Merge pull request #45 from jorolf/flashlight-shader

Add flashlight shader

osu.Game.Resources/Shaders/sh_Flashlight.fs

@@ -0,0 +1,34 @@
+#ifdef GL_ES
+    precision mediump float;
+#endif
+
+varying vec2 v_Position;
+varying vec4 v_Colour;
+
+uniform bool rectangular;
+uniform vec2 flashlightPos;
+uniform float circularFlashlightSize;
+uniform vec2 rectangularFlashlightSize;
+
+const float smoothness = 1.1;
+
+void main(void)
+{
+    if(rectangular)
+    {
+        vec2 diff = abs(v_Position - flashlightPos);
+
+        float alpha = 1.0 - smoothstep(rectangularFlashlightSize.x, rectangularFlashlightSize.x * smoothness, diff.x);
+        alpha *= 1.0 - smoothstep(rectangularFlashlightSize.y, rectangularFlashlightSize.y * smoothness, diff.y);
+
+        gl_FragColor  = v_Colour * vec4(1.0, 1.0, 1.0, 1.0 - alpha);
+    }
+    else
+    {
+        vec2 diff = flashlightPos - v_Position;
+
+        float dist = sqrt(diff.x * diff.x + diff.y * diff.y);
+
+        gl_FragColor = v_Colour * vec4(1.0, 1.0, 1.0, smoothstep(circularFlashlightSize, circularFlashlightSize * smoothness, dist));
+    }
+}

osu.Game.Resources/Shaders/sh_PositionAndColour.vs

@@ -0,0 +1,14 @@
+attribute vec2 m_Position;
+attribute vec4 m_Colour;
+
+varying vec2 v_Position;
+varying vec4 v_Colour;
+
+uniform mat4 g_ProjMatrix;
+
+void main(void)
+{
+	gl_Position = g_ProjMatrix * vec4(m_Position.xy, 1.0, 1.0);
+	v_Position = m_Position;
+	v_Colour = m_Colour;
+}