OpenGL is a graphics standard and API which targets the desktop and workstation markets. It is designed to be easy to accelerate with dedicated computer hardware, and hence most implementations give greatly improved performance over traditional software rendering. Currently, OpenGL is used for ...
0
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0answers
8 views
Help me solve a problem with my rendering engine (Java + OpenGL)
Hey guys I need some help with my game rendering engine from someone with a bit more experience than I currently have as I cannot get my models to load properly.
The game is coded in OpenGL and Java ...
1
vote
0answers
34 views
Instancing meshes messing up scene lighting
I've been rendering a scene (some objects over a large field of grass) to test shadow mapping which is working fine.
But when I use instancing to "gain" performance, I not only get a decrease in ...
2
votes
0answers
16 views
Playing movies in OpenGL?
Is there a library that will let me load a movie file and play it in an OpenGL application? Or maybe just a code sample that someone has lying around? I'm also using GLUT, if that makes a ...
0
votes
0answers
10 views
Scaling geometry in an orthographic view
I'm having trouble understanding the results I'm getting from some of my matrix transformations. I've got an orthographic projection, and am drawing 2D circles on the screen. There is a camera matrix, ...
0
votes
0answers
15 views
Unity Skin Shader to GLSL
I was hoping that I could get some help converting a Unity Skin Shader to a more common GLSL readable format.
I found a skin shader that looks decent and would like to give it a try:
...
0
votes
1answer
27 views
Overlapping surfaces in deferred shader blend through one another
I've just finished implementing deferred shading into my engine, and noticed that when a large object overlaps another smaller object, it blends through it.
For example, in this scene I have a large ...
1
vote
2answers
139 views
Rotating a swinging sword in LWJGL gives wierd results
I'm making a 2d top down game in Java using LWJGL(OpenGL, essentially). I recently tried adding a swinging sword mechanism. My coordinate system is set to the bottom left FOR ALL objects. The rotation ...
0
votes
2answers
392 views
translate-scroll repeated 2d texture using opengl shader
I managed to implement an infinite 2d texture scrolling using the following shader. btw I'm using cocos2d-x 2.2.1.
The vertex shader:
attribute vec4 a_position;
attribute vec2 a_texCoord;
#ifdef ...
0
votes
0answers
17 views
Independent order transparency on ATI video card
What algorithm can I use in order to implement independent order transparency? I have an ATI Mobility Radeon HD 5470 video card.
I use OpenGL.
I looked over "Depth peeling" but it seems to me that I ...
1
vote
1answer
66 views
Procedural texturing with opengl
I have a hexagonal grid of fields, each field has a certain terrain type. I assign every vertex of hexagon with terrain type and pass it as attribute to vertex and then fragment shader. Then I use the ...
0
votes
1answer
40 views
How to make a triangle pixellated with GLFW?
How can one make a triangle look pixelated without modifying the size of the window in GLFW3?
Preferably, I'd like to accomplish this without the use of shaders. For example, by setting the size of ...
1
vote
2answers
37 views
Cursor position to a 3D ray using angles
I've been stuck for a month trying to get gluUnProject working. After my attempts to use gluUnProject failed (as well as attempts to implement gluUnProject functionality manually) I implemented method ...
0
votes
1answer
19 views
Getting ray using gluUnProject or inverted MVP matrix
I've read a lot of topics here, on SO, opengl.org etc.
Example how gluUnProject should work (from NeHe tutorial):
winX = (float)x;
winY = (float)viewport[3] - (float)y;
glReadPixels( x, int(winY), 1, ...
0
votes
3answers
138 views
Editing the pixels of a rendered image
I want to render a simple OpenGL scene as usual, but then I want to superimpose a small image of my own (such as from a bitmap file) on top of the render, such that this image always shows. For ...
0
votes
3answers
35 views
CubeMap - Why size of skybox cube has no effect?
I have normal skybox via CubeMap, but i noticed that the size of the cube has no effect. I would expect that when i have cube size 20.0, i will see different result than with cube of size 1000.0 (same ...
3
votes
1answer
32 views
LibGdx OpenGl prevent black part of Light mask texture from overlapping
I am using this masking texture for a dynamic lighting effect in my game:
It looks beautiful until two lights begin to overlap:
This is obviously because the textures are overlapping when I draw ...
4
votes
4answers
20k views
Starting programming in 3D with C++ [closed]
EDIT: There aren't sufficient enough tutorials for what I'm trying to do in Python, so I'm going to take my time and slowly build up my skills in C++. It's hard to trip and not land in a book of C++ ...
1
vote
2answers
131 views
Easy method of obtaining texture coordinates for sprite sheet
In my (OpenGL ES 2.0 Android) game, I use 2 types of Sprite Sheets. In one type all sprites/frames are of equal size and in the other they are all different shapes and sizes.
It is the latter one to ...
3
votes
1answer
86 views
Render on texture with alpha 0 for the background colour
Sorry if the question is stupid but I am very new to opengl.
I render on a target a scene with a couple of object on a background that is nothing more than the clear colour (which is ...
1
vote
1answer
51 views
How can I calculate the bounding box of a 3D model?
I am making a game in OpenGL and Blender and trying to use JBullet as the collision manager. I am using BoxShapes for collisions, which requires a javax.vecmath.Vector3f representing half of the box ...
0
votes
1answer
21 views
GLUT multiple windows FPS drop sharply
When only the main window is created, the fps is able to reach above 1000.However creating 1 more window, resulted in the fps dropping significantly down to about 100. The draw callback draws a blank ...
2
votes
1answer
66 views
Is Frustum culling still needed today?
I'm reading about efficient Frustum culling algorithms. I found an article about a smart method that first use the Frustum AABB (Axis Aligned Bounding Box) to eliminate most of the scene before check ...
3
votes
2answers
461 views
How are red dot/reflex/holographic sights implemented?
In first-person-shooters like Call of Duty, the hologram only appears when it is behind the glass portion of the sight.
In OpenGL, would it be implemented by rendering the glass to the stencil buffer ...
1
vote
1answer
44 views
Binding and unbinding, what would you do?
Let's assume the following example
creation:
glBindVertexArray(vao)
glBindBuffer(GL_ARRAY_BUFFER, vbo)
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indices)
// Filling up buffers
...
4
votes
2answers
2k views
FBX Importer - Texture Name
I have a problem with the FBX SDK. I read in the data for the vertex position and the uv coordinates. It works fine, but now I want to read for each polygon to which texture it belongs, so that I can ...
0
votes
1answer
197 views
Android OpenGL and non premultiplied textures
As I understand it; by default all bitmaps will will get the alpha channel premultiplied in Android if loaded using BitmapFactory.
My setup:
I have a 32bit bitmap(.bmp) where the alpha channel has a ...
0
votes
0answers
24 views
GLFW - Selecting an OpenGL Context before showing the window
I want to know how i can select an opengl context before displaying the window
I have two different machines. One is opengl 3.1 and the other is opengl 3.3. I want to be able to select the context ...
0
votes
0answers
233 views
How to toggle fullscreen with lwjgl
I'm using glfw in lwjgl-3 to try to create a toggleFullscreen method. However it always gives me errors. I saw this question Toggle Fullscreen at Runtime but it didn't help because glfwOpenWindow() ...
4
votes
1answer
287 views
Projecting onto different size screens by cropping
I am building a phone application which will display a shape on screen. The shape should look the same on different screen sizes. I Decided the best way to do this is to show more of the background on ...
0
votes
1answer
103 views
Encoding Float to RG/RGBA and Blending
Encoding a float value inside a RG or RGBA texture is very interesting and useful but it is also become quite useless when you use blending as the result and the values might be altered because of ...
0
votes
1answer
36 views
Shadertoy getting help moving to glsl
I spent some time writing a shader on shadertoy but now, when I try to translate my code to opengl I don't know how to calculate the uv that they describe as like this:
vec2 uv = fragCoord.xy / ...
7
votes
2answers
1k views
Atmospheric scattering and sky geometry
I'm trying to implement an atmospheric scattering in my graphics (game) engine based on the GPU Gems article: link. An example implementation from that article uses a skydome. My scene is different - ...
1
vote
1answer
473 views
GLSL: Strange light reflections
According to this tutorial I'm trying to make a normal mapping using GLSL, but something is wrong and I can't find the solution. The output render is in this image:
in this image is a plane with ...
6
votes
1answer
2k views
Atmospheric Scattering
I'm trying to implement atmospheric scattering based on Sean O`Neil algorithm that was published in GPU Gems 2. But I have some trouble getting the shader to work.
I've downloaded sample code of ...
2
votes
1answer
360 views
Ogre 3D Visibility Advice
I would like an advice about some real-time rendering optimization.
I'm rendering a BSP level, by only using the mesh, textures, entities, and lightmaps, not using VIS at all.
I'm trying to make my ...
2
votes
1answer
235 views
Rotation going wrong
I'm calculating matrices by hand. Translations are fine:
void Translate (float x, float y, float z, float[4][4] m) {
Identity (m);
m[3][0] = x;
m[3][1] = y;
m[3][2] = z;
}
If ...
-1
votes
1answer
280 views
OpenGl / C++ and some strange light problem on half board [closed]
I have some problem with lights in my opengl "game". I have board with is square (-50,50), (50, 50), (50, -50), (-50,-50) x and z since y doesn't matter at all.
I tried to make something like ...
-2
votes
2answers
1k views
Tilemap rendering with openGL (why the rendering is extremely messed up)
I'm using SDL & openGL to render a tile-map. The issue is that the tile-map rendering is extremely messed up, and I'm just a bit unsure what I'm doing wrong exactly.
It should just be the first ...
0
votes
0answers
67 views
C++/OpenGl/SDL/Cmake Beginner curiosity [closed]
and this is my first time in this forum. I just want to ask for an advise in here, I just dont know where to start. hopefully you can understand and help me. I want to start with a small game project ...
3
votes
1answer
230 views
Pyglet: text.Label().draw to FBO?
I just started OpenGL (PyopenGl) & Pyglet 3 weeks ago, and decided to read the Red Book. So sorry if my question shows my lack of comprehension...
My question is: Is it possible to display/write ...
0
votes
1answer
107 views
How to make TMXTiledMap responsive?
I've been struggling with Cocos2d-x (C++) and finally I got to the point I feel more or less comfortable with that.
My game is a 2D car-based one, with a straight infinite map where I've finally been ...
0
votes
2answers
130 views
Z-Value of clip-space position is always 1.0
I render a lot of quads on the screen into z direction (20 x 2000). I want to get the depth value in a final render target. But it looks like z is always 1.0f. I checked the result with the OpenGL ...
5
votes
1answer
66 views
Dual paraboloid shadows on GLSL
I'm trying to port an XNA example to OpenTK + OpenGL, I found it here http://graphicsrunner.blogspot.com.es/2008/07/dual-paraboloid-shadow-maps.html
But I'm having a really hard time, I think my maps ...
0
votes
1answer
131 views
Invalid coordinates returned by glutMouseFunc()
I am using GLUT's glutMouseFunc() function to retrieve the coordinates of mouse clicks. I want to move the object on that coordinate to another coordinate. But when I click on the object the ...
1
vote
0answers
25 views
Create texture atlas from loaded textures - OpenGL LWJGL Java [duplicate]
In my program I have objects with different textures, that are in the same vbo. I cant have an array of samplers in my shaderprogram, so i have to use a texture atlas. I have seen some ways to make a ...
3
votes
1answer
151 views
Drawing fonts with LWJGL3 with OpenGL
I'm very sorry if this question has already been answered, but since I've been struggling with this for many days I thought I'd give it a shot here.
My goal is to somehow render some text on the ...
3
votes
3answers
382 views
Passing array to uniform in glsl error
Here is my attemps to pass array to uniform array:
struct Vector{ float x,y,z; }
float threshold[2] = { 0.5, 0.25 };
Vector *kernel = new Vector[_kernel_size]; // _kernel_size==16
// fill kernel
...
1
vote
1answer
92 views
OpenGL poor performace with instanced drawing
I'm just started learning OpenGL and this is my first project besides tutorials. I'm trying to load a huge enginering model:
The data is structured in a way that I thought I could use instancing ...
0
votes
1answer
50 views
OpenGL Shaders Ignored
I have been following this tutorial to try and start learning OpenGL. However, upon compiling my code, my triangle turns out to be black. At first I thought that there was something wrong with the ...
3
votes
2answers
99 views
Which consoles may I target with OpenGL?
I'm thinking on technical design for a game/game engine using OpenGL, and I wonder if there is any recent consoles (Xbox360, PS3, Wii U, Xbox one and PS4) that I could work with if I do so.
I found ...
