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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4
votes
0answers
90 views

Slow uniform array

I'm trying to use an uniform array of matrices in my compute shader. However, it's really slow. I've narrowed it down to this lines of code: uniform mat4 someMatrixArray[64]; ... vec4 result = ...
3
votes
0answers
88 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 ...
3
votes
0answers
346 views

deferred rendering and gaussian blur - artifacts

I compute Gaussian blur in two passes (horizontally and vertically). Shaders look like this: Horizontal blur - fragment shader: #version 420 layout (location = 0) out vec4 outColor; in vec2 ...
3
votes
0answers
427 views

AlphaToCoverage + Alpha Blending = Artifacts

I'm experiencing a strange problem using OpenGL SampleAlphaToCoverage mode. There are rendering artifacts when using alpha-blending on pixels that have been rendered using alpha-to-coverage - and I ...
2
votes
0answers
26 views

SDL_AddTimer + SDL_GL_MakeCurrent not working on Windows

I'm messing around with C++, OpenGL and SDL doing a game that should be able to run in Windows and Mac OS X. I have a problem that only happens on Windows. Let me describe the scenario. First I ...
2
votes
0answers
188 views

Blank texture in Frame Buffer Object in Deferred Rendering

I'm running the tutorial 35 from olgdev.atspace.co.uk, and it's so strange that the result is a blank screen. This tutorial is performing the first step of Deferred Shading, which means decoupling of ...
2
votes
0answers
667 views

Arcball 3D camera

I have checked multiple threads before posting, but i havent been able to figure this one out. Ok so i have been following this tutorial, but im not using glm, ive been implementing everything up ...
2
votes
0answers
68 views

uniform z slices in clip-space

1) Context I'm using a regular OpenGL perspective projection matrix created with GLM (glm::perspective) and taking the inverse (glm::inverse) to transform clip-space back into view space (and world ...
2
votes
0answers
274 views

glFramebufferTexture2D gives corruption with cube map textures

I am using glFramebufferTexture2D with cube map textures but it gives corruption in texture. draw_cube() function works perfectly when i draw that on default framebuffer. GLenum ...
2
votes
0answers
284 views

Per fragment lighting with OpenGL 4.x tessellated model

I'm experienced with OpenGL 3+. I'm dabbling with tessellation shaders and have now got to a point where I have a nicely tessellated teapot/plane demo (quick look here) As can be seen from the ...
1
vote
0answers
47 views

OpenGL seems to be getting its colour from the wrong array on some machines

I have a OpenSceneGraph application which displays a 2D mesh and allows the user to make selections on triangles and vertices and colour them. If you aren't familiar with OpenSceneGraph, it's basiclly ...
1
vote
0answers
60 views

How to implement translation, scale, rotation gizmos for manipulating 3D object's transforms?

I am in the process of developing a basic 3D editor. It uses OpenGL for rendering a 3D world. Right now my scene is just a few boxes of different sizes and I am at the stage where I want to be able to ...
1
vote
0answers
63 views

OpenGL/GLM Camera

I want to make a camera that can freely look and walk on X/Z plane and rotate 360 degrees. I'm using OpenGL and the lookAt function from the GLM library to create the view matrix. I've looked through ...
1
vote
0answers
77 views

How to shade hair (line segments) correctly in GLSL

I render my hair geometry in line segments. The problem I have is with the correct shading of the hair. From what I've read I understood that I need the direction of the line segment and the ...
1
vote
0answers
26 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
59 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
52 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
0answers
99 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
58 views

Text alignment in OpenGL with FreeType2

I'm trying to implement font rendering and have got into some trouble with glyph metrics. Here's the code where I get the metrics: Glyph gl; gl.width = face->glyph->metrics.width / 64; ...
1
vote
0answers
85 views

What's the best way to set up an OpenGL draw loop in windows?

On mac os x, there's a way to pass the system a function pointer that is triggered at an ideal time to start your drawing code. These are the CVDisplayLink tools. I'd like to understand how to do ...
1
vote
0answers
58 views

Converting signed normalized integer to unsigned normalized integer image format

Given I have my texture data in client memory as signed normalized integers. I want the samples in the shader in the range [0,1]. Can I simply specify: format = GL_RGBA; internalFormat = GL_RGBA8; ...
1
vote
0answers
77 views

3D Camera Y-Axis wrong angle

I am trying to build a camera class, though I am running into a problem. When I move the camera above/below, and try to move towards the ground, I am moved off in what seems to be about 45 degrees in ...
1
vote
0answers
158 views

opengl volumetric billboard implementation: general idea + geometry shader

A while ago I decided to implement the volumetric billboards technique in my university project (C++ & OpenGL 4.3). I passed the subject but failed to implement the mentioned technique. I'd like ...
1
vote
0answers
114 views

Shadow maps, reducing “shimmering”

I'm doing shadow maps, and my shadows move around, "shimmer", when I move around the camera. It is difficult to spot on still images but very much noticable in motion. I read an MSDN article ...
1
vote
0answers
71 views

FreeGLUT keyboard IO timing and synchronization

Using FreeGLut's keyboard callbacks, glutKeyboardFunc(); glutKeyboardUpFunc(); glutSpecialFunc(); glutSpecialUpFunc(); When in the glutMainLoop pipeline do these functions get called? In other ...
1
vote
0answers
47 views

Sampler object not changing texture filter

I am currently binding a sampler object to a texture (GL_TEXTURE12 to be specific) with glBindSampler(12, sampler); and the initial settings are very visible compared to the textures own settings. ...
1
vote
0answers
83 views

Texture not visible on particles

This is the first time I am working with particles (GL_POINTS) I am using kinematic equations and controlling their movement in vertex shader. I am following an example given in OpenGL 4.0 Cookbook ...
1
vote
0answers
45 views

after calculating normals texture is full of black triangles

After I added normal calculation to my project - the surface of landscape became full of black triangles and even have a deformity on one side. Here I calculate normals int x, y; int Index = 0; ...
1
vote
0answers
159 views

GLSL, Internal error: assembly compile error for fragment shader at offset 513

My vertex and fragment shaders link correctly. When I try and link my shader program I get the error: "Internal error: assembly compile error for fragment shader at offset 513". Pastebin of fragment ...
1
vote
0answers
186 views

Unity Pro - Shadow rendering issue

I am using Unity Pro 4.2.1f4 and I always have this sort of glitch. This is due to the shadows and the bias. Even with a low bias this is happening. I've found a thread that talks about that ...
1
vote
0answers
296 views

c++ opengl unproject not working

first of all, sorry for the bad english. I need to convert my mouse coordinates to world coordinates, I'm trying to use the glm unproject method. 1280x720 is the size of the window, It's hard coded ...
1
vote
0answers
304 views

Geometry shader and triangle adjacency

I'm currently trying to change my project to use GL_TRIANGLE_ADJACENCY instead of GL_TRIANGLES. Following this question, I have managed to construct my index buffer fine, but when it comes to the ...
1
vote
0answers
75 views

Slick2d font rendering makes all other drawings vanish

I'm converting a java game to lwjgl and slick-utils. I've followed the slick2d examples for font loading/rendering but I found that the font shows as a solid box of color unless I add the following ...
1
vote
0answers
165 views

Rotate a point in 3D space with sine and cosine

I got my camera controlled by the mouse. Now I want a sphere to be always in the center of my view(just for testing). I tried that by assigning the sine of the Y rotation of the camera times 10 as the ...
1
vote
0answers
411 views

Creating a new GLFW window and re-using the old context causes crash

I am using GLFW 3.0.2 and when I want to switch the application to fullscreen, I create a new window and intend to use the OpenGL context of the old window so I don't have to reload all the meshes, ...
1
vote
0answers
179 views

GLX/X11 Changing the rendering resolution

I have made a simple application that creates a window with an OpenGL 4.2 context and takes user input. I have implemented making the window go fullscreen with XRandR and can change the display ...
1
vote
0answers
129 views

Matrix array doesn't seem to get populated

I'm trying to stream an array of matrices to a vertex shader, but it seems that only the first matrix works. What could be the problem? I suspect that I upload the matrices in a wrong way. C# ...
1
vote
0answers
83 views

Rotate view matrix based on touch coordinates

I'm working on an Android game where I need to rotate the camera around the origin based on the user dragging their finger. My view matrix has initial position of sitting on the negative z and facing ...
1
vote
0answers
958 views

Multiple Render Targets, Multiple Fragment Shaders

I render a normal and a depth image of a scene. Then I want to reuse these two images to do further texture/image processing in a second fragment shader. I use a framebuffer with 3 textures attached ...
1
vote
0answers
376 views

How to implement OpenGL triple buffering

I'm trying to implement the triple buffering described here ...
1
vote
0answers
129 views

Aiming with a crosshair with a lot of polygons/triangles

I'm working on a 3d kindof game where I'll eventually be able to modify the shapes present in the environment by pulling their faces with a crosshair. The thing is that I don't know how to achieve ...
1
vote
0answers
121 views

Posible to export f-curves in blender?

I work with some friends on a rail shooter game in openGL. For creating our world we are using Blender. Since we want our Tank to follow a path I have started to work with creating bezier curves and ...
1
vote
0answers
95 views

How to put OpenGL in a state for drawing blended, colored, nontextured polys?

Using OpenGL1.1 (sadly) I'm trying to draw a cube, which is colored and alpha blended. It is instead showing up as opaque black. Even without including alpha in the color it still shows up as opaque ...
1
vote
0answers
345 views

Optimal OpenGL 2D Sprite Batching (Best Practice)

I am working on simple 2D engine using OpenGL (3.3+) for rendering and was wondering what the optimal method of sprite batching would be. I plan to put all sprites into one (or fewer) texture atlases. ...
1
vote
0answers
174 views

Sketchy results from ray-plane intersection code

I've set up a demo with simple first-person controls using C++ and OpenGL, and it seems to work reasonably well. My goal is this: when the player looks at a plane and clicks the left mouse button, ...
1
vote
0answers
188 views

Detect Sprites, they are in Shape or Not which random draw in Cocos2d

I have searched a lot on web and found some of help ful links as exact my question. Link 1 Link 2 But still i am not success to achieve this, i have done some of code lines, as like draw line by ...
1
vote
0answers
165 views

Strange rendering issue with monogame/WinGL with HD7670M

I'm having some strange rendering issues with latest monogame/winGL code as seen below; As you can see the xna and tomspilmans WinDX port seems just okay. I'm having this problem on my laptop ...
1
vote
0answers
209 views

How to make an oscillation move on opengl qt

I'm trying to make a character make an oscillation move. That is, the character will start by rotating to a certain angle, say 60 degrees, and then slowly come back to an upright position then rotate ...
1
vote
0answers
379 views

How to pick a 3D object with known mouse coordinates if the camera is rotated 60 degrees?

I am making a simple game engine for a simple RTS game and would like to be able to pick a cube and move it around with the mouse coordinates. The problem is that my camera is rotated 60 degrees just ...
1
vote
0answers
208 views

How do I convert my matrix from OpenGL to Marmalade?

I am using a third party rendering API, Marmalade, on top of OpenGL code and I cannot get my matrices correct. One of the API's authors states this: We're right handed by default, and we treat y ...