From 3580ad6005500abaf9bbb12db73adcfa762bd2e5 Mon Sep 17 00:00:00 2001 From: zxcvdev Date: Sat, 8 Feb 2020 21:32:01 +0100 Subject: [PATCH] Fix GPU Particles The special case atan(y,0) of the built-in shader function atan(y,x) returns different results on different devices. So this commit will add checks when the atan(y,x) function is used in ParticlesMaterial to set the direction of GPU Particles to make sure the desired values are returned (act as atan2(y,x)). --- scene/resources/particles_material.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/scene/resources/particles_material.cpp b/scene/resources/particles_material.cpp index 412b5c259c..baeb88400e 100644 --- a/scene/resources/particles_material.cpp +++ b/scene/resources/particles_material.cpp @@ -316,14 +316,17 @@ void ParticlesMaterial::_update_shader() { if (flags[FLAG_DISABLE_Z]) { - code += " float angle1_rad = atan(direction.y, direction.x) + rand_from_seed_m1_p1(alt_seed) * spread_rad;\n"; + code += " float angle1_rad = rand_from_seed_m1_p1(alt_seed) * spread_rad;\n"; + code += " angle1_rad += direction.x != 0.0 ? atan(direction.y, direction.x) : sign(direction.y) * (pi / 2.0);\n"; code += " vec3 rot = vec3(cos(angle1_rad), sin(angle1_rad), 0.0);\n"; code += " VELOCITY = rot * initial_linear_velocity * mix(1.0, rand_from_seed(alt_seed), initial_linear_velocity_random);\n"; } else { //initiate velocity spread in 3D - code += " float angle1_rad = atan(direction.x, direction.z) + rand_from_seed_m1_p1(alt_seed) * spread_rad;\n"; - code += " float angle2_rad = atan(direction.y, abs(direction.z)) + rand_from_seed_m1_p1(alt_seed) * spread_rad * (1.0 - flatness);\n"; + code += " float angle1_rad = rand_from_seed_m1_p1(alt_seed) * spread_rad;\n"; + code += " float angle2_rad = rand_from_seed_m1_p1(alt_seed) * spread_rad * (1.0 - flatness);\n"; + code += " angle1_rad += direction.z != 0.0 ? atan(direction.x, direction.z) : sign(direction.x) * (pi / 2.0);\n"; + code += " angle2_rad += direction.z != 0.0 ? atan(direction.y, abs(direction.z)) : (direction.x != 0.0 ? atan(direction.y, abs(direction.x)) : sign(direction.y) * (pi / 2.0));\n"; code += " vec3 direction_xz = vec3(sin(angle1_rad), 0.0, cos(angle1_rad));\n"; code += " vec3 direction_yz = vec3(0.0, sin(angle2_rad), cos(angle2_rad));\n"; code += " direction_yz.z = direction_yz.z / max(0.0001,sqrt(abs(direction_yz.z))); // better uniform distribution\n";