I am drawing a an arrow in using opengl es 1.0. I drew the arrow using a rectangle as the shaft and a pyramid as the tip. When the arrow is rotating from certain angles the shaft can be seen through the edge of the arrow tip.
Image of what is occuring: http://i.imgur.com/9K41OE8.png
My draw method
public void draw(GL10 gl) {
gl.glFrontFace(GL10.GL_CW);
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
gl.glEnable(GL10.GL_CULL_FACE);
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glColorPointer(4, GL10.GL_FLOAT, 0, colorBuffer);
gl.glDrawElements(GL10.GL_TRIANGLES, indexBuffer.capacity(), GL10.GL_UNSIGNED_BYTE, indexBuffer);
gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
}
I think it may have something to do with culling, but why would it only occur at the edge of the tip?
Depth testing must be enabled for this to look right. Use this:
gl.glEnable(GL10.GL_DEPTH_TEST);
gl.glDepthMask(GL10.GL_TRUE);
And then don't forget to clear the bits before drawing a frame:
gl.glClear(GL10.GL_DEPTH_BUFFER_BIT | GL10.GL_COLOR_BUFFER_BIT);
Related
I am drawing on a texture and then rendering this texture to the screen using GL_QUADS. There is no problem drawing the texture on screen, but while drawing to the texture the only operation that has any effect is glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); - this sets the whole texture to the colour I want. It is however impossible to draw any primitives.
The following code should absolutely cover the whole texture with black, right?
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, texRenderer.framebufferID); // switch to the texture framebuffer
glClearColor(1.0f,0.5f,0.0f,1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glDisable(GL_DEPTH_TEST);
glDisable(GL_SCISSOR_TEST);
glDisable(GL_CULL_FACE);
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrtho(0, texRenderer.pixelsWidth, 0, texRenderer.pixelsHeight, 1, -1);
// switch to modelview matrix before rendering objects
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glColor4f(0,0,0,1);
glBegin(GL_QUADS);
glVertex2f(-100, -100);
glVertex2f(-100, 100);
glVertex2f(100, 100);
glVertex2f(100, -100);
glEnd();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
//RenderScene(sim, stateMachine, viewSettings, commandMgr, font, texRenderer.pixelsWidth, texRenderer.pixelsHeight, isMainView, drawText);
glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0); // switch back to normal framebuffer
Instead it is orange.
pixelsWidth and pixelsHeight are both equal to 64. I've made sure the viewport is set up correctly. Also glGetError() returns 0.
What have I missed?
Took me 6 hours but the problem is solved. I was wrong. The viewport was not properly set. Before rendering to a texture, be sure to add the following line:
glViewport(0, 0, textureWidth, textureHeight);
And also unbind any currently bound textures using
glBindTexture(GL_TEXTURE_2D, 0);
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 currently working on a 2D game rendered in OpenGL ES in Android. My sprites seem to render correctly but, sadly, they keep on screen when I do not want them renderer. When I draw a frame with nothing in buffers I can still see previously drawn sprites.
This is the code.
public void renderFrame()
{
gl.glClear(GL10.GL_COLOR_BUFFER_BIT);
gl.glEnable(GL10.GL_TEXTURE_2D);
gl.glViewport(0, 0, viewPort.getWidth(), viewPort.getHeight());
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
gl.glOrthof(position.x - frustumWidth * zoom / 2,
position.x + frustumWidth * zoom/ 2,
position.y - frustumHeight * zoom / 2,
position.y + frustumHeight * zoom/ 2,
1, -1);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
gl.glEnable(GL10.GL_BLEND);
gl.glBlendFunc(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureId);
/*
* Buffer filling code goes here
*/
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
verticesIntBuffer.position(0);
gl.glVertexPointer(2, GL10.GL_FLOAT, vertexSize, vertices);
gl.glDrawElements(GL10.GL_TRIANGLES, 6, GL10.GL_UNSIGNED_SHORT,
shortBufferIndices);
gl.glDisable(GL10.GL_BLEND);
}
I presumed glClear would clean buffers but this doesn't look like it in here.
This solution did not work for me either Clearing/releasing OpenGL ES buffers
Any ideas on how to explicity clean buffers? Another ideas of what could be happening due to rendering previous sprites still occurring?
Thanks a lot for your patience.
You should clear both color and depth buffer:
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
I am writing a game which uses opengles. I have created my renderer class and have a sample of my game working on the emulator, however none of the texures display on an actual device. I have read about the most common cause for this being the need for texture to be a factor of 2 however I have tried drawing a square (128x128) with a texture of the same size mapped to it and this only shows on the emulator. Further to that my actual game will be using rectangles so I'm unsure how I can map textures that are squares to rectangles..
This is my code so far (The game is 2d so I'm using ortho mode):
EDIT: I have updated my code, it is now correctly binding textures and using textures of size 128x128, still only seeing textures on the emulator..
public void onSurfaceCreated(GL10 gl, EGLConfig config)
{
byteBuffer = ByteBuffer.allocateDirect(shape.length * 4);
byteBuffer.order(ByteOrder.nativeOrder());
vertexBuffer = byteBuffer.asFloatBuffer();
vertexBuffer.put(cardshape);
vertexBuffer.position(0);
byteBuffer = ByteBuffer.allocateDirect(shape.length * 4);
byteBuffer.order(ByteOrder.nativeOrder());
textureBuffer = byteBuffer.asFloatBuffer();
textureBuffer.put(textureshape);
textureBuffer.position(0);
// Set the background color to black ( rgba ).
gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
// Enable Smooth Shading, default not really needed.
gl.glShadeModel(GL10.GL_SMOOTH);
// Depth buffer setup.
gl.glClearDepthf(1.0f);
// Enables depth testing.
gl.glEnable(GL10.GL_DEPTH_TEST);
// The type of depth testing to do.
gl.glDepthFunc(GL10.GL_LEQUAL);
// Really nice perspective calculations.
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);
gl.glEnable(GL10.GL_TEXTURE_2D);
loadGLTexture(gl);
}
public void onDrawFrame(GL10 gl) {
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glDisable(GL10.GL_DEPTH_TEST);
gl.glMatrixMode(GL10.GL_PROJECTION); // Select Projection
gl.glPushMatrix(); // Push The Matrix
gl.glLoadIdentity(); // Reset The Matrix
gl.glOrthof(0f, 480f, 0f, 800f, -1f, 1f);
gl.glMatrixMode(GL10.GL_MODELVIEW); // Select Modelview Matrix
gl.glPushMatrix(); // Push The Matrix
gl.glLoadIdentity(); // Reset The Matrix
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glLoadIdentity();
gl.glTranslatef(card.x, card.y, 0.0f);
gl.glBindTexture(GL10.GL_TEXTURE_2D, card.texture[0]); //activates texture to be used now
gl.glVertexPointer(2, GL10.GL_FLOAT, 0, vertexBuffer);
gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer);
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
}
public void onSurfaceChanged(GL10 gl, int width, int height) {
// Sets the current view port to the new size.
gl.glViewport(0, 0, width, height);
// Select the projection matrix
gl.glMatrixMode(GL10.GL_PROJECTION);
// Reset the projection matrix
gl.glLoadIdentity();
// Calculate the aspect ratio of the window
GLU.gluPerspective(gl, 45.0f, (float) width / (float) height, 0.1f,
100.0f);
// Select the modelview matrix
gl.glMatrixMode(GL10.GL_MODELVIEW);
// Reset the modelview matrix
gl.glLoadIdentity();
}
public int[] texture = new int[1];
public void loadGLTexture(GL10 gl) {
// loading texture
Bitmap bitmap;
bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.image);
// generate one texture pointer
gl.glGenTextures(0, texture, 0); //adds texture id to texture array
// ...and bind it to our array
gl.glBindTexture(GL10.GL_TEXTURE_2D, texture[0]); //activates texture to be used now
// create nearest filtered texture
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER, GL10.GL_NEAREST);
gl.glTexParameterf(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER, GL10.GL_LINEAR);
// Use Android GLUtils to specify a two-dimensional texture image from our bitmap
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bitmap, 0);
// Clean up
bitmap.recycle();
}
Is there anything I have done wrong? Or something I haven't done? It works perfectly fine in the emulator so I could only assume it was the power of 2 issue but like I said I tried that using a 128x128 texture on a square but it didn't show.. any help would be appreciated..
EDIT: I have also tried setting the minsdkversion is 3, loading the bitmap via an input stream bitmap = BitmapFactory.decodeStream(is), setting BitmapFactory.Options.inScaled to false, putting the images in the nodpi folder and then trying them in the raw folder.. any other ideas?
I'm actually looking for the solution to a similar problem right now. I think I might have a temporary fix for you, however.
The problem appears to be that on the emulator the orthographic view is flipped. To solve this, in my app we added an option in preferences to manually flip the view if nothing draws. Here's the snippet that handles this:
if (!flipped)
{
glOrthof(0, screenWidth, screenHeight, 0, -1, 1); //--Device
}
else
{
glOrthof(0, screenWidth, 0, -screenHeight, -1, 1); //--Emulator
}
Hope this helps! If anybody has a more general solution, I'd be happy to hear it!
I didn't look at your code but I have been on that road before. Developing in OpenGL is a real pain in the ass. If you are not obligated to use OpenGL, then use a graphics engine. Unity is a great one and it's free. Also your game would work on Android, iOS or other platforms. Study your choices carefully. Good luck..
I'm trying to make a copy of MineCraft in Java using OpenGL (LWJGL). The problem I'm facing is that everything of my 2D overlay (aiming cross in the middle, menus, etc...) are all white. The 3D part of the game works great: every cube has a texture on each side.
But when I try to draw the overlay, as I said, every texture is white, but I can see the shape of it (because it has transparent areas). I'll add a picture of it.
(This is supposed to be the inventory)
As you can see, the overlay is completely white. And it should look like this:
I'm already searching the web for hours. Can't seem to find a solution.
This drives my crazy... I already searched for instructions of how to create a 2D overlay on a 3D scene, but they don't help either. So I though, I'll give StackOverflow a try.
Hopefully someone can help me?
Thanks for reading my question and for the (hopefully coming) answers!
Martijn
Here is the code:
Initialising OpenGL
public void initOpenGL() throws IOException
{
// init OpenGL
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0, 800, 600, 0, 1, 300);
glMatrixMode(GL_MODELVIEW);
float color = 0.9f;
glClearColor(color, color, color, color);
glEnable(GL_TEXTURE_2D);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
glShadeModel(GL_FLAT);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glEnable(GL_LINE_SMOOTH);
glEnable(GL_CULL_FACE);
glEnable(GL_FOG);
glFog(GL_FOG_COLOR, MineCraft.wrapDirect(color, color, color, 1.0f));
glFogi(GL_FOG_MODE, GL_LINEAR);
glFogf(GL_FOG_START, _configuration.getViewingDistance() * 0.8f);
glFogf(GL_FOG_END, _configuration.getViewingDistance());
glFogi(NVFogDistance.GL_FOG_DISTANCE_MODE_NV, NVFogDistance.GL_EYE_RADIAL_NV);
glHint(GL_FOG_HINT, GL_NICEST);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
}
Configuring the matrixes for drawing the overlay (Out of inspiration, I literally copied all the OpenGL calls for this method from BlockMania (another open-source MineCraft copy), which works great)
public void renderOverlay()
{
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
GLU.gluOrtho2D(0, conf.getWidth(), conf.getHeight(), 0);
glMatrixMode(GL_MODELVIEW);
glEnable(GL_COLOR_MATERIAL);
glPushMatrix();
glLoadIdentity();
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
/** RENDER **/
if (_activatedInventory != null)
{
_activatedInventory.renderInventory();
}
glDisable(GL_BLEND);
glEnable(GL_DEPTH_TEST);
glEnable(GL_CULL_FACE);
glPopMatrix();
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
}
Drawing the texture itself:
public void renderInventory()
{
Configuration conf = Game.getInstance().getConfiguration();
glTranslatef(conf.getWidth() / 2.0f, conf.getHeight() / 2.0f, 0.0f);
glEnable(GL_TEXTURE_2D);
Texture tex = TextureStorage.getTexture("gui.inventory");
tex.bind(); // newdawn.slick (same library for my whole program, so this works)
float hw = 170; // half width
float hh = 163; // half height
Vector2f _texPosUpLeft = new Vector2f(3, 0);
Vector2f _texPosDownRight = new Vector2f(_texPosUpLeft.x + hw, _texPosUpLeft.y + hh);
_texPosUpLeft.x /= tex.getTextureWidth();
_texPosUpLeft.y /= tex.getTextureHeight();
_texPosDownRight.x /= tex.getTextureWidth();
_texPosDownRight.y /= tex.getTextureHeight();
glColor3f(1, 1, 1); // Changes this doesn't make any effect
glBegin(GL_QUADS);
glTexCoord2f(_texPosUpLeft.x, _texPosUpLeft.y);
glVertex2f(-hw, -hh);
glTexCoord2f(_texPosDownRight.x, _texPosUpLeft.y);
glVertex2f(hw, -hh);
glTexCoord2f(_texPosDownRight.x, _texPosDownRight.y);
glVertex2f(hw, hh);
glTexCoord2f(_texPosUpLeft.x, _texPosDownRight.y);
glVertex2f(-hw, hh);
glEnd();
}
(The texture pack I'm using is CUBISM1.00)
I found it!!
It was the fog. For one or another reason it looks like it thinks the overlay is out of sight and gives it the color of the fog. So, disabling the fog before rendering the overlay solved it.
glDisable(GL_FOG);
/* Render overlay here */
glEnable(GL_FOG);
If there are still people who read this, is this caused by matrix abuse or is this behaviour normal?