private int initVAO(GL3 gl) {
int[] buff = new int[1];
gl.glGenVertexArrays(1, buff, 0);
int vao = buff[0];
Assert.assertTrue("Invalid VAO: " + vao, vao > 0);
gl.glUseProgram(progID);
final int posLoc = gl.glGetAttribLocation(progID, "vPosition");
final int colorLoc = gl.glGetAttribLocation(progID, "vColor");
gl.glUseProgram(0);
gl.glBindVertexArray(vao);
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, vbo);
gl.glBindBuffer(GL3.GL_ELEMENT_ARRAY_BUFFER, ibo);
gl.glEnableVertexAttribArray(posLoc);
gl.glEnableVertexAttribArray(colorLoc);
final int stride = 6 * Buffers.SIZEOF_FLOAT;
final int cOff = 3 * Buffers.SIZEOF_FLOAT;
gl.glVertexAttribPointer(posLoc, 3, GL3.GL_FLOAT, false, stride, 0L);
gl.glVertexAttribPointer(colorLoc, 3, GL3.GL_FLOAT, false, stride, cOff);
gl.glBindVertexArray(0);
// See class documentation above!
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, 0);
gl.glBindBuffer(GL3.GL_ELEMENT_ARRAY_BUFFER, 0);
return vao;
}
@Override
public void display(GLAutoDrawable glad) {
System.out.println("display");
GL3 gl3 = glad.getGL().getGL3();
gl3.glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
gl3.glClear(GL3.GL_COLOR_BUFFER_BIT);
programObject.bind(gl3);
{
programObject.setUniform(gl3, "offset", new float[] {0.5f, 0.5f}, 2);
gl3.glBindBuffer(GL3.GL_ARRAY_BUFFER, vertexBufferObject[0]);
gl3.glEnableVertexAttribArray(0);
gl3.glEnableVertexAttribArray(1);
{
gl3.glVertexAttribPointer(0, 4, GL3.GL_FLOAT, false, 0, 0);
gl3.glVertexAttribPointer(1, 4, GL3.GL_FLOAT, false, 0, 36 * 4 * 4);
gl3.glDrawArrays(GL3.GL_TRIANGLES, 0, 36);
}
gl3.glDisableVertexAttribArray(0);
gl3.glDisableVertexAttribArray(1);
}
programObject.unbind(gl3);
glad.swapBuffers();
}
private void displayVBOOnly(final GL3 gl) {
final int posLoc = gl.glGetAttribLocation(progID, "vPosition");
final int colorLoc = gl.glGetAttribLocation(progID, "vColor");
gl.glEnableVertexAttribArray(posLoc);
gl.glEnableVertexAttribArray(colorLoc);
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, vbo);
final int stride = 6 * Buffers.SIZEOF_FLOAT;
final int cOff = 3 * Buffers.SIZEOF_FLOAT;
gl.glVertexAttribPointer(posLoc, 3, GL3.GL_FLOAT, false, stride, 0L);
gl.glVertexAttribPointer(colorLoc, 3, GL3.GL_FLOAT, false, stride, cOff);
gl.glBindBuffer(GL3.GL_ELEMENT_ARRAY_BUFFER, ibo);
gl.glDrawElements(GL3.GL_TRIANGLES, 3, GL3.GL_UNSIGNED_SHORT, 0L);
gl.glDisableVertexAttribArray(posLoc);
gl.glDisableVertexAttribArray(colorLoc);
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, 0);
gl.glBindBuffer(GL3.GL_ELEMENT_ARRAY_BUFFER, 0);
}
/**
* The main rendering method.
*
* @param renderItem the object that needs to be drawn
*/
private void draw(RenderItem renderItem) {
// Set the material of the shape to be rendered
setMaterial(renderItem.getShape().getMaterial());
// Get reference to the vertex data of the render item to be rendered
GLVertexData vertexData = (GLVertexData) renderItem.getShape().getVertexData();
// Check if the vertex data has been uploaded to OpenGL via a
// "vertex array object" (VAO). The VAO will store the vertex data
// in several "vertex buffer objects" (VBOs) on the GPU. We do this
// only once for performance reasons. Once the data is in the VBOs
// asscociated with a VAO, it is stored on the GPU and rendered more
// efficiently.
if (vertexData.getVAO() == null) {
initArrayBuffer(vertexData);
}
// Set modelview and projection matrices in shader (has to be done in
// every step, since they usually have changed)
setTransformation(renderItem.getT());
// Bind the VAO of this shape. This activates the VBOs that we
// associated with the VAO. We already loaded the vertex data into the
// VBOs on the GPU, so we do not have to send them again.
vertexData.getVAO().bind();
// Try to connect the vertex buffers to the corresponding variables
// in the current vertex shader.
// Note: This is not part of the vertex array object, because the active
// shader may have changed since the vertex array object was initialized.
// We need to make sure the vertex buffers are connected to the right
// variables in the shader
ListIterator<VertexData.VertexElement> itr = vertexData.getElements().listIterator(0);
vertexData.getVAO().rewindVBO();
while (itr.hasNext()) {
VertexData.VertexElement e = itr.next();
int dim = e.getNumberOfComponents();
// Bind the next vertex buffer object
gl.glBindBuffer(GL3.GL_ARRAY_BUFFER, vertexData.getVAO().getNextVBO());
// Tell OpenGL which "in" variable in the vertex shader corresponds
// to the current vertex buffer object.
// We use our own convention to name the variables, i.e.,
// "position", "normal", "color", "texcoord", or others if
// necessary.
int attribIndex = -1;
switch (e.getSemantic()) {
case POSITION:
attribIndex = gl.glGetAttribLocation(activeShaderID, "position");
break;
case NORMAL:
attribIndex = gl.glGetAttribLocation(activeShaderID, "normal");
break;
case COLOR:
attribIndex = gl.glGetAttribLocation(activeShaderID, "color");
break;
case TEXCOORD:
attribIndex = gl.glGetAttribLocation(activeShaderID, "texcoord");
break;
}
gl.glVertexAttribPointer(attribIndex, dim, GL3.GL_FLOAT, false, 0, 0);
gl.glEnableVertexAttribArray(attribIndex);
}
// Render the vertex buffer objects
gl.glDrawElements(
GL3.GL_TRIANGLES,
renderItem.getShape().getVertexData().getIndices().length,
GL3.GL_UNSIGNED_INT,
0);
// We are done with this shape, bind the default vertex array
gl.glBindVertexArray(0);
cleanMaterial(renderItem.getShape().getMaterial());
}
