[PATCH vkd3d] vkd3d-shader/hlsl: swizzle types of srcs can now be specified on sm4_instruction

[Francisco Casas]

Some dxbc instructions require swizzle types that differ from what is
usual for the register type.

e.g.
gather4 requires a register with register type VKD3D_SM4_RT_SAMPLER but
a swizzle type VKD3D_SM4_SWIZZLE_VEC4 instead of the usual
VKD3D_SM4_SWIZZLE_NONE.

The new fields of sm4_instruction can be used to handle these
exceptions.

Also, they shouldn't change the current behaviour of the rest of
the code since they are currently initalized with zeroes everywhere a
sm4_instruction is initialized.

Signed-off-by: Francisco Casas <fcasas at codeweavers.com>
---
 libs/vkd3d-shader/hlsl_sm4.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/libs/vkd3d-shader/hlsl_sm4.c b/libs/vkd3d-shader/hlsl_sm4.c
index 9d45e163..e148c821 100644
--- a/libs/vkd3d-shader/hlsl_sm4.c
+++ b/libs/vkd3d-shader/hlsl_sm4.c
@@ -747,6 +747,10 @@ struct sm4_instruction
     {
         struct sm4_register reg;
         unsigned int swizzle;
+        /* If use_custom_swizzle_type is true, then custom_swizzle_type will be used in the
+         * instruction, instead of the default swizzle type obtained from the register type. */
+        bool use_custom_swizzle_type;
+        enum vkd3d_sm4_swizzle_type custom_swizzle_type;
     } srcs[2];
     unsigned int src_count;
 
@@ -754,7 +758,7 @@ struct sm4_instruction
     unsigned int idx_count;
 };
 
-static unsigned int sm4_swizzle_type(enum vkd3d_sm4_register_type type)
+static unsigned int sm4_default_swizzle_type(enum vkd3d_sm4_register_type type)
 {
     switch (type)
     {
@@ -913,8 +917,10 @@ static void write_sm4_instruction(struct vkd3d_bytecode_buffer *buffer, const st
 
     for (i = 0; i < instr->src_count; ++i)
     {
+        unsigned int swizzle_type = instr->srcs[i].use_custom_swizzle_type ?
+                instr->srcs[i].custom_swizzle_type : sm4_default_swizzle_type(instr->srcs[i].reg.type);
         token = sm4_encode_register(&instr->srcs[i].reg);
-        token |= sm4_swizzle_type(instr->srcs[i].reg.type) << VKD3D_SM4_SWIZZLE_TYPE_SHIFT;
+        token |= swizzle_type << VKD3D_SM4_SWIZZLE_TYPE_SHIFT;
         token |= instr->srcs[i].swizzle << VKD3D_SM4_SWIZZLE_SHIFT;
         if (instr->srcs[i].reg.mod)
             token |= VKD3D_SM4_EXTENDED_OPERAND;
-- 
2.25.1