Android / Using OpenGL on Android
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[[Android]]
* About OpenGL [#d7beaa1e]
>
OpenGL ES (OpenGL for Embedded Systems) is a 2D/3D graphi...
>
- OpenGL ES: The Standard for Embedded Accelerated 3D Gra...
-- http://www.khronos.org/opengles/
* Basic knowledge of OpenGL ES [#s7120182]
** Version [#o6e6b363]
>
There are roughly two different versions of OpenGL ES.
- OpenGL ES 1.x
-- Rendering is done by Fixed-Function Pipeline
[Fixed-Function Pipeline]
Vertex coordinates → Model-view transformation U...
>
- OpenGL ES 2.x
-- In stead of using ?Fixed-Function Pipeline,? this empl...
[Programable Shaders]
Vertex coordinates → Programable Shaders → Re...
>
This article discusses OpenGL ES 1.x Fixed-Function Pipel...
** Coordinates [#d514030a]
>
In OpenGL, x-axis, y-axis, and z-axis are considered as w...
>
>>
&ref(2.PNG);~
Figure1: Coordinates of OpenGL ES
** State Machine [#p255e439]
>
OpenGL ES is a state machine, which executes the predeter...
** Matrix [#c3738f8a]
>
Open GL employs two different types of matrices. One is t...
>>
&ref(3.PNG);~
** Vertex coordinates [#gc56d36d]
>
A point (X, Y, Z, W) is a set of coordinates. To define a...
>
Vertex coordinates
>>
&ref(4.PNG);~
** Model-view transformation [#j0ce9d95]
>
Model-view transformation configures parallel translation...
>
To use a set of translated vertex coordinates and a model...
>
Parallel translation: glTranslatef()
Rotation: glRotatef()
Enlargement/Reduction: glScalef()
>
>>
&ref(5.PNG);~
Figure2: Original
>
>>
&ref(6.PNG);~
Figure3: Parallel Traslation
>
>>
&ref(7.PNG);~
Figure4: Rotation
>
>>
&ref(8.PNG);~
Figure5: Enlargement / Reduction
** Projective transformation [#w8699bb7]
>
To use the projective transformation matrix, Projective t...
** Viewport transformation [#j6525caa]
>
The ratio of screen, which displays the sean, is configur...
>
>>
&ref(9.PNG);~
Figure6: projective transformation and viewport transform...
?w? and ?h? constitute the ratio of screen (Viewport)
?near? and ?far? indicate distance between the view point...
* Commands that removed from OpenGL [#f84d5d4b]
>
Since OpenGL ES is a subset of OpenGL, some functions of ...
** Geometry related commands [#m6a76d2a]
>
- glBegin, glEnd: input vertex coordinates
- double (order form), glMultMatrixd, glTranslated
- Polygon is triangle only
- Evaluator
- Display list
- Texture-coordinate generator
** Vertex coordinates related commands [#x165e44f]
>
- User clip
- A matrix calculation on the vertex color
** Vertex lightning related [#raef5bad]
>
- Index color mode (RGBA color mode only)
- Configure a material on back surface
- Local viewer, Separate specular color
** Rasterization related [#u55f7e86]
>
- glPolygonMode, glLineStipple, glPoygonStipple
- Anti-alias polygon
** Texture related [#lc04cf32]
>
- Single-Dimension, 3-Dimension, Cube map texture
- Texture format, Texture function
** Others [#b66b2f7d]
>
- Bitmap drawing, glDrawPixels, glBitmap
- State acquisitio
- Current raster position, Pixel processing
- Attribute stacks
* Using OpenGL ES on Android [#de0d79fb]
>
On Android, OpenGL ES can work with both Java and NDK (An...
>
>>
&ref(10.PNG);~
Figure7: OpenGL ES on Android
** About Class [#yb9e1fdf]
>
As using OpenGL ES on Android, two classes are required O...
>
GLSurfaceView
- GLSurfaceView is a subclass of SurfaceView and is capab...
-- It puts specific threads, which are separated form UI ...
-- It can handle continued rendering and on-demand render...
-- It does trace and error checking as this is called
>
Method
-onTouchEvent()
--It is similar to View, it notes the handling of touch-s...
> (i.e. By touch-screen operations, shift and/or rotate t...
>
GLSurfaceView.Renderer
- Render the frame
-- A class that inherits from this class is needed to to ...
>
Method
- onSurfaceCreated()
-- This method is called as a surface has been created.
-- As the state of a device is shifted from sleep to resu...
>
- onSurfaceChanged()
-- This method is called as the size of screen has been c...
-- Usually, the configuration of Viewport can be done wit...
>
- onDrawFrame()
-- ?onDrawFrame()? method is called when the frame is abo...
-- THe information, which is required for rendering, is n...
** To adjust the state of Activity [#y06b5c46]
>
?onResume()? and ?onPause()? of GLSurfaceView are can be ...
** Debug Process [#uee0ae6d]
>
GLSurfaceView Does have useful functions for debugging Op...
The method of ?GLSurfaceView.setDebugFlags(),? configures...
>
setDebugFlags(DEBUG_CHECK_GL_ERROR|DEBUG_LOG_GL_CALLS)
>
GLSurfaceView.DEBUG_LOG_GL_CALLS:~
As the commands of OpenGL ES are executed , logs are outp...
>
GLSurfaceView.DEBUG_CHECK_GL_ERROR:~
Errors occur as the commands of OpenGL ES are executed, a...
>
>>
&ref(11.PNG);~
Figure8: Debug outputs
** To work with many different devices [#t4fadc9c]
>
Currently, Android supports many different types of devic...
>
To utilize the functions of OpenGL ES fully, the specific...
>
To examine which functions are supported, glGetString() i...
>
GL_EXTENSIONS:
GL_RENDERER:
GL_VENDOR
GL_VERSION
>
The list of the functions, which are limited on OpenGL ES...
>
>>
&ref(12.PNG);~
* Sample Program [#m6e5399a]
>
This is a sample program, which display a cube and let it...
>
Activity
- OpenGL1.java
>
001:package com.beatcraft.opengl1;
002:
003:import com.beatcraft.opengl1.GLView;
004:
005:import android.app.Activity;
006:import android.os.Bundle;
007:
008:public class OpenGL1 extends Activity {
009: GLView mGLView;
010:
011: @Override
012: public void onCreate(Bundle savedInstanceState) {
013: super.onCreate(savedInstanceState);
014: mGLView = new GLView(this);
015: setContentView(mGLView);
016: }
017: @Override
018: protected void onPause() {
019: super.onPause();
020: mGLView.onPause();
021: }
022: @Override
023: protected void onResume() {
024: super.onResume() ;
025: mGLView.onResume();
026: }
027:}
>
At line #09: ?GLVew?, a derived class of ?GLSurfaceView,?...
At line #14: An instance of GLView
At line #15: GLView is pasted on Activity
At line #20: As Activity is posed (onPause()), GLView is ...
At line #25: When Activity is resumed, GLView is also res...
>
View (GLView)
- GLView.java
>
001:package com.beatcraft.opengl1;
002:
003:import android.content.Context;
004:import android.opengl.GLSurfaceView;
005:import android.util.Log;
006:import android.view.MotionEvent;
007:
008:public class GLView extends GLSurfaceView {
009: private GLRenderer mGLRenderer;
010: private final float TOUCH_SCALE_FACTOR = 180.0f ...
011: private float mPreviousX;
012: private float mPreviousY;
013:
014: public GLView(Context context) {
015: 　　super(context);
016: 　　mGLRenderer = new GLRenderer();
017: 　　setDebugFlags(DEBUG_CHECK_GL_ERROR
| DEBUG_LOG_GL_CALLS);
018:　　 　　setRenderer(mGLRend...
019: }
020:
021: @Override
022: public boolean onTouchEvent(MotionEvent event) {
023: float x = event.getX();
024: float y = event.getY();
025: switch (event.getAction()) {
026: case MotionEvent.ACTION_MOVE:
027: float dx = x - mPreviousX;
028: float dy = y - mPreviousY;
029: mGLRenderer.mRotate_x += dx * TOUCH_SCAL...
030: mGLRenderer.mRotate_y += dy * TOUCH_SCAL...
031: }
032: mPreviousX = x;
033: mPreviousY = y;
034:
035: return true;
036: }
037:}
>
At line #08: GLView, which is inherited from GLSurfaceVie...
At line #09: A class of GLRenderer, which implements the ...
At line #16: An instance of GLRenderer is created.
At line #17: The debug mode of OpenGL ES is set
At line #18: An instance of GLRenderer is registered to G...
At line #21 ~: A series of Processes as screen is touched...
>
Renderer (GLRenderer)
- GLRenderer.java
>
001:package com.beatcraft.opengl1;
002:
003:import java.nio.ByteBuffer;
004:import java.nio.ByteOrder;
005:import java.nio.FloatBuffer;
006:
007:import javax.microedition.khronos.egl.EGLConfig;
008:import javax.microedition.khronos.opengles.GL10;
009:
010:import android.opengl.GLSurfaceView.Renderer;
011:
012:public class GLRenderer implements Renderer {
013:
?
124: @Override
125: public void onSurfaceCreated(GL10 gl, EGLConfig ar...
126: // Initialize Coordinates.
127: gl.glLoadIdentity();
128: // Depth Buffer Test makes effective.
129: gl.glEnable(GL10.GL_DEPTH_TEST);
130: // the operations of dark surface removal is co...
131: gl.glDepthFunc(GL10.GL_LEQUAL);
132: // The light is enabled.
133: gl.glEnable(GL10.GL_LIGHTING);
134: // The light source is specified.
135: gl.glEnable(GL10.GL_LIGHT0);
136:
137: // The vertex array and normal array is set at B...
138: setBuffer();
139: }
140:
141: @Override
142: public void onSurfaceChanged(GL10 gl, int width, i...
143: // Display ratio
144: float ratio = (float) width / height;
145: // Configuration of viewport
146: gl.glViewport(0, 0, width, height);
147: // Setting up the projective matrix
148: gl.glMatrixMode(GL10.GL_PROJECTION);
149: gl.glLoadIdentity();
150: // Configuration of angle (left,right,bottom,to...
151: gl.glFrustumf(-ratio, ratio, -1, 1, 1, 1000);
152: }
>
At line # 125: As a surface is created, this is called.
At line # 142: As the size of a surface is changed, ?onSu...
At line # 146: This is a configuration of a viewport. Rat...
At line # 148: This configures a projective matrix. After...
At line # 151: This sets up the view volume. The area bet...
>
Renderer (GLRenderer) (Continued)
- GLRenderer.java (Continued)
>
154: @Override
155: public void onDrawFrame(GL10 gl) {
156: // Display Screen and clear depth buffer
157: gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DE...
158: // Specify a model-view matrix
159: gl.glMatrixMode(GL10.GL_MODELVIEW);
160: // Initialize the coordinates
161: gl.glLoadIdentity();
162: // Translation (At Z-axis: Move to back)
163: gl.glTranslatef(0, 0, -5f);
164: // Rotation
165: gl.glRotatef(mRotate_x, 0, 1, 0);
166: gl.glRotatef(mRotate_y, 1, 0, 0);
167: // The vertex array makes effective.
168: gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
169: // The normal array mekes effective.
170: gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);
171: // The set of vertex array
172: gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mVertexB...
173: // The set of normal array
174: gl.glNormalPointer(GL10.GL_FLOAT, 0, mNormalBuff...
175: // Rendering (GL_TRIANGLES: Triangles)
176: gl.glDrawArrays(GL10.GL_TRIANGLES, 0, mVertexBuf...
177: }
?
193:}
>
At line # 155: Each time image is rendered, this is execu...
At line # 159: It is the configuration of a model-view ma...
At line #165-166: Based upon the results of touch operati...
At line # 176: From the vertex of the cube, a triangle is...
>
Screen Shot
As touching the screen and sliding a finger, the cube is ...
>>
#ref(./13.png,50%);
* Model data (.obj) [#f9f9016f]
>
?.obj? file is an output file of Advanced Visualizer, whi...
Its extension is ?.obj? and its file format is text style...
>
- Comments:
-- #: The line that starts with ?#? is a line of comment.
>
- Vertex Coordinates:
-- v: ?v? indicates that this line is the information of ...
>
- Texture Coordinates:
-- vt: This line, which begins with ?vt?, indicates the i...
>
- Normal Coordinates:
-- vn: ?vn? indicates this line is a set of normal coordi...
>
- face
-- f: ?f? defines the vertex coordinates, texture coordin...
>
f number/number/number ---> vertex coordinates/texture co...
f number//number ----> vertex coordinates//nor...
f numer ----> vertex coordina...
>
The index is started from the value, whose top digit stat...
>
- Sample of obj file (This defines a cube)
#
# cube.obj
#
v 0.0 0.0 0.0
v 0.0 0.0 1.0
v 0.0 1.0 0.0
v 0.0 1.0 1.0
v 1.0 0.0 0.0
v 1.0 0.0 1.0
v 1.0 1.0 0.0
v 1.0 1.0 1.0
f 1//2 7//2 5//2 1//2 3//2 7//2
f 1//6 4//6 3//6
vn 0.0 0.0 1.0
vn 0.0 0.0 -1.0
vn 0.0 1.0 0.0
vn 0.0 -1.0 0.0
vn 1.0 0.0 0.0
vn -1.0 0.0 0.0
f 1//6 2//6 4//6
f 3//3 8//3 7//3
f 3//3 4//3 8//3
f 5//5 7//5 8//5
f 5//5 8//5 6//5
f 1//4 5//4 6//4
f 1//4 6//4 2//4
f 2//1 6//1 8//1
f 2//1 8//1 4//1
>
Examples of displaying 3D (.obj) model data~
>
#ref(./14.png,50%);~
>
#ref(./15.png,50%);~
* Revision History [#x5ad876e]
>
-- 2012/3/23 The article is initially uploaded.
End:
[[Android]]
* About OpenGL [#d7beaa1e]
>
OpenGL ES (OpenGL for Embedded Systems) is a 2D/3D graphi...
>
- OpenGL ES: The Standard for Embedded Accelerated 3D Gra...
-- http://www.khronos.org/opengles/
* Basic knowledge of OpenGL ES [#s7120182]
** Version [#o6e6b363]
>
There are roughly two different versions of OpenGL ES.
- OpenGL ES 1.x
-- Rendering is done by Fixed-Function Pipeline
[Fixed-Function Pipeline]
Vertex coordinates → Model-view transformation U...
>
- OpenGL ES 2.x
-- In stead of using ?Fixed-Function Pipeline,? this empl...
[Programable Shaders]
Vertex coordinates → Programable Shaders → Re...
>
This article discusses OpenGL ES 1.x Fixed-Function Pipel...
** Coordinates [#d514030a]
>
In OpenGL, x-axis, y-axis, and z-axis are considered as w...
>
>>
&ref(2.PNG);~
Figure1: Coordinates of OpenGL ES
** State Machine [#p255e439]
>
OpenGL ES is a state machine, which executes the predeter...
** Matrix [#c3738f8a]
>
Open GL employs two different types of matrices. One is t...
>>
&ref(3.PNG);~
** Vertex coordinates [#gc56d36d]
>
A point (X, Y, Z, W) is a set of coordinates. To define a...
>
Vertex coordinates
>>
&ref(4.PNG);~
** Model-view transformation [#j0ce9d95]
>
Model-view transformation configures parallel translation...
>
To use a set of translated vertex coordinates and a model...
>
Parallel translation: glTranslatef()
Rotation: glRotatef()
Enlargement/Reduction: glScalef()
>
>>
&ref(5.PNG);~
Figure2: Original
>
>>
&ref(6.PNG);~
Figure3: Parallel Traslation
>
>>
&ref(7.PNG);~
Figure4: Rotation
>
>>
&ref(8.PNG);~
Figure5: Enlargement / Reduction
** Projective transformation [#w8699bb7]
>
To use the projective transformation matrix, Projective t...
** Viewport transformation [#j6525caa]
>
The ratio of screen, which displays the sean, is configur...
>
>>
&ref(9.PNG);~
Figure6: projective transformation and viewport transform...
?w? and ?h? constitute the ratio of screen (Viewport)
?near? and ?far? indicate distance between the view point...
* Commands that removed from OpenGL [#f84d5d4b]
>
Since OpenGL ES is a subset of OpenGL, some functions of ...
** Geometry related commands [#m6a76d2a]
>
- glBegin, glEnd: input vertex coordinates
- double (order form), glMultMatrixd, glTranslated
- Polygon is triangle only
- Evaluator
- Display list
- Texture-coordinate generator
** Vertex coordinates related commands [#x165e44f]
>
- User clip
- A matrix calculation on the vertex color
** Vertex lightning related [#raef5bad]
>
- Index color mode (RGBA color mode only)
- Configure a material on back surface
- Local viewer, Separate specular color
** Rasterization related [#u55f7e86]
>
- glPolygonMode, glLineStipple, glPoygonStipple
- Anti-alias polygon
** Texture related [#lc04cf32]
>
- Single-Dimension, 3-Dimension, Cube map texture
- Texture format, Texture function
** Others [#b66b2f7d]
>
- Bitmap drawing, glDrawPixels, glBitmap
- State acquisitio
- Current raster position, Pixel processing
- Attribute stacks
* Using OpenGL ES on Android [#de0d79fb]
>
On Android, OpenGL ES can work with both Java and NDK (An...
>
>>
&ref(10.PNG);~
Figure7: OpenGL ES on Android
** About Class [#yb9e1fdf]
>
As using OpenGL ES on Android, two classes are required O...
>
GLSurfaceView
- GLSurfaceView is a subclass of SurfaceView and is capab...
-- It puts specific threads, which are separated form UI ...
-- It can handle continued rendering and on-demand render...
-- It does trace and error checking as this is called
>
Method
-onTouchEvent()
--It is similar to View, it notes the handling of touch-s...
> (i.e. By touch-screen operations, shift and/or rotate t...
>
GLSurfaceView.Renderer
- Render the frame
-- A class that inherits from this class is needed to to ...
>
Method
- onSurfaceCreated()
-- This method is called as a surface has been created.
-- As the state of a device is shifted from sleep to resu...
>
- onSurfaceChanged()
-- This method is called as the size of screen has been c...
-- Usually, the configuration of Viewport can be done wit...
>
- onDrawFrame()
-- ?onDrawFrame()? method is called when the frame is abo...
-- THe information, which is required for rendering, is n...
** To adjust the state of Activity [#y06b5c46]
>
?onResume()? and ?onPause()? of GLSurfaceView are can be ...
** Debug Process [#uee0ae6d]
>
GLSurfaceView Does have useful functions for debugging Op...
The method of ?GLSurfaceView.setDebugFlags(),? configures...
>
setDebugFlags(DEBUG_CHECK_GL_ERROR|DEBUG_LOG_GL_CALLS)
>
GLSurfaceView.DEBUG_LOG_GL_CALLS:~
As the commands of OpenGL ES are executed , logs are outp...
>
GLSurfaceView.DEBUG_CHECK_GL_ERROR:~
Errors occur as the commands of OpenGL ES are executed, a...
>
>>
&ref(11.PNG);~
Figure8: Debug outputs
** To work with many different devices [#t4fadc9c]
>
Currently, Android supports many different types of devic...
>
To utilize the functions of OpenGL ES fully, the specific...
>
To examine which functions are supported, glGetString() i...
>
GL_EXTENSIONS:
GL_RENDERER:
GL_VENDOR
GL_VERSION
>
The list of the functions, which are limited on OpenGL ES...
>
>>
&ref(12.PNG);~
* Sample Program [#m6e5399a]
>
This is a sample program, which display a cube and let it...
>
Activity
- OpenGL1.java
>
001:package com.beatcraft.opengl1;
002:
003:import com.beatcraft.opengl1.GLView;
004:
005:import android.app.Activity;
006:import android.os.Bundle;
007:
008:public class OpenGL1 extends Activity {
009: GLView mGLView;
010:
011: @Override
012: public void onCreate(Bundle savedInstanceState) {
013: super.onCreate(savedInstanceState);
014: mGLView = new GLView(this);
015: setContentView(mGLView);
016: }
017: @Override
018: protected void onPause() {
019: super.onPause();
020: mGLView.onPause();
021: }
022: @Override
023: protected void onResume() {
024: super.onResume() ;
025: mGLView.onResume();
026: }
027:}
>
At line #09: ?GLVew?, a derived class of ?GLSurfaceView,?...
At line #14: An instance of GLView
At line #15: GLView is pasted on Activity
At line #20: As Activity is posed (onPause()), GLView is ...
At line #25: When Activity is resumed, GLView is also res...
>
View (GLView)
- GLView.java
>
001:package com.beatcraft.opengl1;
002:
003:import android.content.Context;
004:import android.opengl.GLSurfaceView;
005:import android.util.Log;
006:import android.view.MotionEvent;
007:
008:public class GLView extends GLSurfaceView {
009: private GLRenderer mGLRenderer;
010: private final float TOUCH_SCALE_FACTOR = 180.0f ...
011: private float mPreviousX;
012: private float mPreviousY;
013:
014: public GLView(Context context) {
015: 　　super(context);
016: 　　mGLRenderer = new GLRenderer();
017: 　　setDebugFlags(DEBUG_CHECK_GL_ERROR
| DEBUG_LOG_GL_CALLS);
018:　　 　　setRenderer(mGLRend...
019: }
020:
021: @Override
022: public boolean onTouchEvent(MotionEvent event) {
023: float x = event.getX();
024: float y = event.getY();
025: switch (event.getAction()) {
026: case MotionEvent.ACTION_MOVE:
027: float dx = x - mPreviousX;
028: float dy = y - mPreviousY;
029: mGLRenderer.mRotate_x += dx * TOUCH_SCAL...
030: mGLRenderer.mRotate_y += dy * TOUCH_SCAL...
031: }
032: mPreviousX = x;
033: mPreviousY = y;
034:
035: return true;
036: }
037:}
>
At line #08: GLView, which is inherited from GLSurfaceVie...
At line #09: A class of GLRenderer, which implements the ...
At line #16: An instance of GLRenderer is created.
At line #17: The debug mode of OpenGL ES is set
At line #18: An instance of GLRenderer is registered to G...
At line #21 ~: A series of Processes as screen is touched...
>
Renderer (GLRenderer)
- GLRenderer.java
>
001:package com.beatcraft.opengl1;
002:
003:import java.nio.ByteBuffer;
004:import java.nio.ByteOrder;
005:import java.nio.FloatBuffer;
006:
007:import javax.microedition.khronos.egl.EGLConfig;
008:import javax.microedition.khronos.opengles.GL10;
009:
010:import android.opengl.GLSurfaceView.Renderer;
011:
012:public class GLRenderer implements Renderer {
013:
?
124: @Override
125: public void onSurfaceCreated(GL10 gl, EGLConfig ar...
126: // Initialize Coordinates.
127: gl.glLoadIdentity();
128: // Depth Buffer Test makes effective.
129: gl.glEnable(GL10.GL_DEPTH_TEST);
130: // the operations of dark surface removal is co...
131: gl.glDepthFunc(GL10.GL_LEQUAL);
132: // The light is enabled.
133: gl.glEnable(GL10.GL_LIGHTING);
134: // The light source is specified.
135: gl.glEnable(GL10.GL_LIGHT0);
136:
137: // The vertex array and normal array is set at B...
138: setBuffer();
139: }
140:
141: @Override
142: public void onSurfaceChanged(GL10 gl, int width, i...
143: // Display ratio
144: float ratio = (float) width / height;
145: // Configuration of viewport
146: gl.glViewport(0, 0, width, height);
147: // Setting up the projective matrix
148: gl.glMatrixMode(GL10.GL_PROJECTION);
149: gl.glLoadIdentity();
150: // Configuration of angle (left,right,bottom,to...
151: gl.glFrustumf(-ratio, ratio, -1, 1, 1, 1000);
152: }
>
At line # 125: As a surface is created, this is called.
At line # 142: As the size of a surface is changed, ?onSu...
At line # 146: This is a configuration of a viewport. Rat...
At line # 148: This configures a projective matrix. After...
At line # 151: This sets up the view volume. The area bet...
>
Renderer (GLRenderer) (Continued)
- GLRenderer.java (Continued)
>
154: @Override
155: public void onDrawFrame(GL10 gl) {
156: // Display Screen and clear depth buffer
157: gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DE...
158: // Specify a model-view matrix
159: gl.glMatrixMode(GL10.GL_MODELVIEW);
160: // Initialize the coordinates
161: gl.glLoadIdentity();
162: // Translation (At Z-axis: Move to back)
163: gl.glTranslatef(0, 0, -5f);
164: // Rotation
165: gl.glRotatef(mRotate_x, 0, 1, 0);
166: gl.glRotatef(mRotate_y, 1, 0, 0);
167: // The vertex array makes effective.
168: gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
169: // The normal array mekes effective.
170: gl.glEnableClientState(GL10.GL_NORMAL_ARRAY);
171: // The set of vertex array
172: gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mVertexB...
173: // The set of normal array
174: gl.glNormalPointer(GL10.GL_FLOAT, 0, mNormalBuff...
175: // Rendering (GL_TRIANGLES: Triangles)
176: gl.glDrawArrays(GL10.GL_TRIANGLES, 0, mVertexBuf...
177: }
?
193:}
>
At line # 155: Each time image is rendered, this is execu...
At line # 159: It is the configuration of a model-view ma...
At line #165-166: Based upon the results of touch operati...
At line # 176: From the vertex of the cube, a triangle is...
>
Screen Shot
As touching the screen and sliding a finger, the cube is ...
>>
#ref(./13.png,50%);
* Model data (.obj) [#f9f9016f]
>
?.obj? file is an output file of Advanced Visualizer, whi...
Its extension is ?.obj? and its file format is text style...
>
- Comments:
-- #: The line that starts with ?#? is a line of comment.
>
- Vertex Coordinates:
-- v: ?v? indicates that this line is the information of ...
>
- Texture Coordinates:
-- vt: This line, which begins with ?vt?, indicates the i...
>
- Normal Coordinates:
-- vn: ?vn? indicates this line is a set of normal coordi...
>
- face
-- f: ?f? defines the vertex coordinates, texture coordin...
>
f number/number/number ---> vertex coordinates/texture co...
f number//number ----> vertex coordinates//nor...
f numer ----> vertex coordina...
>
The index is started from the value, whose top digit stat...
>
- Sample of obj file (This defines a cube)
#
# cube.obj
#
v 0.0 0.0 0.0
v 0.0 0.0 1.0
v 0.0 1.0 0.0
v 0.0 1.0 1.0
v 1.0 0.0 0.0
v 1.0 0.0 1.0
v 1.0 1.0 0.0
v 1.0 1.0 1.0
f 1//2 7//2 5//2 1//2 3//2 7//2
f 1//6 4//6 3//6
vn 0.0 0.0 1.0
vn 0.0 0.0 -1.0
vn 0.0 1.0 0.0
vn 0.0 -1.0 0.0
vn 1.0 0.0 0.0
vn -1.0 0.0 0.0
f 1//6 2//6 4//6
f 3//3 8//3 7//3
f 3//3 4//3 8//3
f 5//5 7//5 8//5
f 5//5 8//5 6//5
f 1//4 5//4 6//4
f 1//4 6//4 2//4
f 2//1 6//1 8//1
f 2//1 8//1 4//1
>
Examples of displaying 3D (.obj) model data~
>
#ref(./14.png,50%);~
>
#ref(./15.png,50%);~
* Revision History [#x5ad876e]
>
-- 2012/3/23 The article is initially uploaded.
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