[Mesa-dev] [PATCH] linker: Assign locations for fragment shader output
Ian Romanick
idr at freedesktop.org
Tue Jun 28 13:41:34 PDT 2011
From: Ian Romanick <ian.d.romanick at intel.com>
Fixes an assertion failure in the piglib out-01.frag
ARB_explicit_attrib_location test. The locations set via the layout
qualifier in fragment shader were not being applied to the shader
outputs. As a result all of these variables still had a location of
-1 set.
This may need some more work for pre-3.0 contexts. The problem is
dealing with generic outputs that lack a layout qualifier. There is
no way for the application to specify a location
(glBindFragDataLocation is not supported) or query the location
assigned by the linker (glGetFragDataLocation is not supported).
NOTE: This is a candidate for the 7.10 and 7.11 branches.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38624
Cc: Eric Anholt <eric at anholt.net>
Cc: Kenneth Graunke <kenneth at whitecape.org>
Cc: Vinson Lee <vlee at vmware.com>
---
src/glsl/linker.cpp | 98 +++++++++++++++++++++++++++++++++++---------------
1 files changed, 68 insertions(+), 30 deletions(-)
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index b6479e7..12299b3 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -1194,16 +1194,43 @@ find_available_slots(unsigned used_mask, unsigned needed_count)
}
+/**
+ * Assign locations for either VS inputs for FS outputs
+ *
+ * \param prog Shader program whose variables need locations assigned
+ * \param target_index Selector for the program target to receive location
+ * assignmnets. Must be either \c MESA_SHADER_VERTEX or
+ * \c MESA_SHADER_FRAGMENT.
+ * \param max_index Maximum number of generic locations. This corresponds
+ * to either the maximum number of draw buffers or the
+ * maximum number of generic attributes.
+ *
+ * \return
+ * If locations are successfully assigned, true is returned. Otherwise an
+ * error is emitted to the shader link log and false is returned.
+ *
+ * \bug
+ * Locations set via \c glBindFragDataLocation are not currently supported.
+ * Only locations assigned automatically by the linker, explicitly set by a
+ * layout qualifier, or explicitly set by a built-in variable (e.g., \c
+ * gl_FragColor) are supported for fragment shaders.
+ */
bool
-assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index)
+assign_attribute_or_color_locations(gl_shader_program *prog,
+ unsigned target_index,
+ unsigned max_index)
{
- /* Mark invalid attribute locations as being used.
+ /* Mark invalid locations as being used.
*/
- unsigned used_locations = (max_attribute_index >= 32)
- ? ~0 : ~((1 << max_attribute_index) - 1);
+ unsigned used_locations = (max_index >= 32)
+ ? ~0 : ~((1 << max_index) - 1);
- gl_shader *const sh = prog->_LinkedShaders[0];
- assert(sh->Type == GL_VERTEX_SHADER);
+ assert((target_index == MESA_SHADER_VERTEX)
+ || (target_index == MESA_SHADER_FRAGMENT));
+
+ gl_shader *const sh = prog->_LinkedShaders[target_index];
+ if (sh == NULL)
+ return true;
/* Operate in a total of four passes.
*
@@ -1220,9 +1247,12 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
* 4. Assign locations to any inputs without assigned locations.
*/
- invalidate_variable_locations(sh, ir_var_in, VERT_ATTRIB_GENERIC0);
+ const int generic_base = (target_index == MESA_SHADER_VERTEX)
+ ? VERT_ATTRIB_GENERIC0 : FRAG_RESULT_DATA0;
+
+ invalidate_variable_locations(sh, ir_var_in, generic_base);
- if (prog->Attributes != NULL) {
+ if ((target_index == MESA_SHADER_VERTEX) && (prog->Attributes != NULL)) {
for (unsigned i = 0; i < prog->Attributes->NumParameters; i++) {
ir_variable *const var =
sh->symbols->get_variable(prog->Attributes->Parameters[i].Name);
@@ -1306,18 +1336,21 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
unsigned num_attr = 0;
+ const enum ir_variable_mode direction =
+ (target_index == MESA_SHADER_VERTEX) ? ir_var_in : ir_var_out;
+
foreach_list(node, sh->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
- if ((var == NULL) || (var->mode != ir_var_in))
+ if ((var == NULL) || (var->mode != direction))
continue;
if (var->explicit_location) {
const unsigned slots = count_attribute_slots(var->type);
const unsigned use_mask = (1 << slots) - 1;
- const int attr = var->location - VERT_ATTRIB_GENERIC0;
+ const int attr = var->location - generic_base;
- if ((var->location >= (int)(max_attribute_index + VERT_ATTRIB_GENERIC0))
+ if ((var->location >= (int)(max_index + generic_base))
|| (var->location < 0)) {
linker_error_printf(prog,
"invalid explicit location %d specified for "
@@ -1325,7 +1358,7 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
(var->location < 0) ? var->location : attr,
var->name);
return false;
- } else if (var->location >= VERT_ATTRIB_GENERIC0) {
+ } else if (var->location >= generic_base) {
used_locations |= (use_mask << attr);
}
}
@@ -1349,14 +1382,16 @@ assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index
qsort(to_assign, num_attr, sizeof(to_assign[0]), temp_attr::compare);
- /* VERT_ATTRIB_GENERIC0 is a pseudo-alias for VERT_ATTRIB_POS. It can only
- * be explicitly assigned by via glBindAttribLocation. Mark it as reserved
- * to prevent it from being automatically allocated below.
- */
- find_deref_visitor find("gl_Vertex");
- find.run(sh->ir);
- if (find.variable_found())
- used_locations |= (1 << 0);
+ if (target_index == MESA_SHADER_VERTEX) {
+ /* VERT_ATTRIB_GENERIC0 is a pseudo-alias for VERT_ATTRIB_POS. It can
+ * only be explicitly assigned by via glBindAttribLocation. Mark it as
+ * reserved to prevent it from being automatically allocated below.
+ */
+ find_deref_visitor find("gl_Vertex");
+ find.run(sh->ir);
+ if (find.variable_found())
+ used_locations |= (1 << 0);
+ }
for (unsigned i = 0; i < num_attr; i++) {
/* Mask representing the contiguous slots that will be used by this
@@ -1671,16 +1706,19 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
assign_uniform_locations(prog);
- if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
- /* FINISHME: The value of the max_attribute_index parameter is
- * FINISHME: implementation dependent based on the value of
- * FINISHME: GL_MAX_VERTEX_ATTRIBS. GL_MAX_VERTEX_ATTRIBS must be
- * FINISHME: at least 16, so hardcode 16 for now.
- */
- if (!assign_attribute_locations(prog, 16)) {
- prog->LinkStatus = false;
- goto done;
- }
+ /* FINISHME: The value of the max_attribute_index parameter is
+ * FINISHME: implementation dependent based on the value of
+ * FINISHME: GL_MAX_VERTEX_ATTRIBS. GL_MAX_VERTEX_ATTRIBS must be
+ * FINISHME: at least 16, so hardcode 16 for now.
+ */
+ if (!assign_attribute_or_color_locations(prog, MESA_SHADER_VERTEX, 16)) {
+ prog->LinkStatus = false;
+ goto done;
+ }
+
+ if (!assign_attribute_or_color_locations(prog, MESA_SHADER_FRAGMENT, ctx->Const.MaxDrawBuffers)) {
+ prog->LinkStatus = false;
+ goto done;
}
unsigned prev;
--
1.7.4.4
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