From 05c03c6a1bcfb8ad77d3025f166f02ddaa741aa2 Mon Sep 17 00:00:00 2001 From: Brian Paul Date: Fri, 19 Mar 2010 10:02:16 -0600 Subject: [PATCH] gallivm: simplify and clean-up Z/stencil bit mask/shift code Refactor the code into two helper functions which compute the bit mask and shift terms for Z and stencil. Plus add a bunch of new comments to explain everything. --- src/gallium/auxiliary/gallivm/lp_bld_depth.c | 247 ++++++++++++------- 1 file changed, 160 insertions(+), 87 deletions(-) diff --git a/src/gallium/auxiliary/gallivm/lp_bld_depth.c b/src/gallium/auxiliary/gallivm/lp_bld_depth.c index 5b5ae7b5ea8..4ce1a27a061 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_depth.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_depth.c @@ -368,6 +368,83 @@ lp_depth_type(const struct util_format_description *format_desc, } +/** + * Compute bitmask and bit shift to apply to the incoming fragment Z values + * and the Z buffer values needed before doing the Z comparison. + * + * Note that we leave the Z bits in the position that we find them + * in the Z buffer (typically 0xffffff00 or 0x00ffffff). That lets us + * get by with fewer bit twiddling steps. + */ +static boolean +get_z_shift_and_mask(const struct util_format_description *format_desc, + unsigned *shift, unsigned *mask) +{ + const unsigned total_bits = format_desc->block.bits; + unsigned z_swizzle; + int chan; + unsigned padding_left, padding_right; + + assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS); + assert(format_desc->block.width == 1); + assert(format_desc->block.height == 1); + + z_swizzle = format_desc->swizzle[0]; + + if (z_swizzle == UTIL_FORMAT_SWIZZLE_NONE) + return FALSE; + + padding_right = 0; + for (chan = 0; chan < z_swizzle; ++chan) + padding_right += format_desc->channel[chan].size; + + padding_left = + total_bits - (padding_right + format_desc->channel[z_swizzle].size); + + if (padding_left || padding_right) { + unsigned long long mask_left = (1ULL << (total_bits - padding_left)) - 1; + unsigned long long mask_right = (1ULL << (padding_right)) - 1; + *mask = mask_left ^ mask_right; + } + else { + *mask = 0xffffffff; + } + + *shift = padding_left; + + return TRUE; +} + + +/** + * Compute bitmask and bit shift to apply to the framebuffer pixel values + * to put the stencil bits in the least significant position. + * (i.e. 0x000000ff) + */ +static boolean +get_s_shift_and_mask(const struct util_format_description *format_desc, + unsigned *shift, unsigned *mask) +{ + unsigned s_swizzle; + int chan, sz; + + s_swizzle = format_desc->swizzle[1]; + + if (s_swizzle == UTIL_FORMAT_SWIZZLE_NONE) + return FALSE; + + *shift = 0; + for (chan = 0; chan < s_swizzle; chan++) + *shift += format_desc->channel[chan].size; + + sz = format_desc->channel[s_swizzle].size; + *mask = (1U << sz) - 1U; + + return TRUE; +} + + + /** * Generate code for performing depth and/or stencil tests. * We operate on a vector of values (typically a 2x2 quad). @@ -397,46 +474,51 @@ lp_build_depth_stencil_test(LLVMBuilderRef builder, struct lp_build_context bld; struct lp_build_context sbld; struct lp_type s_type; - unsigned z_swizzle, s_swizzle; LLVMValueRef zs_dst, z_dst = NULL; LLVMValueRef stencil_vals = NULL; - LLVMValueRef z_bitmask = NULL, s_bitmask = NULL, s_shift = NULL; + LLVMValueRef z_bitmask = NULL, stencil_shift = NULL; LLVMValueRef z_pass = NULL, s_pass_mask = NULL; LLVMValueRef orig_mask = mask->value; - assert(depth->enabled || stencil[0].enabled); + /* Sanity checking */ + { + const unsigned z_swizzle = format_desc->swizzle[0]; + const unsigned s_swizzle = format_desc->swizzle[1]; - assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS); - assert(format_desc->block.width == 1); - assert(format_desc->block.height == 1); + assert(z_swizzle != UTIL_FORMAT_SWIZZLE_NONE || + s_swizzle != UTIL_FORMAT_SWIZZLE_NONE); - z_swizzle = format_desc->swizzle[0]; - s_swizzle = format_desc->swizzle[1]; + assert(depth->enabled || stencil[0].enabled); - assert(z_swizzle != UTIL_FORMAT_SWIZZLE_NONE || - s_swizzle != UTIL_FORMAT_SWIZZLE_NONE); + assert(format_desc->colorspace == UTIL_FORMAT_COLORSPACE_ZS); + assert(format_desc->block.width == 1); + assert(format_desc->block.height == 1); - if (stencil[0].enabled) { - assert(format_desc->format == PIPE_FORMAT_Z24S8_UNORM || - format_desc->format == PIPE_FORMAT_S8Z24_UNORM); - } + if (stencil[0].enabled) { + assert(format_desc->format == PIPE_FORMAT_Z24S8_UNORM || + format_desc->format == PIPE_FORMAT_S8Z24_UNORM); + } - /* Sanity checking */ - assert(z_swizzle < 4); - assert(format_desc->block.bits == type.width); - if(type.floating) { - assert(z_swizzle == 0); - assert(format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_FLOAT); - assert(format_desc->channel[z_swizzle].size == format_desc->block.bits); - } - else { - assert(format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED); - assert(format_desc->channel[z_swizzle].normalized); - assert(!type.fixed); - assert(!type.sign); - assert(type.norm); + assert(z_swizzle < 4); + assert(format_desc->block.bits == type.width); + if (type.floating) { + assert(z_swizzle == 0); + assert(format_desc->channel[z_swizzle].type == + UTIL_FORMAT_TYPE_FLOAT); + assert(format_desc->channel[z_swizzle].size == + format_desc->block.bits); + } + else { + assert(format_desc->channel[z_swizzle].type == + UTIL_FORMAT_TYPE_UNSIGNED); + assert(format_desc->channel[z_swizzle].normalized); + assert(!type.fixed); + assert(!type.sign); + assert(type.norm); + } } + /* Setup build context for Z vals */ lp_build_context_init(&bld, builder, type); @@ -449,71 +531,57 @@ lp_build_depth_stencil_test(LLVMBuilderRef builder, lp_build_name(zs_dst, "zsbufval"); - /* Align the source depth bits with the destination's, and mask out any - * stencil or padding bits from both */ - if(format_desc->channel[z_swizzle].size == format_desc->block.bits) { - assert(z_swizzle == 0); - z_dst = zs_dst; - } - else { - /* shift/mask bits to right-justify the Z bits */ - unsigned padding_left; - unsigned padding_right; - unsigned chan; - - assert(format_desc->layout == UTIL_FORMAT_LAYOUT_PLAIN); - assert(format_desc->channel[z_swizzle].type == UTIL_FORMAT_TYPE_UNSIGNED); - assert(format_desc->channel[z_swizzle].size <= format_desc->block.bits); - assert(format_desc->channel[z_swizzle].normalized); - - padding_right = 0; - for(chan = 0; chan < z_swizzle; ++chan) - padding_right += format_desc->channel[chan].size; - padding_left = format_desc->block.bits - - (padding_right + format_desc->channel[z_swizzle].size); - - if(padding_left || padding_right) { - const unsigned long long mask_left = (1ULL << (format_desc->block.bits - padding_left)) - 1; - const unsigned long long mask_right = (1ULL << (padding_right)) - 1; - z_bitmask = lp_build_const_int_vec(type, mask_left ^ mask_right); - } - /* If PIPE_FORMAT_Z24S8, we'll shift zs >> 24 to position stencil_vals */ - if (format_desc->format == PIPE_FORMAT_Z24S8_UNORM) - s_shift = lp_build_const_int_vec(type, 24); - else - s_shift = lp_build_const_int_vec(type, 0); - - s_bitmask = lp_build_const_int_vec(s_type, 0xff); - - stencil_vals = LLVMBuildLShr(builder, zs_dst, s_shift, ""); - stencil_vals = LLVMBuildAnd(builder, stencil_vals, s_bitmask, ""); + /* Compute and apply the Z/stencil bitmasks and shifts. + */ + { + unsigned z_shift, z_mask; + unsigned s_shift, s_mask; + + if (get_z_shift_and_mask(format_desc, &z_shift, &z_mask)) { + if (z_shift) { + LLVMValueRef shift = lp_build_const_int_vec(type, z_shift); + z_src = LLVMBuildLShr(builder, z_src, shift, ""); + } + + if (z_mask != 0xffffffff) { + LLVMValueRef mask = lp_build_const_int_vec(type, z_mask); + z_src = LLVMBuildAnd(builder, z_src, mask, ""); + z_dst = LLVMBuildAnd(builder, zs_dst, mask, ""); + z_bitmask = mask; /* used below */ + } + else { + z_dst = zs_dst; + } + + lp_build_name(z_dst, "zsbuf.z"); + } - if(padding_left) - z_src = LLVMBuildLShr(builder, z_src, - lp_build_const_int_vec(type, padding_left), ""); - if(padding_right) - z_src = LLVMBuildAnd(builder, z_src, z_bitmask, ""); - if(padding_left || padding_right) - z_dst = LLVMBuildAnd(builder, zs_dst, z_bitmask, ""); - else - z_dst = zs_dst; + if (get_s_shift_and_mask(format_desc, &s_shift, &s_mask)) { + if (s_shift) { + LLVMValueRef shift = lp_build_const_int_vec(type, s_shift); + stencil_vals = LLVMBuildLShr(builder, zs_dst, shift, ""); + stencil_shift = shift; /* used below */ + } + else { + stencil_vals = zs_dst; + } + + if (s_mask != 0xffffffff) { + LLVMValueRef mask = lp_build_const_int_vec(type, s_mask); + stencil_vals = LLVMBuildAnd(builder, stencil_vals, mask, ""); + } + + lp_build_name(stencil_vals, "stencil"); + } } - lp_build_name(z_dst, "zsbuf.z"); - - /* - printf("build depth %d stencil %d\n", - depth->enabled, - stencil[0].enabled); - */ if (stencil[0].enabled) { /* convert scalar stencil refs into vectors */ stencil_refs[0] = lp_build_broadcast_scalar(&bld, stencil_refs[0]); stencil_refs[1] = lp_build_broadcast_scalar(&bld, stencil_refs[1]); - s_pass_mask = lp_build_stencil_test(&sbld, stencil, stencil_refs, stencil_vals, face); @@ -569,12 +637,17 @@ lp_build_depth_stencil_test(LLVMBuilderRef builder, * passed the stencil test. */ s_pass_mask = LLVMBuildAnd(bld.builder, orig_mask, s_pass_mask, ""); - stencil_vals = lp_build_stencil_op(&sbld, stencil, Z_PASS_OP, stencil_refs, - stencil_vals, s_pass_mask, face); + stencil_vals = lp_build_stencil_op(&sbld, stencil, Z_PASS_OP, + stencil_refs, stencil_vals, + s_pass_mask, face); } - if (stencil_vals) - stencil_vals = LLVMBuildShl(bld.builder, stencil_vals, s_shift, ""); + /* The Z bits are already in the right place but we may need to shift the + * stencil bits before ORing Z with Stencil to make the final pixel value. + */ + if (stencil_vals && stencil_shift) + stencil_vals = LLVMBuildShl(bld.builder, stencil_vals, + stencil_shift, ""); /* Finally, merge/store the z/stencil values */ if ((depth->enabled && depth->writemask) || -- 2.30.2