Lame to note 36-cocos2d-x-3.2 box2d physical engine Ray-cast use

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Previous review

This famous saying goes:Deep in the human soul, there are many sleeping forces; awakening these forces that people have never dreamed of, cleverly applied, will be able to completely change their lives.[Arison meilun]

In the previous articles, I learned how to portray the physical body we created in the box2d physical engine in a program. This allows us to see a very intuitive object for further learning and understanding.

 

Procedure

We still use the helloworld project.

1. First, the \ cocos2d-x-3.2 \ tests \ CPP-tests \ Classes \ box2dtestbed directory in 6 file GLES-Render.c, GLES-Render.h, raycast. h, test. CPP, test. h, testentries. copy CPP to the classes folder in our factory directory. Then add the six files to our own project.

2. Create a new class, box2d class. The layer class is used to host the physical world.

3. Add the following content to the header file helloworld. Scene. h:

# Include "GLES-Render.h"

# Include "test. H"

# Include "raycast. H"

# Include "box2d. H" contains the header file

 

3. Add the following code to the bool helloworld: Init () function.

Box2d * view = box2d: viewwithentryid ();

Addchild (view, 0, 2 );

View-> setscale (15 );

View-> setanchorpoint (vec2 (0, 0 ));

View-> setposition (vec2 (origin. x + visiblesize. width/2, origin. Y + visiblesize. Height/3 ));

4. Edit the header file test. h,

Find protected in the class definition: add

Friend class box2d;

 

5. Edit testentries. cpp.

Leave only the following information.

# Include <cstring>

Using namespace STD;

# Include "test. H"

# Include "raycast. H"

Testentryg_testentries [] =

{

{"Ray-cast", raycast: Create },

};

Int g_totalentries = sizeof (g_testentries)/sizeof (g_testentries [0]);

 

6. Edit the box2d. h file.

As follows:

# Pragma once

# Include "cocos2d. H"

# Include "GLES-Render.h"

# Include "test. H"

# Include "raycast. H"

Using_ns_cc;

Class test;

Class box2d:

Publiclayer

{

Public:

Staticbox2d * viewwithentryid ();

Bool box2d: initwithentryid ();

Box2d (void );

~ Box2d (void );

Raycast * raycast;

Test * m_test;

Settings settings;

Testentry * m_entry;

Glesdebugdraw * m_debugdraw; // create an example here

B2world * World;

Virtualvoid draw (Renderer * Renderer, const mat4 & transform, uint32_t flags) override;

Protected:

Customcommand _ customcmd;

Void box2d: ondraw (const mat4 & transform, uint32_tflags );

};

7. Edit the box2d. cpp File

As follows:

# Include "box2d. H"

 

Box2d: box2d (void)

{

}

Box2d ::~ Box2d (void)

{

}

Box2d * box2d: viewwithentryid ()

{

Box2d * pview = new box2d ();

Pview-> initwithentryid ();

Pview-> autorelease ();

 

Return pview;

}

Bool box2d: initwithentryid ()

{

M_entry = g_testentries;

M_test = m_entry-> createfcn ();

Returntrue;

}

 

Void box2d: Draw (Renderer * Renderer, const mat4 & transform, uint32_t flags)

{

Layer: Draw (Renderer, transform, flags );

_ Customcmd. INIT (_ globalzorder );

_ Customcmd. func = cc_callback_0 (box2d: ondraw, this, transform, flags );

Renderer-> addcommand (& _ customcmd );

 

}

Void box2d: ondraw (const mat4 & transform, uint32_t flags)

{

Director * Director = Director: getinstance ();

Ccassert (nullptr! = Director, "director is null when seting matrixstack ");

Director-> pushmatrix (matrix_stack_type: matrix_stack_modelview );

Director-> loadmatrix (matrix_stack_type: matrix_stack_modelview, transform );

GL: enablevertexattribs (cocos2d: Gl: vertex_attrib_flag_position );

M_test-> step (& settings );

M_test-> m_world-> drawdebugdata ();

Check_gl_error_debug ();

Director-> popmatrix (matrix_stack_type: matrix_stack_modelview );

}

Compile and run the program as follows:

We have successfully transplanted the raycast test case from the source code. Is it fun?

As for the principle knowledge, I will continue to learn it later.

 

Summary

Next, I will learn the architecture of box2dtextbed IN THE box2d physical engine, so that my friends can shuttle through the code.

Lame to note 36-cocos2d-x-3.2 box2d physical engine Ray-cast use