[Mesa-dev] [PATCH 2/2] radeonsi: force level zero on image instructions in non-fragment shaders

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

Section 8.9 (Texture Functions) of the OpenGL Shading Language 4.5
specification:

   However, automatic level of detail is computed only for fragment shaders.
   Other shaders operate as though the base level of detail were computed as
   zero.

Of course, explicit LOD or derivative variants work in all shader types.

This fixes several GL4x-CTS.texture_gather.* tests.
--
Note that a bunch of texture_gather sub-tests for int and uint textures still
fail because the hardware apparently decides to offset all coordinates by 0.5
for such textures - forcing the NUM_FORMAT to FLOAT changes the coordinate
calculation, but that seems like such a wrong-headed hackwrong somehow (not to
mention that there might be some actual float-handling, with NaNs or whatever
, so...)
---
 src/gallium/drivers/radeonsi/si_shader.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 3f937ee..fa0e718 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -4301,6 +4301,7 @@ static void build_tex_intrinsic(const struct lp_build_tgsi_action *action,
 				struct lp_build_tgsi_context *bld_base,
 				struct lp_build_emit_data *emit_data)
 {
+	struct si_shader_context *ctx = si_shader_context(bld_base);
 	struct lp_build_context *base = &bld_base->base;
 	unsigned opcode = emit_data->inst->Instruction.Opcode;
 	unsigned target = emit_data->inst->Texture.Texture;
@@ -4337,9 +4338,12 @@ static void build_tex_intrinsic(const struct lp_build_tgsi_action *action,
 	case TGSI_OPCODE_TEX:
 	case TGSI_OPCODE_TEX2:
 	case TGSI_OPCODE_TXP:
+		if (ctx->type != PIPE_SHADER_FRAGMENT)
+			infix = ".lz";
 		break;
 	case TGSI_OPCODE_TXB:
 	case TGSI_OPCODE_TXB2:
+		assert(ctx->type == PIPE_SHADER_FRAGMENT);
 		infix = ".b";
 		break;
 	case TGSI_OPCODE_TXL:
@@ -4351,6 +4355,8 @@ static void build_tex_intrinsic(const struct lp_build_tgsi_action *action,
 		break;
 	case TGSI_OPCODE_TG4:
 		name = "llvm.SI.gather4";
+		if (ctx->type != PIPE_SHADER_FRAGMENT)
+			infix = ".lz";
 		break;
 	default:
 		assert(0);
-- 
2.7.4