/*

ahbejarano

Mesh class.

*/

package geetransit.minecraft05.engine;

import java.util.*;

import java.nio.*;

import org.joml.*;

import static org.lwjgl.opengl.GL30.*;

import static org.lwjgl.system.MemoryUtil.*;

public class Mesh {

private static final Vector3f DEFAULT_COLOUR = new Vector3f(0.0f, 0.0f, 0.0f);

private final int vaoId;

private final int vertexCount;

private final List<Integer> vboIdList;

private Texture texture;

private Vector4f color;

public Mesh(float[] posArray, int[] indexArray, float[] coordArray) {

this.vboIdList = new ArrayList<>();

this.vertexCount = indexArray.length;

this.color = new Vector4f();

this.setColor(DEFAULT_COLOUR);

int vboId;

FloatBuffer posBuffer = null;

IntBuffer indexBuffer = null;

FloatBuffer coordBuffer = null;

try {

// Create the VAO

this.vaoId = glGenVertexArrays();

glBindVertexArray(this.vaoId);

// Position VBO

vboId = glGenBuffers();

this.vboIdList.add(vboId);

posBuffer = memAllocFloat(posArray.length);

posBuffer.put(posArray).flip();

glBindBuffer(GL_ARRAY_BUFFER, vboId);

glBufferData(GL_ARRAY_BUFFER, posBuffer, GL_STATIC_DRAW);

glEnableVertexAttribArray(0);

glVertexAttribPointer(0, 3, GL_FLOAT, false, 0, 0);

// Index VBO

vboId = glGenBuffers();

this.vboIdList.add(vboId);

indexBuffer = memAllocInt(indexArray.length);

indexBuffer.put(indexArray).flip();

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, vboId);

glBufferData(GL_ELEMENT_ARRAY_BUFFER, indexBuffer, GL_STATIC_DRAW);

// texture coords VBO

vboId = glGenBuffers();

this.vboIdList.add(vboId);

coordBuffer = memAllocFloat(coordArray.length);

coordBuffer.put(coordArray).flip();

glBindBuffer(GL_ARRAY_BUFFER, vboId);

glBufferData(GL_ARRAY_BUFFER, coordBuffer, GL_STATIC_DRAW);

glEnableVertexAttribArray(1);

glVertexAttribPointer(1, 2, GL_FLOAT, false, 0, 0);

// Unbind the VBO / VAB

glBindBuffer(GL_ARRAY_BUFFER, 0);

glBindVertexArray(0);

} finally {

if (posBuffer != null) memFree(posBuffer);

if (indexBuffer != null) memFree(indexBuffer);

if (coordBuffer != null) memFree(coordBuffer);

}

}

public int getVaoId() { return this.vaoId; }

public int getVertexCount() { return this.vertexCount; }

public Texture getTexture() { return this.texture; }

public Mesh setTexture(Texture texture) { this.texture = texture; return this; }

public boolean isTextured() { return this.texture != null; }

public Vector4f getColor() { return this.color; }

public Mesh setColor(float r, float g, float b) { this.setColor(new Vector3f(r, g, b)); return this; }

public Mesh setColor(float r, float g, float b, float a) { this.setColor(new Vector4f(r, g, b, a)); return this; }

public Mesh setColor(Vector3f color) { this.setColor(new Vector4f(color, 1f)); return this; }

public Mesh setColor(Vector4f color) { this.color.set(color); return this; }

// prepare mesh

public void prepare() { this.prepare(null); }

public void prepare(Mesh lastMesh) {

if (this == lastMesh)

return;

if (this.isTextured())

this.texture.prepare();

glBindVertexArray(this.vaoId);

}

// draw elements

public void render() {

glDrawElements(GL_TRIANGLES, this.vertexCount, GL_UNSIGNED_INT, 0);

}

// Restore state

public void restore() { this.restore(null); }

public void restore(Mesh nextMesh) {

if (this == nextMesh)

return;

glBindVertexArray(0);

}

protected void deleteVbos() {

// Delete the VBO

glBindBuffer(GL_ARRAY_BUFFER, 0);

for (int id : this.vboIdList)

glDeleteBuffers(id);

}

protected void disableVao() {

glDisableVertexAttribArray(0);

}

protected void deleteVao() {

// Delete the VAO

glBindVertexArray(0);

glDeleteVertexArrays(this.vaoId);

}

public void cleanup() { this.cleanup(true); }

public void cleanup(boolean cleanupTexture) {

this.disableVao();

this.deleteVbos();

if (cleanupTexture && this.isTextured())

this.texture.cleanup();

this.deleteVao();

}

}