[Freedreno] [PATCH 1/8] freedreno/a3xx: fix alpha-blending on RGBX formats

[Ilia Mirkin]

Expert debugging assistance provided by Chris Forbes.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---
 src/gallium/drivers/freedreno/a3xx/fd3_emit.c  | 21 +++++++++---
 src/gallium/drivers/freedreno/freedreno_util.c | 46 ++++++++++++++++++++++++++
 src/gallium/drivers/freedreno/freedreno_util.h |  1 +
 3 files changed, 63 insertions(+), 5 deletions(-)

diff --git a/src/gallium/drivers/freedreno/a3xx/fd3_emit.c b/src/gallium/drivers/freedreno/a3xx/fd3_emit.c
index 44f8ac4..7a6557a 100644
--- a/src/gallium/drivers/freedreno/a3xx/fd3_emit.c
+++ b/src/gallium/drivers/freedreno/a3xx/fd3_emit.c
@@ -571,11 +571,12 @@ fd3_emit_state(struct fd_context *ctx, struct fd_ringbuffer *ring,
 		uint32_t i;
 
 		for (i = 0; i < ARRAY_SIZE(blend->rb_mrt); i++) {
-			bool is_float = util_format_is_float(
-					pipe_surface_format(ctx->framebuffer.cbufs[i]));
-			bool is_int = util_format_is_pure_integer(
-					pipe_surface_format(ctx->framebuffer.cbufs[i]));
+			enum pipe_format format = pipe_surface_format(ctx->framebuffer.cbufs[i]);
+			bool is_float = util_format_is_float(format);
+			bool is_int = util_format_is_pure_integer(format);
+			bool has_alpha = util_format_has_alpha(format);
 			uint32_t control = blend->rb_mrt[i].control;
+			uint32_t blend_control = blend->rb_mrt[i].blend_control;
 
 			if (is_int) {
 				control &= (A3XX_RB_MRT_CONTROL_COMPONENT_ENABLE__MASK |
@@ -583,11 +584,21 @@ fd3_emit_state(struct fd_context *ctx, struct fd_ringbuffer *ring,
 				control |= A3XX_RB_MRT_CONTROL_ROP_CODE(ROP_COPY);
 			}
 
+			if (!has_alpha) {
+				blend_control &= ~(
+						A3XX_RB_MRT_BLEND_CONTROL_RGB_SRC_FACTOR__MASK |
+						A3XX_RB_MRT_BLEND_CONTROL_RGB_DEST_FACTOR__MASK);
+				blend_control |=
+					A3XX_RB_MRT_BLEND_CONTROL_RGB_SRC_FACTOR(fd_blend_factor_no_dst_alpha(blend->base.rt[i].rgb_src_factor)) |
+					A3XX_RB_MRT_BLEND_CONTROL_RGB_DEST_FACTOR(fd_blend_factor_no_dst_alpha(blend->base.rt[i].rgb_dst_factor));
+				control &= ~A3XX_RB_MRT_CONTROL_BLEND2;
+			}
+
 			OUT_PKT0(ring, REG_A3XX_RB_MRT_CONTROL(i), 1);
 			OUT_RING(ring, control);
 
 			OUT_PKT0(ring, REG_A3XX_RB_MRT_BLEND_CONTROL(i), 1);
-			OUT_RING(ring, blend->rb_mrt[i].blend_control |
+			OUT_RING(ring, blend_control |
 					COND(!is_float, A3XX_RB_MRT_BLEND_CONTROL_CLAMP_ENABLE));
 		}
 	}
diff --git a/src/gallium/drivers/freedreno/freedreno_util.c b/src/gallium/drivers/freedreno/freedreno_util.c
index 9892b05..30bcf03 100644
--- a/src/gallium/drivers/freedreno/freedreno_util.c
+++ b/src/gallium/drivers/freedreno/freedreno_util.c
@@ -111,6 +111,52 @@ fd_blend_factor(unsigned factor)
 	}
 }
 
+enum adreno_rb_blend_factor
+fd_blend_factor_no_dst_alpha(unsigned factor)
+{
+	switch (factor) {
+	case PIPE_BLENDFACTOR_ONE:
+		return FACTOR_ONE;
+	case PIPE_BLENDFACTOR_SRC_COLOR:
+		return FACTOR_SRC_COLOR;
+	case PIPE_BLENDFACTOR_SRC_ALPHA:
+		return FACTOR_SRC_ALPHA;
+	case PIPE_BLENDFACTOR_DST_ALPHA:
+		return FACTOR_ONE;
+	case PIPE_BLENDFACTOR_DST_COLOR:
+		return FACTOR_DST_COLOR;
+	case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
+		return FACTOR_SRC_ALPHA_SATURATE;
+	case PIPE_BLENDFACTOR_CONST_COLOR:
+		return FACTOR_CONSTANT_COLOR;
+	case PIPE_BLENDFACTOR_CONST_ALPHA:
+		return FACTOR_CONSTANT_ALPHA;
+	case PIPE_BLENDFACTOR_ZERO:
+	case 0:
+		return FACTOR_ZERO;
+	case PIPE_BLENDFACTOR_INV_SRC_COLOR:
+		return FACTOR_ONE_MINUS_SRC_COLOR;
+	case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
+		return FACTOR_ONE_MINUS_SRC_ALPHA;
+	case PIPE_BLENDFACTOR_INV_DST_ALPHA:
+		return FACTOR_ZERO;
+	case PIPE_BLENDFACTOR_INV_DST_COLOR:
+		return FACTOR_ONE_MINUS_DST_COLOR;
+	case PIPE_BLENDFACTOR_INV_CONST_COLOR:
+		return FACTOR_ONE_MINUS_CONSTANT_COLOR;
+	case PIPE_BLENDFACTOR_INV_CONST_ALPHA:
+		return FACTOR_ONE_MINUS_CONSTANT_ALPHA;
+	case PIPE_BLENDFACTOR_INV_SRC1_COLOR:
+	case PIPE_BLENDFACTOR_INV_SRC1_ALPHA:
+	case PIPE_BLENDFACTOR_SRC1_COLOR:
+	case PIPE_BLENDFACTOR_SRC1_ALPHA:
+		/* I don't think these are supported */
+	default:
+		DBG("invalid blend factor: %x", factor);
+		return 0;
+	}
+}
+
 enum adreno_pa_su_sc_draw
 fd_polygon_mode(unsigned mode)
 {
diff --git a/src/gallium/drivers/freedreno/freedreno_util.h b/src/gallium/drivers/freedreno/freedreno_util.h
index 0abc53f..111f45a 100644
--- a/src/gallium/drivers/freedreno/freedreno_util.h
+++ b/src/gallium/drivers/freedreno/freedreno_util.h
@@ -46,6 +46,7 @@
 enum adreno_rb_depth_format fd_pipe2depth(enum pipe_format format);
 enum pc_di_index_size fd_pipe2index(enum pipe_format format);
 enum adreno_rb_blend_factor fd_blend_factor(unsigned factor);
+enum adreno_rb_blend_factor fd_blend_factor_no_dst_alpha(unsigned factor);
 enum adreno_pa_su_sc_draw fd_polygon_mode(unsigned mode);
 enum adreno_stencil_op fd_stencil_op(unsigned op);
 
-- 
2.0.4