JoglTextBillboardProgram.java

package org.andork.jogl.awt;

import static com.jogamp.opengl.GL.GL_ARRAY_BUFFER;
import static com.jogamp.opengl.GL.GL_BLEND;
import static com.jogamp.opengl.GL.GL_DEPTH_TEST;
import static com.jogamp.opengl.GL.GL_FLOAT;
import static com.jogamp.opengl.GL.GL_ONE_MINUS_SRC_ALPHA;
import static com.jogamp.opengl.GL.GL_SRC_ALPHA;
import static com.jogamp.opengl.GL.GL_TEXTURE0;
import static com.jogamp.opengl.GL.GL_TEXTURE_2D;
import static com.jogamp.opengl.GL.GL_TRIANGLES;

import org.andork.jogl.JoglDrawContext;
import org.andork.jogl.JoglResourceManager;
import org.andork.jogl.awt.JoglText.Segment;
import org.andork.jogl.util.JoglUtils;
import org.andork.jogl.util.JoglUtils.LoadedProgram;

import com.jogamp.opengl.GL2ES2;

public class JoglTextBillboardProgram extends JoglTextProgram {
	private static final String vertexShaderCode = "uniform mat4 p;" +
			"uniform mat4 v;" +
			"uniform mat4 m;" +
			"uniform vec2 px;" +

			"uniform vec3 u_origin;" +
			"attribute vec3 a_pos;" +
			"attribute vec2 a_texcoord;" +

			"varying vec2 v_texcoord;" +

			"void main() {" +
			"  v_texcoord = a_texcoord;" +
			"  gl_Position = p * v * m * vec4(u_origin, 1.0);" +
			"  gl_Position.xy += vec2(a_pos.xy * px * gl_Position.w);" +
			"}";

	private static final String fragmentShaderCode = "uniform sampler2D u_texture;" +
			"uniform vec4 u_color;" +
			"varying vec2 v_texcoord;" +

			"void main() {" +
			// " gl_FragColor = vec4(u_color.xyz , u_color.w *
			// texture2D(u_texture, v_texcoord).r);" +
			"  gl_FragColor = vec4(u_color * texture2D(u_texture, v_texcoord));" +
			"  if (gl_FragColor.a == 0.0) {" +
			"    discard;" +
			"  }" +
			"}";

	private LoadedProgram program;

	private int mLoc;

	private int vLoc;

	private int pLoc;

	private int pxLoc;

	private int u_originLoc;

	private int u_colorLoc;

	private int a_posLoc;

	private int a_texcoordLoc;

	private int u_textureLoc;

	public JoglTextBillboardProgram(JoglResourceManager manager) {
		super(manager);
	}

	@Override
	protected void doDispose(GL2ES2 gl) {
		program.dispose(gl);
		program = null;
	}

	@Override
	protected void doInit(GL2ES2 gl) {
		program = JoglUtils.loadProgram2(gl, vertexShaderCode, fragmentShaderCode);

		mLoc = gl.glGetUniformLocation(program.program, "m");
		vLoc = gl.glGetUniformLocation(program.program, "v");
		pLoc = gl.glGetUniformLocation(program.program, "p");
		pxLoc = gl.glGetUniformLocation(program.program, "px");
		u_originLoc = gl.glGetUniformLocation(program.program, "u_origin");
		u_colorLoc = gl.glGetUniformLocation(program.program, "u_color");
		a_posLoc = gl.glGetAttribLocation(program.program, "a_pos");
		a_texcoordLoc = gl.glGetAttribLocation(program.program, "a_texcoord");
		u_textureLoc = gl.glGetUniformLocation(program.program, "u_texture");
	}

	@Override
	public void draw(JoglText text, JoglDrawContext context, GL2ES2 gl, float[] m, float[] n) {
		gl.glUseProgram(program.program);

		gl.glEnable(GL_DEPTH_TEST);

		gl.glEnable(GL_BLEND);
		gl.glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

		gl.glUniformMatrix4fv(mLoc, 1, false, m, 0);

		gl.glUniformMatrix4fv(vLoc, 1, false, context.viewXform(), 0);

		gl.glUniformMatrix4fv(pLoc, 1, false, context.projXform(), 0);

		gl.glUniform2fv(pxLoc, 1, context.pixelScale(), 0);

		gl.glUniform3fv(u_originLoc, 1, text.origin, 0);

		gl.glUniform1i(u_textureLoc, 0);

		gl.glEnableVertexAttribArray(a_posLoc);
		gl.glEnableVertexAttribArray(a_texcoordLoc);

		gl.glActiveTexture(GL_TEXTURE0);

		for (Segment segment : text.segments) {
			gl.glBindBuffer(GL_ARRAY_BUFFER, segment.buffer());
			gl.glBindTexture(GL_TEXTURE_2D, segment.page.getTexture());

			gl.glUniform4fv(u_colorLoc, 1, segment.color, 0);

			gl.glVertexAttribPointer(a_posLoc, 3, GL_FLOAT, false, 20, 0);
			gl.glVertexAttribPointer(a_texcoordLoc, 2, GL_FLOAT, false, 20, 12);

			gl.glDrawArrays(GL_TRIANGLES, 0, segment.count);
		}

		gl.glBindBuffer(GL_ARRAY_BUFFER, 0);
		gl.glBindTexture(GL_TEXTURE_2D, 0);

		gl.glDisable(GL_BLEND);
		gl.glDisable(GL_DEPTH_TEST);

		gl.glUseProgram(0);
	}

}