diff options
Diffstat (limited to 'src/glsl/linker.cpp')
| -rw-r--r-- | src/glsl/linker.cpp | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp index 39169aa10ff..471525e9e21 100644 --- a/src/glsl/linker.cpp +++ b/src/glsl/linker.cpp @@ -258,11 +258,36 @@ validate_vertex_shader_executable(struct gl_shader_program *prog, if (shader == NULL) return true; - find_assignment_visitor find("gl_Position"); - find.run(shader->ir); - if (!find.variable_found()) { - linker_error(prog, "vertex shader does not write to `gl_Position'\n"); - return false; + /* From the GLSL 1.10 spec, page 48: + * + * "The variable gl_Position is available only in the vertex + * language and is intended for writing the homogeneous vertex + * position. All executions of a well-formed vertex shader + * executable must write a value into this variable. [...] The + * variable gl_Position is available only in the vertex + * language and is intended for writing the homogeneous vertex + * position. All executions of a well-formed vertex shader + * executable must write a value into this variable." + * + * while in GLSL 1.40 this text is changed to: + * + * "The variable gl_Position is available only in the vertex + * language and is intended for writing the homogeneous vertex + * position. It can be written at any time during shader + * execution. It may also be read back by a vertex shader + * after being written. This value will be used by primitive + * assembly, clipping, culling, and other fixed functionality + * operations, if present, that operate on primitives after + * vertex processing has occurred. Its value is undefined if + * the vertex shader executable does not write gl_Position." + */ + if (prog->Version < 140) { + find_assignment_visitor find("gl_Position"); + find.run(shader->ir); + if (!find.variable_found()) { + linker_error(prog, "vertex shader does not write to `gl_Position'\n"); + return false; + } } prog->Vert.ClipDistanceArraySize = 0; |