freedreno/a3xx/compiler: refactor trans_samp()

[mesa.git] / src / gallium / drivers / freedreno / freedreno_lowering.h

diff --git a/src/gallium/drivers/freedreno/freedreno_lowering.h b/src/gallium/drivers/freedreno/freedreno_lowering.h
index 2862e5d3b6b313c6e555cd67ecb5a78b2dfbe97c..2d36d8faf8177329e4f071adf739c346d79e702f 100644 (file)
--- a/src/gallium/drivers/freedreno/freedreno_lowering.h
+++ b/src/gallium/drivers/freedreno/freedreno_lowering.h
@@ -33,6 +33,25 @@
 #include "tgsi/tgsi_scan.h"
 
 struct fd_lowering_config {
+       /* For fragment shaders, generate a shader that emulates two
+        * sided color by inserting a BGCOLOR input for each COLOR
+        * input, and insert a CMP instruction to select the correct
+        * color to use based on the TGSI_SEMANTIC_FACE input.
+        *
+        * Note that drivers which use this to emulate two sided color
+        * will:
+        *  a) need to generate (on demand) alternate shaders to use
+        *     depending on the rasterizer state (ie. whether two
+        *     sided shading enabled)
+        *  b) expect to see the BGCOLOR semantic name in fragment
+        *     shaders.  During linkage, the driver should simply
+        *     map VS.OUT.BGCOLOR[n] to FS.IN.BGCOLOR[n] (in the
+        *     same was as linking other outs/ins).
+        */
+       unsigned color_two_side : 1;
+
+       /* TODO support for alpha_to_one as well?? */
+
        /* Individual OPC lowerings, if lower_<opc> is TRUE then
         * enable lowering of TGSI_OPCODE_<opc>
         */