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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Trying to understand light on Opengl, how to simulate a realistic sun light?

I don't know if I'm doing something wrong or missing anything but I want to simulate sun light, like in a sunny day. When the object is facing the directional light, it's well lit and there's no ...
11
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1answer
542 views

How to achieve light that changes color mid-way?

I thought of creating light sources, and some colored windows. Now, the windows are semi-transparent. How could I make it so that when the light (say, pure white) hits the glass and continues through ...
11
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1answer
4k views

How does UVW texture mapping work?

I'm trying to understand the mathematical theory behind UVW mapping. Can anyone explain me how UVW mapping works? Or at least provide me a pointer?
11
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3answers
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What is the difference between OpenGL 1.x and 2.x?

Is there a good tutorial that shows the difference between OpenGL 1.* and 2.*? It would be very helpful to know which functions I should not be calling (like glBegin(), I assume).
11
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1answer
3k views

Modern shadow rendering techniques?

What is the state of the art in terms of shadow rendering? My target is OpenGL 3.2, using a deferred rendering pipeline, if that matters. It's been years since I looked into shadow rendering, and at ...
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1answer
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How to reduce image size without pixelation?

I see lots of games with smooth edges characters and high res images, however when I try to reduce images to say 64x64 for my character I just get a pixelated mess. even if I start with a 64x64 canvas ...
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3answers
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How can I bend an object in OpenGL?

Is there a way one could bend an object, like a cylinder or a plane using OpenGL? I'm an OpenGL beginner (I'm using OpenGL ES 2.0, if that matters, although I suspect, math matters most in this case, ...
10
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2answers
11k views

OpenGL ES 2.0 Point Sprites Size

I am trying to draw point sprites in OpenGL ES 2.0, but all my points end up with a size of 1 pixel...even when I set gl_PointSize to a high value in my vertex shader. How can I make my point sprites ...
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3answers
2k views

Missing features from WebGL and OpenGL ES

I've started using WebGL and am pleased with how easy it is to leverage my OpenGL (and by extension OpenGL ES) experience. However, my understanding is as follows: OpenGL ES is a subset of OpenGL ...
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5answers
756 views

API agnostic bridges (ie. OpenGL/D3D/Whatever). Do you use them, how you make them. Pro's and Con's

You are making a 3d engine. You want best of multiplatform worlds. Suddenly you realize that if you want to use Direct3D on Windows machines and OpenGL on OSX/Linux, you'll have to sacrifice supported ...
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1answer
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OpenGL: Resizing Display and glOrtho/glViewport

I have researched this question from several sources and have yet to find a firm answer saying that "yes that is correct thinking" or "no, here is how it's done." I am trying to ensure resolution ...
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2answers
1k views

Rendering characters, with cut off limbs (Blender models in Java/OpenGL)

What aspects should I take into consideration for creating character animation and rendering classes if I want to be able to have detachable limbs? I've developed a detailed body system that can have ...
10
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2answers
2k views

Large vertex buffer vs multiple draw calls

I'm just getting started with OpenGL, and I'm attempting to use it to create a 2D game. In this game, I have a hexagonal grid made up of a very large variety of differently-colored hexagons. As a ...
10
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1answer
979 views

How do I create good looking plasma explosion effects?

Is this just a billboard quad with a bloom shader?
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votes
5answers
4k views

Skybox texture artifact on edge

I have strange problem with drawing skybox texture on Mac. On iPhone everything is going fine. I have tried to change near and far planes value with no success. It is a skybox of six textures, and ...
10
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2answers
4k views

Efficient skeletal animation

I am looking at adopting a skeletal animation format (as prompted here) for an RTS game. The individual representation of each model on-screen will be small but there will be lots of them! In ...
10
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1answer
3k views

GLSL, all in one or many shader programs?

I am doing some 3D demos using OpenGL and I noticed that GLSL is somewhat "limited" (or is it just me?). Anyway I have many different types of materials. Some materials have ambient and diffuse color, ...
10
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1answer
4k views

How to use multi-thread OpenGL application to update VBO and use it at the same time?

I have simple application. It has two threads. Each thread has it's own rendering context, but they share one VBO (this is working, I tested it). Now what I want: One thread is rendering some data ...
10
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1answer
356 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 ...
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3answers
4k views

Animation in OpenGL using 3D Models

I have created a model in Blender. Now i want to read that 3D model in my c++ program. I figured that a model can be exported to various file formats e.g. .obj, .3ds or COLLADA and then can be read in ...
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2answers
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How many textures can usually I bind at once?

I'm developing a game engine, and it's only going to work on modern (Shader model 4+) hardware. I figure that, by the time I'm done with it, that won't be such an unreasonable requirement. My ...
9
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4answers
14k views

What is the purpose of glScissor?

I know that it is more efficient than stencil test, but am I right assuming that the same functionality could be achieved using projection transformations with viewport?
9
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2answers
2k views

How to make natural looking voxel

I'm developing a voxel game, but I think I use the wrong technique. I currently use flat tiles, to make blocks, and I think theres a better and more efficient way. I have seen a voxel game, which ...
9
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1answer
5k views

GLSL Light (Attenuation, Color and intensity) formula

I'm implementing point lights in my Voxel engine, and I'm really struggling to get a good flow of light, from 100% near the light source to 0% at the light radius. I have 5 arguments for the ...
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6answers
7k views

AAA Games and OpenGL?

What modern AAA games on the top of the market used OpenGL? If applicable, what engine did they use?
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5answers
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OpenGL's matrix stack vs Hand multiplying

Which is more efficient using OpenGL's transformation stack or applying the transformations by hand. I've often heard that you should minimize the number of state transitions in your graphics ...
9
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2answers
4k views

OpenGL: Is it possible to use VAO's without specifying a VBO

On all the tutorials I can find about VAO's (Vertex Array Objects), they show on how to use them by configuring vertex attributes and binding a VBO (Vertex Buffer Object). But I want to create a VAO ...
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3answers
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First time shadow mapping problems

I have implemented basic shadow mapping for the first time in OpenGL using shaders and I'm facing some problems. Below you can see an example of my rendered scene: The process of the shadow mapping ...
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4answers
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How can I orbit a camera about it's target point?

I'm drawing a scene where the camera freely moves about the universe. The camera class keeps track of the view (or look at) point, the position of the camera, and the up vector. These vectors/points ...
9
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4answers
3k views

Order independent transparency in particle system

I'm writing a particle system and would like to find a trick to achieve proper alpha blending without sorting particles because: Each particle is a point sprite in a single mesh and I can't use ...
9
votes
2answers
10k views

GLSL Shader - Change Hue/Saturation/Brightness

I'm trying to change the hue of an image using a GLSL fragment shader. I want to achieve something similar to Photoshop's Hue/Saturation Adjustment layer. In the following image you can see what I've ...
9
votes
1answer
831 views

Mesh manipulation on GPU vs CPU

Just a bit curious - where do you perform mesh manipulations, on the CPU or in the shader? I've been doing everything on the CPU and a friend suggested moving things on to the GPU side. If you're ...
9
votes
3answers
1k views

How can I create a glitter effect?

I am trying to create a glittering effect for my realtime shader but I don't know how. Here is one example, and another example. What technique can I use to implement this?
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1answer
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differences between opengl 3 and opengl 4

I'm just getting started with game programming and I want to start learning opengl. I found a very great tutorial from scratch to get started with opengl 3 and I'm wondering if there is a big ...
9
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1answer
2k views

Should I give each character its own VBO or should I batch them into a single VBO?

I'm making a 3D first person game. Should I give each character its own VBO or should I batch all characters into a single VBO? What are the pros/cons?
9
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2answers
8k views

Most common 3D model format for opengl

I'm a novice that is starting to play with OpenGL ES on Android devices. To practice OpenGL I wanted to create a small game engine and so I was wondering what the best 3D model file format would be. ...
9
votes
1answer
4k views

How can I create a “night sky” effect in OpenGL?

I am creating a game using OpenGL and I want to render the effect of a night sky with a few stars in it. I want to have a shiny black effect in the sky so that it looks good. Could some one help in ...
9
votes
1answer
669 views

Why is it Important to have render targets with the same bit size?

I am currently thinking of what type of GBuffer I'll need for deferred shading, hence I tried also to document myself online about the most common ones and their format. Most of the GBuffer that ...
9
votes
1answer
444 views

In OpenGL, what is “zero state” rendering?

Recently at a job interview, I mentioned that I taught myself modern OpenGL and rendering with vertex buffer objects because my university only taught the fixed function pipeline with immediate mode ...
9
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1answer
2k views

Engine Rendering pipeline : Making shaders generic

I am trying to make a 2D game engine using OpenGL ES 2.0 (iOS for now). I've written Application layer in Objective C and a separate self contained RendererGLES20 in C++. No GL specific call is made ...
9
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2answers
899 views

Handle many lights in a scene (with shaders)

I'm curious about how to handle many lights in a scene. Given a very big map in a role playing game, with dungeons (with lights in there) etc. I know about deferred lighting, but that only answers how ...
9
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2answers
2k views

Are there still advantages to using gl_quads?

OK, I understand that gl_quads are deprecated, and thus we're not 'supposed' to use them anymore. I also understand that a modern PC when running a game using gl_quads is actually drawing two ...
9
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2answers
7k views

How do I use depth testing and texture transparency together in my 2.5D world?

Note: I've already found an answer (which I will post after this question) - I was just wondering if I was doing it right, or if there is a better way. I'm making a "2.5D" isometric game using OpenGL ...
9
votes
1answer
10k views

OpenGL/GLSL: Render to cube map?

I'm trying to figure out how to render my scene to a cube map. I've been stuck on this for a bit and figured I would ask you guys for some help. I'm new to OpenGL and this is the first time I'm using ...
9
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3answers
3k views

Lighting in a Minecraftian World

Minecraft is a game that is largely based on a heightmap and uses that heigtmap information to flood the world with light. From my understanding the highest point in the heightmap is the end of the ...
9
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2answers
2k views

Sorting objects before rendering

I'm trying to implement a scene graph and in all the articles i've come across there is talk about object sorting. So you'd sort your objects by "material" for example. Now untill i sat down and ...
9
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2answers
2k views

OpenGL get the outline of multiple overlapping objects

I just had an idea for my on-going-game made with opengl in c++: I'd like to have a big outline (5-6 pixel) on multiple overlapping object when the player win something. I thought the best way is to ...
9
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1answer
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How does gluLookAt work?

From my understanding, gluLookAt( eye_x, eye_y, eye_z, center_x, center_y, center_z, up_x, up_y, up_z ); is equivalent to: glRotatef(B, 0.0, 0.0, 1.0); ...
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1answer
7k views

How do I generate a 3D race track from a spline?

I want to generate a 3-dimensional race track around a spline that describes its shape. Here's an illustrative video. The track should be an endless tunnel that sweeps along a 3D spline, with some ...
9
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1answer
494 views

Deforming surfaces

I try to accomplish an deforming physic behaviour for levelsurfaces, but don't get an idea how to start with the implemenation so far. Regardless of the shape from the surface (planes, cubes, ...