Drawing single quad texture openGL ES 2.0 - drawing

Question

I'm pretty new at ES 2.0, I'm trying to draw a single texture in openGL ES 2.0.
Here is my code:
data : a pointer to the texture (it is working, I already could test it with ES 1.0)
w : texture width
h : texture height
texture is 256x256 pixels
glGetError does return GL_NO_ERROR on every line…
Hope someone can help ! All I can see is a black screen !
Thanks,
Wise
{
{
enum {
ATTRIB_VERTEX=0,
ATTRIB_TEXTURE_POSITION,
NUM_ATTRIB
};
glClearColor (0.0f, 0.0f, 0.0f, 0.0f);
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
const GLfloat vertices[] = { -0.5f, -0.5f, 0.5f, -0.5f, -0.5f, 0.5f, 0.5f, 0.5f };
const GLfloat texture_coord[] = { 0.0f, 1.0f,0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f };
GLuint texName;
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texName);
glEnableVertexAttribArray(ATTRIB_VERTEX);
glVertexAttribPointer(ATTRIB_VERTEX, 2, GL_FLOAT, 0, 0, vertices);
glEnableVertexAttribArray(ATTRIB_TEXTURE_POSITION);
glVertexAttribPointer(ATTRIB_TEXTURE_POSITION, 2, GL_FLOAT, 0, 0, texture_coord);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA,w,h,
0, GL_RGBA,
GL_UNSIGNED_BYTE, data);
glDrawArrays (GL_TRIANGLES, 0, 4);
}
}

Answer 1

Is That full source ?? If so , you have to do these but you must do setting shader before these .
Setting hadles
ATTRIB_VERTEX = glGetAttribLocation(m_paintProgram, "position");
ATTRIB_TEXTURE_POSITION = glGetAttribLocation(m_paintProgram, "inputTextureCoordinate");
maintextureHandle= glGetUniformLocation(m_EffectProgram[displayMode], "texture0");
giving the value through handles
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texName);
glUniform1i(maintextureHandle, 0); // add
And also you don't have to call this code every time , just call it once
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texName);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D (GL_TEXTURE_2D, 0, GL_RGBA,w,h,0, GL_RGBA,GL_UNSIGNED_BYTE, data);
Actually , your code doesn't have so many required codes such as Shader load, Shader compile, glUseProgram() , glBindFramebuffer() , glviewport(), glBindRenderbuffer things like that. but I can't teach all of them so
I want you to refer to this link and learn more information of opengl es 2.0.
http://examples.oreilly.com/9780596804831/readme.html#WireframeSkeleton