Open GL texture Issues

ThorPrime

Unregistered

Post: #1

Jun 6, 2005 — 08:48 PM

I've been programming for a few years and I'm just starting out with OpenGL.
I decided to start by modifying the tutorials found at http://nehe.gamedev.net/

The problem I am having is that the glColorXf( ) functions seem to break when GL_TEXTURE_2D is enabled. And the effect is different in 10.3 and 10.4
10.3 -

10.4 -

and this is how it looks with textures disabled:

this is the draw code:

Code:

- (BOOL) loadGLTextures

{

    BOOL status = FALSE;

    if( [ self loadBitmap:[ NSString stringWithFormat:@"%@/%s",

        [ [ NSBundle mainBundle ] resourcePath ],

        "NeHe.bmp" ] intoIndex:0 ] ) {

        status = TRUE;

        glGenTextures( 1, &texture[ 0 ] );   // Create the texture

        // Typical texture generation using data from the bitmap

        glBindTexture( GL_TEXTURE_2D, texture[ 0 ] );

        glTexImage2D( GL_TEXTURE_2D, 0, 3, texSize[ 0 ].width,

                      texSize[ 0 ].height, 0, texFormat[ 0 ],

                      GL_UNSIGNED_BYTE, texBytes[ 0 ] );

        // Linear filtering

        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );

        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_NEAREST );

        free( texBytes[ 0 ] );

    }

    return status;

}

- (void) initGL {

    [ self loadGLTextures ];

    //Initilize OpenGL

    //glEnable( GL_TEXTURE_2D );                // Enable texture mapping

    glShadeModel( GL_SMOOTH );                // Enable smooth shading

    glClearColor( 0.0f, 0.0f, 0.0f, 0.5f );   // Black background

    glClearDepth( 1.0f );                     // Depth buffer setup

    glEnable( GL_DEPTH_TEST );                // Enable depth testing

    glDepthFunc( GL_LEQUAL );                 // Type of depth test to do

                                              // Really nice perspective calculations

    glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST );

}

- (void) drawRect: (NSRect) rect {

    if (!initilized) {

        [self initGL];

        initilized = TRUE;

    } 

    // Tutorial A's code

    glViewport(0, 0, (GLsizei) rect.size.width, (GLsizei) rect.size.height);

    glMatrixMode(GL_PROJECTION);                            // Sets the projection matrix.

    glLoadIdentity();                                        // Reset the modelview matrix.

    // calculate the aspect ratio of the window.

    gluPerspective(45.0f, (GLfloat) rect.size.width /(GLfloat) rect.size.height, 0.1f, 1000.0f);

    glMatrixMode(GL_MODELVIEW);                                // Sets the projection matrix.

    glLoadIdentity();                                        // Reset the modelview matrix.

    // Tutorial B's code

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);        // Clear The Screen And The Depth Buffer

    glLoadIdentity(); 

    // Move Left 1.5 Units And Into The Screen 6.0

    glTranslatef( ((GLfloat) position[0]) + -1.5f, ((GLfloat) position[1]),-6.0f);    

    if (triDraw) {

        glRotatef((GLfloat) tRotation,0.0f,1.0f,0.0f);        // Rotate The Triangle On The Y axis

        glBegin(GL_TRIANGLES);                      // Drawing Using Triangles

            glColor4f( 1.0f, 0.0f, 0.0f, 0.5);          // Set color to red

            glVertex3f( 0.0f,  1.0f, 0.0f );      // Top of front

            glColor3f( 0.0f, 1.0f, 0.0f );        // Set color to green

            glVertex3f( -1.0f, -1.0f, 1.0f );     // Bottom left of front

            glColor3f( 0.0f, 0.0f, 1.0f );        // Set color to blue

            glVertex3f(  1.0f, -1.0f, 1.0f );     // Bottom right of front

            glColor3f( 1.0f, 0.0f, 0.0f );        // Red

            glVertex3f( 0.0f, 1.0f, 0.0f );       // Top of right side

            glColor3f( 0.0f, 0.0f, 1.0f );        // Blue

            glVertex3f( 1.0f, -1.0f, 1.0f );      // Left of right side

            glColor3f( 0.0f, 1.0f, 0.0f );        // Green

            glVertex3f( 1.0f, -1.0f, -1.0f );     // Right of right side

            glColor3f( 1.0f, 0.0f, 0.0f );        // Red

            glVertex3f( 0.0f, 1.0f, 0.0f );       // Top of back side

            glColor3f( 0.0f, 1.0f, 0.0f );        // Green

            glVertex3f( 1.0f, -1.0f, -1.0f );     // Left of back side

            glColor3f( 0.0f, 0.0f, 1.0f );        // Blue

            glVertex3f( -1.0f, -1.0f, -1.0f );    // Right of back side

            glColor3f( 1.0f, 0.0f, 0.0f );        // Red

            glVertex3f( 0.0f, 1.0f, 0.0f );       // Top of left side

            glColor3f( 0.0f, 0.0f, 1.0f );        // Blue

            glVertex3f( -1.0f, -1.0f, -1.0f );    // Left of left side

            glColor3f( 0.0f, 1.0f, 0.0f );        // Green

            glVertex3f( -1.0f, -1.0f, 1.0f );     // Right of left side

        glEnd();

        glLoadIdentity();

        glTranslatef(1.5f,0.0f,-7.0f);

    }                                              // Finished Drawing The Triangle

    else {

        glLoadIdentity();

        glTranslatef(0.0f,0.0f,-5.0f);

    }

    glColor3f( 1.0f, 1.0f, 1.0f );        // set the color to white to cover the texture

    glRotatef((GLfloat) sRotation,1.0f,1.0f,0.0f);            // Rotate The Quad On The X axis

    // Now we draw our texture mapped cube

    glBindTexture(GL_TEXTURE_2D, texture[0]);                // Select Our Texture

    glBegin( GL_QUADS );

        // Front face

        glTexCoord2f( 0.0f, 0.0f );

        glVertex3f( -1.0f, -1.0f,  1.0f );   // Bottom left

        glTexCoord2f( 1.0f, 0.0f );

        glVertex3f(  1.0f, -1.0f,  1.0f );   // Bottom right

        glTexCoord2f( 1.0f, 1.0f );

        glVertex3f(  1.0f,  1.0f,  1.0f );   // Top right

        glTexCoord2f( 0.0f, 1.0f );

        glVertex3f( -1.0f,  1.0f,  1.0f );   // Top left

        // Back face

        glTexCoord2f( 1.0f, 0.0f );

        glVertex3f( -1.0f, -1.0f, -1.0f );   // Bottom right

        glTexCoord2f( 1.0f, 1.0f );

        glVertex3f( -1.0f,  1.0f, -1.0f );   // Top right

        glTexCoord2f( 0.0f, 1.0f );

        glVertex3f(  1.0f,  1.0f, -1.0f );   // Top left

        glTexCoord2f( 0.0f, 0.0f );

        glVertex3f(  1.0f, -1.0f, -1.0f );   // Bottom left

        // Top face

        glTexCoord2f( 0.0f, 1.0f );

        glVertex3f( -1.0f,  1.0f, -1.0f );   // Top left

        glTexCoord2f( 0.0f, 0.0f );

        glVertex3f( -1.0f,  1.0f,  1.0f );   // Bottom left

        glTexCoord2f( 1.0f, 0.0f );

        glVertex3f(  1.0f,  1.0f,  1.0f );   // Bottom right

        glTexCoord2f( 1.0f, 1.0f );

        glVertex3f(  1.0f,  1.0f, -1.0f );   // Top right

        // Bottom face

        glTexCoord2f( 1.0f, 1.0f );

        glVertex3f( -1.0f, -1.0f, -1.0f );   // Top right

        glTexCoord2f( 0.0f, 1.0f );

        glVertex3f(  1.0f, -1.0f, -1.0f );   // Top left

        glTexCoord2f( 0.0f, 0.0f );

        glVertex3f(  1.0f, -1.0f,  1.0f );   // Bottom left

        glTexCoord2f( 1.0f, 0.0f );

        glVertex3f( -1.0f, -1.0f,  1.0f );   // Bottom right

        // Right face

        glTexCoord2f( 1.0f, 0.0f );

        glVertex3f(  1.0f, -1.0f, -1.0f );   // Bottom right

        glTexCoord2f( 1.0f, 1.0f );

        glVertex3f(  1.0f,  1.0f, -1.0f );   // Top right

        glTexCoord2f( 0.0f, 1.0f );

        glVertex3f(  1.0f,  1.0f,  1.0f );   // Top left

        glTexCoord2f( 0.0f, 0.0f );

        glVertex3f(  1.0f, -1.0f,  1.0f );   // Bottom left

        // Left face

        glTexCoord2f( 0.0f, 0.0f );

        glVertex3f( -1.0f, -1.0f, -1.0f );   // Bottom left

        glTexCoord2f( 1.0f, 0.0f );

        glVertex3f( -1.0f, -1.0f,  1.0f );   // Bottom right

        glTexCoord2f( 1.0f, 1.0f );

        glVertex3f( -1.0f,  1.0f,  1.0f );   // Top right

        glTexCoord2f( 0.0f, 1.0f );

        glVertex3f( -1.0f,  1.0f, -1.0f );   // Top left

    glEnd();

    [[self openGLContext] flushBuffer];

}

OneSadCookie

Luminary

Posts: 5,125
Joined: 2002.04

Post: #2

Jun 7, 2005 — 10:54 AM

LINEAR_MIPMAP_NEAREST is not a valid magnification mode. try LINEAR.

ThorPrime

Unregistered

Post: #3

Jun 7, 2005 — 07:12 PM

Yeh, I tried playing with that before, it has no effect on the problem.

reubert

Member

Posts: 320
Joined: 2003.06

Post: #4

Jun 8, 2005 — 06:29 PM

This may or may not be related, but you are not enabling blending, and the first color you set in the pyramid has 0.5f alpha. That should probably be glColor3f().

Aside from that, It seems that you are not disabling texturing before drawing the pyramid, and are not providing it any texture coordinates, so it's texturing it with a single pixel, which is likely to be black.

As glEnable(GL_TEXTURE_2D) is commented out at the start I don't see how it ever textures anything, so I'm guessing it was not commented out when you took the screenshots.

in short.. call glEnable(GL_TEXTURE_2D) before the drawing of the cube, and glDisable(GL_TEXTURE_2D) before the pyramid, and I think your problem will disappear.

David

Chopper, iSight Screensavers, DuckDuckDuck: http://majicjungle.com

execomrt

Unregistered

Post: #5

Jun 9, 2005 — 06:05 AM

Can you post the 'original texture' ?

So, assuming you are using NSBitmapImageRep for loading your bitmap, starting from MacOS 10.4, the loadBitmap returns a GL_ARGB (Big endian) instead of GL_RGBA (
Little Endian). Apparently this change is undocumented (or if someone can point to the documentation stating it).

So it's texFormat[ 0 ] = GL_BGRA_EXT;
and replace GL_UNSIGNED_BYTE to GL_UNSIGNED_INT_8_8_8_8_REV
if running on MacOS 10.4 ...

[EDIT]

In, fact you need to use GL_UNSIGNED_BYTE_8_8_8_8_REV on PPC or GL_UNSIGNED_BYTE_8_8_8_8 on Intel.

#if __BIG_ENDIAN__
GL_UNSIGNED_BYTE_8_8_8_8_REV
#else
GL_UNSIGNED_BYTE_8_8_8_8
#endif

ThorPrime

Unregistered

Post: #6

Jun 13, 2005 — 11:13 PM

Ok, the issue was not disabling textures before drawing the pyramid.

Thanks for all the help.

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