Merge pull request #66 from nyquillerium/highp-flashlight

Fix loss of precision for flashlight smoothing distance calculations

osu.Game.Resources/Shaders/sh_CircularFlashlight.fs

@@ -1,9 +1,10 @@
 #include "sh_Flashlight.h"
 
-vec4 getColourAt(vec2 diff, vec2 size, vec4 originalColour)
+// highp precision is necessary for vertex positions to prevent catastrophic failure on GL_ES platforms
+lowp vec4 getColourAt(highp vec2 diff, highp vec2 size, lowp vec4 originalColour)
 {
-    float dist = length(diff);
+    highp float dist = length(diff);
-    float flashlightRadius = length(size);
+    highp float flashlightRadius = length(size);
 
     return originalColour * vec4(1.0, 1.0, 1.0, smoothstep(flashlightRadius, flashlightRadius * smoothness, dist));
 }

osu.Game.Resources/Shaders/sh_Flashlight.h

@@ -1,18 +1,14 @@
-#ifdef GL_ES
+varying highp vec2 v_Position;
-    precision mediump float;
+varying lowp vec4 v_Colour;
-#endif
 
-varying vec2 v_Position;
+uniform highp vec2 flashlightPos;
-varying vec4 v_Colour;
+uniform highp vec2 flashlightSize;
 
-uniform vec2 flashlightPos;
+uniform lowp float flashlightDim;
-uniform vec2 flashlightSize;
-
-uniform float flashlightDim;
 
 const float smoothness = 1.1;
 
-vec4 getColourAt(vec2, vec2, vec4);
+lowp vec4 getColourAt(vec2, vec2, vec4);
 
 void main(void)
 {

osu.Game.Resources/Shaders/sh_RectangularFlashlight.fs

@@ -1,10 +1,10 @@
 #include "sh_Flashlight.h"
 
-vec4 getColourAt(vec2 diff, vec2 size, vec4 originalColour)
+lowp vec4 getColourAt(highp vec2 diff, highp vec2 size, lowp vec4 originalColour)
 {
     diff = abs(diff);
 
-    float alpha = length(smoothstep(size, size * smoothness, diff));
+    lowp float alpha = length(smoothstep(size, size * smoothness, diff));
 
     return originalColour * vec4(1.0, 1.0, 1.0, alpha);
 }