moving the OpenGL examples to the core

java/examples/OpenGL/Shaders/LowLevelGL/LowLevelGL.pde

@@ -0,0 +1,102 @@
+// Draws a triangle using low-level OpenGL calls.
+import java.nio.FloatBuffer;
+
+PGraphicsOpenGL pg;
+PGL pgl;
+
+PShader flatShader;
+
+int vertLoc;
+int colorLoc;
+
+float[] vertices;
+float[] colors;
+
+FloatBuffer vertData;
+FloatBuffer colorData;
+
+void setup() {
+  size(400, 400, P3D);
+  
+  pg = (PGraphicsOpenGL)g;
+  
+  // Get the default shader that Processing uses to
+  // render flat geometry (w/out textures and lights).
+  flatShader = (PShader)getShader(PShader.FLAT);
+
+  vertices = new float[12];
+  vertData = PGL.allocateDirectFloatBuffer(12);
+
+  colors = new float[12];
+  colorData = PGL.allocateDirectFloatBuffer(12);
+}
+
+void draw() {
+  background(0);
+  
+  // The geometric transformations will be automatically passed 
+  // to the shader.
+  rotate(frameCount * 0.01f, width, height, 0);
+  
+  updateGeometry();
+  
+  pgl = pg.beginPGL(); 
+  flatShader.bind();
+
+  vertLoc = pgl.glGetAttribLocation(flatShader.glProgram, "inVertex");
+  colorLoc = pgl.glGetAttribLocation(flatShader.glProgram, "inColor");
+  
+  pgl.glEnableVertexAttribArray(vertLoc);
+  pgl.glEnableVertexAttribArray(colorLoc);
+  
+  pgl.glVertexAttribPointer(vertLoc, 4, PGL.GL_FLOAT, false, 0, vertData);
+  pgl.glVertexAttribPointer(colorLoc, 4, PGL.GL_FLOAT, false, 0, colorData);
+
+  pgl.glDrawArrays(PGL.GL_TRIANGLES, 0, 3);
+
+  pgl.glDisableVertexAttribArray(vertLoc);
+  pgl.glDisableVertexAttribArray(colorLoc);
+  
+  flatShader.unbind();  
+  pg.endPGL();
+}
+
+void updateGeometry() {
+  // Vertex 1
+  vertices[0] = 0;
+  vertices[1] = 0;
+  vertices[2] = 0;
+  vertices[3] = 1;
+  colors[0] = 1;
+  colors[1] = 0;
+  colors[2] = 0;
+  colors[3] = 1;
+
+  // Corner 2
+  vertices[4] = width/2;
+  vertices[5] = height;
+  vertices[6] = 0;
+  vertices[7] = 1;
+  colors[4] = 0;
+  colors[5] = 1;
+  colors[6] = 0;
+  colors[7] = 1;
+  
+  // Corner 3
+  vertices[8] = width;
+  vertices[9] = 0;
+  vertices[10] = 0;
+  vertices[11] = 1;
+  colors[8] = 0;
+  colors[9] = 0;
+  colors[10] = 1;
+  colors[11] = 1;
+  
+  vertData.rewind();
+  vertData.put(vertices);
+  vertData.position(0);
+  
+  colorData.rewind();
+  colorData.put(colors);
+  colorData.position(0);  
+}