framebuffer: fix alpha blending

diff --git a/milkymist/framebuffer/__init__.py b/milkymist/framebuffer/__init__.py
index db1dea6ee919cfe6b06dc67384ad516cd78527b8..e0834e4274449b0b80f7fdea1ef79fa9a9007744 100644 (file)
--- a/milkymist/framebuffer/__init__.py
+++ b/milkymist/framebuffer/__init__.py
@@ -75,7 +75,11 @@ class Blender(PipelinedActor, AutoCSR):
                        for component in ["r", "g", "b"]:
                                incomps = [getattr(pix, component) for pix in inpixs]
                                outcomp = getattr(outpix, component)
-                               self.comb += outcomp.eq(sum(incomp*factor for incomp, factor in zip(incomps, factors)) >> 8)
+                               outcomp_full = Signal(18)
+                               self.comb += [
+                                       outcomp_full.eq(sum(incomp*factor for incomp, factor in zip(incomps, factors))),
+                                       outcomp.eq(outcomp_full[8:])
+                               ]
 
                pipe_stmts = []
                for i in range(latency):
@@ -86,7 +90,7 @@ class Blender(PipelinedActor, AutoCSR):
                self.comb += self.source.payload.eq(outval)
 
 class MixFramebuffer(Module, AutoCSR):
-       def __init__(self, pads, *asmiports, blender_latency=3):
+       def __init__(self, pads, *asmiports, blender_latency=4):
                pack_factor = asmiports[0].hub.dw//(2*bpp)
                packed_pixels = structuring.pack_layout(pixel_layout, pack_factor)
                
@@ -103,7 +107,7 @@ class MixFramebuffer(Module, AutoCSR):
 
                        g.add_connection(dma, cast)
                        g.add_connection(cast, unpack)
-                       g.add_connection(unpack, self.blender, sink_subr=["i"+str(n)+"/p0", "i"+str(n)+"/p1"])
+                       g.add_connection(unpack, self.blender, sink_subr=["i"+str(n)])
 
                        self.comb += dma.generator.trigger.eq(self._enable.storage)
                        setattr(self, "dma"+str(n), dma)