convert OpenGL 1 texturing code to OpenGL 3 - opengl

Question

Simple question:
How does this piece of code
glBindTexture(GL_TEXTURE_2D, texture_);
glColor4f(1,1,1,1);
glBegin(GL_QUADS);
glTexCoord2f(0, 1); glVertex2f(left_, top_);
glTexCoord2f(1, 1); glVertex2f(right_, top_);
glTexCoord2f(1, 0); glVertex2f(right_, bottom_);
glTexCoord2f(0, 0); glVertex2f(left_, bottom_);
glEnd();
translate to modern OpenGL code with vertex arrays?

Answer 1

If you just want to port these lines to vertex arrays, it is as simple as:
static const float texCoords[8] = {
0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f };
float vertices[8] = {
left_, top_, right_, top_, right_, bottom_, left_, bottom_ };
glBindTexture(GL_TEXTURE_2D, texture_);
glColor4f(1,1,1,1);
glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glVertexPointer(2, GL_FLOAT, 0, vertices);
glEnableClientState(GL_VERTEX_ARRAY);
glDrawArrays(GL_QUADS, 0, 4);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableCLientState(GL_VERTEX_ARRAY);
However, this has nothing to do with modern OpenGL, in fact this code is completely valid OpenGL 1.1 code. Modern OpenGL is not just about vertex arrays over immediate mode. It is also about storing vertex data in vertex buffer objects (VBOs) and doing every computation (like transformation, lighting, texturing, ...) with shaders instead of the old fixed-function pipeline. So really porting this to modern OpenGL is in fact not such a simple question.
Since your question suggests that you aren't aware of all this, it doesn't make much sense to explain it here, as it doesn't just come down to 5-10 lines of code that you only need to subsitute for the lines in the question. You should rather consult some serious learning resource on modern OpenGL if that is what you want to do.
If all you want to do is indeed to use vertex arrays instead of immediate mode, then the above code should be sufficient, though it won't really buy you anything in this example, I guess.

Answer 2

BindTexture wll stay... but the rest.
1 in init method create VBO for vertices. Those vertices should be:
float verts[4*(2+3)] = { 0, 1, left_, top_, 0,
1, 1, right_, top_, 0,
1, 0, right_, bottom_, 0,
0, 1, left_, bottom_, 0 };
2 copy verts to GPU (glBufferData)
3 use glVertexAttribPointer to set up buffer data with attribs
4 draw arrays
for instance
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
glBindBuffer(GL_ARRAY_BUFFER, bufID);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(float)*5, sizeof(float)*2);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(float)*5, 0);
glDrawArrays with Triangle_strip