I am attempting to do some very simple 2D drawing with GLKit, including using a texture. However, if I load the texture, but don't even use it in the drawing, somehow it prevents the drawing from taking place!
Here is my setup code:
-(void) setup {
effect = [[GLKBaseEffect alloc] init];
// comment this out - drawing takes place
texture = [GLKTextureLoader textureWithCGImage:[UIImage imageNamed: #"arrow.png"].CGImage options:nil error: nil];
if (texture) {
effect.texture2d0.envMode = GLKTextureEnvModeReplace;
effect.texture2d0.target = GLKTextureTarget2D;
effect.texture2d0.name = texture.name;
};
// end of comment this out...
effect.transform.projectionMatrix = GLKMatrix4MakeOrtho(0.0, self.bounds.size.width, self.bounds.size.height, 0.0, 1, -1);
}
Here is my drawing code:
- (void)drawRect:(CGRect)rect {
GLKVector2 vertices[4];
GLKVector4 colors[4];
vertices[0] = GLKVector2Make(20.0, 30.0);
vertices[1] = GLKVector2Make(120.0, 45.0);
vertices[2] = GLKVector2Make(70.0, 88.0);
vertices[3] = GLKVector2Make(20.0, 80.0);
for(int i = 0; i < 4; i++) {
colors[i] = GLKVector4Make(0.3, 0.8, 0.5, 1.0);
};
glClearColor(0.85, 0.05, 0.1, 1.0);
glClear(GL_COLOR_BUFFER_BIT);
[effect prepareToDraw];
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnableVertexAttribArray(GLKVertexAttribPosition);
glEnableVertexAttribArray(GLKVertexAttribColor);
glVertexAttribPointer(GLKVertexAttribPosition, 2, GL_FLOAT, GL_FALSE, 0, vertices);
glVertexAttribPointer(GLKVertexAttribColor, 4, GL_FLOAT, GL_FALSE, 0, colors);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 3);
glDisableVertexAttribArray(GLKVertexAttribPosition);
glDisableVertexAttribArray(GLKVertexAttribColor);
glDisable(GL_BLEND);
}
For debugging OpenGL, run the code in Debug mode, then pause it and choose "Capture OpenGL ES frame" from the menu bar. This allows you to step through your drawing code and see the OpenGL state after each call. Therefore, you can compare the states between when you do the setup code and when you don't do it, and can pin down the bug.
For the problem itself: Setting the texture2d property of the effect is already enough to use the texture. It is automatically used in the drawing if you put it there. In [effect prepareToDraw], the whole state of the effect is applied - including the specified texture.
Related
i was following the tutorial from raywenderlich website, the gradient seems not to work perfectly, is it only because of the iphone simulator, or is it something else? I can't try myself with an iphone. Here is the image :
And the code :
-(CCSprite *)spriteWithColor:(ccColor4F)bgColor textureSize:(float)textureSize {
// 1: Create new CCRenderTexture
CCRenderTexture *rt = [CCRenderTexture renderTextureWithWidth:textureSize height:screenSize.height];
// 2: Call CCRenderTexture:begin
[rt beginWithClear:bgColor.r g:bgColor.g b:bgColor.b a:bgColor.a];
// 3: Draw into the texture
glDisable(GL_TEXTURE_2D);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
float gradientAlpha = 0.5;
CGPoint vertices[4];
ccColor4F colors[4];
int nVertices = 0;
vertices[nVertices] = CGPointMake(0, 0);
colors[nVertices++] = (ccColor4F){0, 0, 0, 0};
vertices[nVertices] = CGPointMake(textureSize, 0);
colors[nVertices++] = (ccColor4F){0, 0, 0, gradientAlpha};
vertices[nVertices] = CGPointMake(0, screenSize.height);
colors[nVertices++] = (ccColor4F){0, 0, 0, 0};
vertices[nVertices] = CGPointMake(textureSize, screenSize.height);
colors[nVertices++] = (ccColor4F){0, 0, 0, gradientAlpha};
glVertexPointer(2, GL_FLOAT, 0, vertices);
glColorPointer(4, GL_FLOAT, 0, colors);
glDrawArrays(GL_TRIANGLE_STRIP, 0, (GLsizei)nVertices);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnable(GL_TEXTURE_2D);
// 4: Call CCRenderTexture:end
[rt end];
// 5: Create a new Sprite from the texture
return [CCSprite spriteWithTexture:rt.sprite.texture];
}
Thanks
I am beginning to learn OpenGL ES 1.1 for iPhone and would like to draw a 2D image in orthographic projection behind a few 3D objects. Using Jeff Lamarche's tutorials and the book Pro OpenGL ES for iPhone and I've come up with the following couple methods to attempt to do this. If I disable the call to drawSunInRect the 3D objects are rendered just fine and I can move them with touch controls etc. If I uncomment that call and try to draw the sun image, the image appears in the CGRect I supply, but I cannot see any of my other 3D objects - the rest of the screen is black. I've tried to disable/enable depth testing in various places, pass different parameters to glOrthof(), and move around the rectangle but I keep getting the sun image only when the drawSunInRect method is called. I'm assuming it is covering my 3D objects.
// Draw Sun in Rect and with Depth
- (void)drawSunInRect:(CGRect)rect withDepth:(float)depth {
// Get screen bounds
CGRect frame = [[UIScreen mainScreen] bounds];
// Calculate vertices from passed CGRect and depth
GLfloat vertices[] =
{
rect.origin.x, rect.origin.y, depth,
rect.origin.x + rect.size.width , rect.origin.y, depth,
rect.origin.x, rect.size.height+rect.origin.y , depth,
rect.origin.x + rect.size.width , rect.size.height+rect.origin.y ,depth
};
// Map the texture coords - no repeating
static GLfloat textureCoords[] =
{
0.0, 0.0,
1.0, 0.0,
0.0, 1.0,
1.0, 1.0
};
// Disable DEPTH test and setup Ortho
glDisable(GL_DEPTH_TEST);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrthof(0,frame.size.width,frame.size.height,0,0.1f,1000.0);
// Enable blending and configure
glEnable(GL_BLEND);
glBlendFunc(GL_ONE,GL_ONE_MINUS_SRC_ALPHA);
// Enable VERTEX and TEXTURE client states
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
// Enable Textures
glEnable(GL_TEXTURE_2D);
// Projection Matrix Mode for ortho and reset
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
// No lighting or Depth Mask for 2D - no Culling
glDisable(GL_LIGHTING);
glDepthMask(GL_FALSE);
glDisable(GL_CULL_FACE);
glDisableClientState(GL_COLOR_ARRAY);
// Define ortho
glOrthof(0,frame.size.width,frame.size.height,0,0.1f,1000);
// From Jeff Lamarche Tutorials
// glOrthof(-1.0, // Left
// 1.0, // Right
// -1.0 / (rect.size.width / rect.size.height), // Bottom
// 1.0 / (rect.size.width / rect.size.height), // Top
// 0.01, // Near
// 10000.0); // Far
// Setup Model View Matrix
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
// Bind and draw the Texture
glBindTexture(GL_TEXTURE_2D,sunInt);
glVertexPointer(3, GL_FLOAT, 0, vertices);
glTexCoordPointer(2, GL_FLOAT,0,textureCoords);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
// Re-enable lighting
glEnable(GL_LIGHTING);
glDisable(GL_TEXTURE_2D);
glDisable(GL_BLEND);
glDisable(GL_DEPTH_TEST);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
glDepthMask(GL_TRUE);
}
// Override the draw in rect function
- (void)glkView:(GLKView *)view drawInRect:(CGRect)rect
{
// Initialize and init the rotation stuff for the object
// Identity Matrix
glLoadIdentity();
static GLfloat rot = 0.0;
// Clear any remnants in the drawing buffers
// and fill the background with black
glClearColor(0.0f,0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Render the Sun - 2D Sun Image in CGRect
//[self drawSunInRect:CGRectMake(100, 100, 50, 50) withDepth:-30.0]; // 2D Sun Image
// Render the BattleCruiser - 3D Battlecruiser
[self renderTheBattleCruiser];
// Calculate a time interval to use to rotate the cruiser lives
static NSTimeInterval lastDrawTime;
if (lastDrawTime)
{
NSTimeInterval timeSinceLastDraw = [NSDate timeIntervalSinceReferenceDate] - lastDrawTime;
rot += 75 * timeSinceLastDraw;
}
lastDrawTime = [NSDate timeIntervalSinceReferenceDate];
}
UPDATE
I modified the draw sun method to have only 1 push and 1 pop for the GL_PROJECTION. I am still having the same issue. The sun image appears but I cannot see my 3D Objects. I have tried to re-arrange the calls to the render methods so the 3D objects are rendered first but I get the same results. I would appreciate other ideas on how to see my orthographic texture and 3D objects together.
// Draw Sun in Rect and with Depth
- (void)drawSunInRect:(CGRect)rect withDepth:(float)depth {
// Get screen bounds
CGRect frame = [[UIScreen mainScreen] bounds];
// Calculate vertices from passed CGRect and depth
GLfloat vertices[] =
{
rect.origin.x, rect.origin.y, depth,
rect.origin.x + rect.size.width , rect.origin.y, depth,
rect.origin.x, rect.size.height+rect.origin.y , depth,
rect.origin.x + rect.size.width , rect.size.height+rect.origin.y ,depth
};
// Map the texture coords - no repeating
static GLfloat textureCoords[] =
{
0.0, 0.0,
1.0, 0.0,
0.0, 1.0,
1.0, 1.0
};
glEnable(GL_BLEND);
glBlendFunc(GL_ONE,GL_ONE_MINUS_SRC_ALPHA);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnable(GL_TEXTURE_2D);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glDisable(GL_LIGHTING);
glEnable(GL_DEPTH_TEST);
glDisable(GL_CULL_FACE);
glDisableClientState(GL_COLOR_ARRAY);
glOrthof(0,frame.size.width,frame.size.height,0,0,1000);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glColor4f(1,1,1,1);
glBindTexture(GL_TEXTURE_2D,sunInt);
glVertexPointer(3, GL_FLOAT, 0, vertices);
glTexCoordPointer(2, GL_FLOAT,0,textureCoords);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glEnable(GL_LIGHTING);
glDisable(GL_TEXTURE_2D);
glDisable(GL_BLEND);
glDisable(GL_DEPTH_TEST);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
I realized I was calling setClipping only once in my viewController viewDidLoad. I moved it to my glkView method and now I get my Sun image and my 3d object.
I am new to openGL OES on iPhone and have a memory issue with glCopyTexImage2D. So far i understood, this function should copy the current framebuffer to the binded texture. But for some reason it always allocates new memory, which i can see in instruments checking the allocations.
My goal is to read texture images and draw on it, after drawing i want to save the new texture , so i can scroll through the painting. So here is may code:
1) init opengl and framebuffer:
context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES1];
if (!context || ![EAGLContext setCurrentContext:context]) {
[self release];
return nil;
}
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_SRC_COLOR);
// Setup OpenGL states
glMatrixMode(GL_PROJECTION);
CGRect frame = self.bounds;
CGFloat scale = self.contentScaleFactor;
// Setup the view port in Pixels
glOrthof(0, frame.size.width * scale, 0, frame.size.height * scale, -1, 1);
glViewport(0, 0, frame.size.width, frame.size.height * scale);
glDisable(GL_DEPTH_TEST);
glDisable(GL_DITHER);
glMatrixMode(GL_MODELVIEW);
glEnableClientState(GL_VERTEX_ARRAY);
// Set a blending function appropriate for premultiplied alpha pixel data
glEnable(GL_POINT_SPRITE_OES);
glTexEnvf(GL_POINT_SPRITE_OES, GL_COORD_REPLACE_OES, GL_TRUE);
glPointSize(64 / kBrushScale);
2) now i load the saved images into the framebuffer:
if ([[NSFileManager defaultManager] fileExistsAtPath:path]) {
// load texture
NSData* data = [[NSData alloc] initWithContentsOfFile:path];
glGenTextures(1, &drawBoardTextures[i]);
glBindTexture(GL_TEXTURE_2D, drawBoardTextures[i]);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1024, 1024, 0, GL_RGBA, GL_UNSIGNED_BYTE, [data bytes]);
// free memory
[data release];
}
3) and finally render the texture:
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
int width = 1024;
GLfloat quad[] = {0.0,1024.0,1024.0,1024.0,0.0,0.0,1024.0,0.0};
GLfloat quadTex[] = {0.0,1.0,1.0,1.0,0.0,0.0,1.0,0.0};
for (int i=0; i<10; i++) {
quad[0] = width * i;
quad[2] = quad[0] + width;
quad[4] = quad[0];
quad[6] = quad[2];
glBindTexture(GL_TEXTURE_2D, drawBoardTextures[i]);
glVertexPointer(2, GL_FLOAT, 0, quad);
glTexCoordPointer(2, GL_FLOAT, 0, quadTex);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glBindTexture(GL_TEXTURE_2D, 0);
}
4) for now everything works fine, with gltranslatef i can scroll through the textures and also there is no allocation yet observed in instruments. so now i draw on the current window and want to save the result like followed:
int texIndex = offset.x/1024;
float diff = offset.x - (1024*texIndex);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glBindTexture(GL_TEXTURE_2D, drawBoardTextures[texIndex]);
glBindTexture(GL_TEXTURE_2D, drawBoardTextures[texIndex]);
glCopyTexSubImage2D(GL_TEXTURE_2D, 0, diff, 0, 0, 0, 1024-diff, 1024);
glBindTexture(GL_TEXTURE_2D, drawBoardTextures[texIndex + 1]);
glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 1024-diff, 0, diff, 1024);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glFlush();
No the problems starts. instead of writing it directly into the generated textures, it writes it into client memory. for every copied texture it uses ~4 MB of Ram, but every recopy doesn't need any memory. i really don't know what i did wrong.
Does anyone know what the problem is? Thanks alot for your help.
cheers
chris
I created a new iPhone OpenGL Project in Xcode. I filled my background with triangles and gave them a texture, see below:
CGImageRef spriteImage;
CGContextRef spriteContext;
GLubyte *spriteData;
size_t width, height;
// Sets up matrices and transforms for OpenGL ES
glViewport(0, 0, backingWidth, backingHeight);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
//glRotatef(-90,0,0,1);
glOrthof(-1.0f, 1.0f, -1.5f, 1.5f, -1.0f, 1.0f);
glMatrixMode(GL_MODELVIEW);
// Clears the view with black
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
// Sets up pointers and enables states needed for using vertex arrays and textures
glVertexPointer(2, GL_FLOAT, 0, vertices);
glEnableClientState(GL_VERTEX_ARRAY);
//glColorPointer(4, GL_FLOAT, 0, triangleColors);
//glColor4f(0.0f,1.0f,0.0f,1.0f);
//glEnableClientState(GL_COLOR_ARRAY);
glTexCoordPointer(2, GL_FLOAT, 0, spriteTexcoords);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
// Creates a Core Graphics image from an image file
spriteImage = [UIImage imageNamed:#"Bild.png"].CGImage;
// Get the width and height of the image
width = CGImageGetWidth(spriteImage);
height = CGImageGetHeight(spriteImage);
// Texture dimensions must be a power of 2. If you write an application that allows users to supply an image,
// you'll want to add code that checks the dimensions and takes appropriate action if they are not a power of 2.
if(spriteImage) {
// Allocated memory needed for the bitmap context
spriteData = (GLubyte *) calloc(width * height * 4, sizeof(GLubyte));
// Uses the bitmap creation function provided by the Core Graphics framework.
spriteContext = CGBitmapContextCreate(spriteData, width, height, 8, width * 4, CGImageGetColorSpace(spriteImage), kCGImageAlphaPremultipliedLast);
// After you create the context, you can draw the sprite image to the context.
CGContextDrawImage(spriteContext, CGRectMake(0.0, 0.0, (CGFloat)width, (CGFloat)height), spriteImage);
// You don't need the context at this point, so you need to release it to avoid memory leaks.
CGContextRelease(spriteContext);
// Use OpenGL ES to generate a name for the texture.
glGenTextures(1, &spriteTexture);
// Bind the texture name.
glBindTexture(GL_TEXTURE_2D, spriteTexture);
// Set the texture parameters to use a minifying filter and a linear filer (weighted average)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// Specify a 2D texture image, providing the a pointer to the image data in memory
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, spriteData);
// Release the image data
free(spriteData);
// Enable use of the texture
glEnable(GL_TEXTURE_2D);
// Set a blending function to use
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
// Enable blending
glEnable(GL_BLEND);
I have got two questions, bc. I am not so familiar with OpenGL.
I want to write a method, which I give two points as parameters and I want a Line between these two points to be drawn above my triangles (background).
- (void) drawLineFromPoint1:(CGPoint)point1 toPoint2:(CGPoint)point2 {
GLfloat triangle[] = { //Just example points
0.0f, 0.0f,
0.1f, 0.0f,
0.1f, 0.0f,
0.1f, 0.1f
};
GLfloat triangleColors[] = {
0.5f, 0.5f, 0.5f, 1.0f
};
//now draw the triangle
}
Something like that. Now I want to have a 2nd method, which erases this line (and not the background)
My drawing method looks like this:
- (void)drawView
{
// Make sure that you are drawing to the current context
[EAGLContext setCurrentContext:context];
glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
glClear(GL_COLOR_BUFFER_BIT);
glDrawElements(GL_TRIANGLES, number_vertices, GL_UNSIGNED_SHORT, indices);
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}
Would be great if you can give e some hints/help,
cheers
The conventional approach would be to redraw everything whenever you move or erase a line.
Well, I got it to work. I just missed to set the Vertex-Pointer in my drawView to my triangles. This here now works:
- (void)drawView
{
[EAGLContext setCurrentContext:context];
glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
glClear(GL_COLOR_BUFFER_BIT);
glVertexPointer(2, GL_FLOAT, 0, vertices);
glDrawElements(GL_TRIANGLES, number_vertices, GL_UNSIGNED_SHORT, indices);
[self drawLines];
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}
- (void) drawLines{
glDisable(GL_TEXTURE_2D);
GLfloat points[4];
for (Dataset *data in buttons) {
CGPoint s = [data screenPosition];
CGPoint p = [data slot];
points[0] = (GLfloat)(768-s.y);
points[1] = (GLfloat)(1024-s.x);
points[2] = (GLfloat)(768-p.y);
points[3] = (GLfloat)(1024-p.x);
glVertexPointer(2, GL_FLOAT, 0, points);
glDrawArrays(GL_LINE_STRIP, 0, 2);
}
glEnable(GL_TEXTURE_2D);
}
I'm new to OpenGL, so I'm sure this is a dummy mistake, but I've read every post, and reviewed sample code, and I can't find a difference, explaining why glFrustum wont display as I'd like it to.
I initialize OpenGL like:
- (void) initOpenGL{
glEnable(GL_DEPTH_TEST);
glMatrixMode(GL_PROJECTION);
//glLoadIdentity();
//glOrthof(0.0f, self.bounds.size.width, self.bounds.size.height, 0.0f, -10.0f, 10.0f);
const GLfloat zNear = -0.1, zFar = 1000.0, fieldOfView = 60.0;
GLfloat size;
size = zNear * tanf(DEGREES_TO_RADIANS(fieldOfView) / 2.0);
// This give us the size of the iPhone display
CGRect rect = self.bounds;
glFrustumf(-size, size, -size / (rect.size.width / rect.size.height), size / (rect.size.width / rect.size.height), zNear, zFar);
glViewport(0, 0, rect.size.width, rect.size.height);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
#if 0
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
#endif
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
#if TARGET_IPHONE_SIMULATOR
glColor4f(0.0, 0.0, 0.0, 0.0f);
#else
glColor4f(0.0, 0.0, 0.0, 0.0f);
#endif
[[Texture2D alloc] initWithImage:[UIImage imageNamed:#"GreenLineTex.png"] filter:GL_LINEAR];
glInitialised = YES;
And my drawing is done like:
- (void)drawView {
if(!glInitialised) {
[self initOpenGL];
}
[EAGLContext setCurrentContext:context];
glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
glEnable(GL_TEXTURE_2D);
static const GLfloat texCoords[] = {
0.0, 0.0,
1.0, 0.0,
0.0, 1.0,
1.0, 1.0
};
// draw the edges
glEnableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_COLOR_ARRAY);
glTexCoordPointer(2, GL_FLOAT, 0, texCoords);
glBindTexture(GL_TEXTURE_2D, 1);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glBlendFunc(GL_SRC_ALPHA, GL_DST_ALPHA);
for (int i = 0; i < connectionNumber; i++){
Vertex2DSet(&vertices[0], connectionLines[i].lineVertexBeginPoint.x, connectionLines[i].lineVertexBeginPoint.y);
Vertex2DSet(&vertices[1], connectionLines[i].lineVertexBeginPoint.x+connectionLines[i].normalVector.x, connectionLines[i].lineVertexBeginPoint.y+connectionLines[i].normalVector.y);
Vertex2DSet(&vertices[2], connectionLines[i].lineVertexEndPoint.x, connectionLines[i].lineVertexEndPoint.y);
Vertex2DSet(&vertices[3], connectionLines[i].lineVertexEndPoint.x+connectionLines[i].normalVector.x, connectionLines[i].lineVertexEndPoint.y+connectionLines[i].normalVector.y);
glVertexPointer(2, GL_FLOAT, 0, vertices);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}
glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}
Where the block in the for loop is a set of vertices that make up some triangle strips.
If I uncomment the glOrthof() line, then I can see my display, however it's orthographic, and I'd like to move the camera in and out, to change the scaling of the whole scene.
What have I done incorrectly that causes glFrustumf() to display only the clear color?
Short answer: you are looking in the wrong direction.
Long answer:
Your frustum is symmetric while your orthographic matrix isn't. So if your model is set up to be visible in the glOrtho case, it may not be visible with your glFrustum.
Also you shouldn't use glOrtho AND glFrustum together, because the matrices are multiplied and will surely yield a funny projection matrix.
You can use Nate Robins' GL tutors at http://www.xmission.com/~nate/tutors.html to experiment with glFrustum and glOrtho (in the "projection" application).