[Mesa-dev] [PATCH] mesa: bump MAX_VARYING to 32

[Brian Paul]

On 10/26/2012 11:32 AM, Kenneth Graunke wrote:
> On 10/26/2012 09:58 AM, Marek Olšák wrote:
>> We're starting to get apps utilizing more than 16 varyings and
>> most current hardware supports 32 anyway.
>>
>> Tested with r600g.
>> swrast, softpipe and llvmpipe still advertise 16 varyings.
>>
>> This fixes a WebGL crash after launching this demo:
>> https://developer.mozilla.org/en-US/demos/detail/falling-cubes
>>
>> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54402
>>
>> NOTE: This is a candidate for the stable branches.
>> ---
>> src/gallium/auxiliary/tgsi/tgsi_ureg.c | 2 +-
>> src/gallium/include/pipe/p_state.h | 4 ++--
>> src/mesa/main/config.h | 2 +-
>> src/mesa/main/context.c | 2 +-
>> src/mesa/program/prog_print.c | 36 ++++++++++++++++++++++++++++++--
>> 5 files changed, 39 insertions(+), 7 deletions(-)
>>
>> diff --git a/src/gallium/auxiliary/tgsi/tgsi_ureg.c
>> b/src/gallium/auxiliary/tgsi/tgsi_ureg.c
>> index 3fe78e0..3c2a923 100644
>> --- a/src/gallium/auxiliary/tgsi/tgsi_ureg.c
>> +++ b/src/gallium/auxiliary/tgsi/tgsi_ureg.c
>> @@ -73,7 +73,7 @@ struct ureg_tokens {
>>
>> #define UREG_MAX_INPUT PIPE_MAX_ATTRIBS
>> #define UREG_MAX_SYSTEM_VALUE PIPE_MAX_ATTRIBS
>> -#define UREG_MAX_OUTPUT PIPE_MAX_ATTRIBS
>> +#define UREG_MAX_OUTPUT PIPE_MAX_SHADER_OUTPUTS
>> #define UREG_MAX_CONSTANT_RANGE 32
>> #define UREG_MAX_IMMEDIATE 256
>> #define UREG_MAX_ADDR 2
>> diff --git a/src/gallium/include/pipe/p_state.h
>> b/src/gallium/include/pipe/p_state.h
>> index 6d0db0f..f84bfd7 100644
>> --- a/src/gallium/include/pipe/p_state.h
>> +++ b/src/gallium/include/pipe/p_state.h
>> @@ -59,7 +59,7 @@ extern "C" {
>> #define PIPE_MAX_CONSTANT_BUFFERS 32
>> #define PIPE_MAX_SAMPLERS 16
>> #define PIPE_MAX_SHADER_INPUTS 32
>> -#define PIPE_MAX_SHADER_OUTPUTS 32
>> +#define PIPE_MAX_SHADER_OUTPUTS 48 /* 32 GENERICs + POS, PSIZE,
>> FOG, etc. */
>> #define PIPE_MAX_SHADER_SAMPLER_VIEWS 32
>> #define PIPE_MAX_SHADER_RESOURCES 32
>> #define PIPE_MAX_TEXTURE_LEVELS 16
>> @@ -145,7 +145,7 @@ struct pipe_rasterizer_state
>> unsigned line_stipple_factor:8; /**< [1..256] actually */
>> unsigned line_stipple_pattern:16;
>>
>> - unsigned sprite_coord_enable:PIPE_MAX_SHADER_OUTPUTS;
>> + unsigned sprite_coord_enable; /* bitfield referring to 32 GENERIC
>> inputs */
>>
>> float line_width;
>> float point_size; /**< used when no per-vertex size */
>> diff --git a/src/mesa/main/config.h b/src/mesa/main/config.h
>> index 1b72b54..99910d7 100644
>> --- a/src/mesa/main/config.h
>> +++ b/src/mesa/main/config.h
>> @@ -187,7 +187,7 @@
>> #define MAX_PROGRAM_CALL_DEPTH 8
>> #define MAX_PROGRAM_TEMPS 256
>> #define MAX_PROGRAM_ADDRESS_REGS 2
>> -#define MAX_VARYING 16 /**< number of float[4] vectors */
>> +#define MAX_VARYING 32 /**< number of float[4] vectors */
>> #define MAX_SAMPLERS MAX_TEXTURE_IMAGE_UNITS
>> #define MAX_PROGRAM_INPUTS 32
>> #define MAX_PROGRAM_OUTPUTS 64
>> diff --git a/src/mesa/main/context.c b/src/mesa/main/context.c
>> index b00c642..a510738 100644
>> --- a/src/mesa/main/context.c
>> +++ b/src/mesa/main/context.c
>> @@ -614,7 +614,7 @@ _mesa_init_constants(struct gl_context *ctx)
>>
>> ctx->Const.MaxVertexTextureImageUnits = MAX_VERTEX_TEXTURE_IMAGE_UNITS;
>> ctx->Const.MaxCombinedTextureImageUnits =
>> MAX_COMBINED_TEXTURE_IMAGE_UNITS;
>> - ctx->Const.MaxVarying = MAX_VARYING;
>> + ctx->Const.MaxVarying = 16; /* old limit not to break tnl and
>> swrast */
>> ctx->Const.MaxGeometryTextureImageUnits =
>> MAX_GEOMETRY_TEXTURE_IMAGE_UNITS;
>> ctx->Const.MaxVertexVaryingComponents = MAX_VERTEX_VARYING_COMPONENTS;
>> ctx->Const.MaxGeometryVaryingComponents =
>> MAX_GEOMETRY_VARYING_COMPONENTS;
>
> I think there are some crazy restrictions on using more than 16 on our
> hardware...you can apply certain transformations to either the first
> 16, or the second 16.
>
> But it looks like this hunk should cause i965 to continue advertizing
> 16, so I think this should be fine.
>
> Acked-by: Kenneth Graunke <kenneth at whitecape.org>

The i965 driver should probably explicitly set ctx->Const.MaxVarying 
like the i915 driver does:

$ grep Const.MaxVarying src/mesa/drivers/dri/i*/*c
src/mesa/drivers/dri/i915/i915_context.c:   ctx->Const.MaxVarying = 
I915_TEX_UNITS;

-Brian