[AD] blender operations SRC and DST

[Jon Rafkind <workmin@xxxxxxxxxx>]

This patch adds source and destination color as factors for opengl/d3d
blending. I haven't tested the d3d code because I don't have a windows
environment set up. Also the documents aren't updated in this patch but
I can do so after the patch is applied.

Index: include/allegro5/bitmap.h
===================================================================
--- include/allegro5/bitmap.h	(revision 14764)
+++ include/allegro5/bitmap.h	(working copy)
@@ -91,7 +91,9 @@
    ALLEGRO_ZERO = 0,
    ALLEGRO_ONE = 1,
    ALLEGRO_ALPHA = 2,
-   ALLEGRO_INVERSE_ALPHA = 3
+   ALLEGRO_INVERSE_ALPHA = 3,
+   ALLEGRO_SRC_COLOR = 4,
+   ALLEGRO_DST_COLOR = 5,
 };
 
 enum ALLEGRO_BLEND_OPERATIONS {
Index: src/opengl/ogl_bitmap.c
===================================================================
--- src/opengl/ogl_bitmap.c	(revision 14764)
+++ src/opengl/ogl_bitmap.c	(working copy)
@@ -173,8 +173,9 @@
 static INLINE bool setup_blending(ALLEGRO_DISPLAY *ogl_disp)
 {
    int op, src_color, dst_color, op_alpha, src_alpha, dst_alpha;
-   const int blend_modes[4] = {
-      GL_ZERO, GL_ONE, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA
+   const int blend_modes[6] = {
+      GL_ZERO, GL_ONE, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA,
+      GL_SRC_COLOR, GL_DST_COLOR
    };
    const int blend_equations[3] = {
       GL_FUNC_ADD, GL_FUNC_SUBTRACT, GL_FUNC_REVERSE_SUBTRACT
Index: src/win/d3d_disp.cpp
===================================================================
--- src/win/d3d_disp.cpp	(revision 14764)
+++ src/win/d3d_disp.cpp	(working copy)
@@ -2049,20 +2049,24 @@
 
 static int d3d_al_blender_to_d3d(int al_mode)
 {
-   int num_modes = 4;
+   int num_modes = 6;
 
    int allegro_modes[] = {
       ALLEGRO_ZERO,
       ALLEGRO_ONE,
       ALLEGRO_ALPHA,
-      ALLEGRO_INVERSE_ALPHA
+      ALLEGRO_INVERSE_ALPHA,
+      ALLEGRO_SRC_COLOR,
+      ALLEGRO_DST_COLOR
    };
 
    int d3d_modes[] = {
       D3DBLEND_ZERO,
       D3DBLEND_ONE,
       D3DBLEND_SRCALPHA,
-      D3DBLEND_INVSRCALPHA
+      D3DBLEND_INVSRCALPHA,
+      D3DBLEND_SRCCOLOR,
+      D3DBLEND_DESTCCOLOR
    };
 
    int i;