diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp index f7d79e9f50c..b238c267c81 100644 --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp @@ -1475,8 +1475,29 @@ 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]); - emit_dp(ir, result_dst, temp, temp, vector_elements); - emit(ir, TGSI_OPCODE_SNE, result_dst, result_src, st_src_reg_for_float(0.0)); + + /* After the dot-product, the value will be an integer on the + * range [0,4]. Zero stays zero, and positive values become 1.0. + */ + glsl_to_tgsi_instruction *const dp = + emit_dp(ir, result_dst, temp, temp, vector_elements); + 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. + */ + dp->saturate = true; + } else if (result_dst.type == GLSL_TYPE_FLOAT) { + /* Negating the result of the dot-product gives values on the range + * [-4, 0]. Zero stays zero, and negative values become 1.0. This + * 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 { + emit(ir, TGSI_OPCODE_SNE, result_dst, result_src, st_src_reg_for_float(0.0)); + } } else { emit(ir, TGSI_OPCODE_SNE, result_dst, op[0], op[1]); } |