I'm new to this but what I'm trying to do is using vertex array object to display something on a phone emulator. But the problem is that it isn't displaying anything on the phone. What I have understood of using vertex array objects is that a VAO is something like a folder that can points to different buffers and inside the VAO there is vertex buffer objects. What I have done in the code is create two buffers and a VAO. Bind the buffers to an array called mVBOIds. Then bind the VAO to it's own array then i setup the vertex with the buffers.
To populate these buffers I have a file named torus2.raw that has data that looks like this:
# Data order:
# Vertex
# Normal vector
# Texture coordinate
12.329425 0.0 -8.957851 1.0
-0.809017 1.0E-6 0.587785 0.0
0.05 1.0
Where we have the order of data, Vertex has 4 data, Normal Vector has 4 and then Texture coordinate has 2 data.
Here is the code for that part that creates the buffers and VAO and its inside the method onSurfaceCreated:
// Generate VBO Ids and load the VBOs with data
GLES30.glGenBuffers ( 2, mVBOIds, 0 );
GLES30.glBindBuffer ( GLES30.GL_ARRAY_BUFFER, mVBOIds[0] );
mVertices.position ( 0 );
GLES30.glBufferData ( GLES30.GL_ARRAY_BUFFER, mVertices.remaining() * 4,
mVertices, GLES30.GL_STATIC_DRAW );
GLES30.glBindBuffer ( GLES30.GL_ELEMENT_ARRAY_BUFFER, mVBOIds[1] );
mNormals.position ( 0 );
GLES30.glBufferData ( GLES30.GL_ELEMENT_ARRAY_BUFFER, 4 * mNormals.remaining(),
mNormals, GLES30.GL_STATIC_DRAW );
// Generate VAO Id
GLES30.glGenVertexArrays ( 1, mVAOId, 0 );
// Bind the VAO and then setup the vertex
// attributes
GLES30.glBindVertexArray ( mVAOId[0] );
GLES30.glBindBuffer ( GLES30.GL_ARRAY_BUFFER, mVBOIds[0] );
GLES30.glBindBuffer ( GLES30.GL_ELEMENT_ARRAY_BUFFER, mVBOIds[1] );
GLES30.glEnableVertexAttribArray (VERTEX_POS_INDX);
GLES30.glEnableVertexAttribArray (VERTEX_NORM_INDX);
GLES30.glVertexAttribPointer ( VERTEX_POS_INDX, VERTEX_POS_SIZE,
GLES30.GL_FLOAT, false, VERTEX_STRIDE,
0 );
GLES30.glVertexAttribPointer (VERTEX_NORM_INDX, VERTEX_NORM_SIZE,
GLES30.GL_FLOAT, false, VERTEX_STRIDE,
( VERTEX_POS_SIZE * 4 ) );
// Reset to the default VAO
GLES30.glBindVertexArray ( 0 );
GLES30.glClearColor ( 0.15f, 0.15f, 0.15f, 1.0f );
GLES30.glEnable(GLES30.GL_DEPTH_TEST);
After this when I have the buffer and VAO setup, I use onDrawFrame method to get it to show in display:
public void onDrawFrame ( GL10 glUnused )
{
// Initiate the model-view matrix as identity matrix
Matrix.setIdentityM(mViewMatrix, 0);
// Define a translation transformation
Matrix.translateM(mViewMatrix, 0, 0.0f, 0.0f, -60.0f);
// Define a rotation transformation
Matrix.rotateM(mViewMatrix, 0, 90.0f, 1.0f, 0.0f, 0.0f);
// Calculate the model-view and projection transformation as composite transformation
Matrix.multiplyMM (mMVPMatrix, 0, mProjectionMatrix, 0, mViewMatrix, 0);
// Clear the color buffer
GLES30.glClear ( GLES30.GL_COLOR_BUFFER_BIT | GLES30.GL_DEPTH_BUFFER_BIT );
// Use the program object
GLES30.glUseProgram ( mProgramObject );
// Make MVP matrix accessible in the vertex shader
mMVPMatrixHandle = GLES30.glGetUniformLocation(mProgramObject, "uMVPMatrix");
GLES30.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mMVPMatrix, 0);
// Light position:
vLightPositionHandle = GLES30.glGetUniformLocation(mProgramObject, "vLightPosition");
GLES30.glUniform4fv(vLightPositionHandle, 1, lightPosition, 0);
// Light color:
vLightColorDfHandle = GLES30.glGetUniformLocation(mProgramObject, "vLightColorDf");
GLES30.glUniform4fv(vLightColorDfHandle, 1, lightColorDf, 0);
// Material color:
vMaterialColorDfHandle = GLES30.glGetUniformLocation(mProgramObject, "vMaterialColorDf");
GLES30.glUniform4fv(vMaterialColorDfHandle, 1, materialColorDf, 0);
GLES30.glBindVertexArray ( mVAOId[0] );
// Draw with the VAO settings
GLES30.glDrawElements ( GLES30.GL_TRIANGLES, mNormals.remaining(), GLES30.GL_UNSIGNED_SHORT, 0 );
// Return to the default VAO
GLES30.glBindVertexArray ( 0 );
}
But the problem is that I can't get anything to display. I've tried to double check the variabels, check if if the variabels are empty etc but I could not find the culprit. It could also be that I've understood the code differently and made a logical error but I can't see what it is. The result should be a blue-ish donut shaped model.
This is the whole code:
import android.content.Context;
import android.opengl.GLES30;
import android.opengl.GLSurfaceView;
import android.opengl.Matrix;
import android.util.Log;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
import se.hig.dvg306.modul3app.tools.ResourceHandler;
public class Modul3Renderer implements GLSurfaceView.Renderer
{
//
// Constructor - loads model data from a res file and creates byte buffers for
// vertex data and for normal data
//
public Modul3Renderer (Context context)
{
appContext = context;
Log.e(TAG, "--->>> Creating ModelLoader...");
ModelLoader modelLoader = new ModelLoaderImpl ();
Log.e(TAG, "--->>> ...finished.");
Log.e(TAG, "--->>> Loading model...");
Log.e(TAG, "--->>> Starting with vertices...");
float[] mVerticesData; //= new float[0];
try {
mVerticesData = modelLoader.loadModel (context, R.raw.torus2, 0, 10, 0);
} catch (IOException e) {
throw new RuntimeException (e);
}
Log.e(TAG, "--->>> ...finished.");
// Process vertex data
// 4: because of 4 elements per vertex position
nbrOfVertices = mVerticesData.length / 10;
mVertices = ByteBuffer.allocateDirect(mVerticesData.length * 4)
.order(ByteOrder.nativeOrder()).asFloatBuffer();
mVertices.put(mVerticesData).position(0);
Log.e(TAG, "--->>> Starting with normals...");
float[] mNormalData; //= new float[0];
try {
mNormalData = modelLoader.loadModel (context, R.raw.torus2, 4, 4, 6);
} catch (IOException e) {
throw new RuntimeException (e);
}
Log.e(TAG, "--->>> ...finished.");
// Process normal data
// 4: because of 4 elements per vertex position
nbrOfNormals = mNormalData.length / 4;
mNormals = ByteBuffer.allocateDirect(mNormalData.length * 4)
.order(ByteOrder.nativeOrder()).asFloatBuffer();
mNormals.put(mNormalData).position(0);
}
///
// Create a shader object, load the shader source, and
// compile the shader.
//
private int createShader(int type, String shaderSrc )
{
int shader;
int[] compiled = new int[1];
// Create the shader object
shader = GLES30.glCreateShader ( type );
if ( shader == 0 )
{
return 0;
}
// Load the shader source
GLES30.glShaderSource ( shader, shaderSrc );
// Compile the shader
GLES30.glCompileShader ( shader );
// Check the compile status
GLES30.glGetShaderiv ( shader, GLES30.GL_COMPILE_STATUS, compiled, 0 );
if ( compiled[0] == 0 )
{
Log.e ( TAG, GLES30.glGetShaderInfoLog ( shader ) );
GLES30.glDeleteShader ( shader );
return 0;
}
return shader;
}
///
// Initialize the shader and program object
//
public void onSurfaceCreated ( GL10 glUnused, EGLConfig config )
{
int vertexShader;
int fragmentShader;
int programObject;
int[] linked = new int[1];
// Load the source code for the vertex shader program from a res file:
try {
vShaderStr = ResourceHandler.readTextData(appContext, R.raw.vertex_shader);
} catch (IOException e) {
Log.e ( TAG, "--->>> Could not load source code for vertex shader.");
throw new RuntimeException (e);
}
Log.e ( TAG, "--->>> Loaded vertex shader: " + vShaderStr);
// Load the source code for the fragment shader program from a res file:
try {
fShaderStr = ResourceHandler.readTextData(appContext, R.raw.fragment_shader);
} catch (IOException e) {
Log.e ( TAG, "--->>> Could not load source code for fragment shader.");
throw new RuntimeException (e);
}
Log.e ( TAG, "--->>> Loaded fragment shader: " + fShaderStr);
// Create the vertex/fragment shaders
vertexShader = createShader( GLES30.GL_VERTEX_SHADER, vShaderStr );
fragmentShader = createShader( GLES30.GL_FRAGMENT_SHADER, fShaderStr );
// Create the program object
programObject = GLES30.glCreateProgram();
if ( programObject == 0 )
{
return;
}
GLES30.glAttachShader ( programObject, vertexShader );
GLES30.glAttachShader ( programObject, fragmentShader );
// Bind vPosition to attribute 0
GLES30.glBindAttribLocation ( programObject, 0, "vPosition" );
// Bind vNormal to attribute 1
GLES30.glBindAttribLocation ( programObject, 1, "vNormal" );
// Link the program
GLES30.glLinkProgram ( programObject );
// Check the link status
GLES30.glGetProgramiv ( programObject, GLES30.GL_LINK_STATUS, linked, 0 );
if ( linked[0] == 0 )
{
Log.e ( TAG, "Error linking program:" );
Log.e ( TAG, GLES30.glGetProgramInfoLog ( programObject ) );
GLES30.glDeleteProgram ( programObject );
return;
}
// Store the program object
mProgramObject = programObject;
// Generate VBO Ids and load the VBOs with data
GLES30.glGenBuffers ( 2, mVBOIds, 0 );
GLES30.glBindBuffer ( GLES30.GL_ARRAY_BUFFER, mVBOIds[0] );
mVertices.position ( 0 );
GLES30.glBufferData ( GLES30.GL_ARRAY_BUFFER, mVertices.remaining() * 4,
mVertices, GLES30.GL_STATIC_DRAW );
GLES30.glBindBuffer ( GLES30.GL_ELEMENT_ARRAY_BUFFER, mVBOIds[1] );
mNormals.position ( 0 );
GLES30.glBufferData ( GLES30.GL_ELEMENT_ARRAY_BUFFER, 4 * mNormals.remaining(),
mNormals, GLES30.GL_STATIC_DRAW );
// Generate VAO Id
GLES30.glGenVertexArrays ( 1, mVAOId, 0 );
// Bind the VAO and then setup the vertex
// attributes
GLES30.glBindVertexArray ( mVAOId[0] );
GLES30.glBindBuffer ( GLES30.GL_ARRAY_BUFFER, mVBOIds[0] );
GLES30.glBindBuffer ( GLES30.GL_ELEMENT_ARRAY_BUFFER, mVBOIds[1] );
GLES30.glEnableVertexAttribArray (VERTEX_POS_INDX);
GLES30.glEnableVertexAttribArray (VERTEX_NORM_INDX);
GLES30.glVertexAttribPointer ( VERTEX_POS_INDX, VERTEX_POS_SIZE,
GLES30.GL_FLOAT, false, VERTEX_STRIDE,
0 );
GLES30.glVertexAttribPointer (VERTEX_NORM_INDX, VERTEX_NORM_SIZE,
GLES30.GL_FLOAT, false, VERTEX_STRIDE,
( VERTEX_POS_SIZE * 4 ) );
// Reset to the default VAO
GLES30.glBindVertexArray ( 0 );
GLES30.glClearColor ( 0.15f, 0.15f, 0.15f, 1.0f );
GLES30.glEnable(GLES30.GL_DEPTH_TEST);
}
//
// Draw a torus using the shader pair created in onSurfaceCreated()
//
public void onDrawFrame ( GL10 glUnused )
{
// Initiate the model-view matrix as identity matrix
Matrix.setIdentityM(mViewMatrix, 0);
// Define a translation transformation
Matrix.translateM(mViewMatrix, 0, 0.0f, 0.0f, -60.0f);
// Define a rotation transformation
Matrix.rotateM(mViewMatrix, 0, 90.0f, 1.0f, 0.0f, 0.0f);
// Calculate the model-view and projection transformation as composite transformation
Matrix.multiplyMM (mMVPMatrix, 0, mProjectionMatrix, 0, mViewMatrix, 0);
// Clear the color buffer
GLES30.glClear ( GLES30.GL_COLOR_BUFFER_BIT | GLES30.GL_DEPTH_BUFFER_BIT );
// Use the program object
GLES30.glUseProgram ( mProgramObject );
// Make MVP matrix accessible in the vertex shader
mMVPMatrixHandle = GLES30.glGetUniformLocation(mProgramObject, "uMVPMatrix");
GLES30.glUniformMatrix4fv(mMVPMatrixHandle, 1, false, mMVPMatrix, 0);
// Light position:
vLightPositionHandle = GLES30.glGetUniformLocation(mProgramObject, "vLightPosition");
GLES30.glUniform4fv(vLightPositionHandle, 1, lightPosition, 0);
// Light color:
vLightColorDfHandle = GLES30.glGetUniformLocation(mProgramObject, "vLightColorDf");
GLES30.glUniform4fv(vLightColorDfHandle, 1, lightColorDf, 0);
// Material color:
vMaterialColorDfHandle = GLES30.glGetUniformLocation(mProgramObject, "vMaterialColorDf");
GLES30.glUniform4fv(vMaterialColorDfHandle, 1, materialColorDf, 0);
GLES30.glBindVertexArray ( mVAOId[0] );
// Draw with the VAO settings
GLES30.glDrawElements ( GLES30.GL_TRIANGLES, mNormals.remaining(), GLES30.GL_UNSIGNED_SHORT, 0 );
// Return to the default VAO
GLES30.glBindVertexArray ( 0 );
}
//
// Handle surface changes
//
public void onSurfaceChanged ( GL10 glUnused, int width, int height )
{
mWidth = width;
mHeight = height;
GLES30.glViewport(0, 0, width, height);
float ratio = (float) width / height;
// this projection matrix is applied to object coordinates
Matrix.frustumM(mProjectionMatrix, 0, -ratio, ratio, -1.0f, 1.0f, 0.5f, 1000.0f);
}
// Member variables
private Context appContext;
private int mWidth;
private int mHeight;
private int nbrOfVertices;
private FloatBuffer mVertices;
final int VERTEX_POS_SIZE = 4; // x, y and z
final int VERTEX_NORM_SIZE = 4; // r, g, b, and a
final int VERTEX_POS_INDX = 0;
final int VERTEX_NORM_INDX = 1;
private int [] mVBOIds = new int[2];
private int [] mVAOId = new int[1];
private int nbrOfNormals;
private FloatBuffer mNormals;
private int mProgramObject;
private int mMVPMatrixHandle;
// Transformation data:
private final float[] mMVPMatrix = new float[16];
private final float[] mProjectionMatrix = new float[16];
private final float[] mViewMatrix = new float[16];
final int VERTEX_STRIDE = ( 4 * ( VERTEX_POS_SIZE + VERTEX_NORM_SIZE ) );
// Light position and color (only diffuse term now):
private int vLightPositionHandle;
private final float lightPosition [] = {175.0f, 75.0f, 125.0f, 0.0f};
// Light color (only diffuse term now):
private int vLightColorDfHandle;
private final float lightColorDf [] = {0.98f, 0.98f, 0.98f, 1.0f};
// Material color (only diffuse term now):
private int vMaterialColorDfHandle;
private final float materialColorDf [] = {0.62f, 0.773f, 0.843f, 1.0f};
// To be read when creating the instance:
private String vShaderStr;
private String fShaderStr;
private static String TAG = "Modul3Renderer";
}
