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authorMarek Olšák <maraeo@gmail.com>2010-05-08 03:39:35 +0200
committerMarek Olšák <maraeo@gmail.com>2010-05-08 23:03:44 +0200
commit0cbe1e6c14c44da11a41470cd1328cdb67c76732 (patch)
tree4dac0c36420d5dd872b1734d0e57461ce414d5d1 /src/mesa/drivers
parent39d0ece5f51e01b024907847055a2872491800b9 (diff)
r300/compiler: make shadow sampler codegen more readable, add comments
Diffstat (limited to 'src/mesa/drivers')
-rw-r--r--src/mesa/drivers/dri/r300/compiler/radeon_program_tex.c44
1 files changed, 28 insertions, 16 deletions
diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_program_tex.c b/src/mesa/drivers/dri/r300/compiler/radeon_program_tex.c
index 98e391ab0c..e1bb7c7213 100644
--- a/src/mesa/drivers/dri/r300/compiler/radeon_program_tex.c
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_program_tex.c
@@ -116,45 +116,53 @@ int radeonTransformTEX(
struct rc_instruction * inst_rcp = rc_insert_new_instruction(c, inst);
struct rc_instruction * inst_mad = rc_insert_new_instruction(c, inst_rcp);
struct rc_instruction * inst_cmp = rc_insert_new_instruction(c, inst_mad);
+ unsigned tmp_recip_w = rc_find_free_temporary(c);
+ unsigned tmp_texsample = rc_find_free_temporary(c);
+ unsigned tmp_sum = rc_find_free_temporary(c);
int pass, fail;
+ /* Save the output register. */
+ struct rc_dst_register output_reg = inst->U.I.DstReg;
+
+ /* Redirect TEX to a new temp. */
+ inst->U.I.DstReg.File = RC_FILE_TEMPORARY;
+ inst->U.I.DstReg.Index = tmp_texsample;
+ inst->U.I.DstReg.WriteMask = RC_MASK_XYZW;
+
+ /* Compute 1/W. */
inst_rcp->U.I.Opcode = RC_OPCODE_RCP;
inst_rcp->U.I.DstReg.File = RC_FILE_TEMPORARY;
- inst_rcp->U.I.DstReg.Index = rc_find_free_temporary(c);
+ inst_rcp->U.I.DstReg.Index = tmp_recip_w;
inst_rcp->U.I.DstReg.WriteMask = RC_MASK_W;
inst_rcp->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
inst_rcp->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_WWWW;
- inst_cmp->U.I.DstReg = inst->U.I.DstReg;
- inst->U.I.DstReg.File = RC_FILE_TEMPORARY;
- inst->U.I.DstReg.Index = rc_find_free_temporary(c);
- inst->U.I.DstReg.WriteMask = RC_MASK_XYZW;
-
+ /* Perspective-divide r (=depth) by W and add the texture sample (see below). */
inst_mad->U.I.Opcode = RC_OPCODE_MAD;
inst_mad->U.I.DstReg.File = RC_FILE_TEMPORARY;
- inst_mad->U.I.DstReg.Index = rc_find_free_temporary(c);
+ inst_mad->U.I.DstReg.Index = tmp_sum;
inst_mad->U.I.SrcReg[0] = inst->U.I.SrcReg[0];
inst_mad->U.I.SrcReg[0].Swizzle = RC_SWIZZLE_ZZZZ;
inst_mad->U.I.SrcReg[1].File = RC_FILE_TEMPORARY;
- inst_mad->U.I.SrcReg[1].Index = inst_rcp->U.I.DstReg.Index;
+ inst_mad->U.I.SrcReg[1].Index = tmp_recip_w;
inst_mad->U.I.SrcReg[1].Swizzle = RC_SWIZZLE_WWWW;
inst_mad->U.I.SrcReg[2].File = RC_FILE_TEMPORARY;
- inst_mad->U.I.SrcReg[2].Index = inst->U.I.DstReg.Index;
+ inst_mad->U.I.SrcReg[2].Index = tmp_texsample;
inst_mad->U.I.SrcReg[2].Swizzle = compiler->state.unit[inst->U.I.TexSrcUnit].depth_texture_swizzle;
/* Recall that SrcReg[0] is tex, SrcReg[2] is r and:
- * r < tex <=> -tex+r < 0
- * r >= tex <=> not (-tex+r < 0 */
+ * LESS: r < tex <=> -tex+r < 0
+ * GEQUAL: r >= tex <=> not (-tex+r < 0)
+ * GREATER: r > tex <=> tex-r < 0
+ * LEQUAL: r <= tex <=> not ( tex-r < 0)
+ *
+ * This negates either r or tex: */
if (comparefunc == RC_COMPARE_FUNC_LESS || comparefunc == RC_COMPARE_FUNC_GEQUAL)
inst_mad->U.I.SrcReg[2].Negate = inst_mad->U.I.SrcReg[2].Negate ^ RC_MASK_XYZW;
else
inst_mad->U.I.SrcReg[0].Negate = inst_mad->U.I.SrcReg[0].Negate ^ RC_MASK_XYZW;
- inst_cmp->U.I.Opcode = RC_OPCODE_CMP;
- /* DstReg has been filled out above */
- inst_cmp->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
- inst_cmp->U.I.SrcReg[0].Index = inst_mad->U.I.DstReg.Index;
-
+ /* This negates the whole expresion: */
if (comparefunc == RC_COMPARE_FUNC_LESS || comparefunc == RC_COMPARE_FUNC_GREATER) {
pass = 1;
fail = 2;
@@ -163,6 +171,10 @@ int radeonTransformTEX(
fail = 1;
}
+ inst_cmp->U.I.Opcode = RC_OPCODE_CMP;
+ inst_cmp->U.I.DstReg = output_reg;
+ inst_cmp->U.I.SrcReg[0].File = RC_FILE_TEMPORARY;
+ inst_cmp->U.I.SrcReg[0].Index = tmp_sum;
inst_cmp->U.I.SrcReg[pass].File = RC_FILE_NONE;
inst_cmp->U.I.SrcReg[pass].Swizzle = RC_SWIZZLE_1111;
inst_cmp->U.I.SrcReg[fail] = shadow_ambient(compiler, inst->U.I.TexSrcUnit);