--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/trunk/chipmunkd/constraints/cpConstraint.d	Thu Dec 02 02:11:26 2010 +0100
@@ -0,0 +1,146 @@
+
+// written in the D programming language
+
+module chipmunkd.constraints.cpConstraint;
+
+import chipmunkd.chipmunk;
+import chipmunkd.chipmunk_types_h;
+import chipmunkd.cpVect,chipmunkd.cpVect_h;
+import chipmunkd.cpBody;
+
+alias void function(cpConstraint *constraint, cpFloat dt, cpFloat dt_inv) cpConstraintPreStepFunction;
+alias void function(cpConstraint *constraint) cpConstraintApplyImpulseFunction;
+alias cpFloat function(cpConstraint *constraint) cpConstraintGetImpulseFunction;
+
+struct cpConstraintClass {
+	cpConstraintPreStepFunction preStep;
+	cpConstraintApplyImpulseFunction applyImpulse;
+	cpConstraintGetImpulseFunction getImpulse;
+}
+
+
+
+struct cpConstraint {
+	cpConstraintClass *klass;
+	
+	cpBody *a;
+	cpBody *b;
+	cpFloat maxForce;
+	cpFloat biasCoef;
+	cpFloat maxBias;
+	
+	cpDataPointer data;
+}
+
+//#ifdef CP_USE_DEPRECATED_API_4
+//typedef cpConstraint cpJoint;
+//#endif
+
+//void cpConstraintDestroy(cpConstraint *constraint);
+//void cpConstraintFree(cpConstraint *constraint);
+
+static void
+cpConstraintActivateBodies(cpConstraint *constraint)
+{
+	cpBody *a = constraint.a; if(a) cpBodyActivate(a);
+	cpBody *b = constraint.b; if(b) cpBodyActivate(b);
+}
+
+static cpFloat
+cpConstraintGetImpulse(cpConstraint *constraint)
+{
+	return constraint.klass.getImpulse(constraint);
+}
+
+template cpConstraintCheckCast(string constraint, string _struct)
+{
+	enum cpConstraintCheckCast = 
+		"assert("~constraint~".klass == "~_struct~"GetClass(), \"Constraint is not a "~_struct~"\");";
+}
+
+//#define cpConstraintCheckCast(constraint, struct) \
+//	cpAssert(constraint->klass == struct##GetClass(), "Constraint is not a "#struct);
+
+template CP_DefineConstraintGetter(string _struct,string type,string member,string name)
+{
+	enum CP_DefineConstraintGetter = 
+		"static "~type~" "~_struct~"Get"~name~"(cpConstraint *constraint){"~
+		cpConstraintCheckCast!("constraint",_struct)~
+		"cpConstraintActivateBodies(constraint);"~
+		"return (cast("~_struct~"*)constraint)."~member~";"~
+		"}";
+}
+
+//#define CP_DefineConstraintGetter(struct, type, member, name) \
+//static inline type \
+//struct##Get##name(const cpConstraint *constraint){ \
+//	cpConstraintCheckCast(constraint, struct); \
+//	return ((struct *)constraint)->member; \
+//} \
+
+template CP_DefineConstraintSetter(string _struct,string type,string member,string name)
+{
+	enum CP_DefineConstraintSetter = 
+		"static void "~_struct~"Set"~name~"(cpConstraint *constraint,"~type~" value){"~
+		cpConstraintCheckCast!("constraint",_struct)~
+		"cpConstraintActivateBodies(constraint);"~
+		"(cast("~_struct~"*)constraint)."~member~" = value;"~
+		"}";
+}
+
+//#define CP_DefineConstraintSetter(struct, type, member, name) \
+//static inline void \
+//struct##Set##name(cpConstraint *constraint, type value){ \
+//	cpConstraintCheckCast(constraint, struct); \
+//	cpConstraintActivateBodies(constraint); \
+//	((struct *)constraint)->member = value; \
+//} \
+
+template CP_DefineConstraintProperty(string _struct,string type,string member,string name)
+{
+	enum CP_DefineConstraintProperty = 
+		CP_DefineConstraintGetter!(_struct,type,member,name)~CP_DefineConstraintSetter!(_struct,type,member,name);
+		
+}
+
+//#define CP_DefineConstraintProperty(struct, type, member, name) \
+//CP_DefineConstraintGetter(struct, type, member, name) \
+//CP_DefineConstraintSetter(struct, type, member, name)
+//TODO:
+//// Built in Joint types
+public import chipmunkd.constraints.cpPinJoint;
+//#include "cpSlideJoint.h"
+public import chipmunkd.constraints.cpPivotJoint;
+//#include "cpGrooveJoint.h"
+public import chipmunkd.constraints.cpDampedSpring;
+//#include "cpDampedRotarySpring.h"
+//#include "cpRotaryLimitJoint.h"
+//#include "cpRatchetJoint.h"
+//#include "cpGearJoint.h"
+//#include "cpSimpleMotor.h"
+
+
+cpFloat cp_constraint_bias_coef = 0.1f;
+
+void cpConstraintDestroy(cpConstraint *constraint){}
+
+void
+cpConstraintFree(cpConstraint *constraint)
+{
+	if(constraint){
+		cpConstraintDestroy(constraint);
+		cpfree(constraint);
+	}
+}
+
+void
+cpConstraintInit(cpConstraint *constraint, /+const+/ cpConstraintClass *klass, cpBody *a, cpBody *b)
+{
+	constraint.klass = klass;
+	constraint.a = a;
+	constraint.b = b;
+	
+	constraint.maxForce = cast(cpFloat)INFINITY;
+	constraint.biasCoef = cp_constraint_bias_coef;
+	constraint.maxBias = cast(cpFloat)INFINITY;
+}