Committing patch #25675 "Make "Cast Buffer Shadows" option work in viewport and BGE" by me.

Description from the tracker:
"It's really handy to be able to prevent an object/material from casting a shadow. So, I made use of the Cast Buffer Shadows option in the material settings, and made it work in the viewport and the BGE."

source/blender/editors/space_view3d/drawobject.c

@@ -2843,8 +2843,20 @@ static int draw_mesh_object(Scene *scene, ARegion *ar, View3D *v3d, RegionView3D
 	Object *ob= base->object;
 	Object *obedit= scene->obedit;
 	Mesh *me= ob->data;
+	Material *ma=NULL;
 	EditMesh *em= me->edit_mesh;
-	int do_alpha_pass= 0, drawlinked= 0, retval= 0, glsl, check_alpha;
+	int do_alpha_pass= 0, drawlinked= 0, retval= 0, glsl, check_alpha, i;
+
+	/* If we are drawing shadows and any of the materials don't cast a shadow, then don't draw the object */
+	if (v3d->flag2 & V3D_RENDER_SHADOW)
+	{
+		for(i=0; i<ob->totcol; ++i)
+		{
+			ma = give_current_material(ob, i);
+			if (ma && !(ma->mode & MA_SHADBUF))
+				return 1;
+		}
+	}
 	
 	if(obedit && ob!=obedit && ob->data==obedit->data) {
 		if(ob_get_key(ob) || ob_get_key(obedit));

source/blender/editors/space_view3d/view3d_draw.c

@@ -2155,7 +2155,7 @@ static void gpu_update_lamps_shadows(Scene *scene, View3D *v3d)
 		v3d->drawtype = OB_SOLID;
 		v3d->lay &= GPU_lamp_shadow_layer(shadow->lamp);
 		v3d->flag2 &= ~V3D_SOLID_TEX;
-		v3d->flag2 |= V3D_RENDER_OVERRIDE;
+		v3d->flag2 |= V3D_RENDER_OVERRIDE | V3D_RENDER_SHADOW;
 		
 		GPU_lamp_shadow_buffer_bind(shadow->lamp, viewmat, &winsize, winmat);
 

source/blender/makesdna/DNA_view3d_types.h

@@ -247,6 +247,7 @@ typedef struct View3D {
 #define V3D_SOLID_TEX			8
 #define V3D_DISPGP				16
 #define V3D_LOCK_CAMERA			32
+#define V3D_RENDER_SHADOW		64 /* This is a runtime only flag that's used to tell draw_mesh_object() that we're doing a shadow pass instead of a regular draw */
 
 /* View3D->around */
 #define V3D_CENTER		 0

source/gameengine/Converter/BL_BlenderDataConversion.cpp

@@ -350,6 +350,8 @@ bool ConvertMaterial(
 
 		// use lighting?
 		material->ras_mode |= ( mat->mode & MA_SHLESS )?0:USE_LIGHT;
+		// cast shadows?
+		material->ras_mode |= ( mat->mode & MA_SHADBUF )?CAST_SHADOW:0;
 		MTex *mttmp = 0;
 		numchan = getNumTexChannels(mat);
 		int valid_index = 0;

source/gameengine/Ketsji/BL_Material.h

@@ -157,7 +157,8 @@ enum BL_ras_mode
 	ALPHA=8,
 	// TRIANGLE=16,
 	USE_LIGHT=32,
-	WIRE=64
+	WIRE=64,
+	CAST_SHADOW=128
 };
 
 // -------------------------------------

source/gameengine/Ketsji/KX_BlenderMaterial.cpp

@@ -85,6 +85,7 @@ void KX_BlenderMaterial::Initialize(
 	m_flag |= (mMaterial->IdMode>=ONETEX)? RAS_MULTITEX: 0;
 	m_flag |= ((mMaterial->ras_mode & USE_LIGHT)!=0)? RAS_MULTILIGHT: 0;
 	m_flag |= (mMaterial->glslmat)? RAS_BLENDERGLSL: 0;
+	m_flag |= ((mMaterial->ras_mode & CAST_SHADOW)!=0)? RAS_CASTSHADOW: 0;
 
 	// figure max
 	int enabled = mMaterial->num_enabled;

source/gameengine/Rasterizer/RAS_IPolygonMaterial.cpp

@@ -246,6 +246,11 @@ bool RAS_IPolyMaterial::UsesLighting(RAS_IRasterizer *rasty) const
 	return dolights;
 }
 
+bool RAS_IPolyMaterial::CastsShadows() const
+{
+	return (m_flag & RAS_CASTSHADOW) != 0;
+}
+
 bool RAS_IPolyMaterial::UsesObjectColor() const
 {
 	return !(m_flag & RAS_BLENDERGLSL);

source/gameengine/Rasterizer/RAS_IPolygonMaterial.h

@@ -62,7 +62,8 @@ enum MaterialProps
 	RAS_AUTOGEN		=128,
 	RAS_NORMAL		=256,
 	RAS_DEFMULTI	=512,
-	RAS_BLENDERGLSL =1024
+	RAS_BLENDERGLSL =1024,
+	RAS_CASTSHADOW	=2048
 };
 
 /**
@@ -169,6 +170,7 @@ public:
 	virtual void		GetMaterialRGBAColor(unsigned char *rgba) const;
 	virtual bool		UsesLighting(RAS_IRasterizer *rasty) const;
 	virtual bool		UsesObjectColor() const;
+	virtual bool		CastsShadows() const;
 
 	virtual void		Replace_IScene(SCA_IScene *val) {}; /* overridden by KX_BlenderMaterial */
 

source/gameengine/Rasterizer/RAS_MaterialBucket.cpp

@@ -586,6 +586,9 @@ bool RAS_MaterialBucket::ActivateMaterial(const MT_Transform& cameratrans, RAS_I
 	RAS_IRenderTools *rendertools)
 {
 	bool uselights;
+	
+	if(rasty->GetDrawingMode() == RAS_IRasterizer::KX_SHADOW && !m_material->CastsShadows())
+		return false;
 
 	if(!rasty->SetMaterial(*m_material))
 		return false;