Tagged Questions

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 ...

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0
votes
0answers
109 views

FBX SDK Colors problem

I've imported control points, normals, and indices successfully and now i'm trying to import vertex colors, but something is not right. Here's the code: FbxLayerElementMaterial* ...
0
votes
0answers
19 views

How to switch a view off and on again while retaining key event input

I have a couple of views in my app - my main activity and a separate activity which is used for high scores. What I need to know is how I can 'get rid' of one of the views temporarily, and then bring ...
-1
votes
1answer
101 views

Combine Two Shader Program [closed]

For my android application, I want to apply brightness and contrast shader on same image. At present I am using gpuimage plugin. In that I found two separate program for brightness and contrast as ...
0
votes
1answer
51 views

Render on other render targets starting from one already rendered on

I have to perform a double pass convolution on a texture that is actually the color attachment of another render target, and store it in the color attachment of ANOTHER render target. This must be ...
10
votes
1answer
304 views

Rendering only a part of the screen in high detail

If graphics are rendered for a large viewing angle (e.g. a very large TV or a VR headset), the viewer can't actually focus on the entire image, just a part of it. (Actually, this is the case for ...
1
vote
2answers
167 views

OpenGL flickerinng near the edges

I am trying to simulate particles moving around the scene with OpenCL for computation and OpenGL for rendering with GLUT. There is no OpenCL-OpenGL interop yet, so the drawing is done in the older ...
2
votes
0answers
42 views

FBX Importer - Vertex Color

I imported vertex positions, indices and normals successfully in OpenGL using fbx sdk, but I just can't figure out how to import vertex colors. I tried to fetch the pointer to array of colors trough ...
1
vote
0answers
82 views

Creating a voxel chunk with a VBO - How to translate the coordinates of each block and add it to the VBO chunk?

I'm trying to make a voxel engine similar to minecraft as a little learning experience and a way to learn some opengl. I have created a chunk class and I want to put all of the vertices for the whole ...
2
votes
1answer
280 views

OpenGL - have object follow mouse

I want to have an object follow around my mouse on the screen in OpenGL. (I am also using GLEW, GLFW, and GLM). The best idea I've come up with is: Get the coordinates within the window with ...
0
votes
0answers
108 views

OpenGL Drawing textured model (OBJ) black texture

I'm using OpenGL, Glew, GLFW and Glut to create a simple game. I've been following some tutorials and I have now a good model importer with textures (from ogldev.atspace.co.uk) but I'm having an ...
-1
votes
2answers
61 views

GLSL Normals not transforming propertly

I've been stuck on this problem for two days. I've read many articles about transforming normals, but I'm just totaly stuck. I understand choping off W component for "turning off" translation, and ...
0
votes
0answers
133 views

Libgdx - 2D Mesh rendering overlap glitch

I am trying to render a 2D circle segment mesh (quarter circle)using Libgdx/Opengl ES 2.0 but I seem to be getting an overlapping issue as seen in the picture attached. I cant seem to find the cause ...
0
votes
1answer
128 views

How to remove seams from a tile map in 3D?

I am using my OpenGL custom engine to render a tilemap made with Tiled, using a well spread tileset from the web. There is nothing fancy going on. I load the TMX file from Tiled and generate vertex ...
1
vote
1answer
115 views

Are there any reasons to use Legacy (2.X) OpenGL?

The benefits are well documented of the Modern OpenGL 3.X & 4.X API's, but I'm wondering if there are ANY benefits to keeping with the old OpenGL, Or if learning OpenGL 2.X is a complete waste of ...
1
vote
1answer
61 views

I don't understand why one of my vbo is overwritten by another

to create a vbo I use this function: public void loadVBO(){ vboID = GL15.glGenBuffers(); GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vboID); ...
3
votes
1answer
176 views

Open GL perspective projection vs orthographic projection

I am trying to build an engine using OpenGL however I have a question about the kind of projection to use. For a 2D game should I use a perspective projection or an orthographic projection? If I ...
0
votes
1answer
119 views

What is wrong with my specular phong shading

I'm sorry if this should be placed on stackoverflow instead however seeing as this is graphics related I was hoping you guys could help me: I'm attempting to write a phong shader and currently working ...
1
vote
0answers
48 views

Normal map lighting bug in bottom right quadrant [closed]

I am currently working on getting normal maps working in my project, and have run into a problem with lighting. As you can see, the normals in the bottom right quadrant of the lighting isn't ...
1
vote
1answer
51 views

Depth Map resolution shifting

the problem is with shadow mapping as you can see, actually it works fine but in a certain condition that the Depth Map size must be equal to the size of rendering buffer, I use an infinite ...
1
vote
1answer
42 views

How should I handle a modelview stack with multiple shader programs involved?

I'm building a framework where each object has an associated program and each object has a 'draw' method. What is the best choice, to have a single modelview stack handled by a Renderer class or to ...
15
votes
2answers
1k views

Camera vs Viewport

I'm don't have a clear understanding of what precisely is the difference between the camera coordinates and the viewport coordinates. Can anyone please clarify?
0
votes
2answers
62 views

What is the correct way to reset and load new data into GL_ARRAY_BUFFER?

I am using an array buffer for colors data. If I want to load different colors for the current mesh in real time what is the correct way to do it. At the moment I am doing: glBindVertexArray(vao); ...
2
votes
1answer
191 views

draw fog of war using shaders

I am making a RTS game, and I'd like some advice on how to best render fog of wars, given what I'm already doing. You can imagine this game as being a classic RTS like Age of Empires 2, where the fog ...
1
vote
0answers
148 views

Which will be better for a beginner, SDL, SFML or OpenGL? [closed]

I want to make games.For now simple 2D games, but I don't know from where to start. I "know" C++, but i havent worked with classes.I want to begin with game development and I searched in the internet ...
2
votes
4answers
292 views

OpenGL setup on Windows

I have been trying to use OpenGL for two days now. First on Mac, then on Windows. The problem with Mac is that it doesn't support the newer versions of OpenGL. I ran a tutorial that actually did get ...
5
votes
2answers
193 views

How to use OpenGL functions from multiples thread?

I'm writing a small game using OpenGL. I'm implementing basic networking in this game and I'm facing a problem. I have a thread in my client socket class that check for available data, when there ...
0
votes
1answer
80 views

OpenGL ES 1 Pixel Error?

I am developing a game on android using OpenGL ES 1.0 for Android OS. It is a 2d game using a simple Orthographic projection and textures for the sprites. One of these textures has a small line (it ...
-1
votes
1answer
81 views

How do I put different textures on different walls? LWJGL

So far I have it so you are running around in a box, but all of the walls are the same texture! I've loaded up other textures for the walls (I want the walls a different texture than the floor) but it ...
1
vote
1answer
935 views

OpenGL - Calculating camera view matrix

Problem I am calculating the model, view and projection matrices independently to be used in my shader as follows: gl_Position = projection * view * model * vec4(in_Position, 1.0); When I try to ...
2
votes
1answer
325 views

OpenGL 4D textures with bilinear interpolation

I want to use and interpolated 4D texture in OpenGL, i.e. a texture that is accessed with a texture coordinate vector (s, t, p, q) and interpolated linearly in every texture coordinate. The extension ...
1
vote
0answers
97 views

Different way to pass uniforms to seperate draws in glMultiDrawElementsIndirect

Given OpenGL version 4.3 and GLSL 430, what would be the best way to pass a matrix to each model in a draw call to glMultiDrawElementsIndirect? I am thinking of going the way of a TBO and indexing it ...
1
vote
0answers
112 views

Android: Hardware Scaler

I was reading through this: using-hardware-scaler-for-performance and am a little confused by it. It says all you need to do to invoke the scaler is to set it like so: surfaceView = new ...
1
vote
1answer
185 views

Render 2 images that uses different shaders

Based on the giawa/nehe tutorials, how can I render 2 images with different shaders. I'm pretty new to OpenGl and shaders so I'm not completely sure whats happening in my code, but I think the shaders ...
0
votes
0answers
52 views

Issue with turntable rotation openGL

I am trying to implement turn table like rotation in my openGL app. In turn-table like rotation, z-axis is not supposed to roll. But in my app z-axis rolls like anything when I try to rotate the ...
0
votes
0answers
105 views

Help with instancing: seg fault with glVertexAttribDivisor

I'm trying to get the basics of instancing in OpenGL 3.3 and failing miserably. I'm starting with the Jason McKesson's Depth Buffering tutorial, then modifying it so that only the ...
1
vote
1answer
88 views

Why are my objects rotating with my camera?

I am working with this C# library that wraps OpenGL. I am trying to understand why my objects in the scene are rotating as I yaw my camera (view matrix). Here is an image where I have 4 separate ...
0
votes
1answer
228 views

Create 2D sprites with libGdx using a shape and a texture separately

I am creating a 2D game with LibGdx that will have creatures that are generated from dozens of characteristics with potentially millions of unique combinations. For each segment of each creature, I ...
0
votes
1answer
114 views

Making particles accelerate toward a mouse point

I'm currently working on a particle simulation program that makes pixels move towards a mouse point continually accelerating, but i'm running into some math issues. Currently my particle will ...
0
votes
2answers
83 views

Trouble getting shadow maps working

I am trying to implement shadow maps in my game following this tutorial. For some reason, the light is not being occluded. In the above screenshot, the big white sprite in the foreground is a ...
0
votes
1answer
292 views

Calculating Per Vertex Normal in Geometry Shader

I am able to calculate normals per face in my Geometry Shader but i want to calculate per vertex normal for smooth shading. My Geometry shader is #version 430 core layout ( triangles ) in; layout ( ...
1
vote
0answers
189 views

How can I reduce draw calls when using glBufferSubData and DYNAMIC_DRAW?

At first I had the problem where I had about 150 rectangles rendered every tick. I only used STATIC_DRAW and glBufferData. I added support for DYNAMIC_DRAW and glBufferSubData and now I have a very ...
1
vote
0answers
147 views

Point light shadowmapping woes [closed]

I'm doing point light shadow mapping and I'm tearing my hair out trying to iron out a bug. The problem is shadows are basically "inverted" somehow, or wierdly placed. Here's five screenshots; you ...
0
votes
1answer
103 views

Deferred lighting and point light volumes

I'm doing deferred point light shadow mapping and I am drawing my point lights using light volumes. Normally I access the position/diffuse texture/normals using this in the fragment shaders: vec2 ...
3
votes
1answer
211 views

What is the maximum number of shaders I can have in OpenGL 4?

What is the maximum limit of shaders I can have on the GPU? With 1000 different objects, I might have 1000 * 5 shaders (vertex, tcs, tes, geo, frag) on the GPU at a time. Though only one will be ...
0
votes
1answer
110 views

WebGL wrong scaling of rectangle

I'm working with this tutorial http://www.html5rocks.com/en/tutorials/webgl/webgl_transforms/ and my result is, that the rectangle moves in the direction of it's scaling values, and also scales at ...
2
votes
1answer
172 views

Use different values for Depth Test and Depth Write in OpenGL

Is there a way to use something similar to PolygonOffset to make a depth test more permissive (move fragment depth towards eye) but still write the original depth value to the depth buffer? The only ...
1
vote
1answer
115 views

Techniques for managing vertex buffer memory

I'm learning OpenGL and I haven't seen any advice on managing vertex buffers in all of the tutorials I've read. The basic problem is that I have some memory allocated as a buffer B in which I'm going ...
4
votes
1answer
131 views

OpenGL - What steps to take to correctly set up an Uniform Block Array

I have managed to get uniform blocks to work, but I seem to make something wrong when trying to setup an array of uniform blocks. Assume this glsl: layout(std140, binding=1) uniform LightingBlock ...
2
votes
2answers
122 views

OpenGL - How to draw each nth triangle using glVertexAttribPointer

I have a vertex buffer. There are situations when I don't want to render the whole mesh, but let's say each nth triangle of the mesh. I am using VAOs and VBOs. My data in the buffer is like this: ...
0
votes
2answers
98 views

Achieving a fixed frame-rate with varying scenes

I am working on an OpenGL 3D model viewer app for iOS. I have to load, view and navigate extra detailled 3D models on an iPad. I hardly achieve 2 fps, if i load and navigate a very complex model. I ...