Android development of OpenGL ES 3D Space and Gldrawarrays

1. Four pyramid: consisting of 4 triangles.

Square Body: composed of 6 triangles.

Difficulty: When building the vertex coordinates of a 3D space, you must always have the center coordinate of the object (0.0f,0.0f,0.0f) to rotate the object around its own axis.

And the triangles are plotted in a counter-clockwise order.

2.3D Space Drawing:

Gl_apicall void Gl_apientry gldrawarrays (glenum mode, glint-I, glsizei count);

Parameter description:

mode, drawing mode, OpenGL2.0 later, the following parameters are provided: Gl_points, Gl_lines, Gl_line_loop, Gl_line_strip, Gl_triangles, Gl_triangle_strip, Gl_ Triangle_fan.

First, which one from the array cache begins to draw, typically 0.

Count, the number of vertices in the array.

3. Draw Vertex Array:

Draw Triangle Cone

for (int i=0; i<4; i++)

{

Gl.gldrawarrays (Gl10.gl_triangle_strip, i*3, 3);

}

Draw Square Body

for (int i=0; i<6; i++)

{

Gl.gldrawarrays (Gl10.gl_triangle_strip, i*4, 4);

}

[Attach] Build an array of vertices:

[Java]

int one = 0x10000;

Four pyramid vertex arrays:

Private Intbuffer Triggerbuffer = intbuffer.wrap (New int[]{

0,one,0,

-one,-one,0,

One,-one,one,

0,one,0,

One,-one,one,

One,-one,-one,

0,one,0,

One,-one,-one,

-one,-one,-one,

0,one,0,

-one,-one,-one,

-one,-one,one

});

Square Body Vertex array:

Private Intbuffer Quaterbuffer = intbuffer.wrap (New int[]{

One,one,-one,

-one,one,-one,

One,one,one,

-one,one,one,

One,-one,one,

-one,-one,one,

One,-one,-one,

-one,-one,-one,

One,one,one,

-one,one,one,

One,-one,one,

-one,-one,one,

One,-one,-one,

-one,-one,-one,

One,one,-one,

-one,one,-one,

-one,one,one,

-one,one,-one,

-one,-one,one,

-one,-one,-one,

One, one,-one,

One, one, one,

One,-one,-one,

One,-one, one,

});

int one = 0x10000;

Four pyramid vertex arrays:

Private Intbuffer Triggerbuffer = intbuffer.wrap (New int[]{

0,one,0,

-one,-one,0,

One,-one,one,

0,one,0,

One,-one,one,

One,-one,-one,

0,one,0,

One,-one,-one,

-one,-one,-one,

0,one,0,

-one,-one,-one,

-one,-one,one

});

Square Body Vertex array:

Private Intbuffer Quaterbuffer = intbuffer.wrap (New int[]{

One,one,-one,

-one,one,-one,

One,one,one,

-one,one,one,

One,-one,one,

-one,-one,one,

One,-one,-one,

-one,-one,-one,

One,one,one,

-one,one,one,

One,-one,one,

-one,-one,one,

One,-one,-one,

-one,-one,-one,

One,one,-one,

-one,one,-one,

-one,one,one,

-one,one,-one,

-one,-one,one,

-one,-one,-one,

One, one,-one,

One, one, one,

One,-one,-one,

One,-one, one,

});