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Member Since 17 Nov 2012
Offline Last Active Dec 04 2012 05:35 AM

Topics I've Started

Opengl Vbo Errors

25 November 2012 - 06:33 AM

Hey, I'm working on a minecraft-like voxel engine. I keep my block type information in chunks, before creating vectors, and then sending that information off into the GPU as a vbo. This was working fine, but after generating too many different vbo objects (well the pointer that you bind, with the buffer), the game kept crashing. I ignored this for a while, but i've fixed all my other bugs on my list, and this one needs to be addressed.
In order to solve it, I tried running the game without drawing the VBOs, and it didn't crash after alot of time. So from this, I figured having too many vbos was the problem, then I read various things, and people seemed to agree on reducing the calls to bindBuffer, or shoving all your objects(Th into one vbo (ideally) before sending it off. The render information is static, so this shouldn't be too difficult.
In order to solve it, I used indexes, and created just one vboPointer, then for every chunk I had, I just generated it in one of the indexes at a time. There can be anywhere from 30 to 1000 chunks loaded depending on the renderDistance.
Also deleting the buffers seemed to cause it to crash too. So after some research, I figured this was because it releases the buffer position for any future use. I think I tried generating it again, and had no luck.
I would like some clarity on vbo useage, do vbo indexes work for large numbers? Has uanyone had the bg where multiple vbo objects don't work? What should be the best approach for this? Minecraft uses display lists, but don't vbos give a performance boost?
Also, I heard the calls to bindBuffer will take a fair amount of processing, so is it better to bind these on a thread to completely reduce loading times?
One possible solution is too use not one vbo per chunk (16x16x16 blocks), or one for all of them, but one per X-Z position or something like that. But it's very hard to debug vbo errors when I can't understand the problem. Feels like i'm just trying anything, not making any progress on this.

class VboData {
int[] quadLength; // Sizes of Arrays
int vboIndex = -1;
int maxIndex = 0; // Stores the total number of vbos in it
int[] vboQuadID;
int[] vboColorID;
int[] vboNormalID;
int[] vboTexID;
boolean hasGenVbo = false;
VboData() {
//maxIndexTotal = maxChunks;
quadLength = new int[maxIndexTotal];
VboData(int maxIndex_) {
maxIndex = maxIndex_;
//maxIndexTotal = maxChunks;
quadLength = new int[maxIndexTotal];
void dumpMemory() {

int getQuadLength(int index) {
if (maxIndexTotal > -1)
return quadLength[index];
else return 0;
void genAllVBO() {
if (!hasGenVbo) {
println("Total: " + maxIndexTotal);
vboQuadID = new int[maxIndexTotal];
vboColorID = new int[maxIndexTotal];
vboNormalID = new int[maxIndexTotal];
vboTexID = new int[maxIndexTotal];
gl.glGenBuffers(maxIndexTotal, vboQuadID, 0 );
gl.glGenBuffers(maxIndexTotal, vboNormalID, 0);
gl.glGenBuffers(maxIndexTotal, vboTexID, 0);
gl.glGenBuffers(maxIndexTotal, vboColorID, 0 );
hasGenVbo = true;
void clearMemory(int vboIndex_) {
/*if (quadLength[vboIndex_] > 0) {
gl.glDeleteBuffers(1, vboQuadID, 0 );
gl.glDeleteBuffers(1, vboNormalID, 0);
gl.glDeleteBuffers(1, vboTexID, 0);
gl.glDeleteBuffers(1, vboColorID, 0 );
void genAllVBOs(Vector vboVertex, Vector vboColor, Vector vboNormal, Vector vboTexture, int vboIndex_) {
if (vboIndex_ < maxIndexTotal)
vboIndex = vboIndex_;
quadLength[vboIndex_] = vboVertex.size();
genVBO(vboVertex, vboNormal, vboTexture, vboColor);
void genVBO(Vector vboVertex, Vector vboNormal, Vector vboTexture, Vector vboColor) {
int quadLength2 = vboVertex.size();
if (quadLength2 > 0 && vboIndex > -1) {
int normalLength = vboNormal.size();
int texLength = vboTexture.size();
int colorLength = vboColor.size();

gl.glBindBuffer( GL.GL_ARRAY_BUFFER, vboQuadID[vboIndex] );
gl.glBufferData( GL.GL_ARRAY_BUFFER, quadLength2 * 3 * BufferUtil.SIZEOF_FLOAT, myVertex_to_float_buffer( vboVertex ), GL.GL_DYNAMIC_DRAW );
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, 0); // This resets the gl pointer to the start
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, vboNormalID[vboIndex] );
gl.glBufferData( GL.GL_ARRAY_BUFFER, normalLength * 3 * BufferUtil.SIZEOF_FLOAT, myNormal_to_float_buffer( vboNormal ), GL.GL_DYNAMIC_DRAW );
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, 0);
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, vboTexID[vboIndex] );
gl.glBufferData( GL.GL_ARRAY_BUFFER, texLength * 2 * BufferUtil.SIZEOF_FLOAT, myTexture_to_float_buffer( vboTexture ), GL.GL_DYNAMIC_DRAW );
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, 0);

gl.glBindBuffer( GL.GL_ARRAY_BUFFER, vboColorID[vboIndex] );
gl.glBufferData( GL.GL_ARRAY_BUFFER, colorLength * 4 * BufferUtil.SIZEOF_FLOAT, myColor_to_float_buffer( vboColor ), GL.GL_DYNAMIC_DRAW);
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, 0);
class RenderData {
int vboIndex = 0; // It's position in the vbo array
Vector vboVertex;
Vector vboColor;
Vector vboNormal;
Vector vboTexture;
RenderData() {
vboVertex = new Vector();
vboColor = new Vector();
vboNormal = new Vector();
vboTexture = new Vector();
void setMax() {
//if (vboVertex.size() != 0)
//quadLength = vboVertex.size();
void setIndex(int index) {
if (index < maxIndexTotal && index > -1)
vboIndex = index;

void clearMemory() {
vboVertex = null;
vboNormal = null;
vboTexture = null;
vboColor = null;*/
void clearVectors() {
vboVertex = new Vector();
vboNormal = new Vector();
vboTexture = new Vector();
vboColor = new Vector();
void renderVBO(VboData vbo,Texture tex, int quadLength, int vboIndex) {
//if (vbo.quadLength > 0) {
if (isRenderVBO && quadLength > 0 && vboIndex > -1) {

if (isShader) glsl.startShader();
// Enables opengl to draw vertex points from memory

// Points to vertexes in memory
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, vbo.vboTexID[vboIndex]);
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, vbo.vboColorID[vboIndex]);
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, vbo.vboNormalID[vboIndex]);
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, vbo.vboQuadID[vboIndex]);
// Draws the vertexes from memory - hence why needed point
gl.glDrawArrays(GL.GL_QUADS, 0, quadLength);
// Resets the binded buffer
gl.glBindBuffer( GL.GL_ARRAY_BUFFER, 0);
// Ends the opengl drawing

// Disables the client state

if (isShader) glsl.endShader();

Need Better Physics Engine in Game

17 November 2012 - 05:07 AM

Okay, so this is my first Post, so please forgive me as I'm sure I won't be giving out enough information.

I've been working on a project for some time now, and I'm trying to create a better physics engine, however physics is not my best subject. My game is similar to minecraft, there are static chunk objects, and physics objects. My main problem is that it seems very laggy, compared to other games, even with high fps. So i'm wondering if I should be putting the physics step on a thread and just using the position data etc for the rendering in order to get better movement? Another problem is, how do I do rotational collisions? Here is some of my code for collisions.
Attached File  townGen4.png   769.22KB   91 downloads

// This is for when a physics object when it hits the bottom of a block (static position)
void collide(PVector loc_, float r_) {
if (checkTop(loc_,r_,r_,r_)){
vel.y*= -bounce;
loc.y = loc_.y + r_+h+teleport;
hasCollide = true;
} else if (checkBottom(loc_,r_,r_,r_)) {
vel.y *= -(bounce);
loc.y = loc_.y -r_-h-teleport;
hasCollide = true;
isOnGround = true;
if (vel.y > -0.7 && vel.y < 0.7 && inBlockID == 0) {
vel.y = 0;

boolean checkTop(PVector loc_, float w_, float h_, float d_) { // Check Y axis collision
if ( loc_.y + h_ > loc.y - h && loc_.y - h_ < loc.y - h && // Y top's edge is between Blocks borders
loc.x < loc_.x + w_ && loc.x > loc_.x - w_ &&
(loc.z < loc_.z + d_ && loc.z > loc_.z - d_) )
return true;
else return false;
boolean checkBottom(PVector loc_, float w_, float h_, float d_) {
if ( loc_.y - h_ < loc.y + h && loc_.y + h_ > loc.y + h &&
loc.x < loc_.x + w_ && loc.x > loc_.x - w_ &&
(loc.z < loc_.z + d_ && loc.z > loc_.z - d_) )
return true;
else return false;

Would I have to check all the points along a plane to see if it goes through another plane? as they would not be parralel. (The sides of an object)
Also is there a better way to make sure a physics object doesn't clip through the block, besides setting its location outside of it?
(loc.y = loc_.y + r_+h+teleport;)