On Sun, 2012-06-17 at 00:43 +0200, Marcin Slusarz wrote:
> gl_ClipDistance needs special treatment in form of lowering pass
> which transforms gl_ClipDistance representation from float[] to
> vec4[]. There are 2 implementations - at glsl linker level (enabled
> by LowerClipDistance option) and at glsl_to_tgsi level (enabled
> unconditionally for gallium drivers). Second implementation is
> incomplete - it does not take into account transform feedback (see
> commit 642e5b413e0890b2070ba78fde42db381eaf02e5 "mesa: Fix transform
> feedback of unsubscripted gl_ClipDistance array" for details).
>
> There are 2 possible fixes:
> - adding transform feedback support into glsl_to_tgsi version
> - ripping gl_ClipDistance support from glsl_to_tgsi and enabling
> gl_ClipDistance lowering on glsl linker side
>
> This patch implements 2nd option. All it does is:
> - reverts most of the commit 59be691638200797583bce39a83f641d30d97492
> "st/mesa: add support for gl_ClipDistance"
> - changes LowerClipDistance to true
>
> Fixes Piglit tests "EXT_transform_feedback/builtin-varyings
> gl_ClipDistance[{2,3,4,5,6,7,8}]-no-subscript" on nv50.
> ---
>
> Can someone test this patch on radeon hw? The command is:
> ./piglit-run.py -c 0 -t "[Cc]lip[-]*[Dd]istance" tests/quick.tests
> results/quick.results
Fixes 8 transform feedback tests on evergreen, no regressions.
Vadim
>
> ---
> src/mesa/state_tracker/st_extensions.c | 1 +
> src/mesa/state_tracker/st_glsl_to_tgsi.cpp | 49
> +++-------------------------
> 2 files changed, 6 insertions(+), 44 deletions(-)
>
> diff --git a/src/mesa/state_tracker/st_extensions.c
> b/src/mesa/state_tracker/st_extensions.c
> index a9071f5..6a2da58 100644
> --- a/src/mesa/state_tracker/st_extensions.c
> +++ b/src/mesa/state_tracker/st_extensions.c
> @@ -222,6 +222,7 @@ void st_init_limits(struct st_context *st)
> options->MaxUnrollIterations =
> MIN2(screen->get_shader_param(screen, sh, PIPE_SHADER_CAP_MAX_INSTRUCTIONS),
> 65536);
> else
> options->MaxUnrollIterations = 255; /* SM3 limit */
> + options->LowerClipDistance = true;
> }
>
> /* PIPE_SHADER_CAP_MAX_INPUTS for the FS specifies the maximum number
> diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> index 347a22f..3d87d11 100644
> --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> @@ -304,7 +304,6 @@ public:
> int samplers_used;
> bool indirect_addr_temps;
> bool indirect_addr_consts;
> - int num_clip_distances;
>
> int glsl_version;
> bool native_integers;
> @@ -2819,7 +2818,6 @@ glsl_to_tgsi_visitor::glsl_to_tgsi_visitor()
> samplers_used = 0;
> indirect_addr_temps = false;
> indirect_addr_consts = false;
> - num_clip_distances = 0;
> glsl_version = 0;
> native_integers = false;
> mem_ctx = ralloc_context(NULL);
> @@ -4587,17 +4585,9 @@ st_translate_program(
> }
>
> for (i = 0; i < numOutputs; i++) {
> - if (outputSemanticName[i] == TGSI_SEMANTIC_CLIPDIST) {
> - int mask = ((1 << (program->num_clip_distances -
> 4*outputSemanticIndex[i])) - 1) & TGSI_WRITEMASK_XYZW;
> - t->outputs[i] = ureg_DECL_output_masked(ureg,
> - outputSemanticName[i],
> - outputSemanticIndex[i],
> - mask);
> - } else {
> - t->outputs[i] = ureg_DECL_output(ureg,
> - outputSemanticName[i],
> - outputSemanticIndex[i]);
> - }
> + t->outputs[i] = ureg_DECL_output(ureg,
> + outputSemanticName[i],
> + outputSemanticIndex[i]);
> }
> if (passthrough_edgeflags)
> emit_edgeflags(t);
> @@ -4753,8 +4743,7 @@ out:
> static struct gl_program *
> get_mesa_program(struct gl_context *ctx,
> struct gl_shader_program *shader_program,
> - struct gl_shader *shader,
> - int num_clip_distances)
> + struct gl_shader *shader)
> {
> glsl_to_tgsi_visitor* v = new glsl_to_tgsi_visitor();
> struct gl_program *prog;
> @@ -4794,7 +4783,6 @@ get_mesa_program(struct gl_context *ctx,
> v->options = options;
> v->glsl_version = ctx->Const.GLSLVersion;
> v->native_integers = ctx->Const.NativeIntegers;
> - v->num_clip_distances = num_clip_distances;
>
> _mesa_generate_parameters_list_for_uniforms(shader_program, shader,
> prog->Parameters);
> @@ -4919,25 +4907,6 @@ get_mesa_program(struct gl_context *ctx,
> return prog;
> }
>
> -/**
> - * Searches through the IR for a declaration of gl_ClipDistance and returns
> the
> - * declared size of the gl_ClipDistance array. Returns 0 if gl_ClipDistance
> is
> - * not declared in the IR.
> - */
> -int get_clip_distance_size(exec_list *ir)
> -{
> - foreach_iter (exec_list_iterator, iter, *ir) {
> - ir_instruction *inst = (ir_instruction *)iter.get();
> - ir_variable *var = inst->as_variable();
> - if (var == NULL) continue;
> - if (!strcmp(var->name, "gl_ClipDistance")) {
> - return var->type->length;
> - }
> - }
> -
> - return 0;
> -}
> -
> extern "C" {
>
> struct gl_shader *
> @@ -4976,7 +4945,6 @@ st_new_shader_program(struct gl_context *ctx, GLuint
> name)
> GLboolean
> st_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
> {
> - int num_clip_distances[MESA_SHADER_TYPES];
> assert(prog->LinkStatus);
>
> for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
> @@ -4988,11 +4956,6 @@ st_link_shader(struct gl_context *ctx, struct
> gl_shader_program *prog)
> const struct gl_shader_compiler_options *options =
>
> &ctx->ShaderCompilerOptions[_mesa_shader_type_to_index(prog->_LinkedShaders[i]->Type)];
>
> - /* We have to determine the length of the gl_ClipDistance array before
> - * the array is lowered to two vec4s by lower_clip_distance().
> - */
> - num_clip_distances[i] = get_clip_distance_size(ir);
> -
> do {
> unsigned what_to_lower = MOD_TO_FRACT | DIV_TO_MUL_RCP |
> EXP_TO_EXP2 | LOG_TO_LOG2;
> @@ -5014,7 +4977,6 @@ st_link_shader(struct gl_context *ctx, struct
> gl_shader_program *prog)
> || progress;
>
> progress = lower_quadop_vector(ir, false) || progress;
> - progress = lower_clip_distance(ir) || progress;
>
> if (options->MaxIfDepth == 0)
> progress = lower_discard(ir) || progress;
> @@ -5049,8 +5011,7 @@ st_link_shader(struct gl_context *ctx, struct
> gl_shader_program *prog)
> if (prog->_LinkedShaders[i] == NULL)
> continue;
>
> - linked_prog = get_mesa_program(ctx, prog, prog->_LinkedShaders[i],
> - num_clip_distances[i]);
> + linked_prog = get_mesa_program(ctx, prog, prog->_LinkedShaders[i]);
>
> if (linked_prog) {
> static const GLenum targets[] = {
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