I am doing a project on OpenGL 3D. I have several figures, and when I rotate the camera (scene), the figures seem to go beyond it (or beyond Viewport)
Normal condition:
Cropped figure:
How can I increase the viewing area? Or what can be done in this situation?
Now I am trying:
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glDepthFunc(GL_LEQUAL);
glfwPollEvents();
glPushMatrix();
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
GL11.glViewport(0, 0, width, height);
GL11.glMatrixMode(GL11.GL_PROJECTION);
glLoadIdentity();
But it does not bring results.
It seems that the object is clipped by the near plane of then orthographic projection. Change the near plane to solve the issue.
The orthographic projection matrix is set by glOrtho.
By default the projection matrix is the Identity matrix. That is the same as you would do
GL11.glOrtho(-1, 1, -1, 1, 1, -1);
Increase the distance to the near and far plane to solve the issue. e.g:
GL11.glMatrixMode(GL11.GL_PROJECTION);
glLoadIdentity();
GL11.glOrtho(-1, 1, -1, 1, 10, -10);
Related
I have a problem with skybox textures. If you twist the camera, it creates a feeling that one texture overlays another, as in the screenshot:
Skybox show code:
private void drawSkybox(int texId){
glColor4f(1,1,1,1);
glDepthMask(false);
glEnable(GL_TEXTURE_CUBE_MAP);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_CUBE_MAP, texId);
glBindVertexArray(vao[0]);
glBindBuffer (GL_ARRAY_BUFFER, vbo[0]);
glDrawArrays(GL_TRIANGLES, 0, 36);
glBindVertexArray(0);
glBindBuffer (GL_ARRAY_BUFFER, 0);
glDepthMask(true);
glDisable(GL_TEXTURE_CUBE_MAP);
}
My opengl paramters:
glEnable(GL_ALPHA_TEST);
glEnable(GL_DEPTH_TEST);
glEnable(GL_COLOR_MATERIAL);
glEnable(GL_TEXTURE_2D);
glEnable(GL_BLEND);
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glEnable(GL_NORMALIZE);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glShadeModel(GL_SMOOTH);
glColorMask (true, true, true, true);
glHint(GL_LINE_SMOOTH_HINT, GL_DONT_CARE);
And my call drawSkybox:
glViewport(0, 0, WIDTH, HEIGHT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-max, max, -1, 1, 10, -10);
glRotated(cameraX, 1f, 0f, 0);
glRotated(cameraY, 0f, 1f, 0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
drawSkybox(texId);
How i can fix the problem?
I understand that the problem is glDepthMask(false); but how can it be replaced?
If I just remove glDepthMask(false); and replace it with an example with glDepthFunc(GL_LEQUAL); and glDepthFunc(GL_LESS); then the skybox will overlap all other objects and only it will be visible –
Do not change the depth mask or the depth test when you draw the skybox. Keep the depth test function GL_LESS.
private void drawSkybox(int texId){
glColor4f(1,1,1,1);
// glDepthMask(false); <---- DELETE
// [...]
}
But clear the depth buffer again, after drawing the skybox. Draw the skybox first, then the skybox covers the entire screen. Then clear the depth buffer, thus all objects which are draw after, will cover the skybox:
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// [...]
drawSkybox(texId);
glClear(GL_DEPTH_BUFFER_BIT);
// render other objects
// [...]
I am developing a terrain generation app on android with Opengl ES, and I am having problems rotating the camera around itself ( the FPS effect to make it clear).
what I am doing is to move the view with Matrix.setLookAtMand then rotating the view after translating it to the origin.This is a snippet of the code:
Matrix.setLookAtM(mViewMatrix, 0, xrot, eyeY, yrot, xrot, lookY, yrot,0.0f, 1.0f, 0.0f);
Matrix.translateM(mViewMatrix,0,-xrot,0f,-yrot);
Matrix.rotateM(mViewMatrix, 0, mAngleX+mAngleY, 0.0f, 1.0f,0.0f);
Matrix.translateM(mViewMatrix,0,xrot,0f,yrot);
where xrot,yrot,mAngleX+mAngleY are input from the touchscreen.
This code works only in the origin, but when you move it rotates around the y axis of the world and not the camera one. I guess I am not doing it right but I didn't find a way to do it that works anywhere.
I found a way to do it:
Matrix.setIdentityM(mCurrentRotation, 0);
Matrix.rotateM(mCurrentRotation, 0, mAngleY+mAngleX, 0.0f,1.0f, 0.0f);
Matrix.rotateM(mCurrentRotation, 0, mAngleX, 0.0f,0.0f, 1.0f);
mAngleX = 0.0f;
mAngleY = 0.0f;
Matrix.multiplyMM(mTemporaryMatrix, 0, mCurrentRotation, 0, mAccumulatedRotation, 0);
System.arraycopy(mTemporaryMatrix, 0, mAccumulatedRotation, 0, 16);
Matrix.multiplyMM(mMVPMatrix, 0, mViewMatrix, 0, mModelMatrix, 0);
// multiply the rotation just for model*view
Matrix.multiplyMM(mMVPMatrix, 0, mTemporaryMatrix, 0, mMVPMatrix, 0);
//than add projection as usual
Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVPMatrix, 0);
Where mTemporaryMatrix, mCurrentRotation,mAccumulatedRotation, are matrices to calculate total rotation, keep frame rotation and store the whole rotation of the camera, respectively. This solution works for rotation but it doesn't make the camera move in the direction it is pointing.
I am making a platformer which I started developing with default java functions, but now am switching to OpenGL for everything. I have done everything like I always do with OpenGL, and what I did works fine in my other OpenGL projects. Now my problem is that LWJGL/OpenGL is scaling my textures in a very strange way.
It seems to be related to my screen's aspect ratio. (8:5)
I already had to flip the screen to make it the right way round, but as you can see the text is working fine, it's just the textured rect, and it isn't even straight on the bottom.
Here are the most important snippets from the two classes which actually use OpenGL:
Metamorph.java (main class)
public static void initGL()
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, Display.getWidth(), 0, Display.getHeight(), 1, -1);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glMatrixMode(GL_MODELVIEW);
glClearColor(0, 0, 0, 1);
glDisable(GL_DEPTH_TEST);
}
public void render()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
glScalef(1.0f, -1.0f, 1.0f);
glTranslatef(0f, -720f, 0f);
//glScalef(1280f/800, 720f/500, 1f);
renderer.render();
Display.update();
Display.sync(60);
}
Renderer.java (rendering stuff)
private void renderMainMenuWithGL()
{
//System.out.println("Main Menu!");
glColor4f(1, 1, 1, 1);
try
{
Texture bg = loadTexture("mockery");
bg.bind();
} catch (Exception e)
{
e.printStackTrace();
}
//drawQuad(0, 0, 1280, 720, 0, 0, 1280, 720);
glPushMatrix();
{
glBegin(GL_QUADS);
glTexCoord2f(0, 0);glVertex2f(0, 0);
glTexCoord2f(0, 1);glVertex2f(0, 720);
glTexCoord2f(1, 1);glVertex2f(1280, 720);
glTexCoord2f(1, 0);glVertex2f(1280, 0);
glEnd();
}
glPopMatrix();
TrueTypeFont f = loadFont(MAINFONT, Font.PLAIN, 50);
TrueTypeFont fb = loadFont(MAINFONT, Font.PLAIN, 48);
int sel = -1;
if(Mouse.getX() > 1000 && Mouse.getX() < 1240 && Mouse.getY() > 282.5F && Mouse.getY()< 737.5F)
sel = Math.round((Mouse.getY() - 337.5F)/75F);
if(sel == 0)
drawStringRight(fb, 1240, 350, "Story", new Color(0xff516b6b));
else
drawStringRight(f, 1240, 350, "Story", new Color(0xff516b6b));
}
private void drawStringRight(TrueTypeFont f, int x, int y, String s, Color c)
{
glPushMatrix();
f.drawString(x-f.getWidth(s), y, s, c);
glPopMatrix();
}
I am also open to advice on file structure/what I did wrong elsewhere, but keep in mind this is heavily WIP
The only possible problem I can see from what you have posted is the scaling and translating you are doing prior to rendering. You should not need to do this with your projection matrix setup the way it is. Other possibilities are that either the dimensions are not really 1280x720 as you think or you have modified one of the matrices further in the code you have not posted. I would try setting both the modelview and projection matrices to the identity matrix and then use glOrtho as you have above immediatly before drawing your quad, and use Display.getWidth and Display.getHeight instead of 1280/720 for the vertex coords.
This works fine for me:
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, Display.getWidth(), 0, Display.getHeight(), 1, -1);
glBegin(GL_QUADS);
glTexCoord2f(0,0);
glVertex2i(0, 0);
glTexCoord2f(1,0);
glVertex2i(Display.getWidth(), 0);
glTexCoord2f(1,1);
glVertex2i(Display.getWidth(), Display.getHeight());
glTexCoord2f(0,1);
glVertex2i(0, Display.getHeight());
glEnd();
If this still doesnt work, make sure that the viewport is also set to the entire display: glViewport(0,0,Display.getWidth(),Display.getHeight()).
Aswell, I notice that you are using glPushMatrix() and glPopMatrix before and after drawing, which does nothing and is not needed. Push and pop are used to save the current projection or modelview matrix and then reload it later, so that you can apply transformations inbetween and undo them when needed.
You're setting the projection matrix such that the coordinates of the corners of the window are (0,0) through (1680, 1050), and those are mapped into an area that covers 1280x800 pixels. Then you're drawing a 1280x720 image into it, so the screen coordinates of the image come out to span only 800x500 pixels. If you use 1280x720 in your glOrtho() call, I believe it will fix the issue. That is, you want the size of the window, not the size of the display in that call.
I can't figure out why this:
glPushMatrix();
GL11.glBindTexture(this.target, this.textureID);
glColor3f(1, 1, 1);
glTranslated(posX, posY, 0);
glBegin(GL_QUADS);
{
glTexCoord2d(posXLeft, posYTop);
glVertex2d(0, 0);
glTexCoord2d(posXLeft, posYBottom);
glVertex2d(0, verH);
glTexCoord2d(posXRight, posYBottom);
glVertex2d(verW, verH);
glTexCoord2d(posXRight, posYTop);
glVertex2d(verW, 0);
}
glEnd();
glPopMatrix();
is working perfectly, where posX and posY are obviously the position in pixels, posXLeft etc is the ratio of the texture to show.
But this:
glPushMatrix();
GL11.glBindTexture(this.target, this.textureID);
glColor3f(1, 1, 1);
glTranslated(posX, posY, 0);
glBegin(GL_LINES);
{
glVertex2d(10, 10);
glVertex2d(800, 600);
}
glEnd();
glPopMatrix();
isn't. And it should be even easier to draw lines instead of a piece of a texture.
What I want to reach is to add some zig-zag lines on a texture to simulate cracks as it is damaged or broken, but I can't even draw a single line, so I am stuck here.
Any advice?
You still got texturing enabled in your line drawing code. But you don't specify texture coordinates, so you'll draw your line with a solid color as defined by texture at the currently set texture coordinate.
My suggestion: Disable texturing for drawing that line.
As said by datenwolf you have to disable the texturing, thes thing is that than you have to re-enable it, although you will have problems the next cycle of drawing if that property is not set correctly.
the solution is:
glPushMatrix();
GL11.glBindTexture(this.target, this.textureID);
glColor3f(1, 1, 1);
glDisable(GL_TEXTURE_2D);
glTranslated(posX, posY, 0);
glBegin(GL_LINES);
{
glVertex2d(10, 10);
glVertex2d(800, 600);
}
glEnd();
glEnable(GL_TEXTURE_2D);
glPopMatrix();
and that should solve your problem.
I want to create a camera moving above a tiled plane. The camera is supposed to move in the XY-plane only and to look straight down all the time. With an orthogonal projection I expect a pseudo-2D renderer.
My problem is, that I don't know how to translate the camera. After some research it seems to me, that there is nothing like a "camera" in OpenGL and I have to translate the whole world. Changing the eye-position and view center coordinates in the Matrix.setLookAtM-function just leads to distorted results.
Translating the whole MVP-Matrix does not work either.
I'm running out of ideas now; do I have to translate every single vertex every frame directly in the vertex buffer? That does not seem plausible to me.
I derived GLSurfaceView and implemented the following functions to setup and update the scene:
public void onSurfaceChanged(GL10 unused, int width, int height) {
GLES20.glViewport(0, 0, width, height);
float ratio = (float) width / height;
// Setup the projection Matrix for an orthogonal view
Matrix.orthoM(mProjMatrix, 0, -ratio, ratio, -1, 1, 3, 7);
}
public void onDrawFrame(GL10 unused) {
// Draw background color
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
//Setup the camera
float[] camPos = { 0.0f, 0.0f, -3.0f }; //no matter what else I put in here the camera seems to point
float[] lookAt = { 0.0f, 0.0f, 0.0f }; // to the coordinate center and distorts the square
// Set the camera position (View matrix)
Matrix.setLookAtM( vMatrix, 0, camPos[0], camPos[1], camPos[2], lookAt[0], lookAt[1], lookAt[2], 0f, 1f, 0f);
// Calculate the projection and view transformation
Matrix.multiplyMM( mMVPMatrix, 0, projMatrix, 0, vMatrix, 0);
//rotate the viewport
Matrix.setRotateM(mRotationMatrix, 0, getRotationAngle(), 0, 0, -1.0f);
Matrix.multiplyMM(mMVPMatrix, 0, mRotationMatrix, 0, mMVPMatrix, 0);
//I also tried to translate the viewport here
// (and several other places), but I could not find any solution
//draw the plane (actually a simple square right now)
mPlane.draw(mMVPMatrix);
}
Changing the eye-position and view center coordinates in the "LookAt"-function just leads to distorted results.
If you got this from the android tutorial, I think they have a bug in their code. (made a comment about it here)
Try the following fixes:
Use setLookatM to point to where you want the camera to be.
In the shader, change the gl_Position line
from: " gl_Position = vPosition * uMVPMatrix;"
to: " gl_Position = uMVPMatrix * vPosition;"
I'd think the //rotate the viewport section should be removed as well, as this is not rotating the camera properly. You can change the camera's orientation in the setlookat function.