cogl-material: Don't map the shininess value to [0,1]

In OpenGL the 'shininess' lighting parameter is floating point value
limited to the range 0.0→128.0. This number is used to affect the size
of the specular highlight. Cogl materials used to only accept a number
between 0.0 and 1.0 which then gets multiplied by 128.0 before sending
to GL. I think the assumption was that this is just a weird GL quirk
so we don't expose it. However the value is used as an exponent to
raise the attenuation to a power so there is no conceptual limit to
the value.

This removes the mapping and changes some of the documentation.

http://bugzilla.clutter-project.org/show_bug.cgi?id=2222

diff --git a/clutter/cogl/cogl/cogl-material-opengl.c b/clutter/cogl/cogl/cogl-material-opengl.c
index d00d17e..d1e52f2 100644 (file)
--- a/clutter/cogl/cogl/cogl-material-opengl.c
+++ b/clutter/cogl/cogl/cogl-material-opengl.c
@@ -507,14 +507,12 @@ _cogl_material_flush_color_blend_alpha_depth_state (
       CoglMaterialLightingState *lighting_state =
         &authority->big_state->lighting_state;
 
-      /* FIXME - we only need to set these if lighting is enabled... */
-      GLfloat shininess = lighting_state->shininess * 128.0f;
-
       GE (glMaterialfv (GL_FRONT_AND_BACK, GL_AMBIENT, lighting_state->ambient));
       GE (glMaterialfv (GL_FRONT_AND_BACK, GL_DIFFUSE, lighting_state->diffuse));
       GE (glMaterialfv (GL_FRONT_AND_BACK, GL_SPECULAR, lighting_state->specular));
       GE (glMaterialfv (GL_FRONT_AND_BACK, GL_EMISSION, lighting_state->emission));
-      GE (glMaterialfv (GL_FRONT_AND_BACK, GL_SHININESS, &shininess));
+      GE (glMaterialfv (GL_FRONT_AND_BACK, GL_SHININESS,
+                        &lighting_state->shininess));
     }
 
   if (materials_difference & COGL_MATERIAL_STATE_BLEND)

diff --git a/clutter/cogl/cogl/cogl-material.c b/clutter/cogl/cogl/cogl-material.c
index 9818372..c589625 100644 (file)
--- a/clutter/cogl/cogl/cogl-material.c
+++ b/clutter/cogl/cogl/cogl-material.c
@@ -239,6 +239,8 @@ _cogl_material_init_default_material (void)
   lighting_state->emission[2] = 0;
   lighting_state->emission[3] = 1.0;
 
+  lighting_state->shininess = 0.0f;
+
   /* Use the same defaults as the GL spec... */
   alpha_state->alpha_func = COGL_MATERIAL_ALPHA_FUNC_ALWAYS;
   alpha_state->alpha_func_reference = 0.0;
@@ -3620,7 +3622,7 @@ cogl_material_set_shininess (CoglMaterial *material,
 
   g_return_if_fail (cogl_is_material (material));
 
-  if (shininess < 0.0 || shininess > 1.0)
+  if (shininess < 0.0)
     {
       g_warning ("Out of range shininess %f supplied for material\n",
                  shininess);

diff --git a/clutter/cogl/cogl/cogl-material.h b/clutter/cogl/cogl/cogl-material.h
index b72ca32..989c8ce 100644 (file)
--- a/clutter/cogl/cogl/cogl-material.h
+++ b/clutter/cogl/cogl/cogl-material.h
@@ -387,11 +387,12 @@ cogl_material_get_specular (CoglMaterial *material,
 /**
  * cogl_material_set_shininess:
  * @material: A #CoglMaterial object
- * @shininess: The desired shininess; range: [0.0, 1.0]
+ * @shininess: The desired shininess; must be >= 0.0
  *
- * Sets the materials shininess, in the standard OpenGL lighting model,
- * which determines how specular highlights are calculated. A higher
- * @shininess will produce smaller brigher highlights.
+ * Sets the shininess of the material, in the standard OpenGL lighting
+ * model, which determines the size of the specular highlights. A
+ * higher @shininess will produce smaller highlights which makes the
+ * object appear more shiny.
  *
  * The default value is 0.0
  *