OpenGL es 2.0 Android Texture

Question

I cannot seem to render a Texture to my square. I have gotten my program to render the blank square with color. Any help is greatly appreciated.

I've redesigned my code to the following and believe that the problem exists with how I'm setting up my Vertex Coordinates and Texture Coordinates. I also get a libc Fatal signal 11 at my glDrawArrays function.

Here are the Vertex and Texture Coordinates:

private final FloatBuffer vertexBuffer;
private final FloatBuffer textureBuffer;

static final int COORDS_PER_VERTEX = 3;
static float positionCoords[] = { // in counterclockwise order:
    -1.0f, 1.0f, 1.0f,              
    -1.0f, -1.0f, 1.0f,
    1.0f, 1.0f, 1.0f, 
    -1.0f, -1.0f, 1.0f,                 
    1.0f, -1.0f, 1.0f,
    1.0f, 1.0f, 1.0f,
};

static final int COORDS_PER_TEXTURE = 2;
static float textureCoords[] = {
    0.0f, 0.0f,                 
    0.0f, 1.0f,
    1.0f, 0.0f,
    0.0f, 1.0f,
    1.0f, 1.0f,
    1.0f, 0.0f,
};

Here's my draw function in my square class:

public void draw(float[] mvpMatrix) 
{
    int MVPMatrixHandle = GLES20.glGetUniformLocation(shader.getProgram(), "u_MVPMatrix");
    int textureHandler = GLES20.glGetUniformLocation(shader.getProgram(), "u_s_texture");
    int positionHandler = GLES20.glGetAttribLocation(shader.getProgram(), "a_position");
    int texCoordHandler = GLES20.glGetAttribLocation(shader.getProgram(), "a_texCoord");

        Log.d(TAG, "Setting up GLProgram Handlers");
        GlRenderer.checkGlError("Setup GLProgram Handlers");

    GLES20.glEnableVertexAttribArray(positionHandler);
    GLES20.glEnableVertexAttribArray(texCoordHandler);

        GlRenderer.checkGlError("EnableVertexAttribArrays");

    GLES20.glVertexAttribPointer(positionHandler, COORDS_PER_VERTEX,
                                GLES20.GL_FLOAT, false,
                                vertexStride, vertexBuffer);        

    GLES20.glVertexAttribPointer(textureHandler, COORDS_PER_TEXTURE,
                                GLES20.GL_FLOAT, false, 
                                textureStride, textureBuffer);

        GlRenderer.checkGlError("VertexAttribPointers (Position, Texture)");


    GLES20.glUniformMatrix4fv(MVPMatrixHandle, 1, false, mvpMatrix, 0);

    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureID);

    GLES20.glUniform1i(textureHandler, 0);

        GlRenderer.checkGlError("Binding Texture");

    GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);

        GlRenderer.checkGlError("Draw Arrays");

    GLES20.glDisableVertexAttribArray(positionHandler);
    GLES20.glDisableVertexAttribArray(texCoordHandler);

        GlRenderer.checkGlError("DisableVertexAttribArrays");
}

Answer 1

Your SetupGLPositionHandle function looks wrong to me. Why disable the PositionHandle attribute at the end of the function?

The attribute must be enabled at the time glDrawArrays is called.

Answer 2

My main problem in the above code was the fact that I was using the textureHandleinstead of the texCoordHandler in the glVertexAttribPointer //Texture

The code should look like this:

GLES20.glVertexAttribPointer(texCoordHandler, COORDS_PER_TEXTURE,
                            GLES20.GL_FLOAT, false, 
                            textureStride, textureBuffer);

Since this problem arose I've rewritten my code yet again. Adding indices (draworder), combining my Vertex and Texture arrays into a Vertices array, and just reference a vertexBuffer //Contains both position coordinates and texture coordinates instead of a textureBuffer and a vertexBuffer //Only contains position coordinates

I've also changed the GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount); to:

GLES20.glDrawElements(GLES20.GL_TRIANGLES, indices.length, 
                      GLES20.GL_UNSIGNED_SHORT, indexBuffer);