For some reason enabling alpha blending results in me not being able to draw run-of-the-mill coloured shapes. The order in which everything is drawn makes no difference. Even if the only thing being drawn is the coloured shape, it still won't show.
Disabling alpha blending fixes this, but disables alpha blending (obviously). This leads me to believe the problem is in how I'm initializing openGL.
The textured objects are contained in the world, which is commented out. Commenting "world.run();" out makes no difference, only disabling alpha blending does.
public class Core {
int width=800, height=600;
//World world;
public void Start(){
try {
Display.setDisplayMode(new DisplayMode(width,height));
Display.create();
} catch (LWJGLException e) {
e.printStackTrace();
System.exit(0);
}
initGL();
System.out.println("OpenGL version: " + GL11.glGetString(GL11.GL_VERSION));
boolean Close = Display.isCloseRequested();
//world = new World(width, height);
while(!Close){
GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);
if(Keyboard.isKeyDown(Keyboard.KEY_ESCAPE) || Display.isCloseRequested())
Close = true;
//world.run();
GL11.glColor4d(1, 0, 0, 1);
GL11.glBegin(GL11.GL_QUADS);
GL11.glVertex2d(0, 0);
GL11.glVertex2d(0, 50);
GL11.glVertex2d(50, 50);
GL11.glVertex2d(50, 0);
GL11.glEnd();
Display.update();
//Display.sync(60);
}
}
public void initGL(){
GL11.glEnable(GL11.GL_TEXTURE_2D);
GL11.glClearColor(1.0f, 1.0f, 1.0f, 0.0f);
// enable alpha blending
GL11.glEnable(GL11.GL_BLEND);
GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
GL11.glViewport(0,0,width,height);
GL11.glMatrixMode(GL11.GL_MODELVIEW);
GL11.glMatrixMode(GL11.GL_PROJECTION);
GL11.glLoadIdentity();
GL11.glOrtho(0, width, height, 0, 1, -1);
GL11.glMatrixMode(GL11.GL_MODELVIEW);
}
public static void main(String args[]){
Core m = new Core();
m.Start();
}
}
This is for a 2D app where I'm trying to draw metaballs behind the texture of a black-and-white world map.
Run-of-the-mill coloured shapes refers to the following,
GL11.glColor4d(1, 0, 0, 1);
GL11.glBegin(GL11.GL_QUADS);
GL11.glVertex2d(0, 0);
GL11.glVertex2d(0, 50);
GL11.glVertex2d(50, 50);
GL11.glVertex2d(50, 0);
GL11.glEnd();
Even if drawn on its own, as long as alpha blending is enabled, it won't show up.
UPDATE:
The constructor for world was loading (but not drawing) a texture. Removing that part of the code lets the coloured square show up. I have deduced that the problem will occur as long as a texture is loaded, regardless of whether it is displayed or not.
You've got glEnable(GL_TEXTURE_2D) in initGL, but I don't see it disabled anywhere.
You know you have to disable texturing if you want to draw an untextured object, right?
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
// [...]
ok so I have determined that if I change my orthographic matrix coordinate system to
GL11.glOrtho(0, Strings.DISPLAY_WIDTH, Strings.DISPLAY_HEIGHT, 0, -1, 1);
instead of this
GL11.glOrtho(0, Strings.DISPLAY_WIDTH, 0, Strings.DISPLAY_HEIGHT, -1, 1);
I can draw strings with slick right side up however the game im building uses this system
GL11.glOrtho(0, Strings.DISPLAY_WIDTH, 0, Strings.DISPLAY_HEIGHT, -1, 1);
and slick draws things with the top of the matrix being 0 and the bottom being the height of the display is there anyway I can rotate or draw the strings differently without having to change my games coordinate system?
here is my string drawing class
private Font javaFont;
private UnicodeFont uniFont;
public TextHandler(int letterSize) {
this.initHandler(letterSize);
}
private void initHandler(int size) {
this.javaFont = new Font("Times New Roman", Font.BOLD, size);
this.uniFont = new UnicodeFont(this.javaFont);
this.uniFont.getEffects().add(new ColorEffect(java.awt.Color.white));
this.uniFont.addAsciiGlyphs();
try {
this.uniFont.loadGlyphs();
} catch (SlickException e) {
e.printStackTrace();
}
}
public void drawString(String string, float x, float y) {
this.uniFont.drawString(x, y, string, Color.white);
}
and my openGl initialization code if it helps
GL11.glMatrixMode(GL11.GL_PROJECTION);
GL11.glLoadIdentity();
GL11.glOrtho(0, Strings.DISPLAY_WIDTH, 0, Strings.DISPLAY_HEIGHT, -1, 1);
GL11.glMatrixMode(GL11.GL_MODELVIEW);
GL11.glEnable(GL11.GL_TEXTURE_2D);
GL11.glClearColor(0, 0, 1, 0);
GL11.glDisable(GL11.GL_DEPTH_TEST);
Yes, you could set up a rendering system where the first glOrtho call sets up the Slick rendering, and then you render the strings. Then you call glOrtho again, but render the rest of your game. glOrtho simply tells OpenGL to setup an orthographic projection, and what corner of the screen to start rendering from. Slick uses the top left hand corner whereas you are using the bottom left hand corner. OpenGL is a state based machine, so you must render the Slick stuff, switch to the new projection, and then render the rest of your game.
You also don't need that call to glDisable(GL_DEPTH_TEST);. Depth testing is turned off by default.
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 am attempting to make dynamic 2D shadows in my game.
I'm successfully able to render the shadows to a frame buffer. (grey and white squares designate transparency)
Then for debug purposes, I render the contents of the frame buffer on top of another frame buffer which is cleared white every frame, and then render this frame on my game. This works just fine... as long as I render the shadows with 100% opaqueness:
But if I do this before drawing the shadows on the second framebuffer,
spriteBatch.setColor(0f, 0f, 0f, 0.5f);
The transparent shadows tear through the framebuffer and you can see the game world underneath.
Here's my code:
public class Light
{
FrameBuffer shadowbuffer; // for rendering shadows
FrameBuffer buffer; // for debug
OrthographicCamera cam;
public Light(Images images)
{
shadowbuffer = new FrameBuffer(Format.RGBA8888, Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), true);
buffer = new FrameBuffer(Format.RGBA8888, Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), true);
cam = new OrthographicCamera(buffer.getWidth(), buffer.getHeight());
cam.setToOrtho(true);
cam.update();
}
public Texture render(SpriteBatch batch, GameWorld world)
{
batch.end();
batch.setProjectionMatrix(cam.combined);
shadowbuffer.begin();
Gdx.gl.glClearColor(0, 0, 0, 0);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);
batch.begin();
// ... render shadows here ...
batch.end();
shadowbuffer.end();
buffer.begin();
Gdx.gl.glClearColor(0, 0, 0, 0);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT | GL20.GL_DEPTH_BUFFER_BIT);
batch.begin();
batch.setColor(0f, 0f, 0f, .5f);
batch.draw(shadowbuffer.getColorBufferTexture(), 0, 0);
batch.setColor(Color.WHITE);
batch.end();
buffer.end();
batch.begin();
return buffer.getColorBufferTexture();
}
}
I've tried all sorts of different blending settings, but none of them work..
EDIT Here are the blend settings I'm currently using:
batch.enableBlending();
batch.setBlendFunction(GL20.GL_SRC_ALPHA, GL20.GL_ONE_MINUS_SRC_ALPHA);
Do not clear you shadowbuffer to black, clear it to transparent and draw your shadows with black color. Also don't forget to choose right blending function. If you use this method, your parameters will be like
spritebatch.enableBlending();
spritebatch.setBlendFunction(gl.BLEND_SRC_ALPHA,gl.BLEND_ONE_MINUS_SRC_ALPHA);
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.