r300: Fix fogcoord rewriting

We only care about the actual fogcoord itself now, reducing the rewriting
done for the vertex program.

The rewriting of source operand swizzles in the fragment program takes
care that fogcoord.yzw = 001.

This should fix fogcoord rewriting entirely, which had been horribly
broken in the face of dot-product instructions, and just broken (though
not horribly so) in the face of almost every other instruction (the W
component would be incorrect for most arithmetic instructions).

Signed-off-by: Nicolai Hähnle <nhaehnle@gmail.com>

3 files changed, 66 insertions, 45 deletions

diff --git a/src/mesa/drivers/dri/r300/r300_fragprog_common.c b/src/mesa/drivers/dri/r300/r300_fragprog_common.c
index c7914649dd..f5c4c0f4a0 100644
--- a/src/mesa/drivers/dri/r300/r300_fragprog_common.c
+++ b/src/mesa/drivers/dri/r300/r300_fragprog_common.c
@@ -162,6 +162,14 @@ static void insert_WPOS_trailer(struct r300_fragment_program_compiler *compiler)
 	}
 }
 
+
+/**
+ * Rewrite fragment.fogcoord to use a texture coordinate slot.
+ * Note that fogcoord is forced into an X001 pattern, and this enforcement
+ * is done here.
+ *
+ * See also the counterpart rewriting for vertex programs.
+ */
 static void rewriteFog(struct r300_fragment_program_compiler *compiler)
 {
 	struct r300_fragment_program *fp = compiler->fp;
@@ -193,8 +201,12 @@ static void rewriteFog(struct r300_fragment_program_compiler *compiler)
 		while (inst->Opcode != OPCODE_END) {
 			const int src_regs = _mesa_num_inst_src_regs(inst->Opcode);
 			for (i = 0; i < src_regs; ++i) {
-				if (inst->SrcReg[i].File == PROGRAM_INPUT && inst->SrcReg[i].Index == FRAG_ATTRIB_FOGC)
+				if (inst->SrcReg[i].File == PROGRAM_INPUT && inst->SrcReg[i].Index == FRAG_ATTRIB_FOGC) {
 					inst->SrcReg[i].Index = fp->fog_attr;
+					inst->SrcReg[i].Swizzle = combine_swizzles(
+						MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_ZERO, SWIZZLE_ZERO, SWIZZLE_ONE),
+						inst->SrcReg[i].Swizzle);
+				}
 			}
 			++inst;
 		}
diff --git a/src/mesa/drivers/dri/r300/r300_vertprog.c b/src/mesa/drivers/dri/r300/r300_vertprog.c
index 9f807dbc99..c0b116156a 100644
--- a/src/mesa/drivers/dri/r300/r300_vertprog.c
+++ b/src/mesa/drivers/dri/r300/r300_vertprog.c
@@ -74,33 +74,6 @@ USE OR OTHER DEALINGS IN THE SOFTWARE.
 		u_temp_i=VSF_MAX_FRAGMENT_TEMPS-1; \
 	} while (0)
 
-static GLuint combineSwizzles(GLuint src, GLuint swz_x, GLuint swz_y, GLuint swz_z, GLuint swz_w)
-{
-	GLuint ret = 0;
-
-	if (swz_x == SWIZZLE_ZERO || swz_x == SWIZZLE_ONE)
-		ret |= swz_x;
-	else
-		ret |= GET_SWZ(src, swz_x);
-
-	if (swz_y == SWIZZLE_ZERO || swz_y == SWIZZLE_ONE)
-		ret |= swz_y << 3;
-	else
-		ret |= GET_SWZ(src, swz_y) << 3;
-
-	if (swz_z == SWIZZLE_ZERO || swz_z == SWIZZLE_ONE)
-		ret |= swz_z << 6;
-	else
-		ret |= GET_SWZ(src, swz_z) << 6;
-
-	if (swz_w == SWIZZLE_ZERO || swz_w == SWIZZLE_ONE)
-		ret |= swz_w << 9;
-	else
-		ret |= GET_SWZ(src, swz_w) << 9;
-
-	return ret;
-}
-
 static int r300VertexProgUpdateParams(GLcontext * ctx, struct gl_vertex_program *vp, float *dst)
 {
 	int pi;
@@ -1282,24 +1255,28 @@ static void pos_as_texcoord(struct gl_program *prog, int tex_id)
 }
 
 /**
- @TODO
-  We can put X001 swizzle only if input components are directly mapped from output components.
-  For some insts we need to skip source swizzles and add: MOV OUTPUT[fog_attr].yzw, CONST[0].0001
+ * The fogcoord attribute is special in that only the first component
+ * is relevant, and the remaining components are always fixed (when read
+ * from by the fragment program) to yield an X001 pattern.
+ *
+ * We need to enforce this either in the vertex program or in the fragment
+ * program, and this code chooses not to enforce it in the vertex program.
+ * This is slightly cheaper, as long as the fragment program does not use
+ * weird swizzles.
+ *
+ * And it seems that usually, weird swizzles are not used, so...
+ *
+ * See also the counterpart rewriting for fragment programs.
  */
 static void fog_as_texcoord(struct gl_program *prog, int tex_id)
 {
 	struct prog_instruction *vpi;
-	int i;
 
 	vpi = prog->Instructions;
 	while (vpi->Opcode != OPCODE_END) {
 		if (vpi->DstReg.File == PROGRAM_OUTPUT && vpi->DstReg.Index == VERT_RESULT_FOGC) {
 			vpi->DstReg.Index = VERT_RESULT_TEX0 + tex_id;
-			vpi->DstReg.WriteMask = WRITEMASK_XYZW;
-
-			for (i = 0; i < _mesa_num_inst_src_regs(vpi->Opcode); ++i) {
-				vpi->SrcReg[i].Swizzle = combineSwizzles(vpi->SrcReg[i].Swizzle, SWIZZLE_X, SWIZZLE_ZERO, SWIZZLE_ZERO, SWIZZLE_ONE);
-			}
+			vpi->DstReg.WriteMask = WRITEMASK_X;
 		}
 
 		++vpi;
@@ -1329,7 +1306,7 @@ static int translateDP3(struct gl_program *prog, int pos)
 	inst = &prog->Instructions[pos];
 
 	inst->Opcode = OPCODE_DP4;
-	inst->SrcReg[0].Swizzle = combineSwizzles(inst->SrcReg[0].Swizzle, SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_ZERO);
+	inst->SrcReg[0].Swizzle = combine_swizzles4(inst->SrcReg[0].Swizzle, SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_ZERO);
 
 	return 0;
 }
@@ -1341,7 +1318,7 @@ static int translateDPH(struct gl_program *prog, int pos)
 	inst = &prog->Instructions[pos];
 
 	inst->Opcode = OPCODE_DP4;
-	inst->SrcReg[0].Swizzle = combineSwizzles(inst->SrcReg[0].Swizzle, SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_ONE);
+	inst->SrcReg[0].Swizzle = combine_swizzles4(inst->SrcReg[0].Swizzle, SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_ONE);
 
 	return 0;
 }
@@ -1409,13 +1386,13 @@ static int translateXPD(struct gl_program *prog, int pos)
 	inst->Opcode = OPCODE_MUL;
 	inst->DstReg.File = PROGRAM_TEMPORARY;
 	inst->DstReg.Index = tmp_idx;
-	inst->SrcReg[0].Swizzle = combineSwizzles(inst->SrcReg[0].Swizzle, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X, SWIZZLE_W);
-	inst->SrcReg[1].Swizzle = combineSwizzles(inst->SrcReg[1].Swizzle, SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y, SWIZZLE_W);
+	inst->SrcReg[0].Swizzle = combine_swizzles4(inst->SrcReg[0].Swizzle, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X, SWIZZLE_W);
+	inst->SrcReg[1].Swizzle = combine_swizzles4(inst->SrcReg[1].Swizzle, SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y, SWIZZLE_W);
 	++inst;
 
 	inst->Opcode = OPCODE_MAD;
-	inst->SrcReg[0].Swizzle = combineSwizzles(inst->SrcReg[0].Swizzle, SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y, SWIZZLE_W);
-	inst->SrcReg[1].Swizzle = combineSwizzles(inst->SrcReg[1].Swizzle, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X, SWIZZLE_W);
+	inst->SrcReg[0].Swizzle = combine_swizzles4(inst->SrcReg[0].Swizzle, SWIZZLE_Z, SWIZZLE_X, SWIZZLE_Y, SWIZZLE_W);
+	inst->SrcReg[1].Swizzle = combine_swizzles4(inst->SrcReg[1].Swizzle, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_X, SWIZZLE_W);
 	inst->SrcReg[1].Negate ^= NEGATE_XYZW;
 	inst->SrcReg[2].File = PROGRAM_TEMPORARY;
 	inst->SrcReg[2].Index = tmp_idx;
@@ -1768,12 +1745,12 @@ void r300SetupVertexProgram(r300ContextPtr rmesa)
 	struct r300_vertex_program *prog = rmesa->selected_vp;
 	int inst_count = 0;
 	int param_count = 0;
-	
+
 	/* Reset state, in case we don't use something */
 	((drm_r300_cmd_header_t *) rmesa->hw.vpp.cmd)->vpu.count = 0;
 	((drm_r300_cmd_header_t *) rmesa->hw.vpi.cmd)->vpu.count = 0;
 	((drm_r300_cmd_header_t *) rmesa->hw.vps.cmd)->vpu.count = 0;
-	
+
 	R300_STATECHANGE(rmesa, vpp);
 	param_count = r300VertexProgUpdateParams(ctx, prog->Base, (float *)&rmesa->hw.vpp.cmd[R300_VPP_PARAM_0]);
 	bump_vpu_count(rmesa->hw.vpp.cmd, param_count);
diff --git a/src/mesa/drivers/dri/r300/radeon_program.h b/src/mesa/drivers/dri/r300/radeon_program.h
index b411f69bc8..88474d43a2 100644
--- a/src/mesa/drivers/dri/r300/radeon_program.h
+++ b/src/mesa/drivers/dri/r300/radeon_program.h
@@ -52,6 +52,38 @@ enum {
 #define SWIZZLE_0000 MAKE_SWIZZLE4(SWIZZLE_ZERO, SWIZZLE_ZERO, SWIZZLE_ZERO, SWIZZLE_ZERO)
 #define SWIZZLE_1111 MAKE_SWIZZLE4(SWIZZLE_ONE, SWIZZLE_ONE, SWIZZLE_ONE, SWIZZLE_ONE)
 
+static inline GLuint get_swz(GLuint swz, GLuint idx)
+{
+	if (idx & 0x4)
+		return idx;
+	return GET_SWZ(swz, idx);
+}
+
+static inline GLuint combine_swizzles4(GLuint src, GLuint swz_x, GLuint swz_y, GLuint swz_z, GLuint swz_w)
+{
+	GLuint ret = 0;
+
+	ret |= get_swz(src, swz_x);
+	ret |= get_swz(src, swz_y) << 3;
+	ret |= get_swz(src, swz_z) << 6;
+	ret |= get_swz(src, swz_w) << 9;
+
+	return ret;
+}
+
+static inline GLuint combine_swizzles(GLuint src, GLuint swz)
+{
+	GLuint ret = 0;
+
+	ret |= get_swz(src, GET_SWZ(swz, SWIZZLE_X));
+	ret |= get_swz(src, GET_SWZ(swz, SWIZZLE_Y)) << 3;
+	ret |= get_swz(src, GET_SWZ(swz, SWIZZLE_Z)) << 6;
+	ret |= get_swz(src, GET_SWZ(swz, SWIZZLE_W)) << 9;
+
+	return ret;
+}
+
+
 /**
  * Transformation context that is passed to local transformations.
  *