diff src/render/software/SDL_blendline.c @ 5166:d72793305335

Making the API simpler, moved the surface drawing functions to the software renderer.
author Sam Lantinga <slouken@libsdl.org>
date Thu, 03 Feb 2011 02:45:29 -0800
parents src/video/SDL_blendline.c@e743b9c3f6d6
children 4d39eeaad00b
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/render/software/SDL_blendline.c	Thu Feb 03 02:45:29 2011 -0800
@@ -0,0 +1,683 @@
+/*
+    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_blendline.h"
+
+
+static void
+SDL_BlendLine_RGB2(SDL_Surface * dst, int x1, int y1, int x2, int y2,
+                   SDL_BlendMode blendMode, Uint8 _r, Uint8 _g, Uint8 _b, Uint8 _a,
+                   SDL_bool draw_end)
+{
+    const SDL_PixelFormat *fmt = dst->format;
+    unsigned r, g, b, a, inva;
+
+    if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
+        r = DRAW_MUL(_r, _a);
+        g = DRAW_MUL(_g, _a);
+        b = DRAW_MUL(_b, _a);
+        a = _a;
+    } else {
+        r = _r;
+        g = _g;
+        b = _b;
+        a = _a;
+    }
+    inva = (a ^ 0xff);
+
+    if (y1 == y2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            HLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            HLINE(Uint16, DRAW_SETPIXEL_ADD_RGB, draw_end);
+            break;
+        default:
+            HLINE(Uint16, DRAW_SETPIXEL_RGB, draw_end);
+            break;
+        }
+    } else if (x1 == x2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            VLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            VLINE(Uint16, DRAW_SETPIXEL_ADD_RGB, draw_end);
+            break;
+        default:
+            VLINE(Uint16, DRAW_SETPIXEL_RGB, draw_end);
+            break;
+        }
+    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            DLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            DLINE(Uint16, DRAW_SETPIXEL_ADD_RGB, draw_end);
+            break;
+        default:
+            DLINE(Uint16, DRAW_SETPIXEL_RGB, draw_end);
+            break;
+        }
+    } else {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY2_BLEND_RGB, DRAW_SETPIXELXY2_BLEND_RGB,
+                   draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY2_ADD_RGB, DRAW_SETPIXELXY2_ADD_RGB,
+                   draw_end);
+            break;
+        default:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY2_RGB, DRAW_SETPIXELXY2_BLEND_RGB,
+                   draw_end);
+            break;
+        }
+    }
+}
+
+static void
+SDL_BlendLine_RGB555(SDL_Surface * dst, int x1, int y1, int x2, int y2,
+                     SDL_BlendMode blendMode, Uint8 _r, Uint8 _g, Uint8 _b, Uint8 _a,
+                     SDL_bool draw_end)
+{
+    const SDL_PixelFormat *fmt = dst->format;
+    unsigned r, g, b, a, inva;
+
+    if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
+        r = DRAW_MUL(_r, _a);
+        g = DRAW_MUL(_g, _a);
+        b = DRAW_MUL(_b, _a);
+        a = _a;
+    } else {
+        r = _r;
+        g = _g;
+        b = _b;
+        a = _a;
+    }
+    inva = (a ^ 0xff);
+
+    if (y1 == y2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            HLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB555, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            HLINE(Uint16, DRAW_SETPIXEL_ADD_RGB555, draw_end);
+            break;
+        default:
+            HLINE(Uint16, DRAW_SETPIXEL_RGB555, draw_end);
+            break;
+        }
+    } else if (x1 == x2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            VLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB555, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            VLINE(Uint16, DRAW_SETPIXEL_ADD_RGB555, draw_end);
+            break;
+        default:
+            VLINE(Uint16, DRAW_SETPIXEL_RGB555, draw_end);
+            break;
+        }
+    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            DLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB555, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            DLINE(Uint16, DRAW_SETPIXEL_ADD_RGB555, draw_end);
+            break;
+        default:
+            DLINE(Uint16, DRAW_SETPIXEL_RGB555, draw_end);
+            break;
+        }
+    } else {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_BLEND_RGB555, DRAW_SETPIXELXY_BLEND_RGB555,
+                   draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_ADD_RGB555, DRAW_SETPIXELXY_ADD_RGB555,
+                   draw_end);
+            break;
+        default:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_RGB555, DRAW_SETPIXELXY_BLEND_RGB555,
+                   draw_end);
+            break;
+        }
+    }
+}
+
+static void
+SDL_BlendLine_RGB565(SDL_Surface * dst, int x1, int y1, int x2, int y2,
+                     SDL_BlendMode blendMode, Uint8 _r, Uint8 _g, Uint8 _b, Uint8 _a,
+                     SDL_bool draw_end)
+{
+    const SDL_PixelFormat *fmt = dst->format;
+    unsigned r, g, b, a, inva;
+
+    if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
+        r = DRAW_MUL(_r, _a);
+        g = DRAW_MUL(_g, _a);
+        b = DRAW_MUL(_b, _a);
+        a = _a;
+    } else {
+        r = _r;
+        g = _g;
+        b = _b;
+        a = _a;
+    }
+    inva = (a ^ 0xff);
+
+    if (y1 == y2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            HLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB565, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            HLINE(Uint16, DRAW_SETPIXEL_ADD_RGB565, draw_end);
+            break;
+        default:
+            HLINE(Uint16, DRAW_SETPIXEL_RGB565, draw_end);
+            break;
+        }
+    } else if (x1 == x2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            VLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB565, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            VLINE(Uint16, DRAW_SETPIXEL_ADD_RGB565, draw_end);
+            break;
+        default:
+            VLINE(Uint16, DRAW_SETPIXEL_RGB565, draw_end);
+            break;
+        }
+    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            DLINE(Uint16, DRAW_SETPIXEL_BLEND_RGB565, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            DLINE(Uint16, DRAW_SETPIXEL_ADD_RGB565, draw_end);
+            break;
+        default:
+            DLINE(Uint16, DRAW_SETPIXEL_RGB565, draw_end);
+            break;
+        }
+    } else {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_BLEND_RGB565, DRAW_SETPIXELXY_BLEND_RGB565,
+                   draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_ADD_RGB565, DRAW_SETPIXELXY_ADD_RGB565,
+                   draw_end);
+            break;
+        default:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_RGB565, DRAW_SETPIXELXY_BLEND_RGB565,
+                   draw_end);
+            break;
+        }
+    }
+}
+
+static void
+SDL_BlendLine_RGB4(SDL_Surface * dst, int x1, int y1, int x2, int y2,
+                   SDL_BlendMode blendMode, Uint8 _r, Uint8 _g, Uint8 _b, Uint8 _a,
+                   SDL_bool draw_end)
+{
+    const SDL_PixelFormat *fmt = dst->format;
+    unsigned r, g, b, a, inva;
+
+    if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
+        r = DRAW_MUL(_r, _a);
+        g = DRAW_MUL(_g, _a);
+        b = DRAW_MUL(_b, _a);
+        a = _a;
+    } else {
+        r = _r;
+        g = _g;
+        b = _b;
+        a = _a;
+    }
+    inva = (a ^ 0xff);
+
+    if (y1 == y2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            HLINE(Uint32, DRAW_SETPIXEL_BLEND_RGB, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            HLINE(Uint32, DRAW_SETPIXEL_ADD_RGB, draw_end);
+            break;
+        default:
+            HLINE(Uint32, DRAW_SETPIXEL_RGB, draw_end);
+            break;
+        }
+    } else if (x1 == x2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            VLINE(Uint32, DRAW_SETPIXEL_BLEND_RGB, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            VLINE(Uint32, DRAW_SETPIXEL_ADD_RGB, draw_end);
+            break;
+        default:
+            VLINE(Uint32, DRAW_SETPIXEL_RGB, draw_end);
+            break;
+        }
+    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            DLINE(Uint32, DRAW_SETPIXEL_BLEND_RGB, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            DLINE(Uint32, DRAW_SETPIXEL_ADD_RGB, draw_end);
+            break;
+        default:
+            DLINE(Uint32, DRAW_SETPIXEL_RGB, draw_end);
+            break;
+        }
+    } else {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY4_BLEND_RGB, DRAW_SETPIXELXY4_BLEND_RGB,
+                   draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY4_ADD_RGB, DRAW_SETPIXELXY4_ADD_RGB,
+                   draw_end);
+            break;
+        default:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY4_RGB, DRAW_SETPIXELXY4_BLEND_RGB,
+                   draw_end);
+            break;
+        }
+    }
+}
+
+static void
+SDL_BlendLine_RGBA4(SDL_Surface * dst, int x1, int y1, int x2, int y2,
+                    SDL_BlendMode blendMode, Uint8 _r, Uint8 _g, Uint8 _b, Uint8 _a,
+                    SDL_bool draw_end)
+{
+    const SDL_PixelFormat *fmt = dst->format;
+    unsigned r, g, b, a, inva;
+
+    if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
+        r = DRAW_MUL(_r, _a);
+        g = DRAW_MUL(_g, _a);
+        b = DRAW_MUL(_b, _a);
+        a = _a;
+    } else {
+        r = _r;
+        g = _g;
+        b = _b;
+        a = _a;
+    }
+    inva = (a ^ 0xff);
+
+    if (y1 == y2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            HLINE(Uint32, DRAW_SETPIXEL_BLEND_RGBA, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            HLINE(Uint32, DRAW_SETPIXEL_ADD_RGBA, draw_end);
+            break;
+        default:
+            HLINE(Uint32, DRAW_SETPIXEL_RGBA, draw_end);
+            break;
+        }
+    } else if (x1 == x2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            VLINE(Uint32, DRAW_SETPIXEL_BLEND_RGBA, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            VLINE(Uint32, DRAW_SETPIXEL_ADD_RGBA, draw_end);
+            break;
+        default:
+            VLINE(Uint32, DRAW_SETPIXEL_RGBA, draw_end);
+            break;
+        }
+    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            DLINE(Uint32, DRAW_SETPIXEL_BLEND_RGBA, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            DLINE(Uint32, DRAW_SETPIXEL_ADD_RGBA, draw_end);
+            break;
+        default:
+            DLINE(Uint32, DRAW_SETPIXEL_RGBA, draw_end);
+            break;
+        }
+    } else {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY4_BLEND_RGBA, DRAW_SETPIXELXY4_BLEND_RGBA,
+                   draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY4_ADD_RGBA, DRAW_SETPIXELXY4_ADD_RGBA,
+                   draw_end);
+            break;
+        default:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY4_RGBA, DRAW_SETPIXELXY4_BLEND_RGBA,
+                   draw_end);
+            break;
+        }
+    }
+}
+
+static void
+SDL_BlendLine_RGB888(SDL_Surface * dst, int x1, int y1, int x2, int y2,
+                     SDL_BlendMode blendMode, Uint8 _r, Uint8 _g, Uint8 _b, Uint8 _a,
+                     SDL_bool draw_end)
+{
+    const SDL_PixelFormat *fmt = dst->format;
+    unsigned r, g, b, a, inva;
+
+    if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
+        r = DRAW_MUL(_r, _a);
+        g = DRAW_MUL(_g, _a);
+        b = DRAW_MUL(_b, _a);
+        a = _a;
+    } else {
+        r = _r;
+        g = _g;
+        b = _b;
+        a = _a;
+    }
+    inva = (a ^ 0xff);
+
+    if (y1 == y2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            HLINE(Uint32, DRAW_SETPIXEL_BLEND_RGB888, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            HLINE(Uint32, DRAW_SETPIXEL_ADD_RGB888, draw_end);
+            break;
+        default:
+            HLINE(Uint32, DRAW_SETPIXEL_RGB888, draw_end);
+            break;
+        }
+    } else if (x1 == x2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            VLINE(Uint32, DRAW_SETPIXEL_BLEND_RGB888, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            VLINE(Uint32, DRAW_SETPIXEL_ADD_RGB888, draw_end);
+            break;
+        default:
+            VLINE(Uint32, DRAW_SETPIXEL_RGB888, draw_end);
+            break;
+        }
+    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            DLINE(Uint32, DRAW_SETPIXEL_BLEND_RGB888, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            DLINE(Uint32, DRAW_SETPIXEL_ADD_RGB888, draw_end);
+            break;
+        default:
+            DLINE(Uint32, DRAW_SETPIXEL_RGB888, draw_end);
+            break;
+        }
+    } else {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_BLEND_RGB888, DRAW_SETPIXELXY_BLEND_RGB888,
+                   draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_ADD_RGB888, DRAW_SETPIXELXY_ADD_RGB888,
+                   draw_end);
+            break;
+        default:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_RGB888, DRAW_SETPIXELXY_BLEND_RGB888,
+                   draw_end);
+            break;
+        }
+    }
+}
+
+static void
+SDL_BlendLine_ARGB8888(SDL_Surface * dst, int x1, int y1, int x2, int y2,
+                       SDL_BlendMode blendMode, Uint8 _r, Uint8 _g, Uint8 _b, Uint8 _a,
+                       SDL_bool draw_end)
+{
+    const SDL_PixelFormat *fmt = dst->format;
+    unsigned r, g, b, a, inva;
+
+    if (blendMode == SDL_BLENDMODE_BLEND || blendMode == SDL_BLENDMODE_ADD) {
+        r = DRAW_MUL(_r, _a);
+        g = DRAW_MUL(_g, _a);
+        b = DRAW_MUL(_b, _a);
+        a = _a;
+    } else {
+        r = _r;
+        g = _g;
+        b = _b;
+        a = _a;
+    }
+    inva = (a ^ 0xff);
+
+    if (y1 == y2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            HLINE(Uint32, DRAW_SETPIXEL_BLEND_ARGB8888, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            HLINE(Uint32, DRAW_SETPIXEL_ADD_ARGB8888, draw_end);
+            break;
+        default:
+            HLINE(Uint32, DRAW_SETPIXEL_ARGB8888, draw_end);
+            break;
+        }
+    } else if (x1 == x2) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            VLINE(Uint32, DRAW_SETPIXEL_BLEND_ARGB8888, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            VLINE(Uint32, DRAW_SETPIXEL_ADD_ARGB8888, draw_end);
+            break;
+        default:
+            VLINE(Uint32, DRAW_SETPIXEL_ARGB8888, draw_end);
+            break;
+        }
+    } else if (ABS(x1 - x2) == ABS(y1 - y2)) {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            DLINE(Uint32, DRAW_SETPIXEL_BLEND_ARGB8888, draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            DLINE(Uint32, DRAW_SETPIXEL_ADD_ARGB8888, draw_end);
+            break;
+        default:
+            DLINE(Uint32, DRAW_SETPIXEL_ARGB8888, draw_end);
+            break;
+        }
+    } else {
+        switch (blendMode) {
+        case SDL_BLENDMODE_BLEND:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_BLEND_ARGB8888, DRAW_SETPIXELXY_BLEND_ARGB8888,
+                   draw_end);
+            break;
+        case SDL_BLENDMODE_ADD:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_ADD_ARGB8888, DRAW_SETPIXELXY_ADD_ARGB8888,
+                   draw_end);
+            break;
+        default:
+            AALINE(x1, y1, x2, y2,
+                   DRAW_SETPIXELXY_ARGB8888, DRAW_SETPIXELXY_BLEND_ARGB8888,
+                   draw_end);
+            break;
+        }
+    }
+}
+
+typedef void (*BlendLineFunc) (SDL_Surface * dst,
+                               int x1, int y1, int x2, int y2,
+                               SDL_BlendMode blendMode,
+                               Uint8 r, Uint8 g, Uint8 b, Uint8 a,
+                               SDL_bool draw_end);
+
+static BlendLineFunc
+SDL_CalculateBlendLineFunc(const SDL_PixelFormat * fmt)
+{
+    switch (fmt->BytesPerPixel) {
+    case 2:
+        if (fmt->Rmask == 0x7C00) {
+            return SDL_BlendLine_RGB555;
+        } else if (fmt->Rmask == 0xF800) {
+            return SDL_BlendLine_RGB565;
+        } else {
+            return SDL_BlendLine_RGB2;
+        }
+        break;
+    case 4:
+        if (fmt->Rmask == 0x00FF0000) {
+            if (fmt->Amask) {
+                return SDL_BlendLine_ARGB8888;
+            } else {
+                return SDL_BlendLine_RGB888;
+            }
+        } else {
+            if (fmt->Amask) {
+                return SDL_BlendLine_RGBA4;
+            } else {
+                return SDL_BlendLine_RGB4;
+            }
+        }
+    }
+    return NULL;
+}
+
+int
+SDL_BlendLine(SDL_Surface * dst, int x1, int y1, int x2, int y2,
+              SDL_BlendMode blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
+{
+    BlendLineFunc func;
+
+    if (!dst) {
+        SDL_SetError("SDL_BlendLine(): Passed NULL destination surface");
+        return -1;
+    }
+
+    func = SDL_CalculateBlendLineFunc(dst->format);
+    if (!func) {
+        SDL_SetError("SDL_BlendLine(): 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, blendMode, r, g, b, a, SDL_TRUE);
+    return 0;
+}
+
+int
+SDL_BlendLines(SDL_Surface * dst, const SDL_Point * points, int count,
+               SDL_BlendMode blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
+{
+    int i;
+    int x1, y1;
+    int x2, y2;
+    SDL_bool draw_end;
+    BlendLineFunc func;
+
+    if (!dst) {
+        SDL_SetError("SDL_BlendLines(): Passed NULL destination surface");
+        return -1;
+    }
+
+    func = SDL_CalculateBlendLineFunc(dst->format);
+    if (!func) {
+        SDL_SetError("SDL_BlendLines(): 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, blendMode, r, g, b, a, draw_end);
+    }
+    if (points[0].x != points[count-1].x || points[0].y != points[count-1].y) {
+        SDL_BlendPoint(dst, points[count-1].x, points[count-1].y,
+                       blendMode, r, g, b, a);
+    }
+    return 0;
+}
+
+/* vi: set ts=4 sw=4 expandtab: */