[Mesa-dev] [PATCH 4/8] glsl: Add new builtins required by GL_ARB_sample_shading

[Anuj Phogat]

New builtins added by GL_ARB_sample_shading:
in vec2 gl_SamplePosition
in int gl_SampleID
in int gl_NumSamples
out int gl_SampleMask[]

Signed-off-by: Anuj Phogat <anuj.phogat at gmail.com>
---
 src/glsl/builtin_variables.cpp | 11 +++++++++++
 src/glsl/link_varyings.cpp     |  2 ++
 src/mesa/main/mtypes.h         |  7 ++++++-
 src/mesa/program/prog_print.c  |  5 +++++
 4 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/glsl/builtin_variables.cpp b/src/glsl/builtin_variables.cpp
index ae0a03f..c886840 100644
--- a/src/glsl/builtin_variables.cpp
+++ b/src/glsl/builtin_variables.cpp
@@ -30,6 +30,9 @@
 #include "program/prog_statevars.h"
 #include "program/prog_instruction.h"
 
+static struct gl_builtin_uniform_element gl_NumSamples_elements[] = {
+   {NULL, {STATE_NUM_SAMPLES, 0, 0}, SWIZZLE_XYZW}
+};
 
 static struct gl_builtin_uniform_element gl_DepthRange_elements[] = {
    {"near", {STATE_DEPTH_RANGE, 0, 0}, SWIZZLE_XXXX},
@@ -236,6 +239,7 @@ static struct gl_builtin_uniform_element gl_NormalMatrix_elements[] = {
 #define STATEVAR(name) {#name, name ## _elements, Elements(name ## _elements)}
 
 static const struct gl_builtin_uniform_desc _mesa_builtin_uniform_desc[] = {
+   STATEVAR(gl_NumSamples),
    STATEVAR(gl_DepthRange),
    STATEVAR(gl_ClipPlane),
    STATEVAR(gl_Point),
@@ -613,6 +617,7 @@ builtin_variable_generator::generate_constants()
 void
 builtin_variable_generator::generate_uniforms()
 {
+   add_uniform(int_t, "gl_NumSamples");
    add_uniform(type("gl_DepthRangeParameters"), "gl_DepthRange");
    add_uniform(array(vec4_t, VERT_ATTRIB_MAX), "gl_CurrentAttribVertMESA");
    add_uniform(array(vec4_t, VARYING_SLOT_MAX), "gl_CurrentAttribFragMESA");
@@ -789,6 +794,12 @@ builtin_variable_generator::generate_fs_special_vars()
       if (state->AMD_shader_stencil_export_warn)
          var->warn_extension = "GL_AMD_shader_stencil_export";
    }
+
+   if (state->ARB_sample_shading_enable) {
+      add_input(VARYING_SLOT_SAMPLE_ID, int_t, "gl_SampleID");
+      add_input(VARYING_SLOT_SAMPLE_POS, vec2_t, "gl_SamplePosition");
+      add_output(FRAG_RESULT_SAMPLE_MASK, array(int_t, 1), "gl_SampleMask");
+   }
 }
 
 
diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index 4ba6d8a..3595a58 100644
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -938,6 +938,8 @@ is_varying_var(GLenum shaderType, const ir_variable *var)
       case VARYING_SLOT_POS:
       case VARYING_SLOT_FACE:
       case VARYING_SLOT_PNTC:
+      case VARYING_SLOT_SAMPLE_ID:
+      case VARYING_SLOT_SAMPLE_POS:
          return false;
       default:
          return true;
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 5520e86..65ec829 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -236,6 +236,8 @@ typedef enum
    VARYING_SLOT_LAYER, /* Appears as VS or GS output */
    VARYING_SLOT_FACE, /* FS only */
    VARYING_SLOT_PNTC, /* FS only */
+   VARYING_SLOT_SAMPLE_ID, /* FS only */
+   VARYING_SLOT_SAMPLE_POS, /* FS only */
    VARYING_SLOT_VAR0, /* First generic varying slot */
    VARYING_SLOT_MAX = VARYING_SLOT_VAR0 + MAX_VARYING
 } gl_varying_slot;
@@ -272,6 +274,8 @@ typedef enum
 #define VARYING_BIT_FACE BITFIELD64_BIT(VARYING_SLOT_FACE)
 #define VARYING_BIT_PNTC BITFIELD64_BIT(VARYING_SLOT_PNTC)
 #define VARYING_BIT_VAR(V) BITFIELD64_BIT(VARYING_SLOT_VAR0 + (V))
+#define VARYING_BIT_SAMPLE_ID BITFIELD64_BIT(VARYING_SLOT_SAMPLE_ID)
+#define VARYING_BIT_SAMPLE_POS BITFIELD64_BIT(VARYING_SLOT_SAMPLE_POS)
 /*@}*/
 
 
@@ -306,12 +310,13 @@ typedef enum
     * register is written.  No FRAG_RESULT_DATAn will be written.
     */
    FRAG_RESULT_COLOR = 2,
+   FRAG_RESULT_SAMPLE_MASK = 3,
 
    /* FRAG_RESULT_DATAn are the per-render-target (GLSL gl_FragData[n]
     * or ARB_fragment_program fragment.color[n]) color results.  If
     * any are written, FRAG_RESULT_COLOR will not be written.
     */
-   FRAG_RESULT_DATA0 = 3,
+   FRAG_RESULT_DATA0 = 4,
    FRAG_RESULT_MAX = (FRAG_RESULT_DATA0 + MAX_DRAW_BUFFERS)
 } gl_frag_result;
 
diff --git a/src/mesa/program/prog_print.c b/src/mesa/program/prog_print.c
index cf85213..0c56ae6 100644
--- a/src/mesa/program/prog_print.c
+++ b/src/mesa/program/prog_print.c
@@ -150,6 +150,8 @@ arb_input_attrib_string(GLint index, GLenum progType)
       "fragment.(twenty)", /* VARYING_SLOT_LAYER */
       "fragment.(twenty-one)", /* VARYING_SLOT_FACE */
       "fragment.(twenty-two)", /* VARYING_SLOT_PNTC */
+      "fragment.(twenty-three)", /* VARYING_SLOT_SAMPLE_ID */
+      "fragment.(twenty-four)", /* VARYING_SLOT_SAMPLE_POS */
       "fragment.varying[0]",
       "fragment.varying[1]",
       "fragment.varying[2]",
@@ -274,6 +276,8 @@ arb_output_attrib_string(GLint index, GLenum progType)
       "result.(twenty)", /* VARYING_SLOT_LAYER */
       "result.(twenty-one)", /* VARYING_SLOT_FACE */
       "result.(twenty-two)", /* VARYING_SLOT_PNTC */
+      "result.(twenty-three)", /* VARYING_SLOT_SAMPLE_ID */
+      "result.(twenty-four)", /* VARYING_SLOT_SAMPLE_POS */
       "result.varying[0]",
       "result.varying[1]",
       "result.varying[2]",
@@ -311,6 +315,7 @@ arb_output_attrib_string(GLint index, GLenum progType)
       "result.depth", /* FRAG_RESULT_DEPTH */
       "result.(one)", /* FRAG_RESULT_STENCIL */
       "result.color", /* FRAG_RESULT_COLOR */
+      "result.sample_mask", /* FRAG_RESULT_SAMPLE_MASK */
       "result.color[0]", /* FRAG_RESULT_DATA0 (named for GLSL's gl_FragData) */
       "result.color[1]",
       "result.color[2]",
-- 
1.8.1.4