initial support for map overlays

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,
+};