initial support for map overlays

src/composite.c

@@ -273,7 +273,8 @@ alpha_over_wrap(PyObject *self, PyObject *args)
  * also, it multiplies instead of doing an over operation
  */
 PyObject *
-tint_with_mask(PyObject *dest, unsigned char sr, unsigned char sg, unsigned char sb,
+tint_with_mask(PyObject *dest, unsigned char sr, unsigned char sg,
+               unsigned char sb, unsigned char sa,
                PyObject *mask, int dx, int dy, int xsize, int ysize) {
     /* libImaging handles */
     Imaging imDest, imMask;
@@ -332,9 +333,11 @@ tint_with_mask(PyObject *dest, unsigned char sr, unsigned char sg, unsigned char
                 out++;
                 *out = MULDIV255(*out, sb, tmp1);
                 out++;
+                *out = MULDIV255(*out, sa, tmp1);
+                out++;
             } else if (*inmask == 0) {
                 /* do nothing -- source is fully transparent */
-                out += 3;
+                out += 4;
             } else {
                 /* general case */
                 
@@ -345,9 +348,10 @@ tint_with_mask(PyObject *dest, unsigned char sr, unsigned char sg, unsigned char
                 out++;
                 *out = MULDIV255(*out, (255 - *inmask) + MULDIV255(sb, *inmask, tmp1), tmp2);
                 out++;
+                *out = MULDIV255(*out, (255 - *inmask) + MULDIV255(sa, *inmask, tmp1), tmp2);
+                out++;
             }
 
-            out++;
             inmask += mask_stride;
         }
     }

src/overviewer.h

@@ -44,7 +44,8 @@ PyObject *alpha_over(PyObject *dest, PyObject *src, PyObject *mask,
 PyObject *alpha_over_full(PyObject *dest, PyObject *src, PyObject *mask, float overall_alpha,
                           int dx, int dy, int xsize, int ysize);
 PyObject *alpha_over_wrap(PyObject *self, PyObject *args);
-PyObject *tint_with_mask(PyObject *dest, unsigned char sr, unsigned char sg, unsigned char sb,
+PyObject *tint_with_mask(PyObject *dest, unsigned char sr, unsigned char sg,
+                         unsigned char sb, unsigned char sa,
                          PyObject *mask, int dx, int dy, int xsize, int ysize);
 
 /* in iterate.c */
@@ -79,7 +80,7 @@ PyObject *chunk_render(PyObject *self, PyObject *args);
 #include "rendermodes.h"
 
 /* in endian.c */
-void init_endian();
+void init_endian(void);
 unsigned short big_endian_ushort(unsigned short in);
 unsigned int big_endian_uint(unsigned int in);
 

src/rendermode-normal.c

@@ -158,7 +158,7 @@ rendermode_normal_draw(void *data, RenderState *state, PyObject *src, PyObject *
             b = PyInt_AsLong(PyTuple_GET_ITEM(color, 2));
             Py_DECREF(color);
 
-            tint_with_mask(state->img, r, g, b, facemask, state->imgx, state->imgy, 0, 0);
+            tint_with_mask(state->img, r, g, b, 255, facemask, state->imgx, state->imgy, 0, 0);
         }
     }
 }

src/rendermode-overlay.c

@@ -0,0 +1,75 @@
+/* 
+ * This file is part of the Minecraft Overviewer.
+ *
+ * Minecraft Overviewer is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation, either version 3 of the License, or (at
+ * your option) any later version.
+ *
+ * Minecraft Overviewer 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 General
+ * Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "overviewer.h"
+
+static int
+rendermode_overlay_start(void *data, RenderState *state) {
+    PyObject *facemasks_py;
+    RenderModeOverlay *self = (RenderModeOverlay *)data;
+    
+    facemasks_py = PyObject_GetAttrString(state->chunk, "facemasks");
+    /* borrowed reference, needs to be incref'd if we keep it */
+    self->facemask_top = PyTuple_GetItem(facemasks_py, 0);
+    Py_INCREF(self->facemask_top);
+    Py_DECREF(facemasks_py);
+    
+    self->white_color = PyObject_GetAttrString(state->chunk, "white_color");
+    
+    return 0;
+}
+
+static void
+rendermode_overlay_finish(void *data, RenderState *state) {
+    RenderModeOverlay *self = (RenderModeOverlay *)data;
+    
+    Py_XDECREF(self->facemask_top);
+    Py_XDECREF(self->white_color);
+}
+
+static int
+rendermode_overlay_occluded(void *data, RenderState *state) {
+    int x = state->x, y = state->y, z = state->z;
+    
+    if ( (x != 0) && (y != 15) && (z != 127) &&
+         !is_transparent(getArrayByte3D(state->blocks, x-1, y, z)) &&
+         !is_transparent(getArrayByte3D(state->blocks, x, y, z+1)) &&
+         !is_transparent(getArrayByte3D(state->blocks, x, y+1, z))) {
+        return 1;
+    }
+
+    return 0;
+}
+
+static void
+rendermode_overlay_draw(void *data, RenderState *state, PyObject *src, PyObject *mask) {
+    RenderModeOverlay *self = (RenderModeOverlay *)data;
+    
+    /* clear the draw space -- set alpha to 0 within mask */
+    tint_with_mask(state->img, 255, 255, 255, 0, mask, state->imgx, state->imgy, 0, 0);
+    
+    /* do the overlay */
+    alpha_over_full(state->img, self->white_color, self->facemask_top, 0.5, state->imgx, state->imgy, 0, 0);
+}
+
+RenderModeInterface rendermode_overlay = {
+    sizeof(RenderModeOverlay),
+    rendermode_overlay_start,
+    rendermode_overlay_finish,
+    rendermode_overlay_occluded,
+    rendermode_overlay_draw,
+};

src/rendermodes.c

@@ -31,6 +31,10 @@ RenderModeInterface *get_render_mode(RenderState *state) {
         iface = &rendermode_night;
     } else if (strcmp(rendermode, "spawn") == 0) {
         iface = &rendermode_spawn;
+    } else if (strcmp(rendermode, "overlay") == 0) {
+        /* TODO temporarily use overlay directly, but later on
+           you want to use overlay-derived modes */
+        iface = &rendermode_overlay;
     }
     
     Py_DECREF(rendermode_py);

src/rendermodes.h

@@ -71,6 +71,13 @@ typedef struct {
 } RenderModeNormal;
 extern RenderModeInterface rendermode_normal;
 
+/* OVERLAY */
+typedef struct {
+    /* top facemask and white color image, for drawing overlays */
+    PyObject *facemask_top, *white_color;
+} RenderModeOverlay;
+extern RenderModeInterface rendermode_overlay;
+
 /* LIGHTING */
 typedef struct {
     /* inherits from normal render mode */