[Bf-committers] [Bf-blender-cvs] SVN commit: /data/svn/bf-blender [57702] trunk/blender/source/blender/gpu: Fix GLSL not showing shading properly on the backside of faces.

[Daniel Stokes]

The BGE tracker has a bug report referencing this commit. It appears to
cause problems if users set custom normals:
[#36255] Inverted custom vertex
normal's<https://projects.blender.org/tracker/index.php?func=detail&aid=36255&group_id=9&atid=306>

I am not sure if there is a way we can detect if the user is already
controlling normals and not bother flipping them, or possibly adding a UI
option to toggle this flipping.

Regards,
Daniel Stokes


On Mon, Jun 24, 2013 at 6:46 AM, Brecht Van Lommel <
brechtvanlommel at pandora.be> wrote:

> Revision: 57702
>
> http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=57702
> Author:   blendix
> Date:     2013-06-24 13:46:34 +0000 (Mon, 24 Jun 2013)
> Log Message:
> -----------
> Fix GLSL not showing shading properly on the backside of faces. Now it
> flips
> the normal towards the viewer, seems to give consistent results with
> blender
> internal, cycles, normal maps, etc.
>
> Started from patch #32761 by Vitor Balbio, but changed it to do normal
> flipping
> earlier so it solves all cases.
>
> Modified Paths:
> --------------
>     trunk/blender/source/blender/gpu/intern/gpu_codegen.c
>     trunk/blender/source/blender/gpu/shaders/gpu_shader_material.glsl
>
> Modified: trunk/blender/source/blender/gpu/intern/gpu_codegen.c
> ===================================================================
> --- trunk/blender/source/blender/gpu/intern/gpu_codegen.c       2013-06-24
> 13:45:35 UTC (rev 57701)
> +++ trunk/blender/source/blender/gpu/intern/gpu_codegen.c       2013-06-24
> 13:46:34 UTC (rev 57702)
> @@ -461,7 +461,7 @@
>         BLI_ghash_free(definehash, NULL, NULL);
>  }
>
> -static void codegen_print_uniforms_functions(DynStr *ds, ListBase *nodes)
> +static int codegen_print_uniforms_functions(DynStr *ds, ListBase *nodes)
>  {
>         GPUNode *node;
>         GPUInput *input;
> @@ -516,6 +516,8 @@
>         }
>
>         BLI_dynstr_append(ds, "\n");
> +
> +       return builtins;
>  }
>
>  static void codegen_declare_tmps(DynStr *ds, ListBase *nodes)
> @@ -564,8 +566,12 @@
>                                 codegen_convert_datatype(ds,
> input->link->output->type, input->type,
>                                         "tmp", input->link->output->id);
>                         }
> -                       else if (input->source == GPU_SOURCE_BUILTIN)
> -                               BLI_dynstr_appendf(ds, "%s",
> GPU_builtin_name(input->builtin));
> +                       else if (input->source == GPU_SOURCE_BUILTIN) {
> +                               if(input->builtin == GPU_VIEW_NORMAL)
> +                                       BLI_dynstr_append(ds,
> "facingnormal");
> +                               else
> +                                       BLI_dynstr_append(ds,
> GPU_builtin_name(input->builtin));
> +                       }
>                         else if (input->source == GPU_SOURCE_VEC_UNIFORM) {
>                                 if (input->dynamicvec)
>                                         BLI_dynstr_appendf(ds, "unf%d",
> input->id);
> @@ -596,11 +602,12 @@
>  {
>         DynStr *ds = BLI_dynstr_new();
>         char *code;
> +       int builtins;
>
>         /*BLI_dynstr_append(ds, FUNCTION_PROTOTYPES);*/
>
>         codegen_set_unique_ids(nodes);
> -       codegen_print_uniforms_functions(ds, nodes);
> +       builtins = codegen_print_uniforms_functions(ds, nodes);
>
>         //if (G.debug & G_DEBUG)
>         //      BLI_dynstr_appendf(ds, "/* %s */\n", name);
> @@ -608,6 +615,10 @@
>         BLI_dynstr_append(ds, "void main(void)\n");
>         BLI_dynstr_append(ds, "{\n");
>
> +       if(builtins & GPU_VIEW_NORMAL)
> +               BLI_dynstr_append(ds, "\tvec3 facingnormal =
> (gl_FrontFacing)? varnormal: -varnormal;\n");
> +
> +
>         codegen_declare_tmps(ds, nodes);
>         codegen_call_functions(ds, nodes, output);
>
>
> Modified: trunk/blender/source/blender/gpu/shaders/gpu_shader_material.glsl
> ===================================================================
> --- trunk/blender/source/blender/gpu/shaders/gpu_shader_material.glsl
> 2013-06-24 13:45:35 UTC (rev 57701)
> +++ trunk/blender/source/blender/gpu/shaders/gpu_shader_material.glsl
> 2013-06-24 13:46:34 UTC (rev 57702)
> @@ -147,7 +147,7 @@
>         normal = -normalize(nor);       /* blender render normal is
> negated */
>         vcol_attribute(attvcol, vcol);
>         vcol_alpha = attvcol.a;
> -       frontback = 1.0;
> +       frontback = (gl_FrontFacing)? 1.0: 0.0;
>  }
>
>  void mapping(vec3 vec, mat4 mat, vec3 minvec, vec3 maxvec, float domin,
> float domax, out vec3 outvec)
> @@ -2116,7 +2116,7 @@
>  void node_fresnel(float ior, vec3 N, vec3 I, out float result)
>  {
>         float eta = max(ior, 0.00001);
> -       result = fresnel_dielectric(I, N, eta); //backfacing() ? 1.0/eta:
> eta);
> +       result = fresnel_dielectric(I, N, (gl_FrontFacing)? eta: 1.0/eta);
>  }
>
>  /* geometry */
> @@ -2139,7 +2139,7 @@
>         true_normal = N;
>         incoming = I;
>         parametric = vec3(0.0);
> -       backfacing = 0.0;
> +       backfacing = (gl_FrontFacing)? 0.0: 1.0;
>  }
>
>  void node_tex_coord(vec3 I, vec3 N, mat4 viewinvmat, mat4 obinvmat,
>
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