add entity shader

res/shaders/lib/commons.glsl

@@ -3,9 +3,6 @@
 
 #include <constants>
 
-#define PI 3.1415926535897932384626433832795
-#define PI2 (PI*2)
-
 vec4 decompress_light(float compressed_light) {
     vec4 result;
     int compressed = floatBitsToInt(compressed_light);
@@ -24,4 +21,9 @@ vec3 pick_sky_color(samplerCube cubemap) {
     return skyLightColor;
 }
 
+vec3 apply_planet_curvature(vec3 modelPos, vec3 pos3d) {
+    modelPos.y -= pow(length(pos3d.xz)*CURVATURE_FACTOR, 3.0);
+    return modelPos;
+}
+
 #endif // COMMONS_GLSL_

res/shaders/lib/constants.glsl

@@ -1,6 +1,9 @@
 #ifndef CONSTANTS_GLSL_
 #define CONSTANTS_GLSL_
 
+#define PI 3.1415926535897932384626433832795
+#define PI2 (PI*2)
+
 // geometry
 #define CURVATURE_FACTOR 0.002