I tried sampling equirectangular texture as a reflection. It simply does not work as intended. The texture is moving with my camera in a weird manner. Here is what I tried to do.
Fragment shader:
#version 460 core #extension GL_ARB_bindless_texture : require #extension GL_ARB_gpu_shader_int64 : require layout ( location = 0 ) out vec4 FragColor; const float one_o_2pi = 0.1591; const float one_o_1pi = 0.3183; in vec3 normal; in vec3 eye; in vec3 frag_pos; uniform sampler2D tex_pref; vec2 uv_from_vec3(vec3 t_direction) { float theta = acos(t_direction.y); float phi = atan(t_direction.z, t_direction.x); float u = phi * one_o_2pi + 0.5; float v = theta * one_o_1pi + 0.5; if (phi < 0.0) { u += 1.0; } return vec2(u, v); } vec3 pref_env_map(vec3 w_i, float t_roughness) { vec2 pref_tex_coords = uv_from_vec3(w_i); vec3 result = textureLod(tex_pref, pref_tex_coords, 6.0 * t_roughness).rgb; return result; } void main( void ) { vec3 w_o = normalize(eye - frag_pos); vec3 n = normal; if (gl_FrontFacing) n = - n; vec3 w_i = normalize(reflect(-w_o, n)); // The roughness is in the code, this is just a snippet FragColor = vec4(pref_env_map(w_i, roughness), 1.0); } Vertex shader:
#version 460 core // vertex attributes layout ( location = 0 ) in vec4 in_position_ms; layout ( location = 1 ) in vec3 in_normal_ms; //out vec4 outcol; // uniform variables //uniform mat4 P; // Model View Projection uniform mat4 view; // Model View Projection uniform mat4 proj; // Model View Projection uniform vec3 uEye; out vec3 normal; out vec3 eye; out vec3 frag_pos; void main( void ) { mat4 P = proj * view; vec4 position = P * (in_position_ms); gl_Position = position; normal = in_normal_ms; eye = uEye; frag_pos = position.xyz; } ``` 
