diff options
author | José Fonseca <jfonseca@vmware.com> | 2010-09-11 13:21:44 +0100 |
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committer | José Fonseca <jfonseca@vmware.com> | 2010-09-22 15:02:39 +0100 |
commit | 162b0efff6e82cc5f332a71aa16a376a2e9ba40c (patch) | |
tree | 70f06cedecda74c77b8565ae74d626d1d61f6c33 /src/gallium/auxiliary | |
parent | 256b9d99fb704d6c11d6242b7ec40206963f201e (diff) |
gallivm: Add unorm support to lp_build_lerp()
Unfortunately this can cause segfault with LLVM 2.6, if x is a constant.
Diffstat (limited to 'src/gallium/auxiliary')
-rw-r--r-- | src/gallium/auxiliary/gallivm/lp_bld_arit.c | 84 |
1 files changed, 75 insertions, 9 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c index dce3c3745b..ff0c7f7ca8 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c @@ -614,17 +614,15 @@ lp_build_div(struct lp_build_context *bld, /** - * Linear interpolation. - * - * This also works for integer values with a few caveats. + * Linear interpolation -- without any checks. * * @sa http://www.stereopsis.com/doubleblend.html */ -LLVMValueRef -lp_build_lerp(struct lp_build_context *bld, - LLVMValueRef x, - LLVMValueRef v0, - LLVMValueRef v1) +static INLINE LLVMValueRef +lp_build_lerp_simple(struct lp_build_context *bld, + LLVMValueRef x, + LLVMValueRef v0, + LLVMValueRef v1) { LLVMValueRef delta; LLVMValueRef res; @@ -639,12 +637,80 @@ lp_build_lerp(struct lp_build_context *bld, res = lp_build_add(bld, v0, res); - if(bld->type.fixed) + if (bld->type.fixed) { /* XXX: This step is necessary for lerping 8bit colors stored on 16bits, * but it will be wrong for other uses. Basically we need a more * powerful lp_type, capable of further distinguishing the values * interpretation from the value storage. */ res = LLVMBuildAnd(bld->builder, res, lp_build_const_int_vec(bld->type, (1 << bld->type.width/2) - 1), ""); + } + + return res; +} + + +/** + * Linear interpolation. + */ +LLVMValueRef +lp_build_lerp(struct lp_build_context *bld, + LLVMValueRef x, + LLVMValueRef v0, + LLVMValueRef v1) +{ + const struct lp_type type = bld->type; + LLVMValueRef res; + + assert(lp_check_value(type, x)); + assert(lp_check_value(type, v0)); + assert(lp_check_value(type, v1)); + + if (type.norm) { + struct lp_type wide_type; + struct lp_build_context wide_bld; + LLVMValueRef xl, xh, v0l, v0h, v1l, v1h, resl, resh; + LLVMValueRef shift; + + assert(type.length >= 2); + assert(!type.sign); + + /* + * Create a wider type, enough to hold the intermediate result of the + * multiplication. + */ + memset(&wide_type, 0, sizeof wide_type); + wide_type.fixed = TRUE; + wide_type.width = type.width*2; + wide_type.length = type.length/2; + + lp_build_context_init(&wide_bld, bld->builder, wide_type); + + lp_build_unpack2(bld->builder, type, wide_type, x, &xl, &xh); + lp_build_unpack2(bld->builder, type, wide_type, v0, &v0l, &v0h); + lp_build_unpack2(bld->builder, type, wide_type, v1, &v1l, &v1h); + + /* + * Scale x from [0, 255] to [0, 256] + */ + + shift = lp_build_const_int_vec(wide_type, type.width - 1); + + xl = lp_build_add(&wide_bld, xl, + LLVMBuildAShr(bld->builder, xl, shift, "")); + xh = lp_build_add(&wide_bld, xh, + LLVMBuildAShr(bld->builder, xh, shift, "")); + + /* + * Lerp both halves. + */ + + resl = lp_build_lerp_simple(&wide_bld, xl, v0l, v1l); + resh = lp_build_lerp_simple(&wide_bld, xh, v0h, v1h); + + res = lp_build_pack2(bld->builder, wide_type, type, resl, resh); + } else { + res = lp_build_lerp_simple(bld, x, v0, v1); + } return res; } |