[Mesa-dev] [PATCH 3/5] Add NV_fog_distance to the fixed-function vertex program generator

[Brian Paul]

On 09/19/2011 03:48 AM, Nicholas Miell wrote:
> This is all that is needed to implement NV_fog_distance on programmable
> hardware.
> ---
>   src/mesa/main/ffvertex_prog.c |   40 ++++++++++++++++++++++++++++++++++++----
>   1 files changed, 36 insertions(+), 4 deletions(-)
>
> diff --git a/src/mesa/main/ffvertex_prog.c b/src/mesa/main/ffvertex_prog.c
> index 2d2485c..fc7b01a 100644
> --- a/src/mesa/main/ffvertex_prog.c
> +++ b/src/mesa/main/ffvertex_prog.c
> @@ -61,6 +61,7 @@ struct state_key {
>      unsigned rescale_normals:1;
>
>      unsigned fog_source_is_depth:1;
> +   unsigned fog_distance_mode:2;
>      unsigned separate_specular:1;
>      unsigned point_attenuated:1;
>      unsigned point_array:1;
> @@ -108,7 +109,19 @@ static GLuint translate_texgen( GLboolean enabled, GLenum mode )
>      }
>   }
>
> +#define FDM_EYE_RADIAL    0
> +#define FDM_EYE_PLANE     1
> +#define FDM_EYE_PLANE_ABS 2
>
> +static GLuint translate_fog_distance_mode( GLenum mode )
> +{
> +   switch (mode) {
> +   case GL_EYE_RADIAL_NV: return FDM_EYE_RADIAL;
> +   case GL_EYE_PLANE: return FDM_EYE_PLANE;
> +   default: /* shouldn't happen; fall through to a sensible default */
> +   case GL_EYE_PLANE_ABSOLUTE_NV: return FDM_EYE_PLANE_ABS;
> +   }
> +}

Please reformat this code to put the case and return statements on 
separate lines.  Looks good otherwise.

-Brian

>   static GLboolean check_active_shininess( struct gl_context *ctx,
>                                            const struct state_key *key,
> @@ -205,8 +218,10 @@ static void make_state_key( struct gl_context *ctx, struct state_key *key )
>      if (ctx->Transform.RescaleNormals)
>         key->rescale_normals = 1;
>
> -   if (ctx->Fog.FogCoordinateSource == GL_FRAGMENT_DEPTH_EXT)
> +   if (ctx->Fog.FogCoordinateSource == GL_FRAGMENT_DEPTH_EXT) {
>         key->fog_source_is_depth = 1;
> +      key->fog_distance_mode = translate_fog_distance_mode(ctx->Fog.FogDistanceMode);
> +   }
>
>      if (ctx->Point._Attenuated)
>         key->point_attenuated = 1;
> @@ -1308,14 +1323,31 @@ static void build_fog( struct tnl_program *p )
>      struct ureg input;
>
>      if (p->state->fog_source_is_depth) {
> -      input = get_eye_position_z(p);
> +
> +      switch (p->state->fog_distance_mode) {
> +      case FDM_EYE_RADIAL: /* Z = sqrt(Xe*Xe + Ye*Ye + Ze*Ze) */
> +	input = get_eye_position(p);
> +	emit_op2(p, OPCODE_DP3, fog, WRITEMASK_X, input, input);
> +	emit_op1(p, OPCODE_RSQ, fog, WRITEMASK_X, fog);
> +	emit_op1(p, OPCODE_RCP, fog, WRITEMASK_X, fog);
> +	break;
> +      case FDM_EYE_PLANE: /* Z = Ze */
> +	input = get_eye_position_z(p);
> +	emit_op1(p, OPCODE_MOV, fog, WRITEMASK_X, input);
> +	break;
> +      case FDM_EYE_PLANE_ABS: /* Z = abs(Ze) */
> +	input = get_eye_position_z(p);
> +	emit_op1(p, OPCODE_ABS, fog, WRITEMASK_X, input);
> +	break;
> +      default: assert(0); break; /* can't happen */
> +      }
> +
>      }
>      else {
>         input = swizzle1(register_input(p, VERT_ATTRIB_FOG), X);
> +      emit_op1(p, OPCODE_ABS, fog, WRITEMASK_X, input);
>      }
>
> -   /* result.fog = {abs(f),0,0,1}; */
> -   emit_op1(p, OPCODE_ABS, fog, WRITEMASK_X, input);
>      emit_op1(p, OPCODE_MOV, fog, WRITEMASK_YZW, get_identity_param(p));
>   }
>