diff options
| -rw-r--r-- | src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp index 73a647efe34..5f4aef16b66 100644 --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp @@ -1493,11 +1493,34 @@ glsl_to_tgsi_visitor::visit(ir_expression *ir) emit(ir, TGSI_OPCODE_SNE, result_dst, op[0], op[1]); break; - case ir_binop_logic_or: - /* This could be a saturated add and skip the SNE. */ - emit(ir, TGSI_OPCODE_ADD, result_dst, op[0], op[1]); - emit(ir, TGSI_OPCODE_SNE, result_dst, result_src, st_src_reg_for_float(0.0)); + case ir_binop_logic_or: { + /* After the addition, the value will be an integer on the + * range [0,2]. Zero stays zero, and positive values become 1.0. + */ + glsl_to_tgsi_instruction *add = + emit(ir, TGSI_OPCODE_ADD, result_dst, op[0], op[1]); + if (this->prog->Target == GL_FRAGMENT_PROGRAM_ARB && + result_dst.type == GLSL_TYPE_FLOAT) { + /* The clamping to [0,1] can be done for free in the fragment + * shader with a saturate if floats are being used as boolean values. + */ + add->saturate = true; + } else if (result_dst.type == GLSL_TYPE_FLOAT) { + /* Negating the result of the addition gives values on the range + * [-2, 0]. Zero stays zero, and negative values become 1.0. This + * is achieved using SLT. + */ + st_src_reg slt_src = result_src; + slt_src.negate = ~slt_src.negate; + emit(ir, TGSI_OPCODE_SLT, result_dst, slt_src, st_src_reg_for_float(0.0)); + } else { + /* Use an SNE on the result of the addition. Zero stays zero, + * 1 stays 1, and 2 becomes 1. + */ + emit(ir, TGSI_OPCODE_SNE, result_dst, result_src, st_src_reg_for_int(0)); + } break; + } case ir_binop_logic_and: /* the bool args are stored as float 0.0 or 1.0, so "mul" gives us "and". */ |