF;

}

#if ALPHABLEND

void

init_alpha_lookup(void)

{

        int     i, a;

        int     r, g, b;

        extern MWPALENTRY gr_palette[256];

        if(!alpha_to_rgb)

                alpha_to_rgb = (unsigned short *)malloc(

                        sizeof(unsigned short)*32*256);

        if(!rgb_to_palindex)

                rgb_to_palindex = (unsigned char *)malloc(

                        sizeof(unsigned char)*32*32*32);

        if(!rgb_to_palindex || !alpha_to_rgb)

                return;

        /*

         * Precompute alpha to rgb lookup by premultiplying

         * each palette rgb value by each possible alpha

         * and storing it as RGB555.

         */

        for(i=0; i<256; ++i) {

                MWPALENTRY *p = &gr_palette[i];

                for(a=0; a<32; ++a) {

                        alpha_to_rgb[(a<<8)+i] =

                                (((p->r * a / 31)>>3) << 10) |

                                (((p->g * a / 31)>>3) << 5) |

                                 ((p->b * a / 31)>>3);

                }

        }

        /*

         * Precompute RGB555 to palette index table by

         * finding the nearest palette index for all RGB555 colors.

         */

        for(r=0; r<32; ++r) {

                for(g=0; g<32; ++g)

                        for(b=0; b<32; ++b)

                                rgb_to_palindex[ (r<<10)|(g<<5)|b] =

                                        GdFindNearestColor(gr_palette, 256,

                                                MWRGB(r<<3, g<<3, b<<3));

        }

}

#endif

SUBDRIVER fblinear8 = {

        linear8_init,

        linear8_drawpixel,

        linear8_readpixel,

        linear8_drawhorzline,

        linear8_drawvertline,

        gen_fillrect,

        linear8_blit,

        NULL,

        linear8_stretchblit

};