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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Incorrect Normal Matrix

In my game engine I'm passing a normal matrix to my shaders like so: Matrix3f normalMatrix = modelMatrix.invert().transpose(); However this is causing lighting to rotate with my object, producing a ...
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1answer
18 views

Drawing a pixel to RenderTexture

I would like to know how you would go about drawing a single pixel to a RenderTexture in Unity. In XNA, it was just a matter of setting the graphic device's active renderTarget, and drawing to it. ...
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2answers
40 views

How to use TextureArray's Pre-OpenGL 4.2?

I've been using TextureArray's in my current Project; However, I have come to the problem of OpenGL 4.2 functions not being on the present Mac software when ported over. Due to only version 4.1 of ...
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1answer
38 views

Rotate heading relative to agent's local space

I'm having a little trouble translating a point in my game's world space to an object's local space. I have a cannon in my game with a normalized heading vector that's always supposed to point in the ...
2
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1answer
227 views
+50

Recurring stalls in SwapBuffer

I am currently doing measurements on a test scene implemented in OpenGL 4.5 with different "setups". I noticed that in case I have a very high amount of FPS (1550 in this specific case), SwapBuffer ...
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0answers
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Stochastic process simulations in OpenGL [on hold]

I'm planning on taking on a pet project in OpenGL in which I want to simulate particle movement in 3D, 3D Random Walk, Brownian Motion, state transitions (Gambler's Ruin, Inventory) etc. etc. I also ...
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1answer
80 views

OpenGL Shader Storage Buffer Objects array length problem

Ok guys, I think I have a very strange problem. I have an old laptop, but its HD 6370M currently supports opengl 4.4, so i decided to learn how to use some new features of this platform, so after ...
3
votes
1answer
86 views

Image edges are distorted inside game

I dont know how to explain this, so I will use images to describe my problem. The image I made using InkScape: What it looks like in-game (ignore the runner): As you can see the edges are not ...
-1
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0answers
25 views

CEGUI 0.8.4 and SDL2. Crash the app after startup

Do not run the compiled lesson. Link to the lesson. https://bitbucket.org/lucebac/cegui/src/ea8f8c814a4d5dbaa56344218659eb68ce173961/application_templates/SDL2.cpp?at=application-templates-devel Link ...
8
votes
7answers
6k views

Library to load images into textures, Linux, C and OpenGl

I am looking for simple, self-contained C library for Linux to load images from files into OpenGL textures. The licence should be quite liberal: zlib, bsd, mit or something. I have found SOIL, however ...
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0answers
25 views

Why are my GLUT/GLEW models only visible for one frame in the framebuffer?

I'm having this problem with an OpenGL program where the models in the scene are only visible for one (the first) frame when rendering them to a texture, and then to the screen. If I render them ...
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votes
1answer
69 views

Cannot find bug in frustum culling code

I've written some code for frustum culling, but for some reason, it is not working, and i can't find the bug in it... Maybe a bug in the math, somewhere? So, i'm asking you if anyone could check these ...
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1answer
78 views

How to approach animations and OpenGL

There are tons of tools and instructions for making 3d models and animations in various software products. My question is: in video-game engines, when would you use a pre-rendered animation, and when ...
0
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1answer
56 views

Platformer collision advice

I've been trying to implement collision for a platformer but I can't find a good way to get the collision of certain sides without it get glitchy. So i try to get the collision of the top rectangle ...
1
vote
1answer
43 views

How to orthogonalize the “up” vector in a camera based on “eye”, “look” and “up” vectors?

Given a camera position defined as (eye, look, up), where "up" not quite at right angles to eye->look, how would I re-orthogonalize "up"? I've had a hunt around, but did not find anything, yet if I ...
2
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2answers
88 views

Translating an object in the rotation direction

I am creating a graphical scene with OpenGL and SDL, and I'm running into a problem in regards to translating an object in its rotation direction. Each of the graphical objects in the scene has a ...
0
votes
1answer
25 views

trouble getting the lighting and material set up right

I am having some trouble getting the lighting and material set up. Below I have setup lighting and material, however, when ever I turn on spectular reflection for material the sphere that I am ...
1
vote
1answer
48 views

Does glScissor affect stencil and depth buffer operations?

I know glScissor() affects glColorMask() and glDepthMask(), but does it affect the stencil and depth buffers? For example: glEnable(GL_DEPTH_TEST); glEnable(GL_SCISSOR_TEST); ...
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1answer
803 views

Can't get Depth testing to work (cube faces shine through)

I'm making my first steps with OpenGL with LWJGL. I am currenlty constructing a... wait for it... CUBE. Quite creative... Up to now i made it to three of its faces and thats where the Problems began. ...
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1answer
35 views

PBR Metalness Implementation: specColor at Value 1?

I am doing a BRDF supporting the metalness/roughness workflow. I know that in cases of Metalness = 1.0 the reflectance value is taken from the albedo map - so is the specular color to tint the ...
0
votes
3answers
43 views

Why should i set glClearColor and setProjectionMatrix in render method many time in LibGDX?

import com.badlogic.gdx.Game; import com.badlogic.gdx.graphics.OrthographicCamera; import com.badlogic.gdx.graphics.g2d.SpriteBatch; public class MyGame extends Game { public OrthographicCamera ...
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1answer
197 views

What is the correct multiplication order for a 2D matrix?

I'm currently trying to create a camera and entity/model matrix for my 2D game similar to that of Unity3D. I've already tried to find answers to this question on stackoverflow/gamedev but i couldn't ...
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3answers
3k views

Will I have an easier time learning OpenGL in Pygame or Pyglet? (NeHe tutorials downloaded) [closed]

I'm looking between PyGame and Pyglet, Pyglet seems to be somewhat newer and more Pythony, but it's last release according to Wikipedia is January '10. PyGame seems to have more documentation, more ...
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0answers
75 views

Problems with First Person Camera in C++ OpenGL

I'm building a first person camera for my application but I'm having a couple of problems relating to moving the camera. In general, I have 2 vectors, one for the camera's position and one for the ...
1
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1answer
128 views

Simulation of ball movement in a 3d landscape. The easiest way?

I have a landscape(generated via Perlin noise) and a ball. I want the ball to move along the geodesic(implementation of basic physics: gravitation, friction). I thought to do raycast around the ball ...
2
votes
1answer
66 views

Creating polygons with separate outline/fill colors in OpenGL

Subject I am creating a terrain map with triangle strips and I would like to make the bodies of the triangles black, but have their outlines be colored. Problem The solution appears to be to draw ...
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0answers
37 views

Hard time implementing AABB collision into a platformer

I have AABB collision working fine. The problem is I can't get it to work with a platformer style game. The collision makes the player move a bit static when colliding and the gravity wont work with ...
1
vote
2answers
325 views

Calculating shadowmap coordinates for cubemap in shading pass?

I'm trying to implement shadow mapping with cube maps. I believe I've done the first stage by filling the cube map, but for the final shading pass I am unsure how to exactly calculate the cubemap ...
0
votes
1answer
26 views

Opengl textures change color of everything

Whenever I render textures, all shapes get the color of the texture. I'm not sure why, but I think it's something to do with the way I render textures. Here's what I use to draw textures: public void ...
2
votes
2answers
84 views

How can I set up an intuitive perspective projection/view matrix combination in OpenGL, using GLM?

Could anyone help me set up an intuitive perspective camera matrix using OpenGL and the GLM library? By "intuitive" I mean that I want the camera to be looking at the middle of the screen down the -Z ...
2
votes
0answers
53 views

How to handle the birth and death of particle without reading from the buffer

I've implemented a simple particle system where each particle has a position, velocity, age and lifespan stored in different SSBOs. Most of the data including all the position, velocity and age is ...
1
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1answer
76 views

Stepping through 3D noise to generate a cubemap for a sphere

This is somewhat related to a previous question I asked How to create a seamless cubemap noise texture? I have managed to successfully step through a 3D noise function to create a cubemap texture ...
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0answers
21 views

Opengl camera handling

I normally do parallax scrolling with x and y which works, but I'd like to make a camera class instead so I can rotate as well. Right now the camera is set to the player's position but doesn't scroll. ...
1
vote
1answer
1k views

How to achieve anisotropic filtering

I am loading a texture and using glGenerateMipmap() on it to achieve some level of mipmaping. I get different result on nVidia gt 555m, and on Intel HD 3000. The texture rendered by nVidia is not ...
0
votes
2answers
297 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 ...
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0answers
54 views

OpenGL Slow Rendering Procedures . glDrawArrays

Hello i would like to present my problem here. At the moment i have a scene with about 250 trees , 100 ferns , a player model and a custom generated terrain (from height map). For the past few days i ...
3
votes
1answer
86 views

How to generate a RGB * a texture for a glow effect in GLSL?

I would like to create a glow effect in GLSL, there is a tutorial that explains how we multiply RGB * a : I have some questions : is it an operation that is in a fragment shader, where RGBa is ...
3
votes
1answer
232 views

Variance shadow maps don't want to render properly

I've implemented VSM (and also ESM) in my engine but results are for me not as I expected and saw in many examples published on network. I set filtering of shadow maps to GL_LINEAR but when I compare ...
0
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0answers
43 views

uniform perspective on all objects [closed]

I am trying to create an animated clock like this in OpenGL. I was just wondering, how would I make the objects that will be the pieces with the numbers on them appear with perspective as they do in ...
0
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1answer
53 views

How to use multiple custom vertex attributes in OpenGL

My code currently uses glBindAttribLocation and glVertexAttribPointer to specify two custom vertex attributes in indices 6 and 7. This seems to work fine, but I wish to add another attribute and no ...
2
votes
1answer
66 views

Rendering text with SDL2 and OpenGL

I've been trying to have text rendering in my OpenGL scene using SDL2. The tutorial I came across is this one Rendering text I followed the same code, and I get text rendering fine. However the issue ...
0
votes
0answers
23 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() ...
0
votes
1answer
33 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 ...
2
votes
1answer
121 views

Selection with region (when rendering with shaders and VAO)

I am currently render my geometry using "Modern OpenGL" approach (with shaders and buffers). I have already implemented picking of single primitives using glReadPixels. Now I am faced with problem how ...
2
votes
1answer
112 views

Understanding normal mapping

I am trying to understand the basics of normal mapping using this tutorial : http://ogldev.atspace.co.uk/www/tutorial26/tutorial26.html What I don't get there is the following equation : E1 = ( U1 - ...
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vote
2answers
70 views

OpenGL: Is it efficient ok to glPushMatrix, plMultMatrix, plPopMatrix for every object in my scene?

I'm very new to opengl, and I might not fully understand the openGL matrix projection stack thing. So, I have about 300 'objects' in my scene, each with their own position/rotation, and I want to ...
2
votes
1answer
62 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 ...
7
votes
4answers
4k views

Trapping mouse inside window in OpenGL with GLUT?

I perfectly understand that GLUT is limited and the following problem can't probably be solved with OpenGL/GLUT, but since I don't know exactly if it can or not, I better just ask. Maybe I'm doing ...
0
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1answer
53 views

Orthographic viewport zooming

I'm a bit new in opengl so please bear with me. I have a viewport window like this I have implemented zoom in/out features using the arrow keys. The problem is it zooms in and out with the whole ...
2
votes
2answers
368 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 ...