mesa: add support for GL_EXT_polygon_offset_clamp

Nothing enables the extension yet, but the values are now available.
The spec calls for it to only be exposed for GL 3.3+, which is core-only
in mesa. Instead we allow any driver to enable it, including in a compat
context for any GL version.

Signed-off-by: Ilia Mirkin <[email protected]>
Reviewed-by: Glenn Kennard <[email protected]>

9 files changed, 70 insertions, 13 deletions

diff --git a/src/mesa/main/attrib.c b/src/mesa/main/attrib.c
index 4684615a880..07934b9bca0 100644
--- a/src/mesa/main/attrib.c
+++ b/src/mesa/main/attrib.c
@@ -1248,8 +1248,10 @@ _mesa_PopAttrib(void)
                _mesa_FrontFace(polygon->FrontFace);
                _mesa_PolygonMode(GL_FRONT, polygon->FrontMode);
                _mesa_PolygonMode(GL_BACK, polygon->BackMode);
-               _mesa_PolygonOffset(polygon->OffsetFactor,
-                                   polygon->OffsetUnits);
+               _mesa_polygon_offset_clamp(ctx,
+                                          polygon->OffsetFactor,
+                                          polygon->OffsetUnits,
+                                          polygon->OffsetClamp);
                _mesa_set_enable(ctx, GL_POLYGON_SMOOTH, polygon->SmoothFlag);
                _mesa_set_enable(ctx, GL_POLYGON_STIPPLE, polygon->StippleFlag);
                _mesa_set_enable(ctx, GL_CULL_FACE, polygon->CullFlag);
diff --git a/src/mesa/main/dd.h b/src/mesa/main/dd.h
index 40f68b4a7fd..ec8662b3089 100644
--- a/src/mesa/main/dd.h
+++ b/src/mesa/main/dd.h
@@ -579,7 +579,7 @@ struct dd_function_table {
    /** Select a polygon rasterization mode */
    void (*PolygonMode)(struct gl_context *ctx, GLenum face, GLenum mode);
    /** Set the scale and units used to calculate depth values */
-   void (*PolygonOffset)(struct gl_context *ctx, GLfloat factor, GLfloat units);
+   void (*PolygonOffset)(struct gl_context *ctx, GLfloat factor, GLfloat units, GLfloat clamp);
    /** Set the polygon stippling pattern */
    void (*PolygonStipple)(struct gl_context *ctx, const GLubyte *mask );
    /* Specifies the current buffer for reading */
diff --git a/src/mesa/main/dlist.c b/src/mesa/main/dlist.c
index 44e067b2ae3..025f6abd227 100644
--- a/src/mesa/main/dlist.c
+++ b/src/mesa/main/dlist.c
@@ -484,6 +484,9 @@ typedef enum
    /* ARB_uniform_buffer_object */
    OPCODE_UNIFORM_BLOCK_BINDING,
 
+   /* EXT_polygon_offset_clamp */
+   OPCODE_POLYGON_OFFSET_CLAMP,
+
    /* The following three are meta instructions */
    OPCODE_ERROR,                /* raise compiled-in error */
    OPCODE_CONTINUE,
@@ -3191,6 +3194,22 @@ save_PolygonOffsetEXT(GLfloat factor, GLfloat bias)
    save_PolygonOffset(factor, ctx->DrawBuffer->_DepthMaxF * bias);
 }
 
+static void GLAPIENTRY
+save_PolygonOffsetClampEXT(GLfloat factor, GLfloat units, GLfloat clamp)
+{
+   GET_CURRENT_CONTEXT(ctx);
+   Node *n;
+   ASSERT_OUTSIDE_SAVE_BEGIN_END_AND_FLUSH(ctx);
+   n = alloc_instruction(ctx, OPCODE_POLYGON_OFFSET_CLAMP, 3);
+   if (n) {
+      n[1].f = factor;
+      n[2].f = units;
+      n[3].f = clamp;
+   }
+   if (ctx->ExecuteFlag) {
+      CALL_PolygonOffsetClampEXT(ctx->Exec, (factor, units, clamp));
+   }
+}
 
 static void GLAPIENTRY
 save_PopAttrib(void)
@@ -8124,6 +8143,9 @@ execute_list(struct gl_context *ctx, GLuint list)
          case OPCODE_POLYGON_OFFSET:
             CALL_PolygonOffset(ctx->Exec, (n[1].f, n[2].f));
             break;
+         case OPCODE_POLYGON_OFFSET_CLAMP:
+            CALL_PolygonOffsetClampEXT(ctx->Exec, (n[1].f, n[2].f, n[3].f));
+            break;
          case OPCODE_POP_ATTRIB:
             CALL_PopAttrib(ctx->Exec, ());
             break;
@@ -9683,6 +9705,9 @@ _mesa_initialize_save_table(const struct gl_context *ctx)
    SET_ProgramUniformMatrix4x2fv(table, save_ProgramUniformMatrix4x2fv);
    SET_ProgramUniformMatrix3x4fv(table, save_ProgramUniformMatrix3x4fv);
    SET_ProgramUniformMatrix4x3fv(table, save_ProgramUniformMatrix4x3fv);
+
+   /* GL_EXT_polygon_offset_clamp */
+   SET_PolygonOffsetClampEXT(table, save_PolygonOffsetClampEXT);
 }
 
 
diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index bfe7d991b52..220b220d668 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -234,6 +234,7 @@ static const struct extension extension_table[] = {
    { "GL_EXT_pixel_buffer_object",                 o(EXT_pixel_buffer_object),                 GL,             2004 },
    { "GL_EXT_point_parameters",                    o(EXT_point_parameters),                    GLL,            1997 },
    { "GL_EXT_polygon_offset",                      o(dummy_true),                              GLL,            1995 },
+   { "GL_EXT_polygon_offset_clamp",                o(EXT_polygon_offset_clamp),                GL,             2014 },
    { "GL_EXT_provoking_vertex",                    o(EXT_provoking_vertex),                    GL,             2009 },
    { "GL_EXT_rescale_normal",                      o(dummy_true),                              GLL,            1997 },
    { "GL_EXT_secondary_color",                     o(dummy_true),                              GLL,            1999 },
diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index 6091efc7fb8..3f9d745161d 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -392,6 +392,7 @@ EXTRA_EXT2(ARB_transform_feedback3, ARB_gpu_shader5);
 EXTRA_EXT(INTEL_performance_query);
 EXTRA_EXT(ARB_explicit_uniform_location);
 EXTRA_EXT(ARB_clip_control);
+EXTRA_EXT(EXT_polygon_offset_clamp);
 
 static const int
 extra_ARB_color_buffer_float_or_glcore[] = {
diff --git a/src/mesa/main/get_hash_params.py b/src/mesa/main/get_hash_params.py
index c487e98befa..1645ebf701d 100644
--- a/src/mesa/main/get_hash_params.py
+++ b/src/mesa/main/get_hash_params.py
@@ -812,6 +812,9 @@ descriptor=[
   [ "VIEWPORT_BOUNDS_RANGE", "CONTEXT_FLOAT2(Const.ViewportBounds), extra_ARB_viewport_array" ],
   [ "LAYER_PROVOKING_VERTEX", "CONTEXT_ENUM(Light.ProvokingVertex), extra_ARB_viewport_array" ],
   [ "VIEWPORT_INDEX_PROVOKING_VERTEX", "CONTEXT_ENUM(Light.ProvokingVertex), extra_ARB_viewport_array" ],
+
+# GL_EXT_polygon_offset_clamp
+  [ "POLYGON_OFFSET_CLAMP_EXT", "CONTEXT_FLOAT(Polygon.OffsetClamp), extra_EXT_polygon_offset_clamp" ],
 ]}
 
 ]
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 81a7c0eb4eb..1c33ef4605b 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -1004,6 +1004,7 @@ struct gl_polygon_attrib
    GLenum CullFaceMode;		/**< Culling mode GL_FRONT or GL_BACK */
    GLfloat OffsetFactor;	/**< Polygon offset factor, from user */
    GLfloat OffsetUnits;		/**< Polygon offset units, from user */
+   GLfloat OffsetClamp;		/**< Polygon offset clamp, from user */
    GLboolean OffsetPoint;	/**< Offset in GL_POINT mode */
    GLboolean OffsetLine;	/**< Offset in GL_LINE mode */
    GLboolean OffsetFill;	/**< Offset in GL_FILL mode */
@@ -3813,6 +3814,7 @@ struct gl_extensions
    GLboolean EXT_packed_float;
    GLboolean EXT_pixel_buffer_object;
    GLboolean EXT_point_parameters;
+   GLboolean EXT_polygon_offset_clamp;
    GLboolean EXT_provoking_vertex;
    GLboolean EXT_shader_integer_mix;
    GLboolean EXT_stencil_two_side;
diff --git a/src/mesa/main/polygon.c b/src/mesa/main/polygon.c
index e3b90739d03..a1f0aa02da1 100644
--- a/src/mesa/main/polygon.c
+++ b/src/mesa/main/polygon.c
@@ -235,25 +235,33 @@ _mesa_GetPolygonStipple( GLubyte *dest )
    _mesa_GetnPolygonStippleARB(INT_MAX, dest);
 }
 
-
-void GLAPIENTRY
-_mesa_PolygonOffset( GLfloat factor, GLfloat units )
+void
+_mesa_polygon_offset_clamp(struct gl_context *ctx,
+                           GLfloat factor, GLfloat units, GLfloat clamp)
 {
-   GET_CURRENT_CONTEXT(ctx);
-
-   if (MESA_VERBOSE&VERBOSE_API)
-      _mesa_debug(ctx, "glPolygonOffset %f %f\n", factor, units);
-
    if (ctx->Polygon.OffsetFactor == factor &&
-       ctx->Polygon.OffsetUnits == units)
+       ctx->Polygon.OffsetUnits == units &&
+       ctx->Polygon.OffsetClamp == clamp)
       return;
 
    FLUSH_VERTICES(ctx, _NEW_POLYGON);
    ctx->Polygon.OffsetFactor = factor;
    ctx->Polygon.OffsetUnits = units;
+   ctx->Polygon.OffsetClamp = clamp;
 
    if (ctx->Driver.PolygonOffset)
-      ctx->Driver.PolygonOffset( ctx, factor, units );
+      ctx->Driver.PolygonOffset( ctx, factor, units, clamp );
+}
+
+void GLAPIENTRY
+_mesa_PolygonOffset( GLfloat factor, GLfloat units )
+{
+   GET_CURRENT_CONTEXT(ctx);
+
+   if (MESA_VERBOSE&VERBOSE_API)
+      _mesa_debug(ctx, "glPolygonOffset %f %f\n", factor, units);
+
+   _mesa_polygon_offset_clamp(ctx, factor, units, 0.0);
 }
 
 
@@ -268,7 +276,18 @@ _mesa_PolygonOffsetEXT( GLfloat factor, GLfloat bias )
 void GLAPIENTRY
 _mesa_PolygonOffsetClampEXT( GLfloat factor, GLfloat units, GLfloat clamp )
 {
+   GET_CURRENT_CONTEXT(ctx);
+
+   if (!ctx->Extensions.EXT_polygon_offset_clamp) {
+      _mesa_error(ctx, GL_INVALID_OPERATION,
+                  "unsupported function (glPolygonOffsetClampEXT) called");
+      return;
+   }
+
+   if (MESA_VERBOSE&VERBOSE_API)
+      _mesa_debug(ctx, "glPolygonOffsetClampEXT %f %f %f\n", factor, units, clamp);
 
+   _mesa_polygon_offset_clamp(ctx, factor, units, clamp);
 }
 
 
@@ -298,6 +317,7 @@ void _mesa_init_polygon( struct gl_context * ctx )
    ctx->Polygon.StippleFlag = GL_FALSE;
    ctx->Polygon.OffsetFactor = 0.0F;
    ctx->Polygon.OffsetUnits = 0.0F;
+   ctx->Polygon.OffsetClamp = 0.0F;
    ctx->Polygon.OffsetPoint = GL_FALSE;
    ctx->Polygon.OffsetLine = GL_FALSE;
    ctx->Polygon.OffsetFill = GL_FALSE;
diff --git a/src/mesa/main/polygon.h b/src/mesa/main/polygon.h
index 6cf14d3e2ac..41344a2ef0c 100644
--- a/src/mesa/main/polygon.h
+++ b/src/mesa/main/polygon.h
@@ -64,6 +64,9 @@ extern void GLAPIENTRY
 _mesa_GetPolygonStipple( GLubyte *mask );
 
 extern void
+_mesa_polygon_offset_clamp(struct gl_context *ctx,
+                           GLfloat factor, GLfloat units, GLfloat clamp);
+extern void
 _mesa_init_polygon( struct gl_context * ctx );
 
 #endif