Problem loading GL texture (Mixing GL and Cocos)

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Problem loading GL texture (Mixing GL and Cocos)

(22 posts) (3 voices)

Started 2 years ago by Pearapps
Latest reply from yarri

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Pearapps
Member

I am trying to create a 3d cube from a OpenGL ES tuturial. EVERYTHING works except loading this image which is supposed to be on each side. The texture is just not there.

Here is my code:

- (void)draw
{	

    const GLfloat cubeVertices[] = {

        // Define the front face
        -1.0, 1.0, 1.0,             // top left
        -1.0, -1.0, 1.0,            // bottom left
        1.0, -1.0, 1.0,             // bottom right
        1.0, 1.0, 1.0,              // top right

        // Top face
        -1.0, 1.0, -1.0,            // top left (at rear)
        -1.0, 1.0, 1.0,             // bottom left (at front)
        1.0, 1.0, 1.0,              // bottom right (at front)
        1.0, 1.0, -1.0,             // top right (at rear)

        // Rear face
        1.0, 1.0, -1.0,             // top right (when viewed from front)
        1.0, -1.0, -1.0,            // bottom right
        -1.0, -1.0, -1.0,           // bottom left
        -1.0, 1.0, -1.0,            // top left

        // bottom face
        -1.0, -1.0, 1.0,
        -1.0, -1.0, -1.0,
        1.0, -1.0, -1.0,
        1.0, -1.0, 1.0,

        // left face
        -1.0, 1.0, -1.0,
        -1.0, 1.0, 1.0,
        -1.0, -1.0, 1.0,
        -1.0, -1.0, -1.0,

        // right face
        1.0, 1.0, 1.0,
        1.0, 1.0, -1.0,
        1.0, -1.0, -1.0,
        1.0, -1.0, 1.0
    };

    const GLshort squareTextureCoords[] = {
        // Front face
        0, 1,       // top left
        0, 0,       // bottom left
        1, 0,       // bottom right
        1, 1,       // top right

        // Top face
        0, 1,       // top left
        0, 0,       // bottom left
        1, 0,       // bottom right
        1, 1,       // top right

        // Rear face
        0, 1,       // top left
        0, 0,       // bottom left
        1, 0,       // bottom right
        1, 1,       // top right

        // Bottom face
        0, 1,       // top left
        0, 0,       // bottom left
        1, 0,       // bottom right
        1, 1,       // top right

        // Left face
        0, 1,       // top left
        0, 0,       // bottom left
        1, 0,       // bottom right
        1, 1,       // top right

        // Right face
        0, 1,       // top left
        0, 0,       // bottom left
        1, 0,       // bottom right
        1, 1,       // top right
    };
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glMatrixMode(GL_MODELVIEW);
	rota += 0.5;

	glLoadIdentity();
    glTranslatef(0.0, 0.0, -6.0);
	glRotatef(rota, 1.0, 1.0, 1.0);
	glVertexPointer(3, GL_FLOAT, 0, cubeVertices);
    glEnableClientState(GL_VERTEX_ARRAY);

    glTexCoordPointer(2, GL_SHORT, 0, squareTextureCoords);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);

	// Draw the front face in Red
	glColor4f(1.0, 0.0, 0.0, 1.0);
    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);

	// Draw the top face in green
	glColor4f(0.0, 1.0, 0.0, 1.0);
	glDrawArrays(GL_TRIANGLE_FAN, 4, 4);

	// Draw the rear face in Blue
	glColor4f(0.0, 0.0, 1.0, 1.0);
	glDrawArrays(GL_TRIANGLE_FAN, 8, 4);

	// Draw the bottom face
	glColor4f(1.0, 1.0, 0.0, 1.0);
	glDrawArrays(GL_TRIANGLE_FAN, 12, 4);

	// Draw the left face
	glColor4f(0.0, 1.0, 1.0, 1.0);
	glDrawArrays(GL_TRIANGLE_FAN, 16, 4);

	// Draw the right face
	glColor4f(1.0, 0.0, 1.0, 1.0);
	glDrawArrays(GL_TRIANGLE_FAN, 20, 4);

}

and my load texture method

- (void)loadTexture {
	// get image from file
	CGImageRef textureImage = [UIImage imageNamed:@"checkerplate.png"].CGImage;
	if (textureImage == nil) {
		return;
	}

	// get image size
	NSInteger texWidth = CGImageGetWidth(textureImage);
    NSInteger texHeight = CGImageGetHeight(textureImage);

	// allocate bitmap
	GLubyte * textureData = (GLubyte *)malloc(texWidth * texHeight * 4);

	// copy image contents
	CGContextRef textureContext = CGBitmapContextCreate(
														textureData,
														texWidth,
														texHeight,
														8, texWidth * 4,
														CGImageGetColorSpace(textureImage),
														kCGImageAlphaPremultipliedLast);
	CGContextDrawImage(textureContext,
					   CGRectMake(0.0, 0.0, (float)texWidth, (float)texHeight),
					   textureImage);

	// free the image
	CGContextRelease(textureContext);

	// Create the texture
	glGenTextures(1, &textures[0]);
	// Bind the texture
	glBindTexture(GL_TEXTURE_2D, textures[0]);
	// Finally display the texture
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData);
	// deallocate texture data
	free(textureData);
	// Turn into texture mapping state
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glEnable(GL_TEXTURE_2D);
}

THANKS

Posted 2 years ago #

Pearapps
Member

Anyone? Please?

Posted 2 years ago #
yarri
Member

Hi, you need to call loadTexture() at the right "time" within the proper OpenGL context. When do you call that function?

--yarri

Posted 2 years ago #
Pearapps
Member

I call [self loadTexture]; in init

Posted 2 years ago #
Pearapps
Member

I think all of the problem is with the context, But since i am not creating a new one, can I get one from cocos?

Posted 2 years ago #
Pearapps
Member

Do not think cocos is compatible with this.

Posted 2 years ago #
Pearapps
Member

Anyone?

Posted 2 years ago #
Lam
Member

You didn't bind the texture so it wouldn't use a texture to draw for glDrawArrays.

And also if the draw is an overridden draw for a CocosNode then you shouldn't be seeing any shape at all since you haven't converted your vertices correctly.

Oh and the texture is going to be upside down based on the coordinates you've given.

Posted 2 years ago #
Pearapps
Member

Can you fix this for me, I am a noob, I am so sorry.

:(

I have tried everything...

Posted 2 years ago #
Lam
Member

I'm always willing to take my time to 'help' you fix it and understand. Everyone's new to something at one point in their life... I won't fault you for that.

For one thing, are you inheriting a CocosNode?

Since cocos can easily create textures for you maybe you should think of inheriting a TextureNode or Sprite.

Posted 2 years ago #
Pearapps
Member

This is a subclass of CocosNode.

Posted 2 years ago #
Lam
Member
Ok well if you want easy access to a texture then you can subclass TextureNode.
Then you can use textures easily by using the TextureManager.

Rather than loadTexture, which is fine btw, you can get a texture easily with a TextureNode. Assuming you've inherited one then in init:
```
- (id) init
{
   if((self = [super init])){
      self.texture = [[TextureMgr sharedTextureManager] addImage:@"checkerplate.png"];
   }
   return self;
}
```
You can now be assured that a texture has been allocated properly.
Posted 2 years ago #
Lam
Member

Now let's understand cubeVertices for a bit.
The cube vertices will draw a shape with a dimension of 1x1x1 in size.

Since we are in node space the screen size is way too big for a dimension of 1x1x1. That's pretty much a pixel =/

But that's not too bad! Let's just multiply all the dimensions to obtain a visible cube. It should be visible as long as it's under the screen size of 480x320.

Posted 2 years ago #
Pearapps
Member

Multiply what?

The cube is visible, I am sure of that. Maybe i am just stupid.

Posted 2 years ago #
Pearapps
Member

It is already very big.

Posted 2 years ago #
Lam
Member
well first remove
```
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
```
You don't clear during the middle of a draw routine otherwise you've erased every previous cocosnode draw. That will have headaches later on and by doing a glLoadIdentity you've essentially lost all cocosnode transformations so you won't be able to easily use position to adjust your cube.

Then we'll attack the problem again. What does it show now?
Posted 2 years ago #
Pearapps
Member

The same thing

Posted 2 years ago #

Lam
Member

Hmm that's a strange problem. Anyway to get access to a texture you bind first then do stuff.

For example in the loadTexture you did this but I've commented a little more below:

// bind the texture that we are going to use. OpenGL is a state machine so once
// we've called glBindTexture all the code below works on that specific texture.
glBindTexture(GL_TEXTURE_2D, textures[0]);

// Create the texture using the currently bounded name above
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData);

// deallocate texture data
free(textureData);

// Set texture parameters to the currently bounded texture above again.
// Turn into texture mapping state
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

You would then want to do the same thing again when drawing:
But we've changed to a TextureNode so lets do it that way instead.
I generally enable my state before setting pointers to data so...

// We let gl know that we are going to use vertex array in the draw call
glEnableClientState(GL_VERTEX_ARRAY);

// we let gl know that we are also going to pass in texture coordinates.
glEnableClientState(GL_TEXTURE_COORD_ARRAY);

// we also enable texture2D mapping
glEnable(GL_TEXTURE_2D);

// we have to bind the texture we're using here
glBindTexture(GL_TEXTURE_2D, self.texture.name);

glVertexPointer(3, GL_FLOAT, 0, cubeVertices);
glTexCoordPointer(2, GL_SHORT, 0, squareTextureCoords);

.... all the glDrawArray() calls

// we clean up after ourselves by disabling state
glDisable(GL_TEXTURE_2D);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);

And i hope you at least see something if you do that.

Posted 2 years ago #

Pearapps
Member

Do you have AIM?

Posted 2 years ago #
Lam
Member

Unfortunately no i don't. What's wrong with the code though? That should show the texture at any rate.

Posted 2 years ago #
Pearapps
Member

Nah, I will just give up now. It was worth a shot I guess.

Posted 2 years ago #
yarri
Member

For what it's worth, I have two options for mixing 3D and Cocos2D...

1. The old OC3D code which seems to have died:
http://code.google.com/p/oc3d/

2. I actually use Cocos2D to drive SIO2:
http://www.sio2interactive.com
http://sio2interactive.forumotion.net/features-requests-f5/patch-less-footprint-to-load-png-t814.htm

(You'll notice Riq posted some helpful tips there by the way)

--yarri

Posted 2 years ago #

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