lib+blender: Pass alpha channel from c-ray

Blender expects the render buffer to have alpha, so just supply it
instead of patching it in.

bindings/blender_init.py

@@ -297,12 +297,12 @@ def display_bitmap(self, bm):
 		float_count = bm.width * bm.height * bm.stride
 		floats = array('f', bm.data.float_ptr[:float_count])
 		rect = []
-		for i in range(0, len(floats), 3):
+		for i in range(0, len(floats), 4):
 			temp = []
 			temp.append(floats[i + 0])
 			temp.append(floats[i + 1])
 			temp.append(floats[i + 2])
-			temp.append(1.0)
+			temp.append(floats[i + 3])
 			rect.append(temp)
 		result = self.begin_result(0, 0, bm.width, bm.height)
 		layer = result.layers[0].passes["Combined"]

bindings/blender_ui.py

@@ -1,6 +1,8 @@
 import bpy
 from bpy.types import Panel
 
+# Most of this is just a carbon-copy of the Cycles UI boilerplate
+
 class CrayButtonsPanel:
 	bl_space_type = "PROPERTIES"
 	bl_region_type = "WINDOW"

src/lib/renderer/renderer.c

@@ -182,11 +182,11 @@ void renderer_render(struct renderer *r) {
 	// Render buffer is used to store accurate color values for the renderers' internal use
 	if (!r->state.result_buf) {
 		// Allocate
-		r->state.result_buf = newTexture(float_p, camera.width, camera.height, 3);
+		r->state.result_buf = newTexture(float_p, camera.width, camera.height, 4);
 	} else if (r->state.result_buf->width != (size_t)camera.width || r->state.result_buf->height != (size_t)camera.height) {
 		// Resize
 		if (r->state.result_buf) destroyTexture(r->state.result_buf);
-		r->state.result_buf = newTexture(float_p, camera.width, camera.height, 3);
+		r->state.result_buf = newTexture(float_p, camera.width, camera.height, 4);
 	} else {
 		// Clear
 		tex_clear(r->state.result_buf);