add alpha blendering option (disabled by default) using w component of color

add low-level support function demo (test)

Demos3/bullet2/CollisionDetection/SupportFuncDemo.h

@@ -0,0 +1,112 @@
+#ifndef SUPPORT_FUNC_DEMO_H
+#define SUPPORT_FUNC_DEMO_H
+
+#include "Bullet3AppSupport/BulletDemoInterface.h"
+#include "OpenGLWindow/CommonGraphicsApp.h"
+#include "BulletCollision/CollisionShapes/btSphereShape.h"
+
+class MySupportFuncDemo : public BulletDemoInterface
+{
+    CommonGraphicsApp* m_app;
+    btSphereShape* m_sphere;
+    float m_x;
+    float m_y;
+    
+    
+public:
+    
+    MySupportFuncDemo(CommonGraphicsApp* app)
+    :m_app(app),
+    m_x(0),
+    m_y(0)
+    {
+        m_sphere = new btSphereShape(1);
+        {
+            int boxId = m_app->registerCubeShape(10,0.1,10);
+            btVector3 pos(0,-2,0);
+            btQuaternion orn(0,0,0,1);
+            btVector4 color(0.3,0.3,0.3,1);
+            
+            btVector3 scaling(1,1,1);
+            m_app->m_renderer->registerGraphicsInstance(boxId,pos,orn,color,scaling);
+        }
+        
+        {
+            int sphereId = m_app->registerGraphicsSphereShape(1,false,0,0);
+            btVector3 pos(0,0,0);
+            btQuaternion orn(0,0,0,1);
+            btVector4 color(0,1,0,0.6);
+            
+            btVector3 scaling(1,1,1);
+            m_app->m_renderer->registerGraphicsInstance(sphereId,pos,orn,color,scaling);
+        }
+        m_app->m_renderer->writeTransforms();
+        m_app->m_renderer->enableBlend(true);
+    }
+    virtual ~MySupportFuncDemo()
+    {
+        m_app->m_renderer->enableBlend(false);
+        delete m_sphere;
+    }
+    static BulletDemoInterface*    CreateFunc(CommonGraphicsApp* app)
+    {
+        return new MySupportFuncDemo(app);
+    }
+    
+    virtual void    initPhysics()
+    {
+    }
+    virtual void    exitPhysics()
+    {
+        
+    }
+    virtual void	stepSimulation(float deltaTime)
+    {
+        m_x+=0.01f;
+        m_y+=0.02f;
+
+    }
+    virtual void	renderScene()
+    {
+        m_app->m_renderer->renderScene();
+        
+    }
+    virtual void	physicsDebugDraw()
+    {
+        int width=3;
+        btVector3 from(0,0,0);
+        btVector3 to(10.*btSin(m_x),10.*btCos(m_x),10.*btSin(m_y));
+       
+        
+        {
+            btVector3 color(1,0,0);
+            m_app->m_renderer->drawLine(from,to,color,width);
+        }
+        btVector3 dir(to-from);
+        btVector3 sup = m_sphere->btConvexInternalShape::localGetSupportingVertex(dir);
+        btVector3 orth0,orth1;
+        btPlaneSpace1(dir,orth0,orth1);
+        btVector3 color(0,0,1);
+        orth0.normalize();
+        orth1.normalize();
+        
+        m_app->m_renderer->drawLine(sup,sup+orth0*0.4,color,3);
+        m_app->m_renderer->drawLine(sup,sup+orth1*0.4,color,3);
+        
+    }
+    virtual bool	mouseMoveCallback(float x,float y)
+    {
+        
+    }
+    virtual bool	mouseButtonCallback(int button, int state, float x, float y)
+    {
+        
+    }
+    virtual bool	keyboardCallback(int key, int state)
+    {
+        
+    }
+    
+};
+#endif //SUPPORT_FUNC_DEMO
+