- if (p->state->fog_mode && p->state->tnl_do_vertex_fog) {
- struct ureg params = register_param2(p, STATE_INTERNAL,
- STATE_FOG_PARAMS_OPTIMIZED);
- struct ureg tmp = get_temp(p);
- GLboolean useabs = (p->state->fog_mode != FOG_EXP2);
-
- if (useabs) {
- emit_op1(p, OPCODE_ABS, tmp, 0, input);
- }
-
- switch (p->state->fog_mode) {
- case FOG_LINEAR: {
- struct ureg id = get_identity_param(p);
- emit_op3(p, OPCODE_MAD, tmp, 0, useabs ? tmp : input,
- swizzle1(params,X), swizzle1(params,Y));
- emit_op2(p, OPCODE_MAX, tmp, 0, tmp, swizzle1(id,X)); /* saturate */
- emit_op2(p, OPCODE_MIN, fog, WRITEMASK_X, tmp, swizzle1(id,W));
- break;
- }
- case FOG_EXP:
- emit_op2(p, OPCODE_MUL, tmp, 0, useabs ? tmp : input,
- swizzle1(params,Z));
- emit_op1(p, OPCODE_EX2, fog, WRITEMASK_X, negate(tmp));
- break;
- case FOG_EXP2:
- emit_op2(p, OPCODE_MUL, tmp, 0, input, swizzle1(params,W));
- emit_op2(p, OPCODE_MUL, tmp, 0, tmp, tmp);
- emit_op1(p, OPCODE_EX2, fog, WRITEMASK_X, negate(tmp));
- break;
- }
-
- release_temp(p, tmp);
- }
- else {
- /* results = incoming fog coords (compute fog per-fragment later)
- *
- * KW: Is it really necessary to do anything in this case?
- * BP: Yes, we always need to compute the absolute value, unless
- * we want to push that down into the fragment program...
- */
- GLboolean useabs = GL_TRUE;
- emit_op1(p, useabs ? OPCODE_ABS : OPCODE_MOV, fog, WRITEMASK_X, input);
- }