/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2010 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library 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

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

#include "SDL_draw.h"

#include "SDL_drawline.h"

static void

SDL_DrawLine1(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,

              SDL_bool draw_end)

{

    if (y1 == y2) {

        //HLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);

        int length;

        int pitch = (dst->pitch / dst->format->BytesPerPixel);

        Uint8 *pixel;

        if (x1 <= x2) {

            pixel = (Uint8 *)dst->pixels + y1 * pitch + x1;

            length = draw_end ? (x2-x1+1) : (x2-x1);

        } else {

            pixel = (Uint8 *)dst->pixels + y1 * pitch + x2;

            if (!draw_end) {

                ++pixel;

            }

            length = draw_end ? (x1-x2+1) : (x1-x2);

        }

        SDL_memset(pixel, color, length);

    } else if (x1 == x2) {

        VLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);

    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {

        DLINE(Uint8, DRAW_FASTSETPIXEL1, draw_end);

    } else {

        BLINE(x1, y1, x2, y2, DRAW_FASTSETPIXELXY1, draw_end);

    }

}

static void

SDL_DrawLine2(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,

              SDL_bool draw_end)

{

    if (y1 == y2) {

        HLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);

    } else if (x1 == x2) {

        VLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);

    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {

        DLINE(Uint16, DRAW_FASTSETPIXEL2, draw_end);

    } else {

        Uint8 _r, _g, _b, _a;

        const SDL_PixelFormat * fmt = dst->format;

        SDL_GetRGBA(color, fmt, &_r, &_g, &_b, &_a);

        if (fmt->Rmask == 0x7C00) {

            AALINE(x1, y1, x2, y2,

                   DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY_BLEND_RGB555,

                   draw_end);

        } else if (fmt->Rmask == 0xF800) {

            AALINE(x1, y1, x2, y2,

                   DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY_BLEND_RGB565,

                   draw_end);

        } else {

            AALINE(x1, y1, x2, y2,

                   DRAW_FASTSETPIXELXY2, DRAW_SETPIXELXY2_BLEND_RGB,

                   draw_end);

        }

    }

}

static void

SDL_DrawLine4(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color,

              SDL_bool draw_end)

{

    if (y1 == y2) {

        HLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);

    } else if (x1 == x2) {

        VLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);

    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {

        DLINE(Uint32, DRAW_FASTSETPIXEL4, draw_end);

    } else {

        Uint8 _r, _g, _b, _a;

        const SDL_PixelFormat * fmt = dst->format;

        SDL_GetRGBA(color, fmt, &_r, &_g, &_b, &_a);

        if (fmt->Rmask == 0x00FF0000) {

            if (!fmt->Amask) {

                AALINE(x1, y1, x2, y2,

                       DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY_BLEND_RGB888,

                       draw_end);

            } else {

                AALINE(x1, y1, x2, y2,

                       DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY_BLEND_ARGB8888,

                       draw_end);

            }

        } else {

            AALINE(x1, y1, x2, y2,

                   DRAW_FASTSETPIXELXY4, DRAW_SETPIXELXY4_BLEND_RGB,

                   draw_end);

        }

    }

}

typedef void (*DrawLineFunc) (SDL_Surface * dst,

                              int x1, int y1, int x2, int y2,

                              Uint32 color, SDL_bool draw_end);

static DrawLineFunc

SDL_CalculateDrawLineFunc(const SDL_PixelFormat * fmt)

{

    switch (fmt->BytesPerPixel) {

    case 1:

        if (fmt->BitsPerPixel < 8) {

            break;

        }

        return SDL_DrawLine1;

    case 2:

        return SDL_DrawLine2;

    case 4:

        return SDL_DrawLine4;

    }

    return NULL;

}

int

SDL_DrawLine(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color)

{

    DrawLineFunc func;

    if (!dst) {

        SDL_SetError("SDL_DrawLine(): Passed NULL destination surface");

        return -1;

    }

    func = SDL_CalculateDrawLineFunc(dst->format);

    if (!func) {

        SDL_SetError("SDL_DrawLine(): Unsupported surface format");

        return -1;

    }

    /* Perform clipping */

    /* FIXME: We don't actually want to clip, as it may change line slope */

    if (!SDL_IntersectRectAndLine(&dst->clip_rect, &x1, &y1, &x2, &y2)) {

        return 0;

    }

    func(dst, x1, y1, x2, y2, color, SDL_TRUE);

    return 0;

}

int

SDL_DrawLines(SDL_Surface * dst, const SDL_Point * points, int count,

              Uint32 color)

{

    int i;

    int x1, y1;

    int x2, y2;

    SDL_bool draw_end;

    DrawLineFunc func;

    if (!dst) {

        SDL_SetError("SDL_DrawLines(): Passed NULL destination surface");

        return -1;

    }

    func = SDL_CalculateDrawLineFunc(dst->format);

    if (!func) {

        SDL_SetError("SDL_DrawLines(): Unsupported surface format");

        return -1;

    }

    for (i = 1; i < count; ++i) {

        x1 = points[i-1].x;

        y1 = points[i-1].y;

        x2 = points[i].x;

        y2 = points[i].y;

        /* Perform clipping */

        /* FIXME: We don't actually want to clip, as it may change line slope */

        if (!SDL_IntersectRectAndLine(&dst->clip_rect, &x1, &y1, &x2, &y2)) {

            continue;

        }

        /* Draw the end if it was clipped */

        draw_end = (x2 != points[i].x || y2 != points[i].y);

        func(dst, x1, y1, x2, y2, color, draw_end);

    }

    if (points[0].x != points[count-1].x || points[0].y != points[count-1].y) {

        SDL_DrawPoint(dst, points[count-1].x, points[count-1].y, color);

    }

    return 0;

}

/* vi: set ts=4 sw=4 expandtab: */