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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2
votes
1answer
108 views

How do I check why is no output on screen?

I'm using OpenGL 3.3+, and I'm trying to create an orthographic projection to draw on screen. I have the model data in a buffer: X Y 0, 0 50, 100 100, 0 And I create my Model-View-Projection ...
1
vote
0answers
95 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
1answer
82 views

Gamma Space and Linear Space with Shader

I am using Unity and I can choose between two color space mode in the settings: Gamma or Linear Space. I am trying to build a Custom Lighting Surface shader but I am facing some problems with those ...
1
vote
0answers
67 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
1answer
170 views

gl_VertexID values when calling glDrawElements

I am struggling a bit to understand the values that gl_VertexID primitive contains when the vertex shader is executed. I have the standard modern rendering pipeline, in which after setting up ...
0
votes
0answers
166 views

Adding 2d hud/gui to a 3d game engine which has no 2d features

I have been following the 3d game engine tutorial series made by theBennyBox for a few months now, and have finally decided to create a game with it. My problem is that it is a 3d only engine which ...
20
votes
5answers
5k views

Why is an engine like Unity3D emphasized over a native library like OpenGL for beginners?

I am just a beginner in 3D games, my preferred platform is Android. I posted a question in some other forum about "What to use: OpenGL or Unity3d?" They all emphasized Unity3D and using its built-in ...
3
votes
1answer
80 views

Using textureGrad for anisotropic integration approximation

I'm trying to develop a real time rendering method using real time acquired envmap (cubemap) for lightning. This implies that my envmap can change as often as every frame and I therefore cannot use ...
0
votes
1answer
97 views

App using LWJGL can't find display mode extension on Linux

I'm running LWJGL app on Ubuntu virtual machine with no phisical graphic card. I set up Xvfb and Mesa3D but it fails with exception java.lang.ExceptionInInitializerError: null at ...
3
votes
2answers
138 views

OpenGL - Index buffers problem

I have a custom file format that has all the needed information for a 3D mesh (exported from 3ds Max). I've extracted the data for vertices, vertex indices and normals. I pass to OpenGL the vertex ...
0
votes
2answers
341 views

GLSL: can i use matrix transformation functions in vertex shader?

I have a working OpenGL code where i render a terrain with some trees. I am doing all the matrix mathematics on the client side. Because of which the frame rate of my app is very low, around 25-30 ...
0
votes
1answer
83 views

Camera rotation around point, but without centering

Let's say i have the following: Point somewhere in space Camera with position and orientation (up, right, forward) I want to rotate camera around the point, but also keep this point in same place ...
4
votes
1answer
312 views

How to efficiently render a large terrain mesh?

Recently I've been stuck on a problem thinking about the best way to generate a terrain into my game. In another projects I normally used heightmaps, so all the core-work was based on the engine used, ...
2
votes
1answer
103 views

Drawing symmetric equilateral triangles

I'm rendering equilateral triangles of different sizes and I'm having trouble making them symmetric along the vertical axis. Here I have rendered two triangles. The triangle on the left (rendered ...
0
votes
0answers
48 views

Bounding box center after transformation - want degree values for GUI

Similar to my previous question, I have a bounding box that I have transformed and scaled. Now, I want to get its center by doing this operation and store this value. bbCenter = glm::vec3(bbMin_x + ...
0
votes
1answer
54 views

Providing texture coordinates and using indexed drawing at the same time

Please consider the following vertex structure struct vertex { vec3 posL, normalL; }; Using this vertex layout, we can provide the vertex data in an interleaved way, i.e. ...
1
vote
2answers
228 views

glGenVertexArrays causes crash

My code keeps crashing at runtime, I have done some creative debugging and determined that it was the glGenVertexArrays that was causing the crash, I've looked around and come across some answers that ...
1
vote
1answer
135 views

Most efficient way of brighten and darken sprites with OpenGL > 2.0

So I have been shading (brighten/darken +adding color) my sprites by using glTexEnvf with GL_MODULATE and GL_ADD and a vertex color. I only had to rebind the batch every time I needed to change from ...
2
votes
1answer
280 views

How do I fit the camera frustum inside directional light space?

I'm trying to improve the coverage of a shadow map for a directional light. Currently, it works great if the camera is looking straight down. However, if the camera is close to the ground and looking ...
0
votes
0answers
48 views

Focus a turntable style camera on an object

I have a turntable style camera in the maya / blender / alembic / opensubdiv example. I want to be able to match the camera translation to any objects translation pivot point in the scene and then ...
0
votes
0answers
31 views

Keeping relative size with different resolution

I'm making a GUI system and want the components having a konstant relative size, even if I'm changing the resolution. Since I'm using the relative OpenGL coordinates to place them, there is no ...
0
votes
1answer
72 views

Loading Wavefront Data into VAO and Render It

I have successfully loaded a triangulated wavefront(.obj) into 6 vectors, the first 3 vectors contain the locations for vertices, uv coords, and normals. The last three have the indices stored for ...
1
vote
1answer
143 views

Why am I not getting an sRGB default framebuffer?

I'm trying to make my OpenGL Haskell program gamma correct by making appropriate use of sRGB framebuffers and textures, but I'm running into issues making the default framebuffer sRGB. Consider the ...
3
votes
1answer
108 views

Should my GLSL Shader object/wrapper encapsulate loading/setting a VertexArrayObject?

I am working on a 2D game in C++, with a simple rendering layer over OpenGL. I have a wrapper for GLSL shaders and shader programs, these wrappers encapsulate shader objects into C++ classes and ...
4
votes
1answer
204 views

OpenGL rendering looks squeezed

I am rendering bunch of cubes of unit size, but for some reason they look like they are squeezed a bit in the screen-space y axis. Why is this? My projection matrix: Projection = ...
4
votes
3answers
247 views

Make openGL program only update every 1/60 seconds

I'm learning C++ and openGL and have this program as a result from tutorials and playing around. The problem is that the main loop is running at "full speed", making the program unnecessarily cpu ...
1
vote
1answer
109 views

Performing manual clipping in OpenGL

I'm learning OpenGL and I understand that OpenGL performs clipping as part of the pipeline, but is it a good idea to also perform manual clipping? By manual clipping, I mean not asking the GPU to draw ...
0
votes
2answers
95 views

What dimensions should you use for a perspective projection frustum?

What dimensions should you use for a perspective projection frustum? Initially I created a perspective matrix based on the width and height of the screen, with a calculated zNear value based on a ...
0
votes
1answer
112 views

LWJGL Resize window and glTranslate breaking screen resolution

I'm trying to make a 2D Tile RPG game with LWJGL but I'm having a problem with the display resizing. I want the user to be able to re-size the window to whatever size they want just by expanding it ...
2
votes
4answers
360 views

Why would you use software rendering over hardware rendering, today?

As opposed to CPU or software rendering I assume? Wouldn't generally all current rendering be GPU based, seeing as you would be using OpenGL or Direct X? Could someone give me some info here, can't ...
0
votes
2answers
220 views

OpenGL - How can I make the edges of this textured circle smoother?

I'm building a game and I've applied a certain texture (RAW file) to a circle (GL_POLYGON) in OpenGL. It loads correctly, with the right size and all, but the edges seem a bit jagged and I would ...
1
vote
1answer
266 views

How can I implement beam effects like these?

I am interested in the techniques I could use to create the following effects: Can I accomplish this with a particle system or a series of texture quads, or what? You can see this effects in ...
0
votes
1answer
166 views

Render scene twice in OpenGL, overlay second render with tranparency

Is it possible to render two scenes (same scene with different setups) without any alpha, and after that is done just overlay the result from the second render on top of the first layer with a static ...
0
votes
3answers
133 views

OpenGL: glRotatef cause performance drop while rotating -x and -y

I have made a rotating cube and I got some performance drops while using two glRotatef calls. So basically this code is giving me 80FPS: //code 1 GLrotate_x += 0.4f; GLrotate_y += 0.4f; ...
0
votes
0answers
61 views

Using multiple uniform blocks in OpenGL

I'm using OpenGL with JOGL and want to use two unfirorm blocks in my vertex and pixel shaders. The following GLSL-Code shows the definitions:- uniform perObject { Material uMaterial; mat4 ...
0
votes
2answers
179 views

Do Java and Actionscript use OpenGL?

As far as I know there are only 3 base graphics libraries on Windows, the GDI, OpenGL and DirectX, is that correct, so that means that Java, Actionscript and all language use one of these 3 libraries ...
3
votes
0answers
258 views

OpenGL Shadow Mapping from directional light [closed]

I have read this tutorial: http://www.opengl-tutorial.org/intermediate-tutorials/tutorial-16-shadow-mapping/ I wonder, is this the current best technique for generating shadows in an arbitrary 3D ...
0
votes
1answer
165 views

OpenGL: How to improve the performance of rendering context [closed]

I have written a benchmark program that compares the performance of OpenGL and DirectX libraries. The problem is that OpenGL gets much lower performance than Direct3D. At the end the program generates ...
2
votes
1answer
112 views

Possible to create transparency shader which doesn't stack alpha values

The image above best demonstrates what I'm trying to achieve. It's a transparent shader for objects, but wherever the objects with this shader intersect they don't add together but simply merge with ...
0
votes
0answers
287 views

Irrlicht - Camera rotation like FPS

I'm constructing a game in OpenGL and initially I started using GLUT for the general purposes. However, later on I bumped over the problem of 3D model import and, after so many time trying to import ...
0
votes
1answer
91 views

Why do I have to switch T(v) texture coordinates while importing OpenGL to Direct3D?

I am importing my code from OpenGL to Direct3D. My D3DTS_PROJECTION uses D3DXMatrixPerspectiveFovRH, and my D3DTS_VIEW uses D3DXMatrixLookAtRH to set a view equal to OpenGL's view. My question is why ...
0
votes
2answers
66 views

Clamping large content to smaller area

I'm using OpenGL (with LWJGL) in Java, but the question is language independent. I have some region (a rectangle for simplicity), and, let's say, a big tiled map which I want to show in this area. ...
2
votes
1answer
74 views

OpenGL: missing GL_SPECULAR light on the texture

I'am missing specular lighting on the texture. I have #include <GL/glext.h> in the project, so basically I used glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL_EXT, GL_SEPARATE_SPECULAR_COLOR_EXT); ...
2
votes
1answer
72 views

How to store an array into a texture and sampler the texture in vertex shader correctly?

I'm a new learner about OpenGL and GLSL. I'm coding a program in which i wanna store a group of datas in a texture and get the data by sampling the texture in vertex shader. Then i want to set the ...
1
vote
1answer
150 views

How to save am image of a screen using JOGL

Hope this is a better place to ask things like this. I have a 2D scene with some sprites drawn in Swing frame. I need them to be saved as an image. The problem is every tutorial I found seem to be ...
1
vote
1answer
150 views

OpenGL and atlas

I'm trying to draw element from a texture atlas with OpenGL ES 2. Currently, I'm drawing my elements using something like that in the shader: uniform mat4 uCamera; uniform mat4 uModel; attribute ...
1
vote
1answer
73 views

Correcting Lighting in Stencil Reflections

I'm just playing around with OpenGL seeing how different methods of making shadows and reflections work. I've been following this tutorial which describes using GLUT_STENCIL's and MASK's to create a ...
1
vote
1answer
41 views

Having trouble setting color in fragment shader

For some reason, the color isn't applying to the object. Here's my fragment shader code. There's probably something obvious wrong with it that i'm not seeing. #version 330 core out vec3 Color; ...
0
votes
0answers
96 views

Moving objects smoothly, bad perfomance

I just finished developing my mini-game on Android and I got some questions about perfomance and generally "how to": If I have 25+ objects on the creeen (just a polygon with 7-8 angles) its starts to ...
0
votes
1answer
93 views

How does OpenGL determine different outputs with shaders?

Lets say I have this GLSL code: #version 330 out vec4 outputColor; void main() { float lerpValue = gl_FragCoord.y / 500.0f; outputColor = mix(vec4(1.0f, 1.0f, 1.0f, 1.0f), ...