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I'm using OpenGL ES to render some special effects, I don't want to show this to user, I just want to save the result as an UIImage, can anybody please help me?
this is the code I'm using, I can get an image which contains the red clear color I use, but no geometry drawing shown.
#import "RendererGL.h"
#import <GLKit/GLKit.h>
#import <UIKit/UIKit.h>
#import <OpenGLES/EAGL.h>
#import <OpenGLES/EAGLDrawable.h>
#import <OpenGLES/ES2/glext.h>
#import <QuartzCore/QuartzCore.h>
static NSInteger WIDTH_IN_PIXEL = 400;
static NSInteger HEIGHT_IN_PIXEL = 300;
typedef struct {
GLKVector3 positionCoords;
}
SceneVertex;
static const SceneVertex vertices[] =
{
{{-0.5f, -0.5f, 0.0}}, // lower left corner
{{ 0.5f, -0.5f, 0.0}}, // lower right corner
{{-0.5f, 0.5f, 0.0}} // upper left corner
};
#implementation RendererGL
{
EAGLContext* _myContext;
GLuint _framebuffer;
GLuint _colorRenderbuffer;
GLuint _depthRenderbuffer;
GLuint _vertexBufferID;
GLKBaseEffect *_baseEffect;
}
- (id) init
{
self = [super init];
if (self)
{
_myContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
[EAGLContext setCurrentContext:_myContext];
[self setupOffscreenBuffer];
[self setUpEffect];
[self renderImage];
[self saveImage]; //this do works, since I get an image, but the image only contains the red color I used to clear
}
return self;
}
-(void)setUpEffect
{
_baseEffect = [[GLKBaseEffect alloc] init];
_baseEffect.useConstantColor = GL_TRUE;
_baseEffect.constantColor = GLKVector4Make(0.0f, 0.0f, 1.0f, 1.0f);
}
//this code is from apples document
-(void)setupOffscreenBuffer
{
glGenFramebuffers(1, &_framebuffer);
glBindFramebuffer(GL_FRAMEBUFFER, _framebuffer);
glGenRenderbuffers(1, &_colorRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, _colorRenderbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA4, WIDTH_IN_PIXEL, HEIGHT_IN_PIXEL);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, _colorRenderbuffer);
glGenRenderbuffers(1, &_depthRenderbuffer);
glBindRenderbuffer(GL_RENDERBUFFER, _depthRenderbuffer);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, WIDTH_IN_PIXEL, HEIGHT_IN_PIXEL);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, _depthRenderbuffer);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER) ;
if(status != GL_FRAMEBUFFER_COMPLETE) {
NSLog(#"failed to make complete framebuffer object %x", status);
}
}
- (void) renderImage
{
GLenum error = GL_NO_ERROR;
glClearColor(1, 0, 0, 1); //red clear color, this can be seen
glClear(GL_COLOR_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
[_baseEffect prepareToDraw];
glGenBuffers(1, &_vertexBufferID);
glBindBuffer(GL_ARRAY_BUFFER, _vertexBufferID);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
error = glGetError();
if (error != GL_NO_ERROR) {
NSLog(#"error happend, error is %d, line %d",error,__LINE__);
}
glEnableVertexAttribArray(GLKVertexAttribPosition);
glVertexAttribPointer(GLKVertexAttribPosition,3,GL_FLOAT, GL_FALSE, sizeof(SceneVertex), NULL);
glDrawArrays(GL_TRIANGLES,0,3);
error = glGetError();
if (error != GL_NO_ERROR) {
NSLog(#"error happend, error is %d, line %d",error,__LINE__);
}
glFinish();
error = glGetError();
if (error != GL_NO_ERROR) {
NSLog(#"error happend, error is %d, line %d",error,__LINE__);
}
}
-(void)saveImage
{
GLenum error = GL_NO_ERROR;
NSInteger x = 0, y = 0;
NSInteger dataLength = WIDTH_IN_PIXEL * HEIGHT_IN_PIXEL * 4;
GLubyte *data = (GLubyte*)malloc(dataLength * sizeof(GLubyte));
glPixelStorei(GL_PACK_ALIGNMENT, 4);
glReadPixels(x, y, WIDTH_IN_PIXEL, HEIGHT_IN_PIXEL, GL_RGBA, GL_UNSIGNED_BYTE, data);
NSData *pixelsRead = [NSData dataWithBytes:data length:dataLength];
error = glGetError();
if (error != GL_NO_ERROR) {
NSLog(#"error happend, error is %d, line %d",error,__LINE__);
}
CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, data, dataLength, NULL);
CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
CGImageRef iref = CGImageCreate(WIDTH_IN_PIXEL, HEIGHT_IN_PIXEL, 8, 32, WIDTH_IN_PIXEL * 4, colorspace, kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast,
ref, NULL, true, kCGRenderingIntentDefault);
UIGraphicsBeginImageContext(CGSizeMake(WIDTH_IN_PIXEL, HEIGHT_IN_PIXEL));
CGContextRef cgcontext = UIGraphicsGetCurrentContext();
CGContextSetBlendMode(cgcontext, kCGBlendModeCopy);
CGContextDrawImage(cgcontext, CGRectMake(0.0, 0.0, WIDTH_IN_PIXEL, HEIGHT_IN_PIXEL), iref);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
NSData *d = UIImageJPEGRepresentation(image, 1);
NSString *documentDirPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
static NSInteger imageNO = 1;
imageNO++;
NSString *savingPath = [documentDirPath stringByAppendingPathComponent:[NSString stringWithFormat:#"%d.jpg",imageNO]];
BOOL succ = [d writeToFile:savingPath atomically:NO]; //is succeeded
UIGraphicsEndImageContext();
free(data);
CFRelease(ref);
CFRelease(colorspace);
CGImageRelease(iref);
}
#end
I had a very similar problem - to render some lines and get UIImage. I used OpenGL ES 1.1 and multisampling. I removed some additional code that does not refers to rendering and some OpenGL error checks. You can find the full code here: OSPRendererGL. Also, sorry for my one-for-all method.
#interface OSPRendererGL
{
EAGLContext* myContext;
GLuint framebuffer;
GLuint colorRenderbuffer;
GLuint depthRenderbuffer;
GLuint _vertexArray;
GLuint _vertexBuffer;
GLuint resolveFramebuffer;
GLuint msaaFramebuffer, msaaRenderbuffer, msaaDepthbuffer;
int width;
int height;
}
#implementation OSPRendererGL
- (id) init
{
self = [super init];
if (self)
{
myContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
[EAGLContext setCurrentContext:myContext];
[self setupOpenGL];
[EAGLContext setCurrentContext:nil];
width = 256;
height = 256;
}
return self;
}
-(void) setupOpenGL
{
glGenFramebuffersOES(1, &framebuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, framebuffer);
glGenRenderbuffersOES(1, &colorRenderbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, colorRenderbuffer);
glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_RGBA8_OES, width, height);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, colorRenderbuffer);
glGenRenderbuffersOES(1, &depthRenderbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, depthRenderbuffer);
glRenderbufferStorageOES(GL_RENDERBUFFER_OES, GL_DEPTH_COMPONENT16_OES, width, height);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, depthRenderbuffer);
glGenFramebuffersOES(1, &msaaFramebuffer);
glGenRenderbuffersOES(1, &msaaRenderbuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, msaaFramebuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, msaaRenderbuffer);
glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER_OES, 4, GL_RGBA8_OES, width, height);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, msaaRenderbuffer);
glGenRenderbuffersOES(1, &msaaDepthbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, msaaDepthbuffer);
glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER_OES, 4, GL_DEPTH_COMPONENT16_OES, width, height);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_DEPTH_ATTACHMENT_OES, GL_RENDERBUFFER_OES, msaaDepthbuffer);
}
-(UIImage *) renderImageAtZoom:(int)zoom
{
CGRect b = CGRectMake(0, 0, width, height);
OSPCoordinateRect r = OSPRectForMapAreaInRect([self mapArea], b);
double_scale = b.size.width / r.size.x;
double scale = 1.0/_scale;
[EAGLContext setCurrentContext:myContext];
glBindFramebuffer(GL_FRAMEBUFFER_OES, msaaFramebuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, msaaRenderbuffer);
glViewport(0, 0, width, height);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrthof(0.0f, 256.0f, 256.0f, 0.0f, 1.0f, -1.0f);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glScalef(_scale, _scale, 1);
glTranslatef(-r.origin.x, -r.origin.y, 0);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnable(GL_LINE_SMOOTH);
glEnable(GL_POINT_SMOOTH);
glEnable(GL_BLEND);
glClearColor(1, 1, 1, 1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// rendering here
glPopMatrix();
// msaa
glBindFramebufferOES(GL_READ_FRAMEBUFFER_APPLE, msaaFramebuffer);
glBindFramebufferOES(GL_DRAW_FRAMEBUFFER_APPLE, framebuffer);
glResolveMultisampleFramebufferAPPLE();
glBindFramebuffer(GL_FRAMEBUFFER_OES, framebuffer);
glBindRenderbufferOES(GL_RENDERBUFFER, colorRenderbuffer);
// grabbing image from FBO
GLint backingWidth, backingHeight;
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
NSInteger x = 0, y = 0;
NSInteger dataLength = width * height * 4;
GLubyte *data = (GLubyte*)malloc(dataLength * sizeof(GLubyte));
glPixelStorei(GL_PACK_ALIGNMENT, 4);
glReadPixels(x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE, data);
CGDataProviderRef ref = CGDataProviderCreateWithData(NULL, data, dataLength, NULL);
CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB();
CGImageRef iref = CGImageCreate(width, height, 8, 32, width * 4, colorspace, kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast,
ref, NULL, true, kCGRenderingIntentDefault);
UIGraphicsBeginImageContext(CGSizeMake(width, height));
CGContextRef cgcontext = UIGraphicsGetCurrentContext();
CGContextSetBlendMode(cgcontext, kCGBlendModeCopy);
CGContextDrawImage(cgcontext, CGRectMake(0.0, 0.0, width, height), iref);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
free(data);
CFRelease(ref);
CFRelease(colorspace);
CGImageRelease(iref);
[EAGLContext setCurrentContext:nil];
return image;
}
I don't see a call to eglSwapBuffers(). That is required to start rendering the frame on PowerVR, even when rendering to a Renderbuffer. See the example code at:
http://processors.wiki.ti.com/index.php/Render_to_Texture_with_OpenGL_ES
I want to use expose-event to draw something then update or redraw. That's to say, there are a drawing area and a button in window. When clicking button, the drawing area will be redrawn accordingly. My problems are
In the following code, if I changed gtk_container_add (GTK_CONTAINER (box), canvas); to gtk_box_pack_start(GTK_BOX(box), canvas, FALSE, FALSE, 0);, nothing is drawn. Usually we use gtk_box_pack_start to add something into box. Why doesn't it work this time?
The function build_ACC_axis refreshed(deleted what has drawn) drawing area and prepared for new draw. But it didn't delete what has drawn. Why? How to refresh the drawing area?
If the source file is test.c, then compilation is
gcc -o test test.c `pkg-config --cflags --libs gtk+-2.0`
The code is below:
#include <gtk/gtk.h>
#include <glib.h>
static void draw (GdkDrawable *d, GdkGC *gc)
{
/* Draw with GDK */
gdk_draw_line (d, gc, 0, 0, 50, 50);
gdk_draw_line (d, gc, 50, 50, 50, 150);
gdk_draw_line (d, gc, 50, 150, 0, 200);
gdk_draw_line (d, gc, 200, 0, 150, 50);
gdk_draw_line (d, gc, 150, 50, 150, 150);
gdk_draw_line (d, gc, 150, 150, 200, 200);
gdk_draw_line (d, gc, 50, 50, 150, 50);
gdk_draw_line (d, gc, 50, 150, 150, 150);
}
static gboolean expose_cb (GtkWidget *canvas, GdkEventExpose *event, gpointer user_data)
{
GdkGC *gc;
gc = gdk_gc_new (canvas->window);
draw (canvas->window, gc);
g_object_unref (gc);
return FALSE;
}
void build_ACC_axis (GtkWidget *button, GtkWidget *widget)
{
GdkRegion *region;
GtkWidget *canvas = g_object_get_data(G_OBJECT(widget), "plat_GA_canvas");
region = gdk_drawable_get_visible_region(canvas->window);
gdk_window_invalidate_region(canvas->window, region, TRUE);
gtk_widget_queue_draw(canvas);
/* gdk_window_process_updates(canvas->window, TRUE); */
gdk_region_destroy (region);
}
int main (int argc, char **argv)
{
GtkWidget *window;
GtkWidget *canvas, *box, *button;
gtk_init (&argc, &argv);
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_widget_set_size_request(window, 500, 300);
g_signal_connect (G_OBJECT (window), "destroy", G_CALLBACK (gtk_main_quit), NULL);
box = gtk_vbox_new(FALSE, 0);
gtk_container_add (GTK_CONTAINER (window), box);
canvas = gtk_drawing_area_new ();
g_object_set_data(G_OBJECT(window), "plat_GA_canvas", canvas);
/* gtk_box_pack_start(GTK_BOX(box), canvas, FALSE, FALSE, 0); */
gtk_container_add (GTK_CONTAINER (box), canvas);
g_signal_connect (G_OBJECT (canvas), "expose-event", G_CALLBACK (expose_cb), NULL);
button = gtk_button_new_with_label ("ok");
gtk_box_pack_start(GTK_BOX(box), button, FALSE, FALSE, 0);
/* gtk_container_add (GTK_CONTAINER (box), button); */
gtk_signal_connect(GTK_OBJECT(button), "clicked", GTK_SIGNAL_FUNC(build_ACC_axis), window);
gtk_widget_show_all (window);
gtk_main ();
}
I would like to answer my second question. After clicking button, it would send expose-event signal and run expose_cb. Since there is no change in draw function, we can't see the refreshing. Following is the updated code that can show refreshing. The point is to add variable factor. But for the first question, I still didn't know why.
#include <gtk/gtk.h>
#include <glib.h>
int factor;
static void draw (GdkDrawable *d, GdkGC *gc, double fac)
{
/* Draw with GDK */
gdk_draw_line (d, gc, 0, 0, 50, 50 * fac);
gdk_draw_line (d, gc, 50, 50, 50, 150);
gdk_draw_line (d, gc, 50, 150, 0, 200);
gdk_draw_line (d, gc, 200, 0, 150, 50);
gdk_draw_line (d, gc, 150, 50, 150, 150);
gdk_draw_line (d, gc, 150, 150, 200, 200);
gdk_draw_line (d, gc, 50, 50, 150, 50);
gdk_draw_line (d, gc, 50, 150, 150, 150);
}
static gboolean expose_cb (GtkWidget *canvas, GdkEventExpose *event, gpointer user_data)
{
GdkGC *gc;
gc = gdk_gc_new (canvas->window);
draw (canvas->window, gc, factor);
g_object_unref (gc);
return FALSE;
}
void build_ACC_axis (GtkWidget *button, GtkWidget *widget)
{
GdkRegion *region;
GtkWidget *canvas = g_object_get_data(G_OBJECT(widget), "plat_GA_canvas");
region = gdk_drawable_get_visible_region(canvas->window);
gdk_window_invalidate_region(canvas->window, region, TRUE);
/* gtk_widget_queue_draw(canvas); */
gdk_window_process_updates(canvas->window, TRUE);
gdk_region_destroy (region);
factor++;
}
int main (int argc, char **argv)
{
GtkWidget *window;
GtkWidget *canvas, *box, *button;
gtk_init (&argc, &argv);
factor = 1;
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_widget_set_size_request(window, 500, 300);
g_signal_connect (G_OBJECT (window), "destroy", G_CALLBACK (gtk_main_quit), NULL);
box = gtk_vbox_new(FALSE, 0);
gtk_container_add (GTK_CONTAINER (window), box);
canvas = gtk_drawing_area_new ();
g_object_set_data(G_OBJECT(window), "plat_GA_canvas", canvas);
/* gtk_box_pack_start(GTK_BOX(box), canvas, FALSE, FALSE, 0); */
gtk_container_add (GTK_CONTAINER (box), canvas);
g_signal_connect (G_OBJECT (canvas), "expose-event", G_CALLBACK (expose_cb), NULL);
button = gtk_button_new_with_label ("ok");
gtk_box_pack_start(GTK_BOX(box), button, FALSE, FALSE, 0);
/* gtk_container_add (GTK_CONTAINER (box), button); */
gtk_signal_connect(GTK_OBJECT(button), "clicked", GTK_SIGNAL_FUNC(build_ACC_axis), window);
gtk_widget_show_all (window);
gtk_main ();
}
I'm using the CoreGraphcis to create a text texture. Unfortunately the text renders like this (Text color is same as background to demonstrate the strange border).
I've tried playing with stroke colors and borders to I think it is do to OpenGLES 2.0 and not CoreGraphics.
// Create default framebuffer object. The backing will be allocated for the current layer in -resizeFromLayer
glGenFramebuffers(1, &defaultFramebuffer);
glGenRenderbuffers(1, &colorRenderbuffer);
glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);
glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, colorRenderbuffer);
glActiveTexture(GL_TEXTURE0);
glUniform1i(uniforms[UNIFORM_SAMPLER], 0);
// Set up the texture state.
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_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
texture = [[FW2Texture alloc] initWithString:#"Text"];
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture.width, texture.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, texture.imageData);
And the core graphics bit:
-(id)initWithString:(NSString*)str {
if((self = [super init])) {
UIFont *font = [UIFont systemFontOfSize:17];
CGSize size = [str sizeWithFont:font];
NSInteger i;
width = size.width;
if((width != 1) && (((int)width) & (((int)width) - 1))) {
i = 1;
while(i < width)
i *= 2;
width = i;
}
height = size.height;
if((height != 1) && (((int)height) & (((int)height) - 1))) {
i = 1;
while(i < height)
i *= 2;
height = i;
}
NSInteger BitsPerComponent = 8;
int bpp = BitsPerComponent / 2;
int byteCount = width * height * bpp;
uint8_t *data = (uint8_t*) calloc(byteCount, 1);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGBitmapInfo bitmapInfo = kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big;
CGContextRef context = CGBitmapContextCreate(data,
width,
height,
BitsPerComponent,
bpp * width,
colorSpace,
bitmapInfo);
CGColorSpaceRelease(colorSpace);
CGContextSetGrayFillColor(context, 0.5f, 1.0f);
CGContextTranslateCTM(context, 0.0f, height);
CGContextScaleCTM(context, 1.0f, -1.0f);
UIGraphicsPushContext(context);
[str drawInRect:CGRectMake(0,
0,
size.width,
size.height)
withFont:font
lineBreakMode:UILineBreakModeWordWrap
alignment:UITextAlignmentCenter];
UIGraphicsPopContext();
CGContextRelease(context);
imageData = (uint8_t*)[[NSData dataWithBytesNoCopy:data length:byteCount freeWhenDone:YES] bytes];
}
return self;
}
What's your glBlendFunc? You're taking premultiplied alpha from CoreGraphics, so e.g. instead of a border pixel being (r, g, b, 0.5) it'll be (0.5*r, 0.5*g, 0.5*b, 0.5). That means you should composite with blending enabled, using glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA) so that you get srcColour + (1 - alpha of srcColour)*dstColour.
I use xcode Opengl App template to create a sample.
I am new to opengles, and having to try re-write the 'render' method in ES1Renderer.m
I try create a texture and show it on the screen, but nothing showed.
Someone can help me ? I have no idea how to fix it:
- (void)render
{
int imageW = 16;
int imageH = 16;
GLubyte *textureData = (GLubyte *) malloc(imageW * imageH << 2);
for (int i = 0; i < imageW * imageH << 2; i++) {
textureData[i]= 0xff & i;
}
GLuint textureId;
glGenTextures(1, &textureId);
glBindTexture(GL_TEXTURE_2D, textureId);
// when texture area is small, bilinear filter the closest mipmap
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_LINEAR );
// when texture area is large, bilinear filter the original
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
// the texture wraps over at the edges (repeat)
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageW, imageH, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData);
GLenum err = glGetError();
if (err != GL_NO_ERROR)
NSLog(#"Error uploading texture. glError: 0x%04X", err);
free(textureData);
float x = 10.0f;
float y = 10.0f;
float z = 0.0f;
float scaleX = 1.0f;
float scaleY = 1.0f;
float scaleZ = 1.0f;
int w = imageW /2;
int h = imageH /2;
const GLfloat squareVertices[] = {
-w, -h,
w, -h,
-w, h,
w, h,
};
const GLfloat textureCoords[] = {
0, 0,
1, 0,
0, 1,
1, 1,
};
glEnable(GL_TEXTURE_2D);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnableClientState(GL_VERTEX_ARRAY);
glBindTexture(GL_TEXTURE_2D, textureId);
glVertexPointer(2, GL_FLOAT, 0, squareVertices);
glTexCoordPointer(2, GL_FLOAT, 0, textureCoords);
glPushMatrix();
glTranslatef(x, y, z);
glScalef(scaleX, scaleY, scaleZ);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glPopMatrix();
glDisable(GL_TEXTURE_2D);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDisableClientState(GL_VERTEX_ARRAY);
NSLog(#"-->");
glDeleteTextures(1, &textureId);
// This application only creates a single color renderbuffer which is already bound at this point.
// This call is redundant, but needed if dealing with multiple renderbuffers.
glBindRenderbufferOES(GL_RENDERBUFFER_OES, colorRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}
Sadly the OpenGL template provided by Xcode has changed at some point — the current code (as of Xcode 3.2.5, creating an iOS Application with the 'OpenGL ES Application' template) no longer supplies a separate ES1Renderer.m and ES2Renderer.m, preferring to provide a single, simplified EAGLView.m and to perform runtime tests within GLTestViewController.m. With that in mind, I modified GLTestViewController.m's awakeFromNib no longer to attempt to get an ES 2 context:
- (void)awakeFromNib
{
EAGLContext *aContext = nil;//[[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
if (!aContext)
{
aContext = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
}
if (!aContext)
NSLog(#"Failed to create ES context");
else if (![EAGLContext setCurrentContext:aContext])
NSLog(#"Failed to set ES context current");
self.context = aContext;
[aContext release];
[(EAGLView *)self.view setContext:context];
[(EAGLView *)self.view setFramebuffer];
if ([context API] == kEAGLRenderingAPIOpenGLES2)
[self loadShaders];
animating = FALSE;
animationFrameInterval = 1;
self.displayLink = nil;
}
And copied and pasted relevant portions of your code into drawFrame:
- (void)drawFrame
{
[(EAGLView *)self.view setFramebuffer];
// Replace the implementation of this method to do your own custom drawing.
static const GLfloat squareVertices[] = {
-0.5f, -0.33f,
0.5f, -0.33f,
-0.5f, 0.33f,
0.5f, 0.33f,
};
const GLfloat textureCoords[] = {
0, 0,
1, 0,
0, 1,
1, 1,
};
static float transY = 0.0f;
glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
int imageW = 16;
int imageH = 16;
GLubyte *textureData = (GLubyte *) malloc(imageW * imageH << 2);
for (int i = 0; i < imageW * imageH << 2; i++) {
textureData[i]= 0xff & i;
}
GLuint textureId;
glGenTextures(1, &textureId);
glBindTexture(GL_TEXTURE_2D, textureId);
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, imageW, imageH, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData);
free(textureData);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.0f, (GLfloat)(sinf(transY)/2.0f), 0.0f);
transY += 0.075f;
glEnable(GL_TEXTURE_2D);
glVertexPointer(2, GL_FLOAT, 0, squareVertices);
glEnableClientState(GL_VERTEX_ARRAY);
glTexCoordPointer(2, GL_FLOAT, 0, textureCoords);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glDeleteTextures(1, &textureId);
[(EAGLView *)self.view presentFramebuffer];
}
The result works entirely as you seem to intend. At a guess, is it possible either that:
you're setting something other than the identity as your projection matrix, causing your geometry to be clipped because it is placed at z = 0?
you've neglected properly to abandon an attempt at ES 2 rendering, causing unexpected results because tasks like textured rendering aren't hardwired in with ES 2 in the same way that they are with ES1?
For some reason my texture are not drawing, even though my code looks exactly the same as an old project that did. So far, the vertexes and TexCoords look fine, as I am having white squares being drawn, where the texture should be drawn instead.
The process so far goes,
I load up a Contoller and in loadView, I
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_SRC_COLOR);
Then my renderer is loaded up, which does nothing on construction. After that I load up my Texture into gl. This code is a direct copy from my old project and I know it works.
- (GLuint)textureFromPath:(NSString *)path
{
GLuint texture;
glGenTextures(1, &texture);
UIImage *img = [[UIImage alloc] initWithContentsOfFile:path];
if (!img) {
NSLog(#"Image \"%#\" could not be loaded and was not bound", path);
return 0;
}
CGImageRef cgimage = img.CGImage;
float width = CGImageGetWidth(cgimage);
float height = CGImageGetHeight(cgimage);
CGRect bounds = CGRectMake(0, 0, width, height);
CGColorSpaceRef colourSpace = CGColorSpaceCreateDeviceRGB();
void *image = malloc(width * height * 4);
CGContextRef context = CGBitmapContextCreate(image, width, height, 8, 4 * width, colourSpace, kCGImageAlphaPremultipliedLast);
CGColorSpaceRelease(colourSpace);
CGContextClearRect(context, bounds);
CGContextTranslateCTM (context, 0, height);
CGContextScaleCTM (context, 1.0, -1.0);
CGContextDrawImage(context, bounds, cgimage);
CGContextRelease(context);
glBindTexture(GL_TEXTURE_2D, texture);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
[img release];
free(image);
return texture;
}
I then take the generate texture from gl and assign it's postion in the array of the Renderer at 0. I also did this in my old project and worked fine too. So far so good, I feel.
The Application then tells it to startAnimation, which it then calls setFramebuffer, which within it calls createFramebuffer as framebuffer is undefined. It then notifies the Renderer (btw, Renderer is a C++ class) that it has created the framebuffers.
void bufferHasBeenCreated() const {
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrthof(-160.0f, 160.0f, -240.0f, 240.0f, -5.0f, 1.0f);
glViewport(0, 0, 320, 480);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_SRC_COLOR);
}
It then calls the render on Renderer.
void render() {
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glClearColor(0.325f, 0.0f, 0.325f, 1.0f);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
static float rot = 0.0f;
glRotatef(rot, 0.0f, 0.0f, 1.0f);
//glColor4f(0.0f, 0.0f, 1.0f, 1.0f);
glBindTexture(GL_TEXTURE_2D, texture_[0]);
GLenum err = glGetError();
if (err != GL_NO_ERROR)
printf("Error. glError: 0x%04X\n", err);
glVertexPointer(2, GL_FLOAT, 0, pos[0]);
glTexCoordPointer(2, GL_FLOAT, 0, black);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glVertexPointer(2, GL_FLOAT, 0, pos[1]);
glTexCoordPointer(2, GL_FLOAT, 0, black);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glVertexPointer(2, GL_FLOAT, 0, pos[2]);
glTexCoordPointer(2, GL_FLOAT, 0, black);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
rot += 0.5f;
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
}
and then finally it then calls presentFramebuffer, which binds the renderBuffer and setup context.
Edit: I have done some more work on this, and it turns out it is something to do with the context and the buffers. Whenever I do just the context while enabling GL_TEXTURE_2D and GL_BLEND, as you do, the textures don't load. Yet do it when the buffers are loaded up and everything works.
I have got my texture to draw. I pulled all my code out and put it's own file. I will then start pulling it a part again and hopefully get everything working in the structure that I already have.
(Objective-C) ES1Renderer.h
#import <QuartzCore/QuartzCore.h>
#import "OpenGLES.h"
#interface ES1Renderer : UIView {
#private
GLint backingWidth;
GLint backingHeight;
EAGLContext *context;
GLuint viewFramebuffer, viewRenderbuffer;
GLuint texture[1];
BOOL animating;
BOOL displayLinkSupported;
NSInteger animationFrameInterval;
// Use of the CADisplayLink class is the preferred method for controlling your animation timing.
// CADisplayLink will link to the main display and fire every vsync when added to a given run-loop.
// The NSTimer class is used only as fallback when running on a pre 3.1 device where CADisplayLink
// isn't available.
id displayLink;
NSTimer *animationTimer;
}
#property (readonly, nonatomic, getter=isAnimating) BOOL animating;
#property (nonatomic) NSInteger animationFrameInterval;
- (void) startAnimation;
- (void) stopAnimation;
- (void)render;
#end
Next ES1Renderer.m
#import "ES1Renderer.h"
#implementation ES1Renderer
#synthesize animating;
#dynamic animationFrameInterval;
+ (Class)layerClass
{
return [CAEAGLLayer class];
}
- (id)initWithFrame:(CGRect)frame
{
if (self = [super initWithFrame:frame]) {
context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
if (!context || ![EAGLContext setCurrentContext:context])
{
[self release];
return nil;
}
// Generate buffers
glGenFramebuffersOES(1, &viewFramebuffer);
glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
glGenRenderbuffersOES(1, &viewRenderbuffer);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
// Disable Depth
glDisable(GL_DEPTH_TEST);
// Load textures
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_SRC_COLOR);
glGenTextures(1, texture);
UIImage *img = [[UIImage alloc] initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:#"colour" ofType:#"png"]];
if (!img) {
NSLog(#"Image \"colour.png\" could not be loaded and was not bound");
[self release];
return nil;
}
CGImageRef cgimage = img.CGImage;
float width = CGImageGetWidth(cgimage);
float height = CGImageGetHeight(cgimage);
CGRect bounds = CGRectMake(0, 0, width, height);
CGColorSpaceRef colourSpace = CGColorSpaceCreateDeviceRGB();
void *image = malloc(width * height * 4);
CGContextRef imgContext = CGBitmapContextCreate(image,
width, height,
8, 4 * width, colourSpace,
kCGImageAlphaPremultipliedLast);
CGColorSpaceRelease(colourSpace);
CGContextClearRect(imgContext, bounds);
CGContextTranslateCTM (imgContext, 0, height);
CGContextScaleCTM (imgContext, 1.0, -1.0);
CGContextDrawImage(imgContext, bounds, cgimage);
CGContextRelease(imgContext);
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);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
GLenum err = glGetError();
if (err != GL_NO_ERROR)
NSLog(#"Error. glError: 0x%04X\n", err);
free(image);
[img release];
animating = FALSE;
displayLinkSupported = FALSE;
animationFrameInterval = 1;
displayLink = nil;
animationTimer = nil;
// A system version of 3.1 or greater is required to use CADisplayLink. The NSTimer
// class is used as fallback when it isn't available.
NSString *reqSysVer = #"3.1";
NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
if ([currSysVer compare:reqSysVer options:NSNumericSearch] != NSOrderedAscending)
displayLinkSupported = TRUE;
}
return self;
}
- (void)drawView:(id)sender
{
[self render];
GLenum err = glGetError();
if (err != GL_NO_ERROR)
NSLog(#"Error. glError: 0x%04X\n", err);
}
- (void) render
{
//glDisable(GL_TEXTURE_2D);
[EAGLContext setCurrentContext:context];
glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
static const float textureVertices[] = {
-0.5f, -0.33f,
0.5f, -0.33f,
-0.5f, 0.33f,
0.5f, 0.33f,
};
static const float textureCoords[] = {
0.0f, 0.0f,
0.0f, 0.515625f,
0.12890625f, 0.0f,
0.12890625f, 0.515625f,
};
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glClearColor(0.5f, 0.5f, 0.5f, 1.0f);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glBindTexture(GL_TEXTURE_2D, texture[0]);
//glColor4f(0.0f, 0.0f, 0.0f, 1.0f);
glVertexPointer(2, GL_FLOAT, 0, textureVertices);
glTexCoordPointer(2, GL_FLOAT, 0, textureCoords);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}
- (void)layoutSubviews
{
[EAGLContext setCurrentContext:context];
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context renderbufferStorage:GL_RENDERBUFFER_OES fromDrawable:(CAEAGLLayer *)self.layer];
glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, viewRenderbuffer);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_WIDTH_OES, &backingWidth);
glGetRenderbufferParameterivOES(GL_RENDERBUFFER_OES, GL_RENDERBUFFER_HEIGHT_OES, &backingHeight);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glViewport(0, 0, backingWidth, backingHeight);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
if(glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES) != GL_FRAMEBUFFER_COMPLETE_OES)
NSLog(#"failed to make complete framebuffer object %x", glCheckFramebufferStatusOES(GL_FRAMEBUFFER_OES));
}
- (void) dealloc
{
// Tear down GL
if (viewFramebuffer)
{
glDeleteFramebuffersOES(1, &viewFramebuffer);
viewFramebuffer = 0;
}
if (viewRenderbuffer)
{
glDeleteRenderbuffersOES(1, &viewRenderbuffer);
viewRenderbuffer = 0;
}
// Tear down context
if ([EAGLContext currentContext] == context)
[EAGLContext setCurrentContext:nil];
[context release];
context = nil;
displayLink = nil;
animationTimer = nil;
[super dealloc];
}
- (NSInteger) animationFrameInterval
{
return animationFrameInterval;
}
- (void) setAnimationFrameInterval:(NSInteger)frameInterval
{
// Frame interval defines how many display frames must pass between each time the
// display link fires. The display link will only fire 30 times a second when the
// frame internal is two on a display that refreshes 60 times a second. The default
// frame interval setting of one will fire 60 times a second when the display refreshes
// at 60 times a second. A frame interval setting of less than one results in undefined
// behavior.
if (frameInterval >= 1)
{
animationFrameInterval = frameInterval;
if (animating)
{
[self stopAnimation];
[self startAnimation];
}
}
}
- (void) startAnimation
{
if (!animating)
{
if (displayLinkSupported)
{
// CADisplayLink is API new to iPhone SDK 3.1. Compiling against earlier versions will result in a warning, but can be dismissed
// if the system version runtime check for CADisplayLink exists in -initWithCoder:. The runtime check ensures this code will
// not be called in system versions earlier than 3.1.
displayLink = [NSClassFromString(#"CADisplayLink") displayLinkWithTarget:self selector:#selector(drawView:)];
[displayLink setFrameInterval:animationFrameInterval];
[displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
}
else
animationTimer = [NSTimer scheduledTimerWithTimeInterval:(NSTimeInterval)((1.0 / 60.0) * animationFrameInterval) target:self selector:#selector(drawView:) userInfo:nil repeats:TRUE];
animating = TRUE;
}
}
- (void)stopAnimation
{
if (animating)
{
if (displayLinkSupported)
{
[displayLink invalidate];
displayLink = nil;
}
else
{
[animationTimer invalidate];
animationTimer = nil;
}
animating = FALSE;
}
}
#end
There is only one problem with this code. It's out of date. Apple released a new way of doing things, but hell. It works.
Update:
It turns out I had set the context up before loading the textures.