Lighting get darker when texture is aplied
- by noah
Im using OpenGL ES 1.1 for iPhone.
I'm attempting to implement a skybox in my 3d world and started out by following one of Jeff Lamarches tutorials on creating textures. Heres the tutorial: iphonedevelopment.blogspot.com/2009/05/opengl-es-from-ground-up-part-6_25.html
Ive successfully added the image to my 3d world but am not sure why the lighting on the other shapes has changed so much. I want the shapes to be the original color and have the image in the background.
Before: https://www.dropbox.com/s/ojmb8793vj514h0/Screen%20Shot%202012-10-01%20at%205.34.44%20PM.png
After: https://www.dropbox.com/s/8v6yvur8amgudia/Screen%20Shot%202012-10-01%20at%205.35.31%20PM.png
Heres the init OpenGL:
- (void)initOpenGLES1
{
glShadeModel(GL_SMOOTH);
// Enable lighting
glEnable(GL_LIGHTING);
// Turn the first light on
glEnable(GL_LIGHT0);
const GLfloat lightAmbient[] = {0.2, 0.2, 0.2, 1.0};
const GLfloat lightDiffuse[] = {0.8, 0.8, 0.8, 1.0};
const GLfloat matAmbient[] = {0.3, 0.3, 0.3, 0.5};
const GLfloat matDiffuse[] = {1.0, 1.0, 1.0, 1.0};
const GLfloat matSpecular[] = {1.0, 1.0, 1.0, 1.0};
const GLfloat lightPosition[] = {0.0, 0.0, 1.0, 0.0};
const GLfloat lightShininess = 100.0;
//Configure OpenGL lighting
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, matAmbient);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, matDiffuse);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, matSpecular);
glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS, lightShininess);
glLightfv(GL_LIGHT0, GL_AMBIENT, lightAmbient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, lightDiffuse);
glLightfv(GL_LIGHT0, GL_POSITION, lightPosition);
// Define a cutoff angle
glLightf(GL_LIGHT0, GL_SPOT_CUTOFF, 40.0);
// Set the clear color
glClearColor(0, 0, 0, 1.0f);
// Projection Matrix config
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
CGSize layerSize = self.view.layer.frame.size;
// Swapped height and width for landscape mode
gluPerspective(45.0f, (GLfloat)layerSize.height / (GLfloat)layerSize.width, 0.1f, 750.0f);
[self initSkyBox];
// Modelview Matrix config
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// This next line is not really needed as it is the default for OpenGL ES
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glDisable(GL_BLEND);
// Enable depth testing
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
glDepthMask(GL_TRUE);
}
Heres the drawSkybox that gets called in the drawFrame method:
-(void)drawSkyBox
{
glDisable(GL_LIGHTING);
glDisable(GL_DEPTH_TEST);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
static const SSVertex3D vertices[] = {
{-1.0, 1.0, -0.0},
{ 1.0, 1.0, -0.0},
{-1.0, -1.0, -0.0},
{ 1.0, -1.0, -0.0}
};
static const SSVertex3D normals[] = {
{0.0, 0.0, 1.0},
{0.0, 0.0, 1.0},
{0.0, 0.0, 1.0},
{0.0, 0.0, 1.0}
};
static const GLfloat texCoords[] = {
0.0, 0.5,
0.5, 0.5,
0.0, 0.0,
0.5, 0.0
};
glLoadIdentity();
glTranslatef(0.0, 0.0, -3.0);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glVertexPointer(3, GL_FLOAT, 0, vertices);
glNormalPointer(GL_FLOAT, 0, normals);
glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_NORMAL_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glEnable(GL_LIGHTING);
glEnable(GL_DEPTH_TEST);
}
Heres the init Skybox:
-(void)initSkyBox
{
// Turn necessary features on
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_SRC_COLOR);
// Bind the number of textures we need, in this case one.
glGenTextures(1, &texture[0]); // create a texture obj, give unique ID
glBindTexture(GL_TEXTURE_2D, texture[0]); // load our new texture name into the current texture
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
NSString *path = [[NSBundle mainBundle] pathForResource:@"space" ofType:@"jpg"];
NSData *texData = [[NSData alloc] initWithContentsOfFile:path];
UIImage *image = [[UIImage alloc] initWithData:texData];
GLuint width = CGImageGetWidth(image.CGImage);
GLuint height = CGImageGetHeight(image.CGImage);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
void *imageData = malloc( height * width * 4 ); // times 4 because will write one byte for rgb and alpha
CGContextRef cgContext = CGBitmapContextCreate( imageData, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big );
// Flip the Y-axis
CGContextTranslateCTM (cgContext, 0, height);
CGContextScaleCTM (cgContext, 1.0, -1.0);
CGColorSpaceRelease( colorSpace );
CGContextClearRect( cgContext, CGRectMake( 0, 0, width, height ) );
CGContextDrawImage( cgContext, CGRectMake( 0, 0, width, height ), image.CGImage );
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
CGContextRelease(cgContext);
free(imageData);
[image release];
[texData release];
}
Any help is greatly appreciated.
