Add lighting to Pong

examples/pong/pong.py

@@ -2,15 +2,30 @@
 import random
 from pygame.math import Vector2
 from wasabi2d.keyboard import keys
+from wasabi2d import chain
 
 
 mode_1080p = 1920, 1080
 scene = w2d.Scene(
     *mode_1080p,
     fullscreen=True,
-    background='#444455'
 )
 scene.layers[0].set_effect('dropshadow', opacity=0.5)
+scene.layers[99].set_effect('additive')
+scene.chain = [
+    chain.Light(
+        light=[
+            chain.Layers([99]),
+        ],
+        diffuse=[
+            chain.Fill('#444455'),
+            chain.LayerRange(stop=10),
+        ],
+        ambient='#444444'
+    )
+]
+
+
 center = Vector2(scene.width, scene.height) / 2
 
 red_score = scene.layers[-1].add_label(
@@ -31,27 +46,36 @@
     color='cyan'
 )
 
-red = scene.layers[0].add_sprite(
-    'bat_red',
-    pos=(50, center.y)
-)
+red = w2d.Group(
+    [
+        scene.layers[0].add_sprite('bat_red'),
+        scene.layers[99].add_sprite('bat_light', color=(1, 0, 0, 0.5)),
+    ],
+    pos=(50, center.y))
+
 red.up_key = keys.Q
 red.down_key = keys.A
 
-blue = scene.layers[0].add_sprite(
-    'bat_blue',
+blue = w2d.Group(
+    [
+        scene.layers[0].add_sprite('bat_blue'),
+        scene.layers[99].add_sprite('bat_light', color=(0, 1, 1, 0.5)),
+    ],
     pos=(scene.width - 50, center.y)
 )
 blue.up_key = keys.I
 blue.down_key = keys.K
 
-ball = scene.layers[0].add_sprite(
-    'ball',
+ball = w2d.Group(
+    [
+        scene.layers[0].add_sprite('ball'),
+        scene.layers[99].add_sprite('point_light', scale=5, color=(1, 1, 1, 0.3)),
+    ],
     pos=center
 )
 
 SPEED = 1000
-BALL_RADIUS = ball.width / 2
+BALL_RADIUS = ball[0].width / 2
 
 
 def start():
@@ -63,7 +87,7 @@ def start():
 
 
 def collide_bat(bat):
-    bounds = bat.bounds.inflate(BALL_RADIUS, BALL_RADIUS)
+    bounds = bat[0].bounds.inflate(BALL_RADIUS, BALL_RADIUS)
     if bounds.collidepoint(ball.pos):
         x, y = ball.pos
         vx, vy = ball.vel

wasabi2d/chain.py

@@ -219,6 +219,62 @@ def draw(self, scene):
             )
 
 
+LIGHT_PROG = """ \
+#version 330 core
+
+in vec2 uv;
+out vec4 f_color;
+uniform sampler2D diffuse;
+uniform sampler2D light;
+uniform vec4 ambient;
+
+vec4 unpremultiply(vec4 val) {
+    if (val.a < 1e-6) {
+        return vec4(0.0, 0.0, 0.0, 0.0);
+    }
+    return vec4(val.rgb / val.a, val.a);
+}
+
+vec4 sample_unmul(sampler2D sampler) {
+    //return unpremultiply(texture(sampler, uv));
+    return texture(sampler, uv);
+}
+
+void main()
+{
+    vec4 diffuse_frag = sample_unmul(diffuse);
+    vec4 light_frag = sample_unmul(light);
+
+    f_color = (light_frag + ambient) * diffuse_frag;
+}
+"""
+
+
+@dataclass
+class Light(ChainNode):
+    """Light one 'diffuse' layer using the 'light' layer."""
+
+    light: ChainNode
+    diffuse: ChainNode
+    ambient: Tuple[float, float, float, float]
+
+    def __post_init__(self):
+        self.light = to_node(self.light)
+        self.diffuse = to_node(self.diffuse)
+        self.ambient = convert_color(self.ambient)
+
+    def draw(self, scene):
+        """Draw the effect."""
+        with rendered_node(scene, self.diffuse) as diffuse, \
+                rendered_node(scene, self.light) as light:
+            scene.camera.run_shader(
+                LIGHT_PROG,
+                diffuse=diffuse,
+                light=light,
+                ambient=self.ambient,
+            )
+
+
 class Fill(ChainNode):
     """Fill the screen with a single colour.
 

wasabi2d/effects/additive.py

@@ -0,0 +1,24 @@
+from dataclasses import dataclass
+
+import moderngl
+
+from ..shaders import blend_func
+
+
+@dataclass
+class Additive:
+    ctx: moderngl.Context
+
+    def _set_camera(self, camera: 'wasabi2d.scene.Camera'):
+        """Nothing to do here."""
+
+    def draw(self, draw_layer):
+        """Draw the wrapped effects with additive blending."""
+        with blend_func(
+            self.ctx,
+            src=moderngl.SRC_ALPHA,
+            dest=moderngl.ONE,
+            src_a=moderngl.ONE,
+            dest_a=moderngl.ONE,
+        ):
+            draw_layer()

wasabi2d/scene.py

@@ -106,7 +106,7 @@ def __init__(
         self.layers = LayerGroup(ctx, self.camera)
 
         ctx.enable(moderngl.BLEND)
-        self.ctx.blend_func = (
+        self.ctx.extra['blend_func'] = self.ctx.blend_func = (
             moderngl.SRC_ALPHA, moderngl.ONE_MINUS_SRC_ALPHA,
             moderngl.ONE, moderngl.ONE_MINUS_SRC_ALPHA,
         )

wasabi2d/shaders.py

@@ -167,11 +167,9 @@ def blend_func(
     src_a = blend_aliases.get(src_a, src_a)
     dest_a = blend_aliases.get(dest_a, dest_a)
 
-    ctx.blend_func = src, dest, src_a, dest_a
+    prev_blend = ctx.extra['blend_func']
+    ctx.extra['blend_func'] = ctx.blend_func = src, dest, src_a, dest_a
     try:
         yield
     finally:
-        ctx.blend_func = (
-            moderngl.SRC_ALPHA, moderngl.ONE_MINUS_SRC_ALPHA,
-            moderngl.ONE, moderngl.ONE_MINUS_SRC_ALPHA
-        )
+        ctx.blend_func = prev_blend