import com.jogamp.common.nio.Buffers; import com.jogamp.opengl.GL4; import com.jogamp.opengl.GLAutoDrawable; import com.jogamp.opengl.GLContext; import com.jogamp.opengl.GLEventListener; import com.jogamp.opengl.awt.GLCanvas; import org.joml.Matrix4f;

import javax.swing.*; import java.nio.FloatBuffer;

import static com.jogamp.opengl.GL4.*;

public class Program4_3 extends JFrame implements GLEventListener { private GLCanvas myCanvas; private int renderingProgram; private int vao[] = new int[1]; private int vbo[] = new int[2]; private float cameraX, cameraY, cameraZ; private float cubeLocX, cubeLocY, cubeLocZ; private float pyrLocX, pyrLocY, pyrLocZ;

// allocate variables used in display() function, so that they wont need to be allocated during rendering private FloatBuffer vals = Buffers.newDirectFloatBuffer(16); // utility buffer for transferring matrices private Matrix4f pMat = new Matrix4f(); // perspective matrix private Matrix4f vMat = new Matrix4f(); // view matrix private Matrix4f mMat = new Matrix4f(); // model matrix private Matrix4f mvMat = new Matrix4f(); // model-view matrix private int pLoc, mvLoc; private float aspect; private double elapsedTime, startTime, tf;

public Program4_3() { setTitle("Chapter4 - program3"); setSize(600, 600); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

myCanvas = new GLCanvas(); myCanvas.addGLEventListener(this); this.add(myCanvas);

/*Animator anmtr = new Animator(myCanvas); anmtr.start();*/

this.setVisible(true); }

public void init(GLAutoDrawable drawable) { GL4 gl = (GL4) GLContext.getCurrentGL(); renderingProgram = UtilsV7.createShaderProgram("./shaders/vertShader4_1_2.glsl", "./shaders/fragShader4_2.glsl"); setupVertices(); cameraX = 0.0f; cameraY = 0.0f; cameraZ = 8.0f; cubeLocX = 0.0f; cubeLocY = -2.0f; // shifted down the Y-axis to reveal perspective cubeLocZ = 0.0f; pyrLocX = 2.0f; // shifted right pyrLocY = 2.0f; // shifted down the Y-axis to reveal perspective pyrLocZ = 0.0f;

//startTime = System.currentTimeMillis(); }

// reshape() and dispose() are unchanged public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) { }

public void dispose(GLAutoDrawable drawable) { }

public void display(GLAutoDrawable drawable) { GL4 gl = (GL4) GLContext.getCurrentGL(); gl.glClear(GL_DEPTH_BUFFER_BIT); gl.glClear(GL_COLOR_BUFFER_BIT); gl.glUseProgram(renderingProgram);

// get references to the uniform variables for the MV and projection matrices pLoc = gl.glGetUniformLocation(renderingProgram, "p_matrix"); mvLoc = gl.glGetUniformLocation(renderingProgram, "mv_matrix");

// build perspective matrix. This one has fovy=60, aspect ratio matches the screen window. aspect = (float) myCanvas.getWidth() / (float) myCanvas.getHeight(); pMat.setPerspective((float) Math.toRadians(60.0f), aspect, 0.1f, 1000.0f);

// build view matrix vMat.translation(-cameraX, -cameraY, -cameraZ);

/*// use system time to generate slowly-increasing sequence of floating-point values elapsedTime = System.currentTimeMillis() - startTime; // elapsedTime, startTime, and tf tf = elapsedTime / 1000.0; // would all be declared of type double. */

// draw the cube (use buffer #0) mMat.translation(cubeLocX, cubeLocY, cubeLocZ); mvMat.identity(); mvMat.mul(vMat); mvMat.mul(mMat); // copy matrices and variables to corresponding uniform variables // by giving the uniform variable ID, one matrix to be sent, not transposed, and a pointer to the value sent gl.glUniformMatrix4fv(mvLoc, 1, false, mvMat.get(vals)); gl.glUniformMatrix4fv(pLoc, 1, false, pMat.get(vals)); // associate VBO with the corresponding vertex attribute in the vertex shader gl.glBindBuffer(GL_ARRAY_BUFFER, vbo[0]); // Sending to the location ID, 3 vertices of type float, not normalized, and with 0 offsets gl.glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0); gl.glEnableVertexAttribArray(0); // adjust OpenGL settings and draw model gl.glEnable(GL_DEPTH_TEST); gl.glDepthFunc(GL_LEQUAL); gl.glDrawArrays(GL_TRIANGLES, 0, 36);

// draw the pyramid (use buffer #1 and different model matrix) mMat.translation(pyrLocX, pyrLocY, pyrLocZ); mvMat.identity(); mvMat.mul(vMat); mvMat.mul(mMat); gl.glUniformMatrix4fv(mvLoc, 1, false, mvMat.get(vals)); gl.glUniformMatrix4fv(pLoc, 1, false, pMat.get(vals));

// (repeated for clarity) gl.glBindBuffer(GL_ARRAY_BUFFER, vbo[1]); gl.glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0); gl.glEnableVertexAttribArray(0); gl.glEnable(GL_DEPTH_TEST); gl.glDepthFunc(GL_LEQUAL); gl.glDrawArrays(GL_TRIANGLES, 0, 18); }

private void setupVertices() { GL4 gl = (GL4) GLContext.getCurrentGL();

// 36 vertices of the 12 triangles making up a 2 x 2 x 2 cube centered at the origin float[] cubePositions = {-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, 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, 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, -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, -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, -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};

float[ ] pyramidPositions = { -1.0f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 0.0f, 1.0f, 0.0f, // front face 1.0f, -1.0f, 1.0f, 1.0f, -1.0f, -1.0f, 0.0f, 1.0f, 0.0f, // right face 1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, 0.0f, 1.0f, 0.0f, // back face -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, 1.0f, 0.0f, 1.0f, 0.0f, // left face -1.0f, -1.0f, -1.0f, 1.0f, -1.0f, 1.0f, -1.0f, -1.0f, 1.0f, // base left front 1.0f, -1.0f, 1.0f, -1.0f, -1.0f, -1.0f, 1.0f, -1.0f, -1.0f // base right back }; gl.glGenVertexArrays(vao.length, vao, 0); gl.glBindVertexArray(vao[0]); gl.glGenBuffers(vbo.length, vbo, 0);

gl.glBindBuffer(GL_ARRAY_BUFFER, vbo[0]); FloatBuffer cubeBuf = Buffers.newDirectFloatBuffer(cubePositions); gl.glBufferData(GL_ARRAY_BUFFER, cubeBuf.limit() * 4, cubeBuf, GL_STATIC_DRAW);

gl.glBindBuffer(GL_ARRAY_BUFFER, vbo[1]); FloatBuffer pyrBuf = Buffers.newDirectFloatBuffer(pyramidPositions); gl.glBufferData(GL_ARRAY_BUFFER, pyrBuf.limit() * 4, pyrBuf, GL_STATIC_DRAW); } }

fragShader.glsl

#version 430 in vec4 varyingColor; out vec4 color; uniform mat4 mv_matrix; uniform mat4 p_matrix; void main(void) { color = varyingColor; }

vertShader.glsl

#version 430 layout (location=0) in vec3 position; uniform mat4 mv_matrix; uniform mat4 p_matrix; out vec4 varyingColor; void main(void) { gl_Position = p_matrix * mv_matrix * vec4(position,1.0); varyingColor = vec4(position,1.0) * 0.5 + vec4(0.5, 0.5, 0.5, 0.5); }

1. How to modify with explanation above java openGL program to add another simple 3D shape. Be sure to properly specify the number of vertices in the glDrawArrays() command ? (modification with coding and picture results)

2. How to modify above program from exercise 1 so that the additional 3D shape rotates on its axis (just like the earths rotation, but we may choose which axis to rotate on, x, y, or z-axis) ? (modification with coding and picture results)