diff options
Diffstat (limited to 'src/mesa/state_tracker')
| -rw-r--r-- | src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp index b238c267c81..b211fc680a3 100644 --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp @@ -1460,8 +1460,26 @@ glsl_to_tgsi_visitor::visit(ir_expression *ir) glsl_type::vec4_type); assert(ir->operands[0]->type->base_type == GLSL_TYPE_FLOAT); emit(ir, TGSI_OPCODE_SNE, st_dst_reg(temp), op[0], op[1]); + + /* After the dot-product, the value will be an integer on the + * range [0,4]. Zero becomes 1.0, and positive values become zero. + */ emit_dp(ir, result_dst, temp, temp, vector_elements); - emit(ir, TGSI_OPCODE_SEQ, result_dst, result_src, st_src_reg_for_float(0.0)); + + if (result_dst.type == GLSL_TYPE_FLOAT) { + /* Negating the result of the dot-product gives values on the range + * [-4, 0]. Zero becomes 1.0, and negative values become zero. + * This is achieved using SGE. + */ + st_src_reg sge_src = result_src; + sge_src.negate = ~sge_src.negate; + emit(ir, TGSI_OPCODE_SGE, result_dst, sge_src, st_src_reg_for_float(0.0)); + } else { + /* The TGSI negate flag doesn't work for integers, so use SEQ 0 + * instead. + */ + emit(ir, TGSI_OPCODE_SEQ, result_dst, result_src, st_src_reg_for_int(0)); + } } else { emit(ir, TGSI_OPCODE_SEQ, result_dst, op[0], op[1]); } |