OpenGL Java, LWJGL

/* draw a triangle using very simple shaders and a vertex array object and vertex buffer objects */ import org.lwjgl.glfw.*; import org.lwjgl.opengl.*; import java.nio.ByteBuffer; import java.nio.FloatBuffer; import java.nio.IntBuffer; // import static org.lwjgl.glfw.Callbacks.*; import static org.lwjgl.glfw.GLFW.*; // just for the key constants // import static org.lwjgl.system.MemoryUtil.*; public class Ex1 extends Basic { public static void main(String[] args) { Ex1 app = new Ex1( "Six Rectangles", 500, 500, 30 ); app.start(); }// main // instance variables private FloatBuffer backColor; private Shader v1, f1; private int hp1; // handle for the GLSL program private int vao; // handle to the vertex array object private float[] positionData = { -1.0f, 0.6f, 0.0f, -0.4f, 0.6f, 0.0f, -0.4f, 1.0f, 0.0f, -1.0f, 1.0f, 0.0f, -0.4f, 1.0f, 0.0f, -1.0f, 0.6f, 0.0f, -1.0f, 0.2f, 0.0f, -1.0f, -0.2f, 0.0f, 0.0f, -0.2f, 0.0f, 0.0f, 0.2f, 0.0f, -1.0f, 0.2f, 0.0f, 0.0f, -0.2f, 0.0f, -1.0f,-1.0f,0.0f, -1.0f, -0.8f, 0.0f, -0.8f,-1.0f, 0.0f, -0.8f, -0.8f, 0.0f, -0.8f, -1.0f, 0.0f, -1.0f, -0.8f, 0.0f, 1.0f, 0.2f,0.0f, 0.8f, 0.2f, 0.0f, 0.8f, 1.0f, 0.0f, 0.8f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.2f, 0.0f, -0.2f, -0.2f, 0.0f, -0.2f -0.6f, 0.0f, 0.4f, -0.2f, 0.0f, 0.4f, -0.2f, 0.0f, 0.4f, -0.6f, 0.0f, -0.2f, -0.6f, 0.0f, 0.6f, -0.6f, 0.0f, 0.6f, -1.0f, 0.0f, 1.0f, -1.0f, 0.0f, 1.0f, -1.0f, 0.0f, 1.0f, -0.6f, 0.0f, 0.6f, -0.6f, 0.0f }; private float[] colorData = {1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f }; // construct basic application with given title, pixel width and height // of drawing area, and frames per second public Ex1( String appTitle, int pw, int ph, int fps ) { super( appTitle, pw, ph, (long) ((1.0/fps)*1000000000) ); // do other stuff before OpenGL starts up } protected void init() { String vertexShaderCode = "#version 330 core\n"+ "layout (location = 0 ) in vec3 vertexPosition;\n"+ "layout (location = 1 ) in vec3 vertexColor;\n"+ "out vec3 color;\n"+ "void main(void)\n"+ "{\n"+ " color = vertexColor;\n"+ " gl_Position = vec4( vertexPosition, 1.0);\n"+ "}\n"; System.out.println("Vertex shader:\n" + vertexShaderCode + "\n\n" ); v1 = new Shader( "vertex", vertexShaderCode ); String fragmentShaderCode = "#version 330 core\n"+ "in vec3 color;\n"+ "layout (location = 0 ) out vec4 fragColor;\n"+ "void main(void)\n"+ "{\n"+ " fragColor = vec4(color, 1.0 );\n"+ "}\n"; System.out.println("Fragment shader:\n" + fragmentShaderCode + "\n\n" ); f1 = new Shader( "fragment", fragmentShaderCode ); hp1 = GL20.glCreateProgram(); Util.error("after create program"); System.out.println("program handle is " + hp1 ); GL20.glAttachShader( hp1, v1.getHandle() ); Util.error("after attach vertex shader to program"); GL20.glAttachShader( hp1, f1.getHandle() ); Util.error("after attach fragment shader to program"); GL20.glLinkProgram( hp1 ); Util.error("after link program" ); GL20.glUseProgram( hp1 ); Util.error("after use program"); // set background color to white backColor = Util.makeBuffer4( 1.0f, 1.0f, 1.0f, 1.0f ); // create vertex buffer objects and their handles one at a time int positionHandle = GL15.glGenBuffers(); int colorHandle = GL15.glGenBuffers(); System.out.println("have position handle " + positionHandle + " and color handle " + colorHandle ); // connect data to the VBO's // first turn the arrays into buffers FloatBuffer positionBuffer = Util.arrayToBuffer( positionData ); FloatBuffer colorBuffer = Util.arrayToBuffer( colorData ); Util.showBuffer("position buffer: ", positionBuffer ); positionBuffer.rewind(); Util.showBuffer("color buffer: ", colorBuffer ); colorBuffer.rewind(); // now connect the buffers GL15.glBindBuffer( GL15.GL_ARRAY_BUFFER, positionHandle ); Util.error("after bind positionHandle"); GL15.glBufferData( GL15.GL_ARRAY_BUFFER, positionBuffer, GL15.GL_STATIC_DRAW ); Util.error("after set position data"); GL15.glBindBuffer( GL15.GL_ARRAY_BUFFER, colorHandle ); Util.error("after bind colorHandle"); GL15.glBufferData( GL15.GL_ARRAY_BUFFER, colorBuffer, GL15.GL_STATIC_DRAW ); Util.error("after set color data"); // set up vertex array object // using convenience form that produces one vertex array handle vao = GL30.glGenVertexArrays(); Util.error("after generate single vertex array"); GL30.glBindVertexArray( vao ); Util.error("after bind the vao"); System.out.println("vao is " + vao ); // enable the vertex array attributes GL20.glEnableVertexAttribArray(0); // position Util.error("after enable attrib 0"); GL20.glEnableVertexAttribArray(1); // color Util.error("after enable attrib 1"); // map index 0 to the position buffer index 1 to the color buffer GL15.glBindBuffer( GL15.GL_ARRAY_BUFFER, positionHandle ); Util.error("after bind position buffer"); GL20.glVertexAttribPointer( 0, 3, GL11.GL_FLOAT, false, 0, 0 ); Util.error("after do position vertex attrib pointer"); // map index 1 to the color buffer GL15.glBindBuffer( GL15.GL_ARRAY_BUFFER, colorHandle ); Util.error("after bind color buffer"); GL20.glVertexAttribPointer( 1, 3, GL11.GL_FLOAT, false, 0, 0 ); Util.error("after do color vertex attrib pointer"); } protected void processInputs() { // process all waiting input events while( InputInfo.size() > 0 ) { InputInfo info = InputInfo.get(); if( info.kind == 'k' && (info.action == GLFW_PRESS || info.action == GLFW_REPEAT) ) { int code = info.code; }// input event is a key else if ( info.kind == 'm' ) {// mouse moved // System.out.println( info ); } else if( info.kind == 'b' ) {// button action // System.out.println( info ); } }// loop to process all input events } protected void update() { } protected void display() { System.out.println( getStepNumber() ); GL30.glClearBufferfv( GL11.GL_COLOR, 0, backColor ); // activate vaos GL30.glBindVertexArray( vao ); Util.error("after bind vao"); // draw the buffers GL11.glDrawArrays( GL11.GL_TRIANGLES, 0, 36 ); Util.error("after draw arrays"); } }// Ex1