--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/render/software/SDL_drawline.c	Thu Feb 03 02:45:29 2011 -0800
@@ -0,0 +1,210 @@
+/*
+    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: */