Just tried flightgear and running it with rembrandt results in weird rendering issues which probably are a result of the following errors:
The first one seems to be a driver problem. I can't tell if the following ones are errors in the shader or in the driver, but on a first look the shaders looks ok and the driver simply has a problem with the preprocessor stuff. The second ones compares an integer to an float without conversation so this might be an error in the shader.
EE r600_shader.c:158 r600_pipe_shader_create - translation from TGSI failed ! EE r600_state_common.c:754 r600_shader_select - Failed to build shader variant (type=1) -1
FRAGMENT glCompileShader "/usr/share/flightgear/Shaders/urban-gbuffer.frag" FAILED FRAGMENT Shader "/usr/share/flightgear/Shaders/urban-gbuffer.frag" infolog: 0:91(22): preprocessor error: syntax error, unexpected IDENTIFIER, expecting NEWLINE 0:88(1): preprocessor error: Unterminated #if glLinkProgram "" FAILED Program "" infolog: error: linking with uncompiled shader
FRAGMENT glCompileShader "/usr/share/flightgear/Shaders/ubershader-gbuffer.frag" FAILED FRAGMENT Shader "/usr/share/flightgear/Shaders/ubershader-gbuffer.frag" infolog: 0:134(24): error: could not implicitly convert operands to relational operator 0:134(24): error: if-statement condition must be scalar boolean glLinkProgram "" FAILED Program "" infolog: error: linking with uncompiled shader