my issue is with opengl in java, I have it with the lwjgl. I am trying to load textures from a .png file and then draw them on to a screen. The problem I am facing is that when the texture coordinates are selected with glTexCoord2f they are off the texture in some cases. This manifests its self by leaving large black areas past the edge of the drawn texture. The only solution that I have found online is to add GL_CLAMP_TO_EDGE to the GL_TEXTURE_WRAP_S and GL_TEXTURE_WRAP_T parameters. Below is a picture of the textures on a green background with the black boarders. And then I have the code related to my use of opengl. Lastly if it matters I am using Eclipse on Linux. Thank you for any productive answers.
Example
textures on green background
Code: Initializing opengl
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, width, hight, 0, 1, -1);
glMatrixMode(GL_MODELVIEW);
glEnable(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
Code: Drawing The Textures
glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
background.bind();
glBegin(GL_QUADS); //Draw Background
glTexCoord2f(0, 0);
glVertex2i(25, 25);//Upper Left
glTexCoord2f(1, 0);
glVertex2i(900, 25);//Upper Right
glTexCoord2f(1, 1f);
glVertex2i(900, 600);//Lower Right
glTexCoord2f(0, 1f);
glVertex2i(25, 600);//Lower Left
glEnd();
statusBarWraper.bind();
glBegin(GL_QUADS); //Drawing the wrapper
glTexCoord2f(0, 0);
glVertex2i(500, 650);//Upper Left
glTexCoord2f(1, 0);
glVertex2i(1000, 650);//Upper Right
glTexCoord2f(1, 1);
glVertex2i(1000, 700);//Lower Right
glTexCoord2f(0, 1);
glVertex2i(500, 700);//Lower Left
glEnd();
statusBar.bind();
glBegin(GL_QUADS); //Drawing progress Bar
glTexCoord2f(0, 0);
glVertex2i(100, 650);//Upper Left
glTexCoord2f(1, 0);
glVertex2i(400, 650);//Upper Right
glTexCoord2f(1, 1);
glVertex2i(400, 675);//Lower Right
glTexCoord2f(0, 1);
glVertex2i(100, 675);//Lower Left
glEnd();
Related
I am getting an error when I try to set the Matrix mode of my LWJGL program to GL_Projection.
glMatrixMode(GL_PROJECTION);
The error is :
Exception in thread "main" java.lang.IllegalStateException: Function is not supported
at org.lwjgl.BufferChecks.checkFunctionAddress(BufferChecks.java:58)
at org.lwjgl.opengl.GL11.glMatrixMode(GL11.java:2075)
....
I have tracked down the error to when I make my Display. When I remove my ContexAttribs my code doesn't display the error and renders! ( when I comment out the code that needs the contexattribs )
This is my code:
display code:
Display.setDisplayMode(new DisplayMode(WIDTH, HEIGHT));
ContextAttribs attribs = new ContextAttribs(3, 2).withProfileCore(true).withForwardCompatible(true);
Display.create(new PixelFormat().withDepthBits(24).withSamples(4), attribs);
Display.setTitle(TITLE);
Display.setInitialBackground(1, 1, 1);
GL11.glEnable(GL13.GL_MULTISAMPLE);
GL11.glViewport(0, 0, WIDTH, HEIGHT);
initialization method:
glMatrixMode(GL_PROJECTION);
glOrtho(0, width, height, 0, -1, 1);
glMatrixMode(GL_MODELVIEW);
glClearColor(0, 1, 0, 0);
textureID = loadTexture("res/hud.png");
glEnable(GL_TEXTURE_2D);
rendering method:
glClear(GL_COLOR_BUFFER_BIT);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glPushMatrix();
glTranslatef(0, 0, 0);
glBindTexture(GL_TEXTURE_2D, textureID);
glBegin(GL_QUADS);
{
glTexCoord2f(0, 0);
glVertex2f(0, 0);
glTexCoord2f(1, 0);
glVertex2f(width, 0);
glTexCoord2f(1, 1);
glVertex2f(width, height);
glTexCoord2f(0, 1);
glVertex2f(0, height);
}
glEnd();
glPopMatrix();
Does anyone know how I could get this code working with the contextAttribs?
Thanks in advance!
Edit 1: I have all the functions and variables in GL11 statically imported.
First of all, drawing with glBegin/glEnd sequences is deprecated since more than 10 years. See Vertex Specification for a state of the art way of rendering.
With the line
ContextAttribs attribs = new ContextAttribs(3, 2).withProfileCore(true).withForwardCompatible(true);
a OpenGL core profile Context with Forward compatibility bit set is generated.
In this context all the deprecated functions like glBegin/glEnd sequences, matrix stack (glMatrixMode), the standard light model etc. are removed. This causes the error.
See also Fixed Function Pipeline and OpenGL Context
Skip the setting of the forward compatibility bit (.withForwardCompatible(true)) to solve the issue.
I use the following to draw the texture quads
tex.bind();
glTranslatef(x, y, 0);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex2f(0, 0);
glTexCoord2f(1, 0);
glVertex2f(width, 0);
glTexCoord2f(1, 1);
glVertex2f(width, height);
glTexCoord2f(0, 1);
glVertex2f(0, height);
glEnd();
glLoadIdentity();
with these configurations:
try {
Display.setDisplayMode(new DisplayMode(WIDTH, HEIGHT));
Display.create();
} catch (LWJGLException e) {
e.printStackTrace();
}
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, WIDTH, HEIGHT, 0, 1, -1);
glMatrixMode(GL_MODELVIEW);
GL11.glEnable(GL11.GL_TEXTURE_2D);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
GL11.glDisable(GL11.GL_DEPTH_TEST);
GL11.glDisable(GL11.GL_LIGHTING);
GL11.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
GL11.glClearDepth(1);
however now i want to add a menu to the game by drawing a rect over the screen but when i do so, everything turns red (if i set red as color)
case MENU:
GL11.glColor3f(1.0f, 0.0f, 0.0f);
glRectf(50, 50, 50, 50);
Two things:
Whenever you draw using color instead of textures, make sure to disable GL_TEXTURE_2D by calling glDisable(GL_TEXTURE_2D); before the rendering call (in your case before case MENU:). But don't forget to enable it again as soon as you're finished and ready to draw the texture once again (in your case, call glEnable(GL_TEXTURE_2D); after glRectf()). This might not be the reason for the problem that you're experiencing, but it will become a problem later.
The reason as to why everything turns red, is because whenever you render a texture, the currently bound color affects what color components are rendered from the texture. Every pixel in the texture that you're drawing is composed of 3 or 4 values. Red, Green, Blue and possibly an Alpha channel. Since you bind the color to red, and you do not change it before you draw the texture, OpenGL only draws the red component of each pixel within your texture. Thus, the Red component will be ranging from 0-1 in your texture, and the Green and Blue values will be staying at a constant 0.
To fix this, simply call glColor3f(1, 1, 1); After rendering the red rectangle. This will set the rendering color back to white (default) and therefore OpenGL will successfully draw all 3 color components of your texture pixels.
I hope that I've been clear and that this helps.
Good luck! :)
//SK
I am attempting to create a 2D overlay over a 3D scene! I have tried all the solutions I can find on GameDev and StackOverflow, however they have not seemed to work!
My current code:
static void ready3D()
{
glViewport(0, 0, Display.getWidth(),Display.getHeight());
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
GLU.gluPerspective(45, (float) Display.getWidth()/Display.getHeight(), 0.1f, 5000.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glDepthFunc(GL_LEQUAL);
glEnable(GL_DEPTH_TEST);
}
static void ready2D()
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
GLU.gluOrtho2D(0.0f, Display.getWidth(), Display.getHeight(), 0.0f);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glTranslatef(0.375f, 0.375f, 0.0f);
glDisable(GL_DEPTH_TEST);
}
And,
glPushMatrix();
//Overlay start - This is in my render method BTW.
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
ready2D();
glBegin(GL_QUADS);
glColor3f(1, 1, 1);
glVertex2f(0, 0); // bottom-left
glVertex2f(0, 1); // top-left
glVertex2f(1, 1); // top-right
glVertex2f(1, 0); // bottom-right
glEnd();
glPopMatrix();
ready3D();
However the 2D box thing that I am trying to draw does not draw! Obviously I eventually hope to have complicated objects/icons on an overlay, but first things first.
The 3D world still draws totally fine.
Is anyone able to tell me what I am doing wrong?
The order of the vertices in the 2D quad look a bit suspicious to me, if I'm reading that rightly it's going: bottom-left, top-right, bottom-right, top-left, which results in a sort of cross rather than a quad.
Try this:
glVertex2f(0, 0); // bottom-left
glVertex2f(0, 1); // top-left
glVertex2f(1, 1); // top-right
glVertex2f(1, 0); // bottom-right
Note the clockwise ordering which I believe OpenGL is expecting by default for front-facing quads.
My Image is 1280x740 aswell as my game Canvas.
here is my code
// Initialize code OpenGL
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, 1280, 720, 0, 1, -1);
glMatrixMode(GL_MODELVIEW);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_TEXTURE_2D);
// end initializiation
glClear(GL_COLOR_BUFFER_BIT);
getResources().backgroundImage.bind();
glBegin(GL_QUADS);
glTexCoord2f(0,0); // Upper left
glVertex2f(1280,0);
glTexCoord2f(1,0); // Upper Right
glVertex2f(0,0);
glTexCoord2f(1,1); // Bottom Right
glVertex2f(0,740);
glTexCoord2f(0,1); // Bottom Left
glVertex2f(1280,740);
glEnd();
Here is the problem I'm getting, while trying to make this a full-screen texture... the image is actually being scaled down?
Image showing
http://i48.tinypic.com/inrbeu.png
Vertex position is transformed to viewport coordinates by either fixed function pipeline or a vertex shader. Without specifying those, the outcome is probably not what you want.
You need to either setup a projection·modelview or a shader matching your needs.
I am creating a program which draws an object, which needs to "point" toward the mouse. To do so I want to draw the image rotated.
I have this code for drawing the object:
glBindTexture(GL_TEXTURE_2D,img.getTextureID());
glBegin(GL_QUADS);
glTexCoord2f(0,0);
glVertex2f(x-r,y-r);
glTexCoord2f(1,0);
glVertex2f(x+r,y-r);
glTexCoord2f(1,1);
glVertex2f(x+r,y+r);
glTexCoord2f(0,1);
glVertex2f(x-r,y+r);
glEnd();
Pretty basic. But I was having a hard time finding out how to rotate the texture, or draw the texture rotated.
To elaborate on #genpfault's answer:
If you want your texture to rotate around its center, you need to draw it so its center is at (0,0). Try something like this:
glPushMatrix();
glTranslatef(x,y); // move to the proper position
glRotatef( angle, 0, 0, 1 ); // now rotate
glBindTexture(GL_TEXTURE_2D,img.getTextureID());
glBegin(GL_QUADS);
glTexCoord2f(0,0);
glVertex2f(-r,-r);
glTexCoord2f(1,0);
glVertex2f(+r,-r);
glTexCoord2f(1,1);
glVertex2f(+r,+r);
glTexCoord2f(0,1);
glVertex2f(-r,+r);
glEnd();
glPopMatrix(); // pop off the rotation and transformation
Note that glRotatef's angle is in degrees, not radians.
Rotating the texture:
glMatrixMode( GL_TEXTURE );
glLoadIdentity();
glRotatef( angle, 0, 0, 1 );
glMatrixMode( GL_MODELVIEW );
drawTexturedQuad();
Rotating the quad:
glPushMatrix();
glRotatef( angle, 0, 0, 1 );
drawTexturedQuad();
glPopMatrix();