shaderoverlay.py 文件源码

def getOverlay(self, rect):
        """
        Draw the ShaderOverlay and return the result

        parameters:     pygame.Rect bounds of the Overlay
        return values:  pygame.Surface the result
        """
        try:
            surface = pygame.Surface(rect.size, pygame.SRCALPHA, 32)
        except:
            return pygame.Surface((0, 0), pygame.SRCALPHA, 32)
        surface.fill(self._background)

        shapes          = pygame.Surface(rect.size, pygame.SRCALPHA, 32)
        lightsources    = pygame.Surface(rect.size, pygame.SRCALPHA, 32)
        removeAfter     = []

        for ls in self._lightsources:
            quality     = self._lightsources[ls][3]
            intensity   = self._lightsources[ls][2]
            color       = self._lightsources[ls][1]
            radius      = self._lightsources[ls][0]
            r           = ls.rect

            polygon = []
            try:
                for x in xrange(1, 2 * radius + r.w, quality):
                    polygon.append(self.raycast(r.center, (r.left - radius + x, r.top - radius), rect, radius))
                for y in xrange(1, 2 * radius + r.h, quality):
                    polygon.append(self.raycast(r.center, (r.right + radius, r.top - radius + y), rect, radius))
                for x in xrange(1, 2 * radius + r.w, quality):
                    polygon.append(self.raycast(r.center, (r.right + radius - x, r.bottom + radius), rect, radius))
                for y in xrange(1, 2 * radius + r.h, quality):
                    polygon.append(self.raycast(r.center, (r.left - radius, r.bottom + radius - y), rect, radius))
            except:
                removeAfter.append(ls)

            if polygon:
                pygame.draw.polygon(shapes, color, polygon)

            gradient = pygame.Surface(rect.size, pygame.SRCALPHA, 32)
            try:
                for n in range(2 * radius, 0, -1):
                    alpha = intensity - int(intensity * (float(n) / (2 * radius)))
                    pygame.draw.ellipse(gradient, color + (alpha,), r.inflate(n, n))
            except:
                removeAfter.append(ls)

            shapes.blit(gradient, (0, 0), special_flags = pygame.BLEND_RGBA_MULT)
            lightsources.blit(shapes, (0, 0), special_flags = pygame.BLEND_RGBA_MAX)
        surface.blit(lightsources, (0, 0))

        for ls in removeAfter:
            self.removeLightsource(ls)

        return surface