shader outline experiment

assets/shaders/outline.glsl

@@ -0,0 +1,30 @@
+#pragma language glsl3
+
+extern ivec2 texSize;
+extern float time;
+
+vec4 effect(vec4 color, Image tex, vec2 texCoord, vec2 screenCoord)
+{
+    float modY = (0.75 + sin(time) * 0.25) * (0.5 + cos(texCoord.y + 10 * sin(0.1 * time)) * 0.5);
+    vec4 outlineColor = vec4(modY, 0.2 * sin(time) + 0.5, 0.5, 1.0);
+    float outlineSize = 1.0;
+
+    float alpha = Texel(tex, texCoord).a;
+    if (alpha > 0.0)
+        return Texel(tex, texCoord) * color;
+
+    // Если среди соседей есть хоть один прозрачный пиксель, то это граница, обводим её
+    float outline = 0.0;
+    for (float x = -outlineSize; x <= outlineSize; x++) {
+        for (float y = -outlineSize; y <= outlineSize; y++) {
+            vec2 offset = vec2(x, y) / texSize;
+            float neighborAlpha = Texel(tex, texCoord + offset).a;
+            outline = max(outline, neighborAlpha);
+        }
+    }
+
+    if (outline > 0.0)
+        return outlineColor;
+
+    return vec4(0.0);
+}

lib/character/behaviors/sprite.lua

@@ -45,11 +45,20 @@ function sprite:draw()
         function(map)
             local ppm = Tree.level.camera.pixelsPerMeter
             local position = map.displayedPosition
-            if Tree.level.selector.id == self.owner.id then love.graphics.setColor(0.5, 1, 0.5) end
+            if Tree.level.selector.id == self.owner.id then
+                local texW, texH = Tree.assets.files.sprites.character[self.state]:getWidth(),
+                    Tree.assets.files.sprites.character[self.state]:getHeight()
+                local shader = Tree.assets.files.shaders.outline
+                shader:send("texSize", { texW, texH })
+                shader:send("time", love.timer:getTime())
+                love.graphics.setShader(shader)
+            end
+
             self.animationTable[self.state]:draw(Tree.assets.files.sprites.character[self.state],
                 position.x + 0.5,
                 position.y + 0.5, nil, 1 / ppm * self.side, 1 / ppm, 38, 47)
             love.graphics.setColor(1, 1, 1)
+            love.graphics.setShader()
         end
     )
 end