/**
- * Scale a normalized value from src_bits to dst_bits
+ * Scale a normalized value from src_bits to dst_bits.
+ *
+ * The exact calculation is
+ *
+ * dst = iround(src * dst_mask / src_mask)
+ *
+ * or with integer rounding
+ *
+ * dst = src * (2*dst_mask + sign(src)*src_mask) / (2*src_mask)
+ *
+ * where
+ *
+ * src_mask = (1 << src_bits) - 1
+ * dst_mask = (1 << dst_bits) - 1
+ *
+ * but we try to avoid division and multiplication through shifts.
*/
static INLINE LLVMValueRef
scale_bits(struct gallivm_state *gallivm,
LLVMValueRef result = src;
if (dst_bits < src_bits) {
- /* Scale down by LShr */
- result = LLVMBuildLShr(builder,
- src,
- lp_build_const_int_vec(gallivm, src_type, src_bits - dst_bits),
- "");
+ int delta_bits = src_bits - dst_bits;
+
+ if (delta_bits <= dst_bits) {
+ /*
+ * Approximate the rescaling with a single shift.
+ *
+ * This gives the wrong rounding.
+ */
+
+ result = LLVMBuildLShr(builder,
+ src,
+ lp_build_const_int_vec(gallivm, src_type, delta_bits),
+ "");
+
+ } else {
+ /*
+ * Try more accurate rescaling.
+ */
+
+ /*
+ * Drop the least significant bits to make space for the multiplication.
+ *
+ * XXX: A better approach would be to use a wider integer type as intermediate. But
+ * this is enough to convert alpha from 16bits -> 2 when rendering to
+ * PIPE_FORMAT_R10G10B10A2_UNORM.
+ */
+ result = LLVMBuildLShr(builder,
+ src,
+ lp_build_const_int_vec(gallivm, src_type, dst_bits),
+ "");
+
+
+ result = LLVMBuildMul(builder,
+ result,
+ lp_build_const_int_vec(gallivm, src_type, (1LL << dst_bits) - 1),
+ "");
+
+ /*
+ * Add a rounding term before the division.
+ *
+ * TODO: Handle signed integers too.
+ */
+ if (!src_type.sign) {
+ result = LLVMBuildAdd(builder,
+ result,
+ lp_build_const_int_vec(gallivm, src_type, (1LL << (delta_bits - 1))),
+ "");
+ }
+
+ /*
+ * Approximate the division by src_mask with a src_bits shift.
+ *
+ * Given the src has already been shifted by dst_bits, all we need
+ * to do is to shift by the difference.
+ */
+
+ result = LLVMBuildLShr(builder,
+ result,
+ lp_build_const_int_vec(gallivm, src_type, delta_bits),
+ "");
+ }
+
} else if (dst_bits > src_bits) {
/* Scale up bits */
int db = dst_bits - src_bits;
/* Convert */
lp_build_conv(gallivm, fs_type, blend_type, &blend_color, 1, &blend_color, 1);
+ if (out_format_desc->colorspace == UTIL_FORMAT_COLORSPACE_SRGB) {
+ /*
+ * since blending is done with floats, there was no conversion.
+ * However, the rules according to fixed point renderbuffers still
+ * apply, that is we must clamp inputs to 0.0/1.0.
+ * (This would apply to separate alpha conversion too but we currently
+ * force has_alpha to be true.)
+ * TODO: should skip this with "fake" blend, since post-blend conversion
+ * will clamp anyway.
+ * TODO: could also skip this if fragment color clamping is enabled. We
+ * don't support it natively so it gets baked into the shader however, so
+ * can't really tell here.
+ */
+ struct lp_build_context f32_bld;
+ assert(row_type.floating);
+ lp_build_context_init(&f32_bld, gallivm, row_type);
+ for (i = 0; i < src_count; i++) {
+ src[i] = lp_build_clamp(&f32_bld, src[i], f32_bld.zero, f32_bld.one);
+ }
+ if (dual_source_blend) {
+ for (i = 0; i < src_count; i++) {
+ src1[i] = lp_build_clamp(&f32_bld, src1[i], f32_bld.zero, f32_bld.one);
+ }
+ }
+ /* probably can't be different than row_type but better safe than sorry... */
+ lp_build_context_init(&f32_bld, gallivm, blend_type);
+ blend_color = lp_build_clamp(&f32_bld, blend_color, f32_bld.zero, f32_bld.one);
+ }
+
/* Extract alpha */
blend_alpha = lp_build_extract_broadcast(gallivm, blend_type, row_type, blend_color, lp_build_const_int32(gallivm, 3));
*/
convert_to_blend_type(gallivm, block_size, out_format_desc, dst_type, row_type, dst, src_count);
+ /*
+ * FIXME: Really should get logic ops / masks out of generic blend / row
+ * format. Logic ops will definitely not work on the blend float format
+ * used for SRGB here and I think OpenGL expects this to work as expected
+ * (that is incoming values converted to srgb then logic op applied).
+ */
for (i = 0; i < src_count; ++i) {
dst[i] = lp_build_blend_aos(gallivm,
&variant->key.blend,
!key->alpha.enabled &&
!key->depth.enabled &&
!shader->info.base.uses_kill
- ? TRUE : FALSE;
+ ? TRUE : FALSE;
+
+ if ((!shader || shader->info.base.num_tokens <= 1) &&
+ !key->depth.enabled && !key->stencil[0].enabled) {
+ variant->ps_inv_multiplier = 0;
+ } else {
+ variant->ps_inv_multiplier = 1;
+ }
if ((LP_DEBUG & DEBUG_FS) || (gallivm_debug & GALLIVM_DEBUG_IR)) {
lp_debug_fs_variant(variant);
llvmpipe->pipe.set_constant_buffer = llvmpipe_set_constant_buffer;
}
+
+/*
+ * Rasterization is disabled if there is no pixel shader and
+ * both depth and stencil testing are disabled:
+ * http://msdn.microsoft.com/en-us/library/windows/desktop/bb205125
+ */
+boolean
+llvmpipe_rasterization_disabled(struct llvmpipe_context *lp)
+{
+ boolean null_fs = !lp->fs || lp->fs->info.base.num_tokens <= 1;
+
+ return (null_fs &&
+ !lp->depth_stencil->depth.enabled &&
+ !lp->depth_stencil->stencil[0].enabled);
+}
projects / mesa.git / blobdiff