r600g: document why texture offset emulation is needed

diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index 0016d29..ddf79ee 100644 (file)
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -4800,8 +4800,9 @@ static int tgsi_tex(struct r600_shader_ctx *ctx)
        if (inst->Texture.NumOffsets) {
                assert(inst->Texture.NumOffsets == 1);
 
+               /* The texture offset feature doesn't work with the TXF instruction
+                * and must be emulated by adding the offset to the texture coordinates. */
                if (txf_add_offsets) {
-                       /* Add the offsets for texelFetch manually. */
                        const struct tgsi_texture_offset *off = inst->TexOffsets;
 
                        switch (inst->Texture.Texture) {