Workbench: Spherical Harmonics tests

Added a compile directive in order to test SH4 in stead of SH2Win.
For now I disabled SH4, it is a bit more clear, but has a small
performance impact. Will check later for a better approach

1 files changed, 31 insertions, 8 deletions

diff --git a/source/blender/draw/engines/workbench/shaders/workbench_world_light_lib.glsl b/source/blender/draw/engines/workbench/shaders/workbench_world_light_lib.glsl
index b13c4f1b43b..3eda4455487 100644
--- a/source/blender/draw/engines/workbench/shaders/workbench_world_light_lib.glsl
+++ b/source/blender/draw/engines/workbench/shaders/workbench_world_light_lib.glsl
@@ -7,17 +7,40 @@ vec3 spherical_harmonics(vec3 N, vec3 spherical_harmonics_coefs[STUDIOLIGHT_SPHE
 	sh += 0.282095 * spherical_harmonics_coefs[0];
 
 #if STUDIOLIGHT_SPHERICAL_HARMONICS_LEVEL > 0
-	sh += -0.488603 * N.z * spherical_harmonics_coefs[1];
-	sh += 0.488603 * N.y * spherical_harmonics_coefs[2];
-	sh += -0.488603 * N.x * spherical_harmonics_coefs[3];
+	float nx = N.x;
+	float ny = N.y;
+	float nz = N.z;
+	sh += -0.488603 * nz * spherical_harmonics_coefs[1];
+	sh += 0.488603 * ny * spherical_harmonics_coefs[2];
+	sh += -0.488603 * nx * spherical_harmonics_coefs[3];
 #endif
 
 #if STUDIOLIGHT_SPHERICAL_HARMONICS_LEVEL > 1
-	sh += 1.092548 * N.x * N.z * spherical_harmonics_coefs[4];
-	sh += -1.092548 * N.z * N.y * spherical_harmonics_coefs[5];
-	sh += 0.315392 * (3.0 * N.y * N.y - 1.0) * spherical_harmonics_coefs[6];
-	sh += -1.092548 * N.x * N.y * spherical_harmonics_coefs[7];
-	sh += 0.546274 * (N.x * N.x - N.z * N.z) * spherical_harmonics_coefs[8];
+	float nx2 = nx * nx;
+	float ny2 = ny * ny;
+	float nz2 = nz * nz;
+
+	sh += 1.092548 * nx * nz * spherical_harmonics_coefs[4];
+	sh += -1.092548 * nz * ny * spherical_harmonics_coefs[5];
+	sh += 0.315392 * (3.0 * ny2 - 1.0) * spherical_harmonics_coefs[6];
+	sh += -1.092548 * nx * ny * spherical_harmonics_coefs[7];
+	sh += 0.546274 * (nx2 - nz2) * spherical_harmonics_coefs[8];
+#endif
+
+#if STUDIOLIGHT_SPHERICAL_HARMONICS_LEVEL > 3
+	float nx4 = nx2 * nx2;
+	float ny4 = ny2 * ny2;
+	float nz4 = nz2 * nz2;
+
+	sh += (2.5033429417967046 * nx * nz * (nx2 - nz2)) * spherical_harmonics_coefs[9];
+	sh += (-1.7701307697799304 * nz * ny * (3.0 * nx2 - nz2)) * spherical_harmonics_coefs[10];
+	sh += (0.9461746957575601 * nz * nx * (-1.0 +7.0*ny2)) * spherical_harmonics_coefs[11];
+	sh += (-0.6690465435572892 * nz * ny * (-3.0 + 7.0 * ny2)) * spherical_harmonics_coefs[12];
+	sh += ((105.0*ny4-90.0*ny2+9.0)/28.359261614) * spherical_harmonics_coefs[13];
+	sh += (-0.6690465435572892 * nx * ny * (-3.0 + 7.0 * ny2)) * spherical_harmonics_coefs[14];
+	sh += (0.9461746957575601 * (nx2 - nz2) * (-1.0 + 7.0 * ny2)) * spherical_harmonics_coefs[15];
+	sh += (-1.7701307697799304 * nx * ny * (nx2 - 3.0 * nz2)) * spherical_harmonics_coefs[16];
+	sh += (0.6258357354491761 * (nx4 - 6.0 * nz2 * nx2 + nz4)) * spherical_harmonics_coefs[17];
 #endif
 
 	return sh;