OpenGL ES color for Android Development

I. Basic Knowledge:

1. Smooth coloring ):

Combine different colors of multiple vertices to create a beautiful color mix.

2. Monotonic coloring:

Apply a fixed color to the image.

3. Triangle-defined color array (smooth coloring ):

[Java]

Int one = 0x10000;

// Vertex color value of the triangle (r, g, B,)

Private IntBuffer colorBuffer = IntBuffer. wrap (new int [] {

One, 0, 0, one,

0, one, 0, one,

0, 0, one, one,

});

Int one = 0x10000;

// Vertex color value of the triangle (r, g, B,)

Private IntBuffer colorBuffer = IntBuffer. wrap (new int [] {

One, 0, 0, one,

0, one, 0, one,

0, 0, one, one,

});

[Java]

// Enable the color rendering function.

Gl. glableclientstate (GL10.GL _ COLOR_ARRAY );

// Set the triangle vertex color

Gl. glColorPointer (4, GL10.GL _ FIXED, 0, colorBuffer );

// Disable the color rendering function.

Gl. glDisableClientState (GL10.GL _ COLOR_ARRAY );

// Enable the color rendering function.

Gl. glableclientstate (GL10.GL _ COLOR_ARRAY );

// Set the triangle vertex color

Gl. glColorPointer (4, GL10.GL _ FIXED, 0, colorBuffer );

// Disable the color rendering function.

Gl. glDisableClientState (GL10.GL _ COLOR_ARRAY );

4. color array defined by the square (monotonous coloring ):

[Java]

/* Render the square */

// Set the current color to blue

Gl. glColor4f (1.0f, 0.5f, 1.0f, 1.0f );

/* Render the square */

// Set the current color to blue

Gl. glColor4f (1.0f, 0.5f, 1.0f, 1.0f );

Ii. code editing:

[Activity01.java]

[Java]

Package com. yarin. android. Examples_12_02;

Import android. app. Activity;

Import android. opengl. GLSurfaceView;

Import android. opengl. GLSurfaceView. Renderer;

Import android. OS. Bundle;

Public class Activity01 extends Activity

{

Renderer render = new GLRender ();

/** Called when the activity is first created .*/

@ Override

Public void onCreate (Bundle savedInstanceState)

{

Super. onCreate (savedInstanceState );

GLSurfaceView glView = new GLSurfaceView (this );

GlView. setRenderer (render );

SetContentView (glView );

}

}

Package com. yarin. android. Examples_12_02;

Import android. app. Activity;

Import android. opengl. GLSurfaceView;

Import android. opengl. GLSurfaceView. Renderer;

Import android. OS. Bundle;

Public class Activity01 extends Activity

{

Renderer render = new GLRender ();

/** Called when the activity is first created .*/

@ Override

Public void onCreate (Bundle savedInstanceState)

{

Super. onCreate (savedInstanceState );

GLSurfaceView glView = new GLSurfaceView (this );

GlView. setRenderer (render );

SetContentView (glView );

}

}

[GLRender. java]

[Java]

Package com. yarin. android. Examples_12_02;

Import java. nio. IntBuffer;

Import javax. microedition. khronos. egl. EGLConfig;

Import javax. microedition. khronos. opengles. GL10;

Import android. opengl. GLSurfaceView. Renderer;

Public class GLRender implements Renderer

{

Int one = 0x10000;

// Three triangle vertices

Private IntBuffer triggerBuffer = IntBuffer. wrap (new int [] {

0, one, 0, // top Vertex

-One,-one, 0, // sit down

One,-one, 0,}); // bottom right

// Four vertices of a square

Private IntBuffer quaterBuffer = IntBuffer. wrap (new int [] {

One, one, 0,

-One, one, 0,

One,-one, 0,

-One,-one, 0 });

// Vertex color value of the triangle (r, g, B,)

Private IntBuffer colorBuffer = IntBuffer. wrap (new int [] {

One, 0, 0, one,

0, one, 0, one,

0, 0, one, one,

});

@ Override

Public void onDrawFrame (GL10 gl)

{

// Clear screen and deep Cache

Gl. glClear (GL10.GL _ COLOR_BUFFER_BIT | GL10.GL _ DEPTH_BUFFER_BIT );

// Reset the current model observation matrix

Gl. glLoadIdentity ();

// Move 1.5 units left and 6.0 to the screen

Gl. glTranslatef (-1.5f, 0.0f,-6.0f );

// Set a fixed-point Array

Gl. glableclientstate (GL10.GL _ VERTEX_ARRAY );

// Set the color array -- enable the color rendering function.

Gl. glableclientstate (GL10.GL _ COLOR_ARRAY );

// Set the triangle vertex color

Gl. glColorPointer (4, GL10.GL _ FIXED, 0, colorBuffer );

// Set triangle vertices

Gl. glVertexPointer (3, GL10.GL _ FIXED, 0, triggerBuffer );

// Draw a triangle

Gl. glDrawArrays (GL10.GL _ TRIANGLES, 0, 3 );

// Disable color array -- disable color rendering.

Gl. glDisableClientState (GL10.GL _ COLOR_ARRAY );

/* Render the square */

// Set the current color to blue

Gl. glColor4f (1.0f, 0.5f, 1.0f, 1.0f );

// Reset the current model observation matrix

Gl. glLoadIdentity ();

// Move 1.5 units left and 6.0 to the screen

Gl. glTranslatef (1.5f, 0.0f,-6.0f );

// Set and draw a square

Gl. glVertexPointer (3, GL10.GL _ FIXED, 0, quaterBuffer );

Gl. glDrawArrays (GL10.GL _ TRIANGLE_STRIP, 0, 4 );

// Cancel the vertex Array

Gl. glDisableClientState (GL10.GL _ VERTEX_ARRAY );

}

@ Override

Public void onSurfaceChanged (GL10 gl, int width, int height)

{

// TODO Auto-generated method stub

Float ratio = (float) width/height;

// Set the size of the OpenGL scenario

Gl. glViewport (0, 0, width, height );

// Sets the projection matrix.

Gl. glMatrixMode (GL10.GL _ PROJECTION );

// Reset the Projection Matrix

Gl. glLoadIdentity ();

// Set the preview size

Gl. glFrustumf (-ratio, ratio,-1, 1, 1, 10 );

// Select the model observation matrix

Gl. glMatrixMode (GL10.GL _ MODELVIEW );

// Reset the model observation matrix

Gl. glLoadIdentity ();

}

@ Override

Public void onSurfaceCreated (GL10 gl, EGLConfig config)

{

// Enable shadow Smoothing

Gl. glShadeModel (GL10.GL _ SMOOTH );

// Black background

Gl. glClearColor (0, 0, 0, 0 );

// Set the deep Cache

Gl. glClearDepthf (1.0f );

// Enable deep Test

Gl. glable (GL10.GL _ DEPTH_TEST );

// Type of the deep Test

Gl. glDepthFunc (GL10.GL _ LEQUAL );

// Notify the system to correct the Perspective

Gl. glHint (GL10.GL _ PERSPECTIVE_CORRECTION_HINT, GL10.GL _ FASTEST );

}

}

Package com. yarin. android. Examples_12_02;

Import java. nio. IntBuffer;

Import javax. microedition. khronos. egl. EGLConfig;

Import javax. microedition. khronos. opengles. GL10;

Import android. opengl. GLSurfaceView. Renderer;

Public class GLRender implements Renderer

{

Int one = 0x10000;

// Three triangle vertices

Private IntBuffer triggerBuffer = IntBuffer. wrap (new int [] {

0, one, 0, // top Vertex

-One,-one, 0, // sit down

One,-one, 0,}); // bottom right

// Four vertices of a square

Private IntBuffer quaterBuffer = IntBuffer. wrap (new int [] {

One, one, 0,

-One, one, 0,

One,-one, 0,

-One,-one, 0 });

// Vertex color value of the triangle (r, g, B,)

Private IntBuffer colorBuffer = IntBuffer. wrap (new int [] {

One, 0, 0, one,

0, one, 0, one,

0, 0, one, one,

});

@ Override

Public void onDrawFrame (GL10 gl)

{

// Clear screen and deep Cache

Gl. glClear (GL10.GL _ COLOR_BUFFER_BIT | GL10.GL _ DEPTH_BUFFER_BIT );

// Reset the current model observation matrix

Gl. glLoadIdentity ();

// Move 1.5 units left and 6.0 to the screen

Gl. glTranslatef (-1.5f, 0.0f,-6.0f );

// Set a fixed-point Array

Gl. glableclientstate (GL10.GL _ VERTEX_ARRAY );

// Set the color array -- enable the color rendering function.

Gl. glableclientstate (GL10.GL _ COLOR_ARRAY );

// Set the triangle vertex color

Gl. glColorPointer (4, GL10.GL _ FIXED, 0, colorBuffer );

// Set triangle vertices

Gl. glVertexPointer (3, GL10.GL _ FIXED, 0, triggerBuffer );

// Draw a triangle

Gl. glDrawArrays (GL10.GL _ TRIANGLES, 0, 3 );

// Disable color array -- disable color rendering.

Gl. glDisableClientState (GL10.GL _ COLOR_ARRAY );

/* Render the square */

// Set the current color to blue

Gl. glColor4f (1.0f, 0.5f, 1.0f, 1.0f );

// Reset the current model observation matrix

Gl. glLoadIdentity ();

// Move 1.5 units left and 6.0 to the screen

Gl. glTranslatef (1.5f, 0.0f,-6.0f );

// Set and draw a square

Gl. glVertexPointer (3, GL10.GL _ FIXED, 0, quaterBuffer );

Gl. glDrawArrays (GL10.GL _ TRIANGLE_STRIP, 0, 4 );

// Cancel the vertex Array

Gl. glDisableClientState (GL10.GL _ VERTEX_ARRAY );

}

@ Override

Public void onSurfaceChanged (GL10 gl, int width, int height)

{

// TODO Auto-generated method stub

Float ratio = (float) width/height;

// Set the size of the OpenGL scenario

Gl. glViewport (0, 0, width, height );

// Sets the projection matrix.

Gl. glMatrixMode (GL10.GL _ PROJECTION );

// Reset the Projection Matrix

Gl. glLoadIdentity ();

// Set the preview size

Gl. glFrustumf (-ratio, ratio,-1, 1, 1, 10 );

// Select the model observation matrix

Gl. glMatrixMode (GL10.GL _ MODELVIEW );

// Reset the model observation matrix

Gl. glLoadIdentity ();

}

@ Override

Public void onSurfaceCreated (GL10 gl, EGLConfig config)

{

// Enable shadow Smoothing

Gl. glShadeModel (GL10.GL _ SMOOTH );

// Black background

Gl. glClearColor (0, 0, 0, 0 );

// Set the deep Cache

Gl. glClearDepthf (1.0f );

// Enable deep Test

Gl. glable (GL10.GL _ DEPTH_TEST );

// Type of the deep Test

Gl. glDepthFunc (GL10.GL _ LEQUAL );

// Notify the system to correct the Perspective

Gl. glHint (GL10.GL _ PERSPECTIVE_CORRECTION_HINT, GL10.GL _ FASTEST );

}

}

Iii. Running effect: