private FloatBuffer vals = Buffers.newDirectFloatBuffer(16); private Matrix4f pMat = new Matrix4f(); private Matrix4f vMat = new Matrix4f(); private Matrix4f mMat = new Matrix4f(); private Matrix4f mvMat = new Matrix4f(); 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); 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; cubeLocZ = 0.0f; pyrLocX = 2.0f; pyrLocY = 2.0f; pyrLocZ = 0.0f; } public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) { } public void dispose(GLAutoDraw

private FloatBuffer vals = Buffers.newDirectFloatBuffer(16);
private Matrix4f pMat = new Matrix4f();
private Matrix4f vMat = new Matrix4f();
private Matrix4f mMat = new Matrix4f();
private Matrix4f mvMat = new Matrix4f();
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);

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;
cubeLocZ = 0.0f;
pyrLocX = 2.0f;
pyrLocY = 2.0f;
pyrLocZ = 0.0f;

}

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);

pLoc = gl.glGetUniformLocation(renderingProgram, "p_matrix");
mvLoc = gl.glGetUniformLocation(renderingProgram, "mv_matrix");

aspect = (float) myCanvas.getWidth() / (float) myCanvas.getHeight();
pMat.setPerspective((float) Math.toRadians(60.0f), aspect, 0.1f, 1000.0f);


vMat.translation(-cameraX, -cameraY, -cameraZ);

mMat.translation(cubeLocX, cubeLocY, cubeLocZ);
mvMat.identity();
mvMat.mul(vMat);
mvMat.mul(mMat);

gl.glUniformMatrix4fv(mvLoc, 1, false, mvMat.get(vals));
gl.glUniformMatrix4fv(pLoc, 1, false, pMat.get(vals));

gl.glBindBuffer(GL_ARRAY_BUFFER, vbo[0]);

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, 36);

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));

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();
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,
1.0f, -1.0f, 1.0f, 1.0f, -1.0f, -1.0f, 0.0f, 1.0f, 0.0f,
1.0f, -1.0f, -1.0f, -1.0f, -1.0f, -1.0f, 0.0f, 1.0f, 0.0f,
-1.0f, -1.0f, -1.0f, -1.0f, -1.0f, 1.0f, 0.0f, 1.0f, 0.0f,
-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
};
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);
}
}

 

Shader Coding:

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); }

 

Questions :

1. How to modify with explanation above Java openGL coding to add sphere 3D shape. Be sure to properly specify the number of vertices in the glDrawArrays() command ?

2. How to modify with explanation above Java openGL coding from No.1, so that the additional 3D shape rotates on its axis (just like the earth’s rotation, but we may choose which axis to rotate on, x, y, or z-axis) ?