mesa: Also track a remapped version of the color logic op

With the exception of NVIDIA hardware, these are is the values that all
hardware and Gallium want.  The remapping is currently implemented in at
least 6 places.  This starts the process of consolidating to a single
place.

v2: sed --in-place -e 's/color_logic_ops/gl_logicop_mode/g' $(grep -lr
color_logic_ops src/) suggested by Brian.  Added some comments about the
selection of bit patterns for gl_logicop_mode and the GLenums.
Suggested by Nicolai.  Folded the GLenum_to_color_logicop macro into its
only users.

Signed-off-by: Ian Romanick <[email protected]>
Reviewed-by: Brian Paul <[email protected]> [v1]
Reviewed-by: Nicolai Hähnle <[email protected]>

2 files changed, 58 insertions, 0 deletions

diff --git a/src/mesa/main/blend.c b/src/mesa/main/blend.c
index 01721ab615d..1c3711766ec 100644
--- a/src/mesa/main/blend.c
+++ b/src/mesa/main/blend.c
@@ -849,6 +849,24 @@ _mesa_AlphaFunc( GLenum func, GLclampf ref )
    }
 }
 
+static const enum gl_logicop_mode color_logicop_mapping[16] = {
+   COLOR_LOGICOP_CLEAR,
+   COLOR_LOGICOP_AND,
+   COLOR_LOGICOP_AND_REVERSE,
+   COLOR_LOGICOP_COPY,
+   COLOR_LOGICOP_AND_INVERTED,
+   COLOR_LOGICOP_NOOP,
+   COLOR_LOGICOP_XOR,
+   COLOR_LOGICOP_OR,
+   COLOR_LOGICOP_NOR,
+   COLOR_LOGICOP_EQUIV,
+   COLOR_LOGICOP_INVERT,
+   COLOR_LOGICOP_OR_REVERSE,
+   COLOR_LOGICOP_COPY_INVERTED,
+   COLOR_LOGICOP_OR_INVERTED,
+   COLOR_LOGICOP_NAND,
+   COLOR_LOGICOP_SET
+};
 
 static ALWAYS_INLINE void
 logic_op(struct gl_context *ctx, GLenum opcode, bool no_error)
@@ -884,6 +902,7 @@ logic_op(struct gl_context *ctx, GLenum opcode, bool no_error)
    FLUSH_VERTICES(ctx, ctx->DriverFlags.NewLogicOp ? 0 : _NEW_COLOR);
    ctx->NewDriverState |= ctx->DriverFlags.NewLogicOp;
    ctx->Color.LogicOp = opcode;
+   ctx->Color._LogicOp = color_logicop_mapping[opcode & 0x0f];
 
    if (ctx->Driver.LogicOpcode)
       ctx->Driver.LogicOpcode(ctx, opcode);
@@ -1189,6 +1208,7 @@ void _mesa_init_color( struct gl_context * ctx )
    ctx->Color.IndexLogicOpEnabled = GL_FALSE;
    ctx->Color.ColorLogicOpEnabled = GL_FALSE;
    ctx->Color.LogicOp = GL_COPY;
+   ctx->Color._LogicOp = COLOR_LOGICOP_COPY;
    ctx->Color.DitherFlag = GL_TRUE;
 
    /* GL_FRONT is not possible on GLES. Instead GL_BACK will render to either
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index e587f63df2f..0c47be4ec72 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -413,6 +413,43 @@ union gl_color_union
    GLuint ui[4];
 };
 
+/**
+ * Remapped color logical operations
+ *
+ * With the exception of NVIDIA hardware, which consumes the OpenGL enumerants
+ * directly, everything wants this mapping of color logical operations.
+ *
+ * Fun fact: These values are just the bit-reverse of the low-nibble of the GL
+ * enumerant values (i.e., `GL_NOOP & 0x0f` is `b0101' while
+ * \c COLOR_LOGICOP_NOOP is `b1010`).
+ *
+ * Fun fact #2: These values are just an encoding of the operation as a table
+ * of bit values. The result of the logic op is:
+ *
+ *    result_bit = (logic_op >> (2 * src_bit + dst_bit)) & 1
+ *
+ * For the GL enums, the result is:
+ *
+ *    result_bit = logic_op & (1 << (2 * src_bit + dst_bit))
+ */
+enum PACKED gl_logicop_mode {
+   COLOR_LOGICOP_CLEAR = 0,
+   COLOR_LOGICOP_NOR = 1,
+   COLOR_LOGICOP_AND_INVERTED = 2,
+   COLOR_LOGICOP_COPY_INVERTED = 3,
+   COLOR_LOGICOP_AND_REVERSE = 4,
+   COLOR_LOGICOP_INVERT = 5,
+   COLOR_LOGICOP_XOR = 6,
+   COLOR_LOGICOP_NAND = 7,
+   COLOR_LOGICOP_AND = 8,
+   COLOR_LOGICOP_EQUIV = 9,
+   COLOR_LOGICOP_NOOP = 10,
+   COLOR_LOGICOP_OR_INVERTED = 11,
+   COLOR_LOGICOP_COPY = 12,
+   COLOR_LOGICOP_OR_REVERSE = 13,
+   COLOR_LOGICOP_OR = 14,
+   COLOR_LOGICOP_SET = 15
+};
 
 /**
  * Color buffer attribute group (GL_COLOR_BUFFER_BIT).
@@ -488,6 +525,7 @@ struct gl_colorbuffer_attrib
    GLboolean IndexLogicOpEnabled;	/**< Color index logic op enabled flag */
    GLboolean ColorLogicOpEnabled;	/**< RGBA logic op enabled flag */
    GLenum LogicOp;			/**< Logic operator */
+   enum gl_logicop_mode _LogicOp;
 
    /*@}*/