Original Post
I'm working on a simple little game for the iPhone, and I'd like to use textures, however I can't quite seem to get it working...
After some research I found this page and this site. Both are great references, and taught me a little bit about textures, however, after loading a texture using either function I can't get the texture displayed, here's what my code looks like:
Very Simple Texture Display Function (not working)
Normally, I'd not create an array every single frame only to display an image, but this is just an example. When I run this function, I get nothing. Blank- no image, nothing (unless of course I'd previously enabled a color array and hadn't disabled it afterwards)
Second Simple Display Function (this one uses a quick little class)
This function on the other hand, does change the display, instead of outputting the texture however it outputs a black square...
Setup Background
In my init function I'm calling
Two LONG Texture Loading Functions
I'd appreciate any help you can offer! I'm loving learning OpenGL, there's an awful lot to learn!
After some research I found this page and this site. Both are great references, and taught me a little bit about textures, however, after loading a texture using either function I can't get the texture displayed, here's what my code looks like:
Very Simple Texture Display Function (not working)
void drawTexture(GLuint texture, float x, float y, float w, float h){
glBindTexture(GL_TEXTURE_2D,texture);
GLfloat box[] = {x,y+h, x+w,y+h, x,y, x+w,y};
GLfloat tex[] = {0,0, 1,0, 1,1, 0,1};
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glVertexPointer(2, GL_FLOAT, 0,box);
glTexCoordPointer(2, GL_FLOAT, 0, tex);
glDrawArrays(GL_TRIANGLE_STRIP,0,4);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
}Normally, I'd not create an array every single frame only to display an image, but this is just an example. When I run this function, I get nothing. Blank- no image, nothing (unless of course I'd previously enabled a color array and hadn't disabled it afterwards)
Second Simple Display Function (this one uses a quick little class)
void draw_rect(RectObject* robj){
glVertexPointer(2, GL_FLOAT, 0, [robj vertices]);
glEnableClientState(GL_VERTEX_ARRAY);
glColorPointer(4, GL_UNSIGNED_BYTE, 0, [robj colors]);
glEnableClientState(GL_COLOR_ARRAY);
if ([robj texture] != -1){
glEnable(GL_TEXTURE_COORD_ARRAY);
glEnable(GL_TEXTURE_2D);
glClientActiveTexture([robj texture]);
glTexCoordPointer(2, GL_FLOAT, 0, defaultTexCoord);
glBindTexture(GL_TEXTURE_2D, [robj texture]);
}
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glDisable(GL_TEXTURE_2D);
glDisable(GL_TEXTURE_COORD_ARRAY);
}This function on the other hand, does change the display, instead of outputting the texture however it outputs a black square...
Setup Background
In my init function I'm calling
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_SRC_COLOR);Two LONG Texture Loading Functions
struct Texture2D LoadImage(NSString* path)
{
struct Texture2D tex;
tex.texture = -1;
// Id for texture
GLuint texture;
// Generate textures
glGenTextures(1, &texture);
// Bind it
glBindTexture(GL_TEXTURE_2D, texture);
// Set a few parameters to handle drawing the image
//at lower and higher sizes than original
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, GL_TRUE);
//NSString *path = [[NSString alloc] initWithUTF8String:imagefile.c_str()];
path = [[NSBundle mainBundle] pathForResource:path ofType:@""];
NSData *texData = [[NSData alloc] initWithContentsOfFile:path];
UIImage *image = [[UIImage alloc] initWithData:texData];
if (image == nil)
return tex;
// Get Image size
GLuint width = CGImageGetWidth(image.CGImage);
GLuint height = CGImageGetHeight(image.CGImage);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
// Allocate memory for image
void *imageData = malloc( height * width * 4 );
CGContextRef imgcontext = CGBitmapContextCreate(
imageData, width, height, 8, 4 * width, colorSpace,
kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big );
CGColorSpaceRelease( colorSpace );
CGContextClearRect( imgcontext,
CGRectMake( 0, 0, width, height ) );
CGContextTranslateCTM( imgcontext, 0, height - height );
CGContextDrawImage( imgcontext,
CGRectMake( 0, 0, width, height ), image.CGImage );
// Generate texture in opengl
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height,
0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
// Release context
CGContextRelease(imgcontext);
// Free Stuff
free(imageData);
[image release];
[texData release];
// Create and return texture
tex.texture=texture;
tex.width=width;
tex.height=height;
//= new Texture2D(texture,width, height);
return tex;
}
GLuint makeTexture(NSString* path){
GLuint texture[1]={-1};
glGenTextures(1, texture);
glBindTexture(GL_TEXTURE_2D, texture[0]);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
path = [[NSBundle mainBundle] pathForResource:path ofType:@"png"];
NSData *texData = [[NSData alloc] initWithContentsOfFile:path];
UIImage *image = [[UIImage alloc] initWithData:texData];
if (image == nil)
NSLog(@"Do real error checking here");
GLuint width = CGImageGetWidth(image.CGImage);
GLuint height = CGImageGetHeight(image.CGImage);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
void *imageData = malloc( height * width * 4 );
CGContextRef context = CGBitmapContextCreate( imageData, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big );
CGColorSpaceRelease( colorSpace );
CGContextClearRect( context, CGRectMake( 0, 0, width, height ) );
CGContextTranslateCTM( context, 0, height - height );
CGContextDrawImage( context, CGRectMake( 0, 0, width, height ), image.CGImage );
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
CGContextRelease(context);
free(imageData);
[image release];
[texData release];
return texture[0];
}I'd appreciate any help you can offer! I'm loving learning OpenGL, there's an awful lot to learn!