st/xa: Update xa_yuv_planar_blit semantics

Change and document the interpretation of the color conversion matrix
in order to make the function more versatile and to simplify the
generated shader.

Signed-off-by: Thomas Hellstrom <[email protected]>
Reviewed-by: Jakob Bornecrantz <[email protected]>

4 files changed, 15 insertions, 11 deletions

diff --git a/src/gallium/state_trackers/xa/xa_context.h b/src/gallium/state_trackers/xa/xa_context.h
index d9bb86c828a..b547abf96a3 100644
--- a/src/gallium/state_trackers/xa/xa_context.h
+++ b/src/gallium/state_trackers/xa/xa_context.h
@@ -40,6 +40,14 @@ extern struct xa_context *xa_context_create(struct xa_tracker *xa);
 
 extern void xa_context_destroy(struct xa_context *r);
 
+/**
+ * xa_yuv_planar_blit - 2D blit with color conversion and scaling.
+ *
+ * Performs a scaled blit with color conversion according to
+ * (R,G,B,A)^T = (CM)^T (Y,U,V,1)^T, where @conversion_matrix or CM in the
+ * formula is a four by four coefficient matrix. The input variable
+ * @yuv is an array of three xa_yuv_component surfaces.
+ */
 extern int xa_yuv_planar_blit(struct xa_context *r,
 			      int src_x,
 			      int src_y,
diff --git a/src/gallium/state_trackers/xa/xa_tgsi.c b/src/gallium/state_trackers/xa/xa_tgsi.c
index ed1690ed369..c7454c9d6ac 100644
--- a/src/gallium/state_trackers/xa/xa_tgsi.c
+++ b/src/gallium/state_trackers/xa/xa_tgsi.c
@@ -320,7 +320,7 @@ create_yuv_shader(struct pipe_context *pipe, struct ureg_program *ureg)
 {
     struct ureg_src y_sampler, u_sampler, v_sampler;
     struct ureg_src pos;
-    struct ureg_src matrow0, matrow1, matrow2;
+    struct ureg_src matrow0, matrow1, matrow2, matrow3;
     struct ureg_dst y, u, v, rgb;
     struct ureg_dst out = ureg_DECL_output(ureg,
 					   TGSI_SEMANTIC_COLOR,
@@ -342,24 +342,20 @@ create_yuv_shader(struct pipe_context *pipe, struct ureg_program *ureg)
     matrow0 = ureg_DECL_constant(ureg, 0);
     matrow1 = ureg_DECL_constant(ureg, 1);
     matrow2 = ureg_DECL_constant(ureg, 2);
+    matrow3 = ureg_DECL_constant(ureg, 3);
 
     ureg_TEX(ureg, y, TGSI_TEXTURE_2D, pos, y_sampler);
     ureg_TEX(ureg, u, TGSI_TEXTURE_2D, pos, u_sampler);
     ureg_TEX(ureg, v, TGSI_TEXTURE_2D, pos, v_sampler);
 
-    ureg_SUB(ureg, u, ureg_src(u), ureg_scalar(matrow0, TGSI_SWIZZLE_W));
-    ureg_SUB(ureg, v, ureg_src(v), ureg_scalar(matrow0, TGSI_SWIZZLE_W));
-
-    ureg_MUL(ureg, rgb, ureg_scalar(ureg_src(y), TGSI_SWIZZLE_X), matrow0);
+    ureg_MOV(ureg, rgb, matrow3);
+    ureg_MAD(ureg, rgb,
+	     ureg_scalar(ureg_src(y), TGSI_SWIZZLE_X), matrow0, ureg_src(rgb));
     ureg_MAD(ureg, rgb,
 	     ureg_scalar(ureg_src(u), TGSI_SWIZZLE_X), matrow1, ureg_src(rgb));
     ureg_MAD(ureg, rgb,
 	     ureg_scalar(ureg_src(v), TGSI_SWIZZLE_X), matrow2, ureg_src(rgb));
 
-    /* rgb.a = 1; */
-    ureg_MOV(ureg, ureg_writemask(rgb, TGSI_WRITEMASK_W),
-	     ureg_scalar(matrow0, TGSI_SWIZZLE_X));
-
     ureg_MOV(ureg, out, ureg_src(rgb));
 
     ureg_release_temporary(ureg, rgb);
diff --git a/src/gallium/state_trackers/xa/xa_tracker.h b/src/gallium/state_trackers/xa/xa_tracker.h
index abc2457a056..d3adedb88df 100644
--- a/src/gallium/state_trackers/xa/xa_tracker.h
+++ b/src/gallium/state_trackers/xa/xa_tracker.h
@@ -37,7 +37,7 @@
 #include <stdint.h>
 
 #define XA_TRACKER_VERSION_MAJOR 0
-#define XA_TRACKER_VERSION_MINOR 5
+#define XA_TRACKER_VERSION_MINOR 6
 #define XA_TRACKER_VERSION_PATCH 0
 
 #define XA_FLAG_SHARED         (1 << 0)
diff --git a/src/gallium/state_trackers/xa/xa_yuv.c b/src/gallium/state_trackers/xa/xa_yuv.c
index da00b116ade..36213593d15 100644
--- a/src/gallium/state_trackers/xa/xa_yuv.c
+++ b/src/gallium/state_trackers/xa/xa_yuv.c
@@ -99,7 +99,7 @@ xa_yuv_bind_samplers(struct xa_context *r, struct xa_surface *yuv[])
 static void
 xa_yuv_fs_constants(struct xa_context *r, const float conversion_matrix[])
 {
-    const int param_bytes = 12 * sizeof(float);
+    const int param_bytes = 16 * sizeof(float);
 
     renderer_set_constants(r, PIPE_SHADER_FRAGMENT,
 			   conversion_matrix, param_bytes);