1 files changed, 147 insertions, 1 deletions
diff --git a/source/blender/gpu/shaders/material/gpu_shader_material_tex_sky.glsl b/source/blender/gpu/shaders/material/gpu_shader_material_tex_sky.glsl
index 981d17b4283..b6aad5904ff 100644
--- a/source/blender/gpu/shaders/material/gpu_shader_material_tex_sky.glsl
+++ b/source/blender/gpu/shaders/material/gpu_shader_material_tex_sky.glsl
@@ -1,4 +1,150 @@
-void node_tex_sky(vec3 co, out vec4 color)
+float sky_angle_between(float thetav, float phiv, float theta, float phi)
+{
+  float cospsi = sin(thetav) * sin(theta) * cos(phi - phiv) + cos(thetav) * cos(theta);
+
+  if (cospsi > 1.0) {
+    return 0.0;
+  }
+  if (cospsi < -1.0) {
+    return M_PI;
+  }
+
+  return acos(cospsi);
+}
+
+vec3 sky_spherical_coordinates(vec3 dir)
+{
+  return vec3(M_PI_2 - atan(dir.z, length(dir.xy)), atan(dir.x, dir.y), 0);
+}
+
+/* Preetham */
+/* lam03+lam4: 5 floats passed as vec4+float */
+float sky_perez_function(vec4 lam03, float lam4, float theta, float gamma)
+{
+  float ctheta = cos(theta);
+  float cgamma = cos(gamma);
+
+  return (1.0 + lam03[0] * exp(lam03[1] / ctheta)) *
+         (1.0 + lam03[2] * exp(lam03[3] * gamma) + lam4 * cgamma * cgamma);
+}
+
+vec3 xyY_to_xyz(float x, float y, float Y)
+{
+  float X, Z;
+
+  if (y != 0.0) {
+    X = (x / y) * Y;
+  }
+  else {
+    X = 0.0;
+  }
+
+  if (y != 0.0 && Y != 0.0) {
+    Z = ((1.0 - x - y) / y) * Y;
+  }
+  else {
+    Z = 0.0;
+  }
+
+  return vec3(X, Y, Z);
+}
+
+void node_tex_sky_preetham(vec3 co,
+                           vec4 config_Y03,
+                           float config_Y4,
+                           vec4 config_x03,
+                           float config_x4,
+                           vec4 config_y03,
+                           float config_y4,
+                           vec2 sun_angles,
+                           vec3 radiance,
+                           vec3 xyz_to_r,
+                           vec3 xyz_to_g,
+                           vec3 xyz_to_b,
+                           out vec4 color)
+{
+  /* convert vector to spherical coordinates */
+  vec3 spherical = sky_spherical_coordinates(co);
+  float theta = spherical[0];
+  float phi = spherical[1];
+
+  float suntheta = sun_angles[0];
+  float sunphi = sun_angles[1];
+
+  /* angle between sun direction and dir */
+  float gamma = sky_angle_between(theta, phi, suntheta, sunphi);
+
+  /* clamp theta to horizon */
+  theta = min(theta, M_PI_2 - 0.001);
+
+  /* compute xyY color space values */
+  float Y = radiance[0] * sky_perez_function(config_Y03, config_Y4, theta, gamma);
+  float x = radiance[1] * sky_perez_function(config_x03, config_x4, theta, gamma);
+  float y = radiance[2] * sky_perez_function(config_y03, config_y4, theta, gamma);
+
+  /* convert to RGB */
+  vec3 xyz = xyY_to_xyz(x, y, Y);
+  color = vec4(dot(xyz_to_r, xyz), dot(xyz_to_g, xyz), dot(xyz_to_b, xyz), 1);
+}
+
+/* Hosek / Wilkie */
+float sky_radiance_hosekwilkie(
+    vec4 config03, vec4 config47, float config8, float theta, float gamma)
+{
+  float ctheta = cos(theta);
+  float cgamma = cos(gamma);
+
+  float expM = exp(config47[0] * gamma);
+  float rayM = cgamma * cgamma;
+  float mieM = (1.0 + rayM) / pow((1.0 + config8 * config8 - 2.0 * config8 * cgamma), 1.5);
+  float zenith = sqrt(ctheta);
+
+  return (1.0 + config03[0] * exp(config03[1] / (ctheta + 0.01))) *
+         (config03[2] + config03[3] * expM + config47[1] * rayM + config47[2] * mieM +
+          config47[3] * zenith);
+}
+
+void node_tex_sky_hosekwilkie(vec3 co,
+                              vec4 config_x03,
+                              vec4 config_x47,
+                              vec4 config_y03,
+                              vec4 config_y47,
+                              vec4 config_z03,
+                              vec4 config_z47,
+                              vec3 config_xyz8,
+                              vec2 sun_angles,
+                              vec3 radiance,
+                              vec3 xyz_to_r,
+                              vec3 xyz_to_g,
+                              vec3 xyz_to_b,
+                              out vec4 color)
+{
+  /* convert vector to spherical coordinates */
+  vec3 spherical = sky_spherical_coordinates(co);
+  float theta = spherical[0];
+  float phi = spherical[1];
+
+  float suntheta = sun_angles[0];
+  float sunphi = sun_angles[1];
+
+  /* angle between sun direction and dir */
+  float gamma = sky_angle_between(theta, phi, suntheta, sunphi);
+
+  /* clamp theta to horizon */
+  theta = min(theta, M_PI_2 - 0.001);
+
+  vec3 xyz;
+  xyz.x = sky_radiance_hosekwilkie(config_x03, config_x47, config_xyz8[0], theta, gamma) *
+          radiance.x;
+  xyz.y = sky_radiance_hosekwilkie(config_y03, config_y47, config_xyz8[1], theta, gamma) *
+          radiance.y;
+  xyz.z = sky_radiance_hosekwilkie(config_z03, config_z47, config_xyz8[2], theta, gamma) *
+          radiance.z;
+
+  color = vec4(dot(xyz_to_r, xyz), dot(xyz_to_g, xyz), dot(xyz_to_b, xyz), 1);
+}
+
+void node_tex_sky_nishita(vec3 co, out vec4 color)
 {
   color = vec4(1.0);
 }