--- /dev/null
+/*
+ * Copyright 2014 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+
+/**
+ * This utility transforms the fragment shader to support anti-aliasing points.
+ */
+
+#include "util/u_debug.h"
+#include "util/u_math.h"
+#include "tgsi_info.h"
+#include "tgsi_aa_point.h"
+#include "tgsi_transform.h"
+
+#define INVALID_INDEX 9999
+
+struct aa_transform_context
+{
+ struct tgsi_transform_context base;
+
+ unsigned tmp; // temp register
+ unsigned color_out; // frag color out register
+ unsigned color_tmp; // frag color temp register
+ unsigned num_tmp; // number of temp registers
+ unsigned num_imm; // number of immediates
+ unsigned num_input; // number of inputs
+ unsigned aa_point_coord_index;
+};
+
+static inline struct aa_transform_context *
+aa_transform_context(struct tgsi_transform_context *ctx)
+{
+ return (struct aa_transform_context *) ctx;
+}
+
+/**
+ * TGSI declaration transform callback.
+ */
+static void
+aa_decl(struct tgsi_transform_context *ctx,
+ struct tgsi_full_declaration *decl)
+{
+ struct aa_transform_context *ts = aa_transform_context(ctx);
+
+ if (decl->Declaration.File == TGSI_FILE_OUTPUT &&
+ decl->Semantic.Name == TGSI_SEMANTIC_COLOR &&
+ decl->Semantic.Index == 0) {
+ ts->color_out = decl->Range.First;
+ }
+ else if (decl->Declaration.File == TGSI_FILE_INPUT) {
+ ts->num_input++;
+ }
+ else if (decl->Declaration.File == TGSI_FILE_TEMPORARY) {
+ ts->num_tmp = MAX2(ts->num_tmp, decl->Range.Last + 1);
+ }
+
+ ctx->emit_declaration(ctx, decl);
+}
+
+/**
+ * TGSI immediate declaration transform callback.
+ */
+static void
+aa_immediate(struct tgsi_transform_context *ctx,
+ struct tgsi_full_immediate *imm)
+{
+ struct aa_transform_context *ts = aa_transform_context(ctx);
+
+ ctx->emit_immediate(ctx, imm);
+ ts->num_imm++;
+}
+
+/**
+ * TGSI transform prolog callback.
+ */
+static void
+aa_prolog(struct tgsi_transform_context *ctx)
+{
+ struct aa_transform_context *ts = aa_transform_context(ctx);
+ unsigned tmp0;
+ unsigned texIn;
+ unsigned imm;
+
+ /* Declare two temporary registers, one for temporary and
+ * one for color.
+ */
+ ts->tmp = ts->num_tmp++;
+ ts->color_tmp = ts->num_tmp++;
+
+ tgsi_transform_temps_decl(ctx, ts->tmp, ts->color_tmp);
+
+ /* Declare new generic input/texcoord */
+ texIn = ts->num_input++;
+ tgsi_transform_input_decl(ctx, texIn, TGSI_SEMANTIC_GENERIC,
+ ts->aa_point_coord_index, TGSI_INTERPOLATE_LINEAR);
+
+ /* Declare extra immediates */
+ imm = ts->num_imm++;
+ tgsi_transform_immediate_decl(ctx, 0.5, 0.5, 0.45, 1.0);
+
+ /*
+ * Emit code to compute fragment coverage.
+ * The point always has radius 0.5. The threshold value will be a
+ * value less than, but close to 0.5, such as 0.45.
+ * We compute a coverage factor from the distance and threshold.
+ * If the coverage is negative, the fragment is outside the circle and
+ * it's discarded.
+ * If the coverage is >= 1, the fragment is fully inside the threshold
+ * distance. We limit/clamp the coverage to 1.
+ * Otherwise, the fragment is between the threshold value and 0.5 and we
+ * compute a coverage value in [0,1].
+ *
+ * Input reg (texIn) usage:
+ * texIn.x = x point coord in [0,1]
+ * texIn.y = y point coord in [0,1]
+ * texIn.z = "k" the smoothing threshold distance
+ * texIn.w = unused
+ *
+ * Temp reg (t0) usage:
+ * t0.x = distance of fragment from center point
+ * t0.y = boolean, is t0.x > 0.5, also misc temp usage
+ * t0.z = temporary for computing 1/(0.5-k) value
+ * t0.w = final coverage value
+ */
+
+ tmp0 = ts->tmp;
+
+ /* SUB t0.xy, texIn, (0.5, 0,5) */
+ tgsi_transform_op2_inst(ctx, TGSI_OPCODE_SUB,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_WRITEMASK_XY,
+ TGSI_FILE_INPUT, texIn,
+ TGSI_FILE_IMMEDIATE, imm);
+
+ /* DP2 t0.x, t0.xy, t0.xy; # t0.x = x^2 + y^2 */
+ tgsi_transform_op2_inst(ctx, TGSI_OPCODE_DP2,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_WRITEMASK_X,
+ TGSI_FILE_TEMPORARY, tmp0,
+ TGSI_FILE_TEMPORARY, tmp0);
+
+ /* SQRT t0.x, t0.x */
+ tgsi_transform_op1_inst(ctx, TGSI_OPCODE_SQRT,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_WRITEMASK_X,
+ TGSI_FILE_TEMPORARY, tmp0);
+
+ /* compute coverage factor = (0.5-d)/(0.5-k) */
+
+ /* SUB t0.w, 0.5, texIn.z; # t0.w = 0.5-k */
+ tgsi_transform_op2_swz_inst(ctx, TGSI_OPCODE_SUB,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_WRITEMASK_W,
+ TGSI_FILE_IMMEDIATE, imm, TGSI_SWIZZLE_X,
+ TGSI_FILE_INPUT, texIn, TGSI_SWIZZLE_Z);
+
+ /* SUB t0.y, 0.5, t0.x; # t0.y = 0.5-d */
+ tgsi_transform_op2_swz_inst(ctx, TGSI_OPCODE_SUB,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_WRITEMASK_Y,
+ TGSI_FILE_IMMEDIATE, imm, TGSI_SWIZZLE_X,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_SWIZZLE_X);
+
+ /* DIV t0.w, t0.y, t0.w; # coverage = (0.5-d)/(0.5-k) */
+ tgsi_transform_op2_swz_inst(ctx, TGSI_OPCODE_DIV,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_WRITEMASK_W,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_SWIZZLE_Y,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_SWIZZLE_W);
+
+ /* If the coverage value is negative, it means the fragment is outside
+ * the point's circular boundary. Kill it.
+ */
+ /* KILL_IF tmp0.w; # if tmp0.w < 0 KILL */
+ tgsi_transform_kill_inst(ctx, TGSI_FILE_TEMPORARY, tmp0,
+ TGSI_SWIZZLE_W, FALSE);
+
+ /* If the distance is less than the threshold, the coverage/alpha value
+ * will be greater than one. Clamp to one here.
+ */
+ /* MIN tmp0.w, tmp0.w, 1.0 */
+ tgsi_transform_op2_swz_inst(ctx, TGSI_OPCODE_MIN,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_WRITEMASK_W,
+ TGSI_FILE_TEMPORARY, tmp0, TGSI_SWIZZLE_W,
+ TGSI_FILE_IMMEDIATE, imm, TGSI_SWIZZLE_W);
+}
+
+/**
+ * TGSI instruction transform callback.
+ */
+static void
+aa_inst(struct tgsi_transform_context *ctx,
+ struct tgsi_full_instruction *inst)
+{
+ struct aa_transform_context *ts = aa_transform_context(ctx);
+ unsigned i;
+
+ /* Look for writes to color output reg and replace it with
+ * color temp reg.
+ */
+ for (i = 0; i < inst->Instruction.NumDstRegs; i++) {
+ struct tgsi_full_dst_register *dst = &inst->Dst[i];
+ if (dst->Register.File == TGSI_FILE_OUTPUT &&
+ dst->Register.Index == ts->color_out) {
+ dst->Register.File = TGSI_FILE_TEMPORARY;
+ dst->Register.Index = ts->color_tmp;
+ }
+ }
+
+ ctx->emit_instruction(ctx, inst);
+}
+
+/**
+ * TGSI transform epilog callback.
+ */
+static void
+aa_epilog(struct tgsi_transform_context *ctx)
+{
+ struct aa_transform_context *ts = aa_transform_context(ctx);
+
+ /* add alpha modulation code at tail of program */
+ assert(ts->color_out != INVALID_INDEX);
+ assert(ts->color_tmp != INVALID_INDEX);
+
+ /* MOV output.color.xyz colorTmp */
+ tgsi_transform_op1_inst(ctx, TGSI_OPCODE_MOV,
+ TGSI_FILE_OUTPUT, ts->color_out,
+ TGSI_WRITEMASK_XYZ,
+ TGSI_FILE_TEMPORARY, ts->color_tmp);
+
+ /* MUL output.color.w colorTmp.w tmp0.w */
+ tgsi_transform_op2_inst(ctx, TGSI_OPCODE_MUL,
+ TGSI_FILE_OUTPUT, ts->color_out,
+ TGSI_WRITEMASK_W,
+ TGSI_FILE_TEMPORARY, ts->color_tmp,
+ TGSI_FILE_TEMPORARY, ts->tmp);
+}
+
+/**
+ * TGSI utility to transform a fragment shader to support antialiasing point.
+ *
+ * This utility accepts two inputs:
+ *\param tokens_in -- the original token string of the shader
+ *\param aa_point_coord_index -- the semantic index of the generic register
+ * that contains the point sprite texture coord
+ *
+ * For each fragment in the point, we compute the distance of the fragment
+ * from the point center using the point sprite texture coordinates.
+ * If the distance is greater than 0.5, we'll discard the fragment.
+ * Otherwise, we'll compute a coverage value which approximates how much
+ * of the fragment is inside the bounding circle of the point. If the distance
+ * is less than 'k', the coverage is 1. Else, the coverage is between 0 and 1.
+ * The final fragment color's alpha channel is then modulated by the coverage
+ * value.
+ */
+struct tgsi_token *
+tgsi_add_aa_point(const struct tgsi_token *tokens_in,
+ const int aa_point_coord_index)
+{
+ struct aa_transform_context transform;
+ const uint num_new_tokens = 200; /* should be enough */
+ const uint new_len = tgsi_num_tokens(tokens_in) + num_new_tokens;
+ struct tgsi_token *new_tokens;
+
+ /* allocate new tokens buffer */
+ new_tokens = tgsi_alloc_tokens(new_len);
+ if (!new_tokens)
+ return NULL;
+
+ /* setup transformation context */
+ memset(&transform, 0, sizeof(transform));
+ transform.base.transform_declaration = aa_decl;
+ transform.base.transform_instruction = aa_inst;
+ transform.base.transform_immediate = aa_immediate;
+ transform.base.prolog = aa_prolog;
+ transform.base.epilog = aa_epilog;
+
+ transform.tmp = INVALID_INDEX;
+ transform.color_out = INVALID_INDEX;
+ transform.color_tmp = INVALID_INDEX;
+
+ assert(aa_point_coord_index != -1);
+ transform.aa_point_coord_index = (unsigned)aa_point_coord_index;
+
+ transform.num_tmp = 0;
+ transform.num_imm = 0;
+ transform.num_input = 0;
+
+ /* transform the shader */
+ tgsi_transform_shader(tokens_in, new_tokens, new_len, &transform.base);
+
+ return new_tokens;
+}
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