# HG changeset patch
# User Sam Lantinga <slouken@libsdl.org>
# Date 1229815160 0
# Node ID 1ef2f1e75ff7c30925760dca6cebf3ae80eee7ca
# Parent  9328f53a0ca2bbcc5ddc934c1de76a2ddf1268cd
Date: Sat, 20 Dec 2008 23:25:19 +0100
From: Couriersud
Subject: 32 & 16 bit versions of blendrect and blendline

attached are 32, 16 and 15 bit versions of the blendrect and blendline
functionality. There was an issue with the bresenham alg. in drawline
which I also fixed.

diff -r 9328f53a0ca2 -r 1ef2f1e75ff7 src/video/SDL_blendline.c
--- a/src/video/SDL_blendline.c	Sat Dec 20 23:10:20 2008 +0000
+++ b/src/video/SDL_blendline.c	Sat Dec 20 23:19:20 2008 +0000
@@ -24,11 +24,117 @@
 #include "SDL_video.h"
 #include "SDL_blit.h"
 
+#define ABS(_x) ((_x) < 0 ? -(_x) : (_x))
+
+#define SWAP(_x, _y) do { int tmp; tmp = _x; _x = _y; _y = tmp; } while (0)
+
+#define BRESENHAM(x0, y0, x1, y1, op) \
+{ \
+    int deltax, deltay, steep, error, xstep, ystep, x, y; \
+ \
+    deltax = ABS(x1 - x0); \
+    deltay = ABS(y1 - y0); \
+    steep = (deltay > deltax); \
+    if (steep) { \
+        SWAP(x0, y0); \
+        SWAP(x1, y1); \
+        SWAP(deltax, deltay); \
+    } \
+    error = (x1 - x0) / 2; \
+    y = y0; \
+    if (x0 > x1) { \
+        xstep = -1; \
+    } else { \
+        xstep = 1; \
+    } \
+    if (y0 < y1) { \
+        ystep = 1; \
+    } else { \
+        ystep = -1; \
+    } \
+    if (!steep) { \
+        for (x = x0; x != x1; x += xstep) { \
+            op(x, y); \
+            error -= deltay; \
+            if (error < 0) { \
+                y += ystep; \
+                error += deltax; \
+            } \
+        } \
+    } else { \
+        for (x = x0; x != x1; x += xstep) { \
+            op(y, x); \
+            error -= deltay; \
+            if (error < 0) { \
+                y += ystep; \
+                error += deltax; \
+            } \
+        } \
+    } \
+}
+
+#define MUL(_a, _b) (((Uint16)(_a)*(Uint16)(_b))/255)
+#define SHIFTAND(_v, _s, _a) (((_v)>>(_s)) & _a)
+
+#define SETPIXEL_MASK(x, y, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
+do { \
+	type *pixel = (type *)(dst->pixels + y * dst->pitch + x * bpp); \
+	if (a) { \
+		*pixel = (r<<rshift) | (g<<gshift) | (b<<bshift); \
+	} \
+} while (0)
+
+#define SETPIXEL_BLEND(x, y, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
+do { \
+	type *pixel = (type *)(dst->pixels + y * dst->pitch + x * bpp); \
+	Uint8 sr = MUL(inva, SHIFTAND(*pixel, rshift, rmask)) + (Uint16) r; \
+	Uint8 sg = MUL(inva, SHIFTAND(*pixel, gshift, gmask)) + (Uint16) g; \
+	Uint8 sb = MUL(inva, SHIFTAND(*pixel, bshift, bmask)) + (Uint16) b; \
+	*pixel = (sr<<rshift) | (sg<<gshift) | (sb<<bshift);  \
+} while (0)
+
+#define SETPIXEL_ADD(x, y, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
+do { \
+	type *pixel = (type *)(dst->pixels + y * dst->pitch + x * bpp); \
+	Uint16 sr = SHIFTAND(*pixel, rshift, rmask) + (Uint16) r; \
+	Uint16 sg = SHIFTAND(*pixel, gshift, gmask) + (Uint16) g; \
+	Uint16 sb = SHIFTAND(*pixel, bshift, bmask) + (Uint16) b; \
+	if (sr>rmask) sr = rmask;  \
+	if (sg>gmask) sg = gmask;  \
+	if (sb>bmask) sb = bmask;  \
+	*pixel = (sr<<rshift) | (sg<<gshift) | (sb<<bshift);  \
+} while (0)
+
+#define SETPIXEL_MOD(x, y, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
+do { \
+	type *pixel = (type *)(dst->pixels + y * dst->pitch + x * bpp); \
+	Uint8 sr = MUL(SHIFTAND(*pixel, rshift, rmask), r); \
+	Uint8 sg = MUL(SHIFTAND(*pixel, gshift, gmask), g); \
+	Uint8 sb = MUL(SHIFTAND(*pixel, bshift, bmask), b); \
+	*pixel = (sr<<rshift) | (sg<<gshift) | (sb<<bshift);  \
+} while (0)
+
+
+#define SETPIXEL15_MASK(x, y) SETPIXEL_MASK(x, y, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
+#define SETPIXEL15_BLEND(x, y) SETPIXEL_BLEND(x, y, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
+#define SETPIXEL15_ADD(x, y) SETPIXEL_ADD(x, y, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
+#define SETPIXEL15_MOD(x, y) SETPIXEL_MOD(x, y, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
+
+#define SETPIXEL16_MASK(x, y) SETPIXEL_MASK(x, y, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
+#define SETPIXEL16_BLEND(x, y) SETPIXEL_BLEND(x, y, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
+#define SETPIXEL16_ADD(x, y) SETPIXEL_ADD(x, y, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
+#define SETPIXEL16_MOD(x, y) SETPIXEL_MOD(x, y, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
+
+#define SETPIXEL32_MASK(x, y) SETPIXEL_MASK(x, y, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
+#define SETPIXEL32_BLEND(x, y) SETPIXEL_BLEND(x, y, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
+#define SETPIXEL32_ADD(x, y) SETPIXEL_ADD(x, y, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
+#define SETPIXEL32_MOD(x, y) SETPIXEL_MOD(x, y, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
 
 int
 SDL_BlendLine(SDL_Surface * dst, int x1, int y1, int x2, int y2,
               int blendMode, Uint8 r, Uint8 g, Uint8 b, Uint8 a)
 {
+    Uint8 inva = 0xff - a;
     /* This function doesn't work on surfaces < 8 bpp */
     if (dst->format->BitsPerPixel < 8) {
         SDL_SetError("SDL_BlendLine(): Unsupported surface format");
@@ -42,8 +148,71 @@
        }
      */
 
-    SDL_Unsupported();
-    return -1;
+    if ((blendMode == SDL_BLENDMODE_BLEND)
+        || (blendMode == SDL_BLENDMODE_ADD)) {
+        r = MUL(r, a);
+        g = MUL(g, a);
+        b = MUL(b, a);
+    }
+    switch (dst->format->BitsPerPixel) {
+    case 15:
+        switch (blendMode) {
+        case SDL_BLENDMODE_MASK:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL15_MASK);
+            break;
+        case SDL_BLENDMODE_BLEND:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL15_BLEND);
+            break;
+        case SDL_BLENDMODE_ADD:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL15_ADD);
+            break;
+        case SDL_BLENDMODE_MOD:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL15_MOD);
+            break;
+        }
+        break;
+    case 16:
+        switch (blendMode) {
+        case SDL_BLENDMODE_MASK:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL16_MASK);
+            break;
+        case SDL_BLENDMODE_BLEND:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL16_BLEND);
+            break;
+        case SDL_BLENDMODE_ADD:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL16_ADD);
+            break;
+        case SDL_BLENDMODE_MOD:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL16_MOD);
+            break;
+        }
+        break;
+    case 24:
+    case 32:
+        if (dst->format->BytesPerPixel != 4) {
+            SDL_Unsupported();
+            return -1;
+        }
+        switch (blendMode) {
+        case SDL_BLENDMODE_MASK:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL32_MASK);
+            break;
+        case SDL_BLENDMODE_BLEND:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL32_BLEND);
+            break;
+        case SDL_BLENDMODE_ADD:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL32_ADD);
+            break;
+        case SDL_BLENDMODE_MOD:
+            BRESENHAM(x1, y1, x2, y2, SETPIXEL32_MOD);
+            break;
+        }
+        break;
+    default:
+        SDL_Unsupported();
+        return -1;
+    }
+    return 0;
 }
 
 /* vi: set ts=4 sw=4 expandtab: */
diff -r 9328f53a0ca2 -r 1ef2f1e75ff7 src/video/SDL_blendrect.c
--- a/src/video/SDL_blendrect.c	Sat Dec 20 23:10:20 2008 +0000
+++ b/src/video/SDL_blendrect.c	Sat Dec 20 23:19:20 2008 +0000
@@ -24,11 +24,79 @@
 #include "SDL_video.h"
 #include "SDL_blit.h"
 
+#define MUL(_a, _b) (((Uint16)(_a)*(Uint16)(_b))/255)
+#define SHIFTAND(_v, _s, _a) (((_v)>>(_s)) & (_a))
+
+#define SETPIXEL_MASK(p, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
+do { \
+	if (a) { \
+		p = (r<<rshift) | (g<<gshift) | (b<<bshift); \
+	} \
+} while (0)
+
+#define SETPIXEL_BLEND(p, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
+do { \
+	Uint8 sr = MUL(inva, SHIFTAND(p, rshift, rmask)) + (Uint16) r; \
+	Uint8 sg = MUL(inva, SHIFTAND(p, gshift, gmask)) + (Uint16) g; \
+	Uint8 sb = MUL(inva, SHIFTAND(p, bshift, bmask)) + (Uint16) b; \
+	p = (sr<<rshift) | (sg<<gshift) | (sb<<bshift);  \
+} while (0)
+
+#define SETPIXEL_ADD(p, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
+do { \
+	Uint16 sr = SHIFTAND(p, rshift, rmask) + (Uint16) r; \
+	Uint16 sg = SHIFTAND(p, gshift, gmask) + (Uint16) g; \
+	Uint16 sb = SHIFTAND(p, bshift, bmask) + (Uint16) b; \
+	if (sr>rmask) sr = rmask;  \
+	if (sg>gmask) sg = gmask;  \
+	if (sb>bmask) sb = bmask;  \
+	p = (sr<<rshift) | (sg<<gshift) | (sb<<bshift);  \
+} while (0)
+
+#define SETPIXEL_MOD(p, type, bpp, rshift, gshift, bshift, rmask, gmask, bmask) \
+do { \
+	Uint8 sr = MUL(SHIFTAND(p, rshift, rmask), r); \
+	Uint8 sg = MUL(SHIFTAND(p, gshift, gmask), g); \
+	Uint8 sb = MUL(SHIFTAND(p, bshift, bmask), b); \
+	p = (sr<<rshift) | (sg<<gshift) | (sb<<bshift);  \
+} while (0)
+
+
+#define SETPIXEL15_MASK(p) SETPIXEL_MASK(p, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
+#define SETPIXEL15_BLEND(p) SETPIXEL_BLEND(p, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
+#define SETPIXEL15_ADD(p) SETPIXEL_ADD(p, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
+#define SETPIXEL15_MOD(p) SETPIXEL_MOD(p, Uint16, 2, 10, 5, 0, 0x1f, 0x1f, 0x1f);
+
+#define SETPIXEL16_MASK(p) SETPIXEL_MASK(p, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
+#define SETPIXEL16_BLEND(p) SETPIXEL_BLEND(p, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
+#define SETPIXEL16_ADD(p) SETPIXEL_ADD(p, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
+#define SETPIXEL16_MOD(p) SETPIXEL_MOD(p, Uint16, 2, 11, 5, 0, 0x1f, 0x3f, 0x1f);
+
+#define SETPIXEL32_MASK(p) SETPIXEL_MASK(p, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
+#define SETPIXEL32_BLEND(p) SETPIXEL_BLEND(p, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
+#define SETPIXEL32_ADD(p) SETPIXEL_ADD(p, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
+#define SETPIXEL32_MOD(p) SETPIXEL_MOD(p, Uint32, 4, 16, 8, 0, 0xff, 0xff, 0xff);
+
+#define BLENDRECT(type, op) \
+do { \
+	int y = dstrect->y; \
+    int h = dstrect->h; \
+    while (h--) { \
+        type *pixel = (type *)(dst->pixels + y * dst->pitch + dstrect->x * dst->format->BytesPerPixel); \
+    	int w = dstrect->w; \
+    	while (w--) { \
+    		op(*pixel); \
+    		pixel++; \
+    	} \
+    	y++; \
+    } \
+} while (0)
 
 int
 SDL_BlendRect(SDL_Surface * dst, SDL_Rect * dstrect, int blendMode, Uint8 r,
               Uint8 g, Uint8 b, Uint8 a)
 {
+    Uint16 inva = 0xff - a;
     /* This function doesn't work on surfaces < 8 bpp */
     if (dst->format->BitsPerPixel < 8) {
         SDL_SetError("SDL_BlendRect(): Unsupported surface format");
@@ -45,7 +113,71 @@
         dstrect = &dst->clip_rect;
     }
 
-    SDL_Unsupported();
+    if ((blendMode == SDL_BLENDMODE_BLEND)
+        || (blendMode == SDL_BLENDMODE_ADD)) {
+        r = MUL(r, a);
+        g = MUL(g, a);
+        b = MUL(b, a);
+    }
+    switch (dst->format->BitsPerPixel) {
+    case 15:
+        switch (blendMode) {
+        case SDL_BLENDMODE_MASK:
+            BLENDRECT(Uint16, SETPIXEL15_MASK);
+            break;
+        case SDL_BLENDMODE_BLEND:
+            BLENDRECT(Uint16, SETPIXEL15_BLEND);
+            break;
+        case SDL_BLENDMODE_ADD:
+            BLENDRECT(Uint16, SETPIXEL15_ADD);
+            break;
+        case SDL_BLENDMODE_MOD:
+            BLENDRECT(Uint16, SETPIXEL15_MOD);
+            break;
+        }
+        break;
+    case 16:
+        switch (blendMode) {
+        case SDL_BLENDMODE_MASK:
+            BLENDRECT(Uint16, SETPIXEL16_MASK);
+            break;
+        case SDL_BLENDMODE_BLEND:
+            BLENDRECT(Uint16, SETPIXEL16_BLEND);
+            break;
+        case SDL_BLENDMODE_ADD:
+            BLENDRECT(Uint16, SETPIXEL16_ADD);
+            break;
+        case SDL_BLENDMODE_MOD:
+            BLENDRECT(Uint16, SETPIXEL16_MOD);
+            break;
+        }
+        break;
+    case 24:
+    case 32:
+        if (dst->format->BytesPerPixel != 4) {
+            SDL_Unsupported();
+            return -1;
+        }
+        switch (blendMode) {
+        case SDL_BLENDMODE_MASK:
+            BLENDRECT(Uint32, SETPIXEL32_MASK);
+            break;
+        case SDL_BLENDMODE_BLEND:
+            BLENDRECT(Uint32, SETPIXEL32_BLEND);
+            break;
+        case SDL_BLENDMODE_ADD:
+            BLENDRECT(Uint32, SETPIXEL32_ADD);
+            break;
+        case SDL_BLENDMODE_MOD:
+            BLENDRECT(Uint32, SETPIXEL32_MOD);
+            break;
+        }
+        break;
+    default:
+        SDL_Unsupported();
+        return -1;
+    }
+    return 0;
     return -1;
 }
 
diff -r 9328f53a0ca2 -r 1ef2f1e75ff7 src/video/SDL_drawline.c
--- a/src/video/SDL_drawline.c	Sat Dec 20 23:10:20 2008 +0000
+++ b/src/video/SDL_drawline.c	Sat Dec 20 23:19:20 2008 +0000
@@ -24,9 +24,9 @@
 #include "SDL_video.h"
 #include "SDL_blit.h"
 
-#define ABS(x) (x < 0 ? -x : x)
+#define ABS(_x) ((_x) < 0 ? -(_x) : (_x))
 
-#define SWAP(x, y) (x ^= y ^= x ^= y)
+#define SWAP(_x, _y) do { int tmp; tmp = _x; _x = _y; _y = tmp; } while (0)
 
 #define BRESENHAM(x0, y0, x1, y1, op, color) \
 { \
@@ -34,16 +34,16 @@
  \
     deltax = ABS(x1 - x0); \
     deltay = ABS(y1 - y0); \
-    steep = deltay > deltax; \
-    error = deltax / 2; \
+    steep = (deltay > deltax); \
     if (steep) { \
         SWAP(x0, y0); \
         SWAP(x1, y1); \
+        SWAP(deltax, deltay); \
     } \
+    error = (x1 - x0) / 2; \
     y = y0; \
     if (x0 > x1) { \
         xstep = -1; \
-        deltax = -deltax; \
     } else { \
         xstep = 1; \
     } \
@@ -57,7 +57,7 @@
             op(x, y, color); \
             error -= deltay; \
             if (error < 0) { \
-                y = y + ystep; \
+                y += ystep; \
                 error += deltax; \
             } \
         } \
@@ -66,7 +66,7 @@
             op(y, x, color); \
             error -= deltay; \
             if (error < 0) { \
-                y = y + ystep; \
+                y += ystep; \
                 error += deltax; \
             } \
         } \