--- /dev/null
+/*
+ * Copyright © 2018 Collabora Ltd
+ *
+ * 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, sublicense,
+ * 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 NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS 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.
+ */
+
+#include "st_tgsi_lower_depth_clamp.h"
+#include "tgsi/tgsi_transform.h"
+#include "tgsi/tgsi_scan.h"
+
+struct tgsi_depth_clamp_transform {
+ struct tgsi_transform_context base;
+
+ struct tgsi_shader_info info;
+
+ int depth_range_const;
+ int next_generic;
+ int imm;
+ int depth_var;
+ int pos_input;
+ int pos_output;
+ int pos_input_temp;
+ int pos_output_temp;
+ int depth_range_corrected;
+ bool depth_clip_minus_one_to_one;
+};
+
+static inline struct tgsi_depth_clamp_transform *
+tgsi_depth_clamp_transform(struct tgsi_transform_context *tctx)
+{
+ return (struct tgsi_depth_clamp_transform *)tctx;
+}
+
+static void
+transform_decl(struct tgsi_transform_context *tctx,
+ struct tgsi_full_declaration *decl)
+{
+ struct tgsi_depth_clamp_transform *ctx = tgsi_depth_clamp_transform(tctx);
+
+ /* find the next generic index usable for our inserted varying */
+ if (ctx->info.processor == PIPE_SHADER_FRAGMENT) {
+ if (decl->Declaration.File == TGSI_FILE_INPUT &&
+ decl->Semantic.Name == TGSI_SEMANTIC_GENERIC)
+ ctx->next_generic = MAX2(ctx->next_generic, decl->Semantic.Index + 1);
+ } else {
+ if (decl->Declaration.File == TGSI_FILE_OUTPUT &&
+ decl->Semantic.Name == TGSI_SEMANTIC_GENERIC)
+ ctx->next_generic = MAX2(ctx->next_generic, decl->Semantic.Index + 1);
+ }
+
+ if (decl->Declaration.File == TGSI_FILE_OUTPUT &&
+ decl->Semantic.Name == TGSI_SEMANTIC_POSITION) {
+ assert(decl->Semantic.Index == 0);
+ ctx->pos_output = decl->Range.First;
+ } else if (decl->Declaration.File == TGSI_FILE_INPUT &&
+ decl->Semantic.Name == TGSI_SEMANTIC_POSITION) {
+ assert(decl->Semantic.Index == 0);
+ if (ctx->info.processor == PIPE_SHADER_FRAGMENT)
+ ctx->pos_input = decl->Range.First;
+ }
+
+ tctx->emit_declaration(tctx, decl);
+}
+
+static void
+prolog_common(struct tgsi_depth_clamp_transform *ctx)
+{
+ assert(ctx->depth_range_const >= 0);
+ if (ctx->info.const_file_max[0] < ctx->depth_range_const)
+ tgsi_transform_const_decl(&ctx->base, ctx->depth_range_const,
+ ctx->depth_range_const);
+
+ /* declare a temp for the position-output */
+ ctx->pos_output_temp = ctx->info.file_max[TGSI_FILE_TEMPORARY] + 1;
+ tgsi_transform_temp_decl(&ctx->base, ctx->pos_output_temp);
+}
+
+static void
+prolog_last_vertex_stage(struct tgsi_transform_context *tctx)
+{
+ struct tgsi_depth_clamp_transform *ctx = tgsi_depth_clamp_transform(tctx);
+
+ prolog_common(ctx);
+
+ ctx->imm = ctx->info.immediate_count;
+ tgsi_transform_immediate_decl(tctx, 0.5, 0.0, 0.0, 0.0);
+
+ /* declare the output */
+ ctx->depth_var = ctx->info.num_outputs;
+ tgsi_transform_output_decl(tctx, ctx->depth_var,
+ TGSI_SEMANTIC_GENERIC,
+ ctx->next_generic,
+ TGSI_INTERPOLATE_LINEAR);
+}
+
+static void
+epilog_last_vertex_stage(struct tgsi_transform_context *tctx)
+{
+ struct tgsi_depth_clamp_transform *ctx = tgsi_depth_clamp_transform(tctx);
+
+ int mad_dst_file = TGSI_FILE_TEMPORARY;
+ int mad_dst_index = ctx->pos_output_temp;
+
+ if (!ctx->depth_clip_minus_one_to_one) {
+ mad_dst_file = TGSI_FILE_OUTPUT;
+ mad_dst_index = ctx->depth_var;
+ }
+
+ /* move from temp-register to output */
+ tgsi_transform_op1_inst(tctx, TGSI_OPCODE_MOV,
+ TGSI_FILE_OUTPUT, ctx->pos_output,
+ TGSI_WRITEMASK_XYZW,
+ TGSI_FILE_TEMPORARY, ctx->pos_output_temp);
+
+ /* Set gl_position.z to 0.0 to avoid clipping */
+ tgsi_transform_op1_swz_inst(tctx, TGSI_OPCODE_MOV,
+ TGSI_FILE_OUTPUT, ctx->pos_output,
+ TGSI_WRITEMASK_Z,
+ TGSI_FILE_IMMEDIATE, ctx->imm,
+ TGSI_SWIZZLE_Y);
+
+ /* Evaluate and pass true depth value in depthRange terms */
+ /* z = gl_Position.z / gl_Position.w */
+
+ struct tgsi_full_instruction inst;
+
+ inst = tgsi_default_full_instruction();
+ inst.Instruction.Opcode = TGSI_OPCODE_DIV;
+ inst.Instruction.NumDstRegs = 1;
+ inst.Dst[0].Register.File = TGSI_FILE_TEMPORARY;
+ inst.Dst[0].Register.Index = ctx->pos_output_temp;
+ inst.Dst[0].Register.WriteMask = TGSI_WRITEMASK_X;
+ inst.Instruction.NumSrcRegs = 2;
+ tgsi_transform_src_reg_xyzw(&inst.Src[0], TGSI_FILE_TEMPORARY, ctx->pos_output_temp);
+ tgsi_transform_src_reg_xyzw(&inst.Src[1], TGSI_FILE_TEMPORARY, ctx->pos_output_temp);
+ inst.Src[0].Register.SwizzleX =
+ inst.Src[0].Register.SwizzleY =
+ inst.Src[0].Register.SwizzleZ =
+ inst.Src[0].Register.SwizzleW = TGSI_SWIZZLE_Z;
+
+ inst.Src[1].Register.SwizzleX =
+ inst.Src[1].Register.SwizzleY =
+ inst.Src[1].Register.SwizzleZ =
+ inst.Src[1].Register.SwizzleW = TGSI_SWIZZLE_W;
+
+ tctx->emit_instruction(tctx, &inst);
+
+
+ /* OpenGL Core Profile 4.5 - 13.6.1
+ * The vertex's windows z coordinate zw is given by zw = s * z + b.
+ *
+ * * With clip control depth mode ZERO_TO_ONE
+ * s = f - n, b = n, and hence
+ *
+ * zw_0_1 = z * gl_DepthRange.diff + gl_DepthRange.near
+ */
+ tgsi_transform_op3_swz_inst(tctx, TGSI_OPCODE_MAD,
+ mad_dst_file, mad_dst_index,
+ TGSI_WRITEMASK_X,
+ TGSI_FILE_TEMPORARY, ctx->pos_output_temp,
+ TGSI_SWIZZLE_X,
+ false,
+ TGSI_FILE_CONSTANT, ctx->depth_range_const,
+ TGSI_SWIZZLE_Z,
+ TGSI_FILE_CONSTANT, ctx->depth_range_const,
+ TGSI_SWIZZLE_X);
+
+ /* If clip control depth mode is NEGATIVE_ONE_TO_ONE, then
+ * s = 0.5 * (f - n), b = 0.5 * (n + f), and hence
+ *
+ * zw_m1_1 = 0.5 * (zw_01 + gl_DepthRange.far)
+ */
+ if (ctx->depth_clip_minus_one_to_one) {
+ /* z += gl_DepthRange.far */
+ tgsi_transform_op2_swz_inst(tctx, TGSI_OPCODE_ADD,
+ TGSI_FILE_TEMPORARY, ctx->pos_output_temp,
+ TGSI_WRITEMASK_X,
+ TGSI_FILE_TEMPORARY, ctx->pos_output_temp,
+ TGSI_SWIZZLE_X,
+ TGSI_FILE_CONSTANT, ctx->depth_range_const,
+ TGSI_SWIZZLE_Y, false);
+ /* z *= 0.5 */
+ tgsi_transform_op2_swz_inst(tctx, TGSI_OPCODE_MUL,
+ TGSI_FILE_OUTPUT, ctx->depth_var,
+ TGSI_WRITEMASK_X,
+ TGSI_FILE_TEMPORARY, ctx->pos_output_temp,
+ TGSI_SWIZZLE_X,
+ TGSI_FILE_IMMEDIATE, ctx->imm,
+ TGSI_SWIZZLE_X, false);
+ }
+}
+
+
+static void
+prolog_fs(struct tgsi_transform_context *tctx)
+{
+ struct tgsi_depth_clamp_transform *ctx = tgsi_depth_clamp_transform(tctx);
+
+ prolog_common(ctx);
+
+ ctx->depth_range_corrected = ctx->info.file_max[TGSI_FILE_TEMPORARY] + 2;
+ tgsi_transform_temp_decl(tctx, ctx->depth_range_corrected);
+
+ /* declare the input */
+ ctx->depth_var = ctx->info.num_inputs;
+ tgsi_transform_input_decl(tctx, ctx->depth_var,
+ TGSI_SEMANTIC_GENERIC,
+ ctx->next_generic,
+ TGSI_INTERPOLATE_LINEAR);
+
+ /* declare the output */
+ if (ctx->pos_output < 0) {
+ ctx->pos_output = ctx->info.num_outputs;
+ tgsi_transform_output_decl(tctx, ctx->pos_output,
+ TGSI_SEMANTIC_POSITION,
+ 0,
+ TGSI_INTERPOLATE_LINEAR);
+ }
+
+ if (ctx->info.reads_z) {
+ ctx->pos_input_temp = ctx->info.file_max[TGSI_FILE_TEMPORARY] + 3;
+ tgsi_transform_temp_decl(tctx, ctx->pos_input_temp);
+
+ assert(ctx->pos_input_temp >= 0);
+ /* copy normal position */
+ tgsi_transform_op1_inst(tctx, TGSI_OPCODE_MOV,
+ TGSI_FILE_TEMPORARY, ctx->pos_input_temp,
+ TGSI_WRITEMASK_XYZW,
+ TGSI_FILE_INPUT, ctx->pos_input);
+ /* replace z-component with varying */
+ tgsi_transform_op1_swz_inst(tctx, TGSI_OPCODE_MOV,
+ TGSI_FILE_TEMPORARY, ctx->pos_input_temp,
+ TGSI_WRITEMASK_Z,
+ TGSI_FILE_INPUT, ctx->depth_var,
+ TGSI_SWIZZLE_X);
+ }
+}
+
+static void
+epilog_fs(struct tgsi_transform_context *tctx)
+{
+ struct tgsi_depth_clamp_transform *ctx = tgsi_depth_clamp_transform(tctx);
+
+ unsigned src0_file = TGSI_FILE_INPUT;
+ unsigned src0_index = ctx->depth_var;
+ unsigned src0_swizzle = TGSI_SWIZZLE_X;
+
+ if (ctx->info.writes_z) {
+ src0_file = TGSI_FILE_TEMPORARY;
+ src0_index = ctx->pos_output_temp;
+ src0_swizzle = TGSI_SWIZZLE_Z;
+ }
+
+ /* it is possible to have gl_DepthRange.near > gl_DepthRange.far, so first
+ * we have to sort the two */
+ tgsi_transform_op2_swz_inst(tctx, TGSI_OPCODE_MIN,
+ TGSI_FILE_TEMPORARY, ctx->depth_range_corrected,
+ TGSI_WRITEMASK_X,
+ TGSI_FILE_CONSTANT, ctx->depth_range_const,
+ TGSI_SWIZZLE_X,
+ TGSI_FILE_CONSTANT, ctx->depth_range_const,
+ TGSI_SWIZZLE_Y,
+ false);
+
+ tgsi_transform_op2_swz_inst(tctx, TGSI_OPCODE_MAX,
+ TGSI_FILE_TEMPORARY, ctx->depth_range_corrected,
+ TGSI_WRITEMASK_Y,
+ TGSI_FILE_CONSTANT, ctx->depth_range_const,
+ TGSI_SWIZZLE_X,
+ TGSI_FILE_CONSTANT, ctx->depth_range_const,
+ TGSI_SWIZZLE_Y,
+ false);
+
+ /* gl_FragDepth = max(gl_FragDepth, min(gl_DepthRange.near, gl_DepthRange.far)) */
+ tgsi_transform_op2_swz_inst(tctx, TGSI_OPCODE_MAX,
+ TGSI_FILE_TEMPORARY, ctx->pos_output_temp,
+ TGSI_WRITEMASK_X,
+ src0_file, src0_index, src0_swizzle,
+ TGSI_FILE_TEMPORARY, ctx->depth_range_corrected,
+ TGSI_SWIZZLE_X, false);
+
+ /* gl_FragDepth = min(gl_FragDepth, max(gl_DepthRange.near, gl_DepthRange.far)) */
+ tgsi_transform_op2_swz_inst(tctx, TGSI_OPCODE_MIN,
+ TGSI_FILE_OUTPUT, ctx->pos_output,
+ TGSI_WRITEMASK_Z,
+ TGSI_FILE_TEMPORARY, ctx->pos_output_temp,
+ TGSI_SWIZZLE_X,
+ TGSI_FILE_TEMPORARY, ctx->depth_range_corrected,
+ TGSI_SWIZZLE_Y, false);
+}
+
+static void
+transform_instr(struct tgsi_transform_context *tctx,
+ struct tgsi_full_instruction *inst)
+{
+ struct tgsi_depth_clamp_transform *ctx = tgsi_depth_clamp_transform(tctx);
+
+ if (ctx->pos_output >= 0) {
+ /* replace writes to gl_Position / gl_FragDepth with a temp-variable
+ */
+ for (int i = 0; i < inst->Instruction.NumDstRegs; ++i) {
+ if (inst->Dst[i].Register.File == TGSI_FILE_OUTPUT &&
+ inst->Dst[i].Register.Index == ctx->pos_output) {
+ inst->Dst[i].Register.File = TGSI_FILE_TEMPORARY;
+ inst->Dst[i].Register.Index = ctx->pos_output_temp;
+ }
+ }
+ }
+
+ if (ctx->info.reads_z) {
+ /* replace reads from gl_FragCoord with temp-variable
+ */
+ assert(ctx->pos_input_temp >= 0);
+ for (int i = 0; i < inst->Instruction.NumSrcRegs; ++i) {
+ if (inst->Src[i].Register.File == TGSI_FILE_INPUT &&
+ inst->Src[i].Register.Index == ctx->pos_input) {
+ inst->Src[i].Register.File = TGSI_FILE_TEMPORARY;
+ inst->Src[i].Register.Index = ctx->pos_input_temp;
+ }
+ }
+ }
+
+ /* In a GS each we have to add the z-write opilog for each emit
+ */
+ if (ctx->info.processor == PIPE_SHADER_GEOMETRY &&
+ inst->Instruction.Opcode == TGSI_OPCODE_EMIT)
+ epilog_last_vertex_stage(tctx);
+
+ tctx->emit_instruction(tctx, inst);
+}
+
+const struct tgsi_token *
+st_tgsi_lower_depth_clamp(const struct tgsi_token *tokens,
+ int depth_range_const,
+ bool clip_negative_one_to_one)
+{
+ struct tgsi_depth_clamp_transform ctx = {};
+ struct tgsi_token *newtoks;
+ int newlen;
+
+ tgsi_scan_shader(tokens, &ctx.info);
+
+ /* we only want to do this for the fragment shader, and the shader-stage
+ * right before it, but in the first pass there might be no "next" shader
+ */
+ if (ctx.info.processor != PIPE_SHADER_FRAGMENT &&
+ ctx.info.processor != PIPE_SHADER_GEOMETRY &&
+ ctx.info.processor != PIPE_SHADER_VERTEX &&
+ ctx.info.processor != PIPE_SHADER_TESS_EVAL &&
+ (ctx.info.properties[TGSI_PROPERTY_NEXT_SHADER] > PIPE_SHADER_VERTEX &&
+ (ctx.info.properties[TGSI_PROPERTY_NEXT_SHADER] != PIPE_SHADER_FRAGMENT))) {
+ return tokens;
+ }
+
+ ctx.base.transform_declaration = transform_decl;
+ ctx.base.transform_instruction = transform_instr;
+
+ if (ctx.info.processor == PIPE_SHADER_FRAGMENT) {
+ ctx.base.prolog = prolog_fs;
+ ctx.base.epilog = epilog_fs;
+ } else {
+ ctx.base.prolog = prolog_last_vertex_stage;
+ ctx.base.epilog = epilog_last_vertex_stage;
+ }
+
+ ctx.pos_output = ctx.pos_input = -1;
+ ctx.depth_range_const = depth_range_const;
+ ctx.depth_clip_minus_one_to_one = clip_negative_one_to_one;
+
+ /* We add approximately 30 tokens per Z write, so add this per vertex in
+ * a GS and some additional tokes for VS and TES
+ */
+ newlen = tgsi_num_tokens(tokens) +
+ 30 * ctx.info.properties[TGSI_PROPERTY_GS_MAX_OUTPUT_VERTICES] +
+ 120;
+
+ newtoks = tgsi_alloc_tokens(newlen);
+ if (!newtoks)
+ return tokens;
+
+ tgsi_transform_shader(tokens, newtoks, newlen, &ctx.base);
+
+ return newtoks;
+}
+
+const struct tgsi_token *
+st_tgsi_lower_depth_clamp_fs(const struct tgsi_token *tokens,
+ int depth_range_const)
+{
+ return st_tgsi_lower_depth_clamp(tokens, depth_range_const, false);
+}
\ No newline at end of file
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