Texture notes:

	// Only gen once! Or at least match with glDeleteTextures()
	// Don't call it twice when resizing a framebuffer attachment e.t.c.
	PF_GL(glGenTextures(1, &handle));

	PF_GL(glBindTexture(GL_TEXTURE_2D, handle));

	// If an unusual data alignment (e.g: RGB, RG, R) is used, set this to 1.
	// Otherwise, stick to RGBA and 4.
	PF_GL(glPixelStorei(GL_UNPACK_ALIGNMENT, 4));

	// Upload RGBA data.
	PF_GL(glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, width, height,
		0, PF_GL_TEX_FORMAT_RGBA8, GL_UNSIGNED_BYTE, tex_default_data));

	PF_GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT));
	PF_GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT));

	// Configure interpolation without mipmaps...
	PF_GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
	PF_GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR));

	// Or with mipmaps...
	PF_GL(glGenerateMipmap(GL_TEXTURE_2D));
	PF_GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR));
	PF_GL(glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
		GL_LINEAR_MIPMAP_LINEAR));

	// 'Smoothstep interpolation' is worth implementing :)

Mesh notes:

	PF_GL(glGenBuffers(1, &handle));
	PF_GL(glBindBuffer(GL_ARRAY_BUFFER, handle));

	// Static mesh...
	vert_stride = 2;
	f32* verts_data = pf_alloc_push(alloc, vert_stride * PF_GL_TRI_VERT_COUNT]
	verts_data[0] = -1.0;
	verts_data[1] = -1.0;
	verts_data[2] = -1.0;
	verts_data[3] =  3.0;
	verts_data[4] =  3.0;
	verts_data[5] = -1.0;
	PF_GL(glBufferData(GL_ARRAY_BUFFER,
		PF_GL_TRI_VERT_COUNT * vert_stride * sizeof(f32),
		verts_data, GL_STATIC_DRAW));

	// Or pre-allocated dynamic...
	u64 max_vert_count = 100;
	u64 vert_data_stride = 8;
	PF_GL(glBufferData(GL_ARRAY_BUFFER,
		max_vert_count * vert_data_stride * sizeof(f32),
		0,
		GL_DYNAMIC_DRAW));



Program notes:

	// Use helper to build an entire program from vert and frag sources.
	u8* prog_err_str = 0;
	u64 prog_err_str_size = 0;
	u32 prog = 0;
	if (!pf_gl_build_program_from_vert_and_frag_shaders(
		alloc,
		prog_vert_shd_src_str, prog_vert_shd_src_str_size,
		prog_frag_shd_src_str, prog_frag_shd_src_str_size,
		&prog_err_str, &prog_err_str_size, &prog)) {
		pf_print_str(alloc, prog__err_str, prog_err_str_size);
		PF_ASSERT_MSG(0, PF_ASSERT_MSG_FATAL_ERRORS);
	}


	// Cache attribute / uniform locations.
	PF_GL(glUseProgram(prog));
	PF_GL(prog_attr_loc__pos_xy =
		glGetAttribLocation(prog, (char*)"a__pos_xy"));
	PF_GL(prog_uniform_loc__tex = glGetUniformLocation(
		prog, (char*)"u__tex"));


Draw notes:

	u64 vert_attrib_ptr_offset = 0;

	PF_GL(glEnableVertexAttribArray(prog_attr_loc__pos_xy__uv_xy);
	u64 vert_attrib_components_count = 2; // Pack into vec4s if possible!
	PF_GL(glVertexAttribPointer(
		prog_attr_loc__pos_xy__uv_xy,
		vert_attrib_components_count,
		GL_FLOAT, false,
		vert_data_stride * sizeof(f32),
		(void*)vert_attrib_ptr_offset));

	vert_attrib_ptr_offset +=
		vert_attrib_components_count * sizeof(f32);

	// ... continue for each attribute in strided data array.

	// Write if the buffer is GL_DYNAMIC_DRAW...
	u64 verts_to_draw_count = PF_GL_TRI_VERT_COUNT; // Draw one triangle.
	PF_GL(glBufferSubData(GL_ARRAY_BUFFER, 0,
		vert_data_stride * sizeof(f32) * verts_to_draw_count,
		verts_data));

	// Draw!
	PF_GL(glDrawArrays(GL_TRIANGLES, 0, verts_to_draw_count));