On 01/17/2018 03:53 AM, Nicolai Hähnle wrote:
> On 12.01.2018 23:56, Ian Romanick wrote:
>> From: Ian Romanick <ian.d.roman...@intel.com>
>>
>> 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.
>>
>> Signed-off-by: Ian Romanick <ian.d.roman...@intel.com>
>> ---
>> src/mesa/main/blend.c | 22 ++++++++++++++++++++++
>> src/mesa/main/mtypes.h | 29 +++++++++++++++++++++++++++++
>> 2 files changed, 51 insertions(+)
>>
>> diff --git a/src/mesa/main/blend.c b/src/mesa/main/blend.c
>> index 01721ab..f47b102 100644
>> --- a/src/mesa/main/blend.c
>> +++ b/src/mesa/main/blend.c
>> @@ -849,6 +849,26 @@ _mesa_AlphaFunc( GLenum func, GLclampf ref )
>> }
>> }
>> +static const enum color_logic_ops 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
>> +};
>> +
>> +#define GLenum_to_color_logicop(x) color_logicop_mapping[x & 0x0f]
>> static ALWAYS_INLINE void
>> logic_op(struct gl_context *ctx, GLenum opcode, bool no_error)
>> @@ -884,6 +904,7 @@ 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 = GLenum_to_color_logicop(opcode);
>> if (ctx->Driver.LogicOpcode)
>> ctx->Driver.LogicOpcode(ctx, opcode);
>> @@ -1189,6 +1210,7 @@ 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 226eb94..2fbfd27 100644
>> --- a/src/mesa/main/mtypes.h
>> +++ b/src/mesa/main/mtypes.h
>> @@ -418,6 +418,34 @@ 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 simply a natural 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
Oh interesting.
> That OpenGL has them reversed is really quite odd. I'd love to hear the
> history behind it.
Big endian vs little endian perhaps?
> (I think it might be useful to add this information in the comment, but
> I'll leave that decision up to you.)
>
> Patches 1, 3, & the core + radeon parts of 4:
>
> Reviewed-by: Nicolai Hähnle <nicolai.haeh...@amd.com>
>
>
>> + */
>> +enum PACKED color_logic_ops {
>> + 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).
>> @@ -493,6 +521,7 @@ struct gl_colorbuffer_attrib
>> GLboolean IndexLogicOpEnabled; /**< Color index logic op
>> enabled flag */
>> GLboolean ColorLogicOpEnabled; /**< RGBA logic op enabled flag */
>> GLenum LogicOp; /**< Logic operator */
>> + enum color_logic_ops _LogicOp;
>> /*@}*/
>>
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